At 18:03, my experience flying this plane would not lead me to the conclusion you stated. As soon as you start your takeoff roll, you should hold the stick full aft. As your air speed increases the canard will start flying quite soon and lift the nose. When this happens, move the stick forward and hold the canard approximately on the horizon, which will keep the nosewheel off the ground for the remainder of the takeoff roll. Once enough speed is obtained, the main wing will start flying and the aircraft will leave the ground. This method is not unlike a tailwheel pilot lifting the tail of the plane as soon as the tail starts flying, and continuing the takeoff roll using the main gear only. No need to worry about the nosewheel bouncing and reducing the angle of attack. You can easily control the pitch attitude of this aircraft with the nosewheel off the ground. Another advantage in doing it this way is that with the nosewheel off the ground, you are less likely to throw debris or foreign objects into your prop, which is something you should try and avoid with any pusher aircraft.
Interesting video. My buddy in an early Velocity during testing did stall the rear wing. He went to full right aileron, full right rudder, full nose down, and full power. Eventually the plane started dropping off to the right and into a knife edge, gained speed and started flying again. Took 5000 feet tho. But even with the rear wing stalled the plane is dropping at a slow decent rate and likely survivable.
Yes. I don't recall if I mentioned that in this video or the previous one, but several people have stalled the main wing on a Cozy, rode it down, and survived - it comes down at about 40-45 mph, so it's not going to be nice, but it can be survivable.
@@tymoteuszkazubski2755 at that point I’d make the canards movable it would be more economical both cost and amount of lift, but then you’d have to make them be constantly adjusted and monitored by computer which in turn would make this too expensive for private use? Reason: it would provably be too dangerous / difficult to fly otherwise.
Just like with your montage clarification video I have huge respect for you Scott that you strive to rather have the correct info out rather than ego boost. Kudos
The whole thing with the swept wing and aspect ratio comes down to one simple concept...spanwise flow is inefficient so avoid it if at all possible. Higher aspect ratio wings have less chord so spanwise flow is reduced and thus provides a higher lift:drag ratio. Sweeping the wings back increases spanwise flow because even at zero AOA, there is spanwise flow equivalent to the angle of the sweep. The more sweep or AOA you give it, the more spanwise flow you'll get. Take it to the extreme and imagine a 100% swept wing, basically folded all the way back like a kitfox in transit. In that configuration, you have 100% spanwise flow and your wings are almost useless (they'll still make some lift, but not much). The other extreme is AOA with a low aspect ratio (imagine a wing with the same chord as its span), keep increasing AOA of this wing all the way to 90deg, the air will hit the center of the wing and flow in all directions....forward to the leading edge, back to the trailing edge, and out to the wingtip all at the same time, this could also be considered 100% spanwise flow as the air simply radiates outward from the center of the wing. Your wing is useless as anything but an airbrake at this point. Decrease the AOA of this wing to say 45deg and you'll notice that all the air is flowing rearward and spanwise at around 45deg, tons of air spilling over the wingtip which is very inefficient but making some lift. Swap that wing with a high aspect glider wing at 45deg and you'll see that the air is still traveling out at 45deg but very little of it is actually able to spill over the wingtip, now you're making the same lift but with far less drag. This is how aspect ratio and swept wings affect aerodynamic efficiency. Swept wings are only an efficient gambit when you're talking transonic and supersonic flight regimes, and it's not because spanwise flow reduces at those speeds, it's because the shape delays transonic flow and shock waves from being created. It becomes less important to gain efficiency from aspect ratio and more important to gain efficiency by reducing shockwave buildup the faster you go. As you mentioned, swept wings in slower speed canard aircraft are only there to get the vertical and rudder far enough back to effect a positive change and inherent stability in that axis. As for canards not being able to use flaps...well that's not entirely true. If you could aerodynamically balance the flaps with leading edge slats then there would be no change in pitch moment and no need for elevator input. You'd gain considerable lift and the flaps wouldn't act like elevators that pushed the nose down, giving you either slower stall speeds or more efficiency by not needing as big of a wing.
Excellent summary. I actually meant to mention the use of swept wing in higher speed aircraft for transonic flow purposes. Interesting thought about flaps being balanced with slats - it would work, if you could make sure that they would be balanced at all angles of attack and speeds. Other, larger canards either add simultaneous flaps on the canard (adding droop to both elevators), or like the Beech Starship, reduce the efficiency (and hence lift) of the canard in cruise by sweeping it back.
Thanks for explaining why there aren't flaps, I was going through the comments before asking. As soon as I saw your comment I realised I should have been able to work out the reason. On seeing the plane, I haven't seen this plane before, this video just turned up as a TH-cam recommendation, I didn't think about the swept wing, which as you say is really only required for transonic and supersonic flight, so the fact it is used to get the rudder further back is interesting. The two planes of similar performance are both straight wings, showing that the sweep isn't required for aerodynamic reasons.
@@martinhiner2059 Most of the newer airliners with slats and multi-segment flaps take this principle into account and sequence the slats to deploy as a function of flap position. This minimizes the pitch effect and takes some of the workload off the pilot so they can focus on the landing instead. I'm sure it's well documented, the only caveat is that with conventional aircraft it doesn't have to be perfectly balanced aerodynamically, they can get away with some pitching moment because just a bit of trimming will take care of it. With a canard, this would require a lot more attention to aerodynamic balancing of those forces, as the resulting pitching moment could easily overpower the elevator's effectiveness at slow speed. Assuming you were able to get the finished product close to correct from simulations, having infinitely adjustable flaps and slats operating independently during test flights would allow you to find the perfect settings to effect hands off level flight, just a matter of deploying a bit of flaps and then adding some slat deployment until you no longer needed elevator input to counter the flaps. Mark those positions, then move to the next flap position and repeat. Eventually you'll have enough data points to graph out a flap to slat movement ratio throughout their entire deflection and lock those in with either mechanical linkages or sequencing them electronically/hydraulically. And just like that, you'd have effective and predictable flaps, which would alleviate one of the biggest downsides to a canard aircraft. Someone could make a hell of an airplane utilizing this design.
You may not want a Canard Airplane because it will spoil you. Your C182 flying friends will ask what your fuel burn and cruise speed is and say the F bomb.
@@PetesGuide Small wetted area. Due to compact design. No rear fuselage. Seats on the floor, reclined passengers. Little to no baggage space. Etc, etc. This reduced flat-plate drag area. Leas drag, means more speed for the same power. Or leas power for the same speed. Less power means less fuel consumption.
Yes but 182 can take a full cooler, camping gear, bicycle, dog and girlfriend/wife in to a Idaho back country strip. I love my 182 and want a longez/cozy very much. Everyone needs 2 airplanes 😂 nice video
I had a Varieze and sold it and I have been kicking myself ever since. Perhaps a velocity or a standard cozy is in my future. Canards aren’t popular because of its configuration but if a standard pilot could fly one for 5-10 hours opinions would change. Very safe efficient airframe.
Pusher Canards require a paved, Asphalt or Concrete Airstrip, otherwise, Stones rised by front wheel will hit the Propeller, even more, it's TO and landing Speed is high. Canards do Stall, after a Propeller Blade loss, Pilot on a Velocity pulled stick instead of pulling it to gain airspeed, machine entered a flat, Impossible to recover, high speed fall, killing pilot. See 'Des couacs chez les canards', 'Kwaks among ducks' , in Homebuilt Aircraft & Kitplanes Site. Blessings +
I was reading comments and I slowly got angry because NOBODY even mentioned Burton. Finally here is one, and spot on: regrets selling one. Burton designs are great, and pilots who don't understand that, well, maybe it simply is not the plane they are used to. I understood high landing speeds is a big deal, not everybody likes this. And that is just one detail. But don't they want the advantages? Don't aerobatic specs make them think again? Ten times more pilot fun, what is WRONG with that? Do they prefer twin turboprop monsters, doing 300 knots cruising speed, weighing ten times a Long EZ? Why? Proud of spending fortunes each year? What is it, why pilots say no thank you, seeing those Burton canards? Their are business jet size canards, as well. Amazing that people can focus on the disadvantages only, for these planes are great, or what?
I own a canard and I think that every airplane is a compromise in design. These aircraft are designed to optimize for good cruise performance, that pilots really like. This optimization results in choices that reduce drag like less wing area and less frontal area. I think if they had more wing area the takeoff and landing speed they could be more comparable to other light aircraft but that would also increase weight and drag and also reduce cruise speed. Another factor is weight growth. Since these are homebuilt people can add items that add weight like avionics and upholstery and really nice paints that can make them heavier also reducing their takeoff performance. One plus of these is the overall simplicity of the design. I had a instructor once show me how you can make a steeper final approach at a slightly reduced power and on landing flair the speed can be bleed off faster making a shorter landing distance. It works but you have to make sure you keep your speed up to a safe level to avoid a hard landing. Overall the increased speed is very impressive and perhaps worth the tradeoffs.
Eye opening! My criteria for a safe airplane is one that can land at a very slow airspeed -- as in an emergency landing off-airport. The canard offers some advantages in efficiency and high speed, but not in low landing speed -- and that's because there are no flaps or leading edge configurations on the main wing.
In my case you are talking to a non-pilot of limited technical background. I found it to be informative in a manner I was able to follow. Anytime you have alternatives you will find people telling everyone why this new idea is the greatest thing since sliced bread. Probably the most significant thing you said in the whole video is "there is no free lunch." I want speed and efficient fuel use. You pointed out where the lunch is paid for, higher takeoff and landing speeds and a longer runway needed. I am not going to be trying to land in little back-country meadows. I also liked how you mentioned to not try to compare this plane with a Cessna 172. All in all, a great presentation.
Thanks for your very kind comments. Yes, when it comes to engineering, everything is a compromise. You can have more of THIS, but you'll pay for it in THAT.
@@CanardBoulevardUnless it's a comparison after decades of progress, for example a computer from the late 90's with a current smartphone, laptop or PC. Still it is more complex, less tolerant to EMF interference, ... so there is a (reasonable) tradeoff.
Because you seem to like the technical details - that 'optimal wing shape is an ellipse' thing has a whole lot of assumptions baked in, its not merely an aerodynamic argument, its how to maximise efficiency with a mechanical spar with weight and stress limitations such that the extra lift at tips doesnt disproportionately add to bending moments at the root. Different spar designs and overall weight distributions have very different optimal wing shapes.
100% correct. I didn't want to start talking about structural design (although I guess I did a bit with talking about winglets - or perhaps that was my first video? I don't recall which, but I did). You could have the wing make full lift out to the tip, but you need a ton of structure at the root to support that, and now you have more wingtip vortices...one thing leads to another. Like I said, there's no free lunch! :)
@@peceed Elliptical LIFT DISTRIBUTION has the lowest induced drag, for a given wingspan (aspect ratio, if you factor in a fixed wing area). You can obtain an elliptical loading with any wing planform shape. But it will be elliptical lift distribution at one angle of attack and lift coefficient. An elliptical wing shape, without twist, will have an elliptical lift distribution at all angle of attack. (Negating Reynolds number effects).
@@CanardBoulevard Yes, your comment on structure was in this video, and was a consideration I didn’t get from another respected TH-camr’s video on the true nature of winglets on commercial aircraft. Thanks.
The rear stabilizer in a conventionally configured aircraft is an upside-down wing. Inverted. It's lift component is downwards. It counteracts the CofG which is forward of the Main wings centre of pressure.
My thoughts: It's not technically a Canard; it's a twin-wing configuration, meaning there's another set of wings contributing to lift. Canards usually function similar to elevators but positioned in front, making the aircraft inherently unstable. That's why they're often seen in jets designed for agility (requiring fly-by-wire systems). The horizontal tail (HT) generally provides a moment arm, not necessarily 'better lift' than the main wing. For instance, in stable trimmed flight, when a gust upsets the plane, the change in angle (AoA) on the HT generates lift (a moment arm) to stabilize the plane. The center of gravity (C.G) doesn't need to be ahead of the center of lift for the wing (not considering the entire plane's aerodynamics center of lift), it is also known as the center of pressure (CP). In this case of a twin-wing setup, yes, it MUST be ahead because of the additional set of lift-generating wings in front (which is why it's not called a canard). However, the model plane you're using is not a twin-wing but a typical tailed airplane. Thus, the C.G can fall within a certain range, depending on the size of the plane's tail. For instance, in a typical configuration like the model you're holding, the CP might be around 25% from the leading edge (LE). Depending on the tail size and distance, the C.G typically ranges from around 20% to 35% LE. Moving the C.G further forward enhances stability but also makes it more prone to being head-heavy and challenging to pitch up.
Way too many words. I have built both a varieze and a Defiant. Both. Canards. They are called loaded canards. You were wrong calling them twin wings. NOBODY calls them that. I considered the Defiant to be a Tandem wing aircraft because of the size of the Canard. It was still a Canard however. I have over 2000 hours flying these aircraft. They were both awesome aircraft.
Great job on making such a detailed follow up video with multiple rounds of corrections. The world would be a far better place if more people were a like you.
As long as the area loading is higher on the canard and a decalage is present the configuration is stable in pitch. With a tailplane configuration the taiplane must push down, effectively increasing the wing lift and the induced drag Dind = (lift/span)² /(q π) A well designed canard AC must be more efficient. Proof is the round the world Dick Rutan's flight. BTW if the sailplane you showed is a Diamant, well I designed the first prototype. For your information Max L/D = span/2√(π e/CDA) CDA is drag area ~ 1 ft² Span is dominant e is span loading efficiency The high canard load is partly absorbed by the wing inner span.
"The high canard load is partly absorbed by the wing inner span." - you got it, this is the fact that escapes most canard pilots. The canard causes reduced efficiency of the inner portion of the main wing, requiring a larger overall main wing to compensate, with a corresponding increase in drag.
A minor contribution to the swept wing discussion. Swept wings provide some degree of yaw stability. When a swept wing aircraft yaws to the left, the right wing essentially becomes longer and the left shorter relative to airflow. The right wing increases its frontal cross section section creating greater drag. Conversely, the left wing decreases it's frontal area decreasing drag. The increasing drag on the right and drecreasing drag on the left pulls the aircraft back toward a neutral yaw position. As least that's what I remember from my education from four decades ago.
Yup, but you need the initial engineering to dampen that yaw correction, or else you end up with annoying dutch roll at some speeds. The frontal area does increase, but a lot of the increased drag is also because you reduce spanwise flow on the forward wing, increasing lift, which increases drag.
Unfortunately the propeller is also flying through disturbed air causing a lot of stress and inefficiency. It's also prone to damage from rocks and debris.
@@CanardBoulevard The rear mounted prop is not in a disturbed airflow, its centered on the fueselage. The XL-RG is a 230ktas plane in cruise with a TSIO-550-C 310hp engine, if there is prop inefficiency then its a nit given the performance of the aircraft.
@@speedomars How is it not in disturbed airflow? It is in the air stream which has generated lift at the canard and the main wing root, passed over and around the non-cylindrical, non-concentric fuselage, has been over or through the engine cowling…. It was not stated that it was necessarily turbulent, just disturbed. At best, each blade is cutting through a varying velocity vector field of airflow, in effect producing a cyclically varying angle of attack and hence varying bending moment of the prop disk on the prop shaft. This would seem to me* to induce a sort of high frequency p-factor, among other effects of assorted (and quite possibly negligible) magnitudes. Re XL-RG: Prop inefficiency is a quantitative matter, it is not qualitatively prop ineffectiveness. * Your cue that this has not been tested in the heat of battle, just my best analysis from much reading and thinking, and a lifetime of curios observation.
@@For_What_It-s_Worth What some are leaving out of the conversation is the swept wing design of the Velocity. When a swept wing travels at high speed, the airflow has little time to react and simply flows over the wing almost straight from front to back. At lower speeds the air does have time to react, and is pushed spanwise by the angled leading edge, towards the wing tip. Either way, the airflow behind this wing does not produce the kind of dirty air some are assuming on this particular pusher aircraft design.
The swept wing design is to reduce drag and give the aircraft better handling in slow flight. The performance is best in class. If there is a complaint about this aircraft (Velocity XL-RG) it is that pilots with experience in Cessnas, Pipers or even Mooneys and Cirrus have to deal with far higher performance specs. And no-flap, flat landings requiring longer, paved runways.
Very interesting to hear your corrections, thanks for including the original takes. Hearing the misconceptions said out loud and then the explanation of why they're incorrect is actually a lot more information than just hearing correct facts
At 18:30, what you say is true for conventional propeller aircraft, but not for jet aircraft. To some extent, this is not even true for conventional aircraft with T-tails. This is one reason why many flight instructors felt that the Piper Tomahawk made a better trainer when compared to the Cessna 152, for those eventually wanting to fly jets. With any pusher aircraft, jet aircraft, and conventional aircraft with T-tails, one cannot simply just blast the throttle and get pitch authority back. This forces the pilot to learn the proper technique of a stabilized approach, so that these types of aggressive antics are not required to maintain pitch control.
Forces, Leaver Arms, Moments, Mass, Moment of Inertia, Center of Gravity, Aerodynamic Center, Angle of Attack, Angle of Sideslip, Angle of Incidence, Wing Twist, Wing Strakes, Vortex Generators....and Trailers? Your talk is just all over the place, bouncing around, focusing various things, glossing over...some true, some not so much, like a stream of consciousness video about Burt Ratans radically different design. Grade=C Maybe scripting out your stream of consciousness to stay focused oh smaller chunks of the many unique design features of Burt's creation. Great TH-cam Video, have fun flying
1. This video would apply only to Eze and derivatives. These were designed to a set of requirements. C172 were designed to other requirements. Some of the requirements overlap, and many don’t. The pilot has to decide which plane’s requirements best match his needs. No plane does all. 2. Landing Speed/flaps. Canards can and do have flaps. Clever is the Rutan/Beech Starship. Here the flaps and canard are linked. Flaps deployed-canard straight; flaps up-canard swept. Sweeping the canard flattened its lift curve slope obeying the “canard stall first rule”. 3. An Eze main wing sweep moves the Aerodynamic center further back. If Rutan had used a straight wing, the engine would be further forward relative to the AC. It would have needed a driveshaft. The wing vortillon (?) are aerodynamic fix that came some years after the Eze debut. Aerodynamic bandaids are hardly new or unique to canards. 4. A swept wing provides dihedral effect. The EZEs rudder winglets an added bonus.. 5. The canard wake affecting the wing is not necessarily bad. Rutan’s location may have improved pitch stability by increasing the wings stall AoA. 6. Modern fly by wire jets have all surfaces lifting..like a canard. The only plane to circumnavigate the planet was a canard. So canards have a few virtues.
So, the horizontal stabilizer of a conventionally-tailed aircraft can generate lift. It depends on how stable the vehicle is. In unstable designs like an F-16, the deflection on the all moving tail will actually be greater than the angle of attack during straight and level flight. On very stable aircraft like a Cessna 172, this is correct. In between, you can have situations where the tail generates net lift but the elevator itself does not.
Great information!!!! I enjoy still learning new things about things thought i thoroughly understood. I work on my friends velocity from time to time and i have a never ending joke of "It goes through the prop." Loose cowling screw?... "It goes the prop". FOD? "it goes through the prop". Money? "it goes through the prop". I have seen some battle scars of canard planes and things pinging off the props too. Anyways, nice videos thanks for another one.
Seems to me flaps are doable but you would need to trim the canard for them , in effect having flaps on the canard. Or something like that. I remember building an RC aircraft like that and it cam in a a steep angle of attack.
Every airplane is a compromise, interesting points about the canard airframe. I don't think there is any one design that checks all the boxes that we all seem to want in an aircraft. And even if there was, it still would not fit everyone's idea of the mission they want an airplane to fly.
You're right. It really depends on what your mission is - and you really have to know this in advance in order to make an informed decision on the type of aircraft that will suit those missions.
in regards to a conventional C.L.T. S.E. tractor prop- cruciform aircraft configuration, there are usually a built in nose down incidence on the horizontal stab of those with a fixed horizontal stab, the main wing usually has a nose up incidence, of which, both are based off the level line along the aircraft's fuselage.. So therefore when you apply engine power you have to add forward trim or aft trim as you decrease power in order to maintain level flight during power changes.
I'm no expert on aerodynamics but please check me on this. There are some disadvantages from having prop wash over lifting surfaces as it would be in a conventional engine-in-front airplane. As the prop wash flows over lifting surfaces it causes an increase in dynamic pressure and changes the local angle of attack. This can result in many different effects including an altered lift distribution, increased control surface authority, and changes in the aircraft stability. If the vertical stabilizer is directly behind the prop as in many conventional airplanes, it also creates some yaw torque from the spiraling air generated by the prop. We don't have that problem in our canards. No prop wash over vertical stabilizers and wings means only clean air over those surfaces making for a much smoother ride on the ground (where it's most noticeable) and in the air. Canardists are not very concerned about adverse yaw, P-factor, or Torque effects. During transition training we pretty much forget all about that nonsense. TGFT
You got it! I never thought to talk about that vortex around the vertical stab on conventional aircraft. But you're right, we hardly have to use our feet. :) But there are advantages AND disadvantages to having propwash over control surfaces. You get instant response on a conventional aircraft - you add power, you can instantly make pitch adjustments with that power because of the added airflow over the horizontal stabilizer (unless it's a T-tail, which is just dumb on propeller aircraft, in my opinion and experience). Canards you have to increase airspeed first, so you have to fly it more like a jet - increase power, wait for airspeed increase to get added effectiveness.
@@CanardBoulevard Had never thought much about it till now but I think you're right. I've learned something new. I subscribed to your channel as there aren't many on Canards and I learn from your work on the Cozy because, just like you, I bought mine (Long-EZ). Good interacting with you!
I have always thought that a canard was more efficient. When you pull back the stick in a conventional aircraft you push the tail down - the reverse of your desire to increase altitude. With a canard the control causes the nose to rise - the very direction you desire.
At first glance this is correct. But when the forward wing lifts up, it generates a downwash. The rear wing flies in the constantly generated downwash. And it has to constantly "climb" in the downwash wherever is goes. Even when flying level.
Great breakdown. You even threw in things that I wasn't aware of as well. I love the physics of it all! When you spoke about CG I've in the past talked about that to some folks when it comes to driving a car. It's more like CP (center point) they way I explain it. Heh See, some have formed the habit of if they have to turn they go slightly the opposite way (if they have to make a right turn they go slightly left then right) then make the turn. If they knew the CP then they'd realize that's not necessary. Especially since the wheelbase length isn't like some long van or truck that has to do things like that. If you're in a regular size car, just setup for the turn. And realize your CP is before the rear wheel. I know none of that has to do with flying but when you were talking about that it just all seemed the same, but different. I hope that all made sense. Still, I wonder if this plane isn't as popular because of the maybe "conditioning" of what regular flight is known to be. I find it interesting that the Wright Brothers basically flew a Canard. But, somewhere in there things got changed to what we know as flight now. I wonder why. Anyhoo, as I typed on the intro video before this, I'm a simmer. I will get my license eventually. So, I like to look at planes that would fit what I'm trying to accomplish. Which is a lot of personal flights. That includes Experimental planes. Thanks a lot for this video! It was a lot of fun for me. I'll be checking out more of your videos in the future. Cheers! ✌🏾
As a truck driver, I hate when people counter steer before a corner. Increases the likelihood that they will get killed by an inattentive truck driver. The more critical thing to consider in turning an automobile is that the point of rotation is the rear wheels. (Especially noticeable when backing) I’ve always been curious about the CP of a canard aircraft, and about the CG range. I’m not sure I understood his explanation. Wright Flyer was a forward all-flying control surface like a backward Cub. (Reportedly pretty longitudinally unstable, increasing with speed.) That’s often excepted from canard lists because it was not intended to function as a lifting surface.
Longitudinal stability is NOT about stalling one of the aerodynamic surfaces! It is the ability of the airplane to return to level flight after a disturbance, e.g. a gust. This happens at small AoAs; you don’t stall the canard every time you encounter a small gust. If the overall AoA is increased by a gust, both the canard’s and the main wing’s list are increased. This results in a pitching moment around the aircraft’s center of gravity which is it’s mechanical center of motion. In order to return to level flight, this pitching moment needs to counter the initial disturbance, hence be nose down. This is the case if the sum of the added lift acts aft of the center of gravity. The point where this combined lift acts upon is the airplane’s neutral point. (This is valid not only for canard airplanes) Static longitudinal stability is when the airplane returns to level flight after a disturbance with the elevator fixed. Dynamic longitudinal stability is with the elevator free.
Indeed, the swept wings in airliners are about increasing critical mach number, so if your aircraft had swept wings for the same reason, you would have an heck of a fast canard! 😎
Actually, you can add fowler flaps to a canard aircraft, but you will have to add them to both the main wing and to the canard itself. The size of the flaps will have to be around 20% larger for the canard than for the main wing due to the fact that the flaps will tend to move the center of lift rearward as they extend.
Scott I still love the Cozy and the Long EZ, despite your warning...hahaha. I do have one question, why can't you put flaps on that type of wing design? Great video!!!
@@CanardBoulevard I did just check out that video, I had already watched it, but I didn't correlate what you said about the flaps in that video with this video. Thanks for directing me over there. I still stand with my original statement that I love the cozy and Long EZ. Cheers from Texas.
Depends on the intent of Your design. If great stall resistance for inexperienced private pilots, who might not fly for extended periods of time while building, if that is Your goal. Canard is the solution.
@@Triple_J.1 True. I should have been more specific that the subject was aerodynamic efficiency. People hear that both surfaces lift and assume it's more efficient than a conventional layout.
Rutan's number one reason for the canard design was to reduce low speed stall/spin accidents in the landing pattern. The canard stalls before the main wing and pushes the nose down, which is what you want. Unfortunately many fatal accidents in the landing pattern are caused when the pilot pulls back on the stick when the plane starts to stall in a turn.....this increases the stall, which turns into a spin with fatal results.
I built and fly a Cozy IV I love the plane the way it flys and I enjoy blowing the doors off Cessnas It does have its limitations but all in all it is a great plane. I liked my first plane a Longeze better it was more of a pilots plane. It had an 0235 which limited it a bit. Thanks for your video.
@@CraigLandsberg-lk1ep O-235 is an aircraft engine with 235 cubic inches of displacement. It makes significantly less power than for instance the IO-360 in my airplane.
IDK how I came across this vid, but glad I did. Absolutely fascinating comparisons. I'm not a pilot (wish I was) but have a keen interest in fluid dynamics & aviation. Can't wait to watch ur other vids!
High Scott! Very ilustrative explanation you gave. On detail that you mentioned in conventional planes does not entirely true.. but is valid for your explanation. The vertical force in a Tail horizontal surface in a conventional configuration plane could be upward, cero or downward.. For example when take of at high CLift the main wing moment ia very high and nose-up so a tail will probably will get a upward force specially is cg is at rear limits. Also depending of the position of the cg related to the main wing lift. In a case that the plane has a very effective tail volume and neutral point is at the very rear, then the cg can be behind the main wing line of lift and in this case the tail hirizotal will trim the plane with an upward force
Burt Rutan is a Stability and Control. Structures. And Performance expert. He is a genius, not due to wacky designs, that comes from insanity. But due to the simplicity in his designs. Form follows function. And everything is simple. Look at SpaceShipOne. Its engine had only one moving part. Its cabin pressurization and reaction controlla used: Air. Compressed air. That is all.
Enjoyed this thanks. Unfortunately your explanation of the rotation forces about the main gear is incorrect. The part you got right: blown horizontal tail is more effective than canard. If you calculate the CG location relative to the main gear (moment arm) it is similar to a conventional aircraft, and is not why the rotation requires more speed .
OK lets draw triangles here. Where the body is one side (A) and the tip to tip of the wings form 2 triangles, so one tip to the body is (B) as the leading edge of the wing is the hypotenuse of each (C). If a straight wing has the same length as the (C) then yes the swept wing has less lift. But if we take a straight wing that is the same length as (B) then slice it up and set the slices off set to each other to create a chunky type of swept wing (as though it where made with building blocks) then do we have a similar lift ratio ? but with the swept dynamically stable behavior your talking about here ( 6:10 ) ? I think is how the lift expectation of a swept wing is miss understood as (B) is actually the angle of attack Hens the use of Vortilons and so the wing should be considered in size as the length of (B) not the length of the leading edge ?
Kudos for correcting your correction video. Few creators do that. Now I am off to Marc's channel in search of his treatment (if any) of "three lifting surfaces" design, that is, Piaggio P.180.
Scott Hey, Jeff here! I just had to make a comment because the two major things I love right now is aviation, for years I've been a pilot for a while and my Honda goldwing! And I was watching your video and I was thinking I know that voice!..... And I think I finally figured it out did you host goldwingdocs? If so, I never realized you were into aviation also! Your Gold Wing and mine I think are almost exactly the same! Glacier white! Well, I just wanted to say hi and I'll keep watching your video and I always had a love for kennard aircraft also. I know it's someday here I do want to build a kit I just find out that life gets in the way LOL
Double bonus points for putting out a correction video! But now you have to make another one. You can have a vortex or vorticies, but not a vorticie :(
(16:50) _“We can´t have flaps in this design.“_ By “this design“, do you mean (just) the Cozy? The Cessna Starship, a canard design, has flaps, made possible because the canard wings translate forward, thus compensating for the change of the center of lift of the main wing when they are actuated.
Correct, but this type of mechanism is not practical in a small canard such as this. The weight (and complexity of fail-safe interlocks) would be prohibitive.
6:45 wrong. tail produce lift but direction of that lift is down. when AoA increse lift produced by tail DECRISED, and that allows center of mass pitch down because is before point of lift. effect is: to be airborn you need 1000kN of lift but in conventical airplane you generate 1100kN of lift on main wings and 100kN of down lift on the tail. Total drag is generated from 1200kN of generated lift. in canard you generate 100kN on canard an 900kN on main wing Total drag is generated from 1000kN of generated lift. that is why canard is more fuel efficient. danger of canard is if main wing stall first AoA increase making situation verry bad. because you don't have natural "anatomy" for recovery.
yeah the config looks cool but I don't like the configuration over conventional because it's more complex for little to no benefit. If we look at the really high performance designs that gliders are, they are very conventional. As for the elegance of rear propulsion, that's one of several reasons why I'm advocating for getting small turbofan jet engines in GA. For light planes they can be so small that they can be very cheap and a big surprise to many is that if you take them to altitude they will give you both extreme speed and fuel efficiency that you can't beat with piston props. World distance record belongs to rutan's global flyer which is a glider design with an off the shelf Williams FJ44-4 jet engine and it did 40000km at 500km/h without refueling. Try that in a Cessna 172 :) Light GA planes with great aero and tiny turbofan jet engines can just have borderline magical performance. Fighter jet agility, private jet freedom but LSA fuel economy. A polish carbon fiber glider plane called Gekon weighs 69kg with gear and avionics. That means a personal jet doesn't need to weigh the 3300kg that a Phenom 100 does. Or even the 1600kg of an Eclipse 500. Low weight and high glide directly translates to fuel efficiency. An Eclipse actually beats a Baron 58 for fuel economy so imagine how great a light tandem 2 seater could be. And when designed for high speed it can actually have quite a small wing. So it can actually be cheaper to make.
Trouble is, to get a jet efficient, you need to take advantage of air compressability. That requires lots of altitude. So… high altitude, advantage of speed, pressurized cabin, we’re edging closer to that Eclipse. Also, takes production volume to bring costs down.
@@russbell6418 true that a jet shines best at FL600 at mach 3 but an Eclipse already has better fuel economy than a Baron 58 and Eclipse is bigger so if you cut the weight down by 75% which is very possible and engines too then I thrust you can see the fuel economy of a jet can easily be in the workable range, even much below FL400. Say 15000feet. The cleanliness, the lightness, the silence and the coolness and safety of twin jet just sweeps everything else off the floor. Piston props need not apply. I did the math on a 4 seater and the jet engines only need to weigh 15kg each. That really helps lighten the bird. And 400kg empty weight is a conservative estimate. If pushed it could be lower still. A carbon fiber bubble can be very light. What's possible with carbon and turbofans as a replacement for a bonanza would blow you away.
Hello Scott, I have enjoyed your videos and have learned alot. You said you have lead shot in the front. Does that mean the Cozy was designed for a person of a certain weight? Or is there something missing from yours? Also, is a cozy designed for an optimal flight characteristic? Has anyone tried to put large tires on it for rough field conditions and soft surface? Thanks
The C/G in a canard is narrower, such that if you are alone in the front, you will require ballast in order for the aircraft to be inside its C/G window. The gear of these aircraft is designed for hard surfaces - the nosegear in particular would not survive bush use, and a larger tire on it would prevent it from being retracted.
Hi Scott. Many thanks for a fascinating video. Wonderful to get the aerodynamic perspective. What I still don’t quite understand is why the Canard doesn’t have flaps. The rear wing needs to have more lift than the front stabilisers at low speeds to give a nose down configuration to land. Surely flaps would give the main (rear) wing more lift and hence the required nose-down configuration - or am I missing something?
Deploying flaps moves the center of lift of the main wing rearward. This means there is more area between the center of lift and the center of gravity, causing a pitch-down moment. The canard will have to generate more lift to compensate for this, without exceeding its critical angle of attack. You don't want the canard capable of generating more lift without exceeding critical AOA, because it MUST stall first in order to protect the main wing. So the only way to get around this is to also add flaps to the canard so that it can generate more lift when the main wing flaps deploy. You would need a mechanism that absolutely, positively prevents one system from actuating without the other actuating simultaneously - if that were to happen, it would be absolutely disastrous. Something like that would add a LOT of weight, comparably, to a small airplane like this.
Amazing aircraft out of the mind of one man , Burt Rutan - yes the aerodynamics on the Rutan Canard are hard to explain - another really complex one is Piaggio Avanati with the same engines can cruise 100KTAS ( 25% )faster than the Starship with similar power plants but to many the Boomarang was the one Rutan actually wanted to commercialize - great discussion
@@arcanondrum6543 The weight was the main problem, and not having a conventional tail (like the Avanti) is another problem. And the FAA wanted a wing that was very beefy, making the certified version much heavier than the proof-of-concept made by Rutan.
@@ErikssonTord_2 Everyone has to obey the same laws of physics and the FAA. Starship and the Adam A500 are, according to Rutan; "someone else's fault". Two big, very expensive flops with two words in common; Burt Rutan.
About the Downwash from Canard over Main Wing, any comment about the Saab Viggen approach, Canard located well higher than Main wing? A chart is in Homebuilt Aircraft Site. Blessings +
I love you man anybody inviting a critique or a comment or a correction especially is the top of the mountain to me. I love to watch people with money that have a disaster from being stupid because I'm poor from being stupid and my whole life is a disaster to look up from for a minute when someone buys an airplane. How does the kennard airplane respond to being overloaded? Most airplanes will fly straight overloaded and if you turn them even a little bit it's too much and they crash easy spin in. How does the kennard Wing respond to this pilot error have taken off with too much weight
The answer is...it depends. If you load outside of C/G, all bets are off. You could turn into a lawn dart if too far forward, or fall in an unrecoverable stall if too far aft. But when it just comes to overloading it while remaining in C/G - it's just an airplane, so it does what most airplanes do: climb poorly, stall at a higher airspeed. In a conventional airplane, if you overload it so you're using all your lift to just keep the thing in the air, if you then turn (which uses some of your lift to change the direction of the aircraft) it no longer has enough lift to fly - so either you descend, or you stall.
@@CanardBoulevard well I had a slightly more sophisticated view of it mathematically when you look at that extra weight and you had add bank angle, and a reduction of efficiency you might be looking at a situation where you will never have enough control authority to pull it out of the spiral. All of these things are nonlinear geometric changes so if you get very far in the direction of this geometry with the extra weight, it hits a "tipping point". Not physically tipping the airplane but just these things have lined up to hold you locked into something and you don't have enough control authority to restore to normal flight.
Re: aspect ratio, efficiency and lift and stall-resistance. Efficient sleek planes that are stall-proof and super STOL have been proven. They are not used solely because they violate "If it looks right, it'll fly right" (even more than a canard). They look funny. Aspect ratio is not a simple comparison between span & chord. It is span^2 divided by area. Expressed as an integer, not a ratio. There have been very many very-low aspect-ratio planform planes that have done very well. First, see the Arup planes from Indiana in the '30s. Aspect ratio under 2 ("Air"+"Up") The trick they have is that at such low aspect-ratio, when flown very slowly with very high "A" (above 25° has been demonstrated), the wing-tip vortices wrap around above it capturing a "bubble" of low pressure above the wing, amplifying the lift they get at such slow speeds. At the same time, it traps air from the front over the top of the wing, keeping it from separating and giving strong smooth flow to the trailing edge controls. Such wings do not stall, as in losing all lift due to separation of flow and losing control surface effectiveness. They'll "mush" down if they're kept flying in such a way, but they don't depart. They are not always burdened with carrying around all this extra drag: The vortex-driven "parachute lift" is elective and temporary, in order to fly slowly and not stall. Many of the type have proven to be sleek and quick on available power when flown normally. If these very-low aspect-ratio planes are supposed to be inefficient and have lots of induced drag, what is this supposed inefficiency, if it does not manifest in power vs speed or fuel vs range? Because many of the sort have been excellent. Charles Zimmerman worked for NACA in the '30s, saw the Arup S-2 fly for NACA, and later copied the very-low aspect-ratio and it's ability to be stall proof at very slow speeds very high "A", as the starting pint for his work with Vought and the Navy into a VTOL tail-sitter. He wrote about the "parachute lift" effect for UAC and NACA. Barnaby Wainfan also wrote extensively about for NASA when they were looking at the Facetmobile. The "Parachute lift" effect and stall-proof nature of it is a known phenomenon. Arup S-2 and S-4 th-cam.com/video/Nxz1UF67EQI/w-d-xo.htmlsi=Vf_lHaIBwL200EMg th-cam.com/video/_XrSFVDa3mY/w-d-xo.htmlsi=Ur6PD3w6fJKd2HrN The S-2 from 1934 was 780 lbs, flew 85 knots on 37 hp, with landing speed under 18 kts. It would not stall. Video shows it to be nimble and yet stable, with 45° climb. The Arup S-4 was 1150 lbs, dual control side by side. flew 100 kts on 70 hp. Between the two, they flew several seasons at air shows, frequently carrying advertising because nobody but _nobody_ wanted to buy or invest. They flew on until the age of the airframes retired them. The only incident was a fuel leak and fire an fatal crash of the similar Hoffman/Younghusband plane, which had many successful flights, demonstrating the same sorts of performance. Next, see the Nemeth "parachute plane" of the '30s. Built on the fuselage of an Alliance Argo biplane, with a 15' diameter circular wing parasol on struts. Faster than the original, stall-proof, super-STOL, 45° climb, 60° super-slow descent with practically zero landing roll with any wind. th-cam.com/video/mw7hPbTSdME/w-d-xo.htmlsi=Z-EjTj-Yx6NvWBDN th-cam.com/video/0lMik-MkUlE/w-d-xo.htmlsi=cegLX6BwghPZNtD7 Then there's the similar Farman 1020. Like the Nemeth, built on the fuselage of a known successful (monoplane) Stall-proof, faster than the original. The '40s Eshelman, commonly known as the "flying flounder". Aspect ratio under 1. Super-STOL and stall-proof, 156kts on 110 hp. th-cam.com/video/JpV68abt8uc/w-d-xo.htmlsi=zB734mtnraibffd0 th-cam.com/video/idsA1dUD9QA/w-d-xo.htmlsi=xTFn0X3ejIZmjd0f In the '80s, The Hatfield "Little Bird" by one who flew the original Arup planes. Sleek and efficient, STOL, stall proof. th-cam.com/video/zK63GJ0saBA/w-d-xo.htmlsi=uJQL3KF9-Wx_NqzY and other videos. Hatfield openly challenges the "conventional wisdom" which says they glide poorly and are draggy and difficult. since 2015, the Rowe "UFO" from Aus. th-cam.com/video/_-u0Y7cDngM/w-d-xo.htmlsi=NkS0IO4he0hsRzl2 th-cam.com/video/_-u0Y7cDngM/w-d-xo.htmlsi=NkS0IO4he0hsRzl2 Next, the '90s Wainfan "Facetmobile". Wainfan also challenges the status quo about such things. They're misunderstood, and much maligned, but fly very well and should be more accepted. 740lbs max weight, 100kts on 47hp, with 340 lb useful load. Won't stall. th-cam.com/video/LK7FhK5eL70/w-d-xo.htmlsi=Z_Ebe3sLBXp1gDtZ Oshkosh 2023 Airventure Low Aspect Ratio Forum on Low Aspect Ratio Sport Airplanes - Barnaby Wainfan th-cam.com/video/tzokRT3rbB0/w-d-xo.htmlsi=8t4X1kX8OIT4XzQn
10:22 that is NOT correct. Your span wise lift distribution is moved out and bending moment increases as if the winglets were folded down making the wing longer. NO free lunch. The winglet reduces induced drag but reducing the wasted energy form wing tip vortices. The reasons airliners use winglets are two fold. One is span of wing and gate area at terminal is limited. Two it is great for a logo. Some of the latest airliners do not use winglets and just use longer wings and accept their gate access at a terminal will be limited.
You mentioned downwash (or maybe largely turbulent air) at the main wing because of the canard - is that less an issue with the Q200 because of the greater vertical offset between the canard and main wings?
No. A wing created a huge amount of downwash. From wingtip to wingtip, in a large circles over and under the entire aircraft. And that downwash descends at a certain rate. And that creates a downwash angle behind the wing. The rear wing, or horizontal stabilizer, exist in this downwash. And must "climb" up it indefinitely. They effectively have to climb even when flying level. This makes tandem and Canard aircraft inherently less efficient in terms of Lift-Induced drag. (Drag due to rearward tilt of the lift vector. Due to flying at an angle of attack).
I’m going to watch the videos you suggested. This video was awesome. I would really like to talk to you and Mark about the design of the cozy I have taken on. The canard on mine has the ability to adjust the angle of sweep.
Not flying yet. I’d estimate it at 85% complete. It’s a project that got started in the mid 90’s by my grandfather, I spent a lot of hours as a child helping him on it. The Cozy plans were childhood reading to me. Now in his upper 90’s, although extremely spry, and in the best shape of anyone I have ever seen at that age, he can’t finish it. It has been a dream of mine to finish it, and get him some stick time. I’m at a point in my life now that I can take on the task, and so here I am with a hanger and a plane that needs completion. He modified the design some. Like I mentioned the sweeping canard, it also has a IO-540 mounted to it, retractable rear gears, and a widened fuselage, among a few others. I’ve heard his rationale for the sweeping canard, but I’d like to pick the brain of a few others.
@@a.j.bradley6851 an IO-540 AND retractable mains. This will be a truly unique airplane. I'd love to hear more about the sweeping canard. Have you joined the Cozy Builders mailing list? There is a TON of collective knowledge there as well. If not, I'd highly suggest jointing: www.cozybuilders.org/mail_list/
I very much enjoy your videos! I have a question. I am 6’6” tall and was wondering if the seat is adjustable enough to accommodate a tall person? Thank you so much!!
The seat is not adjustable...at all. You can modify the rudder pedals slightly. I am 6'0" and my head is reasonably close to the canopy. At 6'6" I think you would have a hard time.
Canard downwash - Dragonfly better? Traditional airplane - to reduce loss due downward tail force, could you have moveable CG? Put more weight on the tail during cruise?
I'm no aircraft engineer, but I was wondering if an all-moving canard could help with the stall recovery. Having it rotate far enough to let the nose drop straight down when needed.
You're wondering correctly. That's one of the most important things about a canard - and without any new individual rotation of the foreplane. The difference in the angles of incidence [i.e., built into the airframe] means that, as the aircraft gradually rotates towards dangerous angles of attack [with the airflow] the foreplane should always get to the stall angle before the mainplane does. The nose then begins to drop, so that the angles of attack decrease, improving matters for both planes. Canard pilots can use this feature to make very rapid descents.
@@robwilde855 I understand how normal canard configurations avoid main wing stall. My question about an all-moving canard is aimed at an alternative solution: If the main wing does stall, rotating the canards to almost vertical should eliminate most of the drag that stalled canards generate, making the nose drop faster than the stalled main wing, letting the pilot recover.
Sorry, I didn't read carefully enough. I see what you mean now. My feelings about that are: 1) You say "if the main wing does stall..." - Well, it shouldn't, ever, unless you do something to deliberately cause it. Because the foreplane will always be stalling before the main wing can, and so the main's increase of angle of attack always stops and then begins to reduce before it can get far enough to stall. [These relationships of angles of incidence between fore and aft planes, for ANY type of aircraft, are integral to basic design, by the way; they are essential for stability, and could not be done away with in any "alternative solution".] 2) The drag of the stalled foreplane is acting mostly in the rearward direction; so not much of that drag force is preventing downward movement. Also a normally-stalled nose already drops at a reasonable rate, certainly fast enough to give the mainplane no chance of getting to the stall. So, is a faster drop really needed? 3) Your extended rotation: Are you thinking of more rearward rotation, or a forward rotation, to get to the final 'vertical' position? In other words is the foreplane to continue to increase its angle of incidence, or is it to reverse its movement and decrease the angle? If it is to move forwards, it will unstall, and assuming that that doesn't momentarily lift the nose higher [!], then as it rotates forward it will naturally pull the nose down with some force. If on the other hand it is to move even further 'back' and increase the drag, that would produce a very large force, more than the pivots are designed at present to handle. And what this 'ninety-degree airbrake' would do to the airflow, shedding violent eddies up and down, is rather alarming to contemplate. Even if that were taken care of, then the aircraft would never be able to fly in any stable way for more than a moment or two with such a flat-on aerodynamic surface, so the foreplane's natural position would have to be restored very quickly, going back through all those same problems. 4) Without the benefit of a practical experiment I think your idea, though ostensibly sensible and promising, might be somewhat a 'solution searching for a problem'. If, however, experiment showed that it did make a difference in some way, then the mechanical problems of the design and operation of a suitable and safe system might be too much, I mean not worth the time and expenditure and complication required. Cheers.@@matejlieskovsky9625
@@robwilde855 Fair enough. Thank you for your response! I might think some more about it, but alas, I am busy enough with my own area of expertise most of the time. Just to clarify: I was thinking about the foreplanes rotating forward. The whole idea was probably somewhat like making the foreplanes closer to control-only canards, removing the drag caused by needing a highly loaded foreplane. But you are right that I failed to consider the passive stability of the airframe. While a stall should be recoverable with such canards, it would be too easy to enter for a non-fly-by-wire aircraft.
@@matejlieskovsky9625 You are correct. With a Canard that can rotate downward nearly vertical, it will break the stall. But a canard that pivots (all-flying) is a thing to be carefully engineered. It will need irreversible controls. Or a very finely tuned anti-servo tab.
14:00 - You could just put the canard a foot lower fairly easily and not interfere with the main wing. I higher back wing is very common in conventional designs. Even if the front canard didn't produce a net positive lift, at least it's not producing a negative lift like a conventional tail. So it's really not a wash at all.
^ This does not work in Theory or in Practice. A wing generates downwash when it creates lift. The rear wing has to fly in this downward deflected air. So it always has to climb. The front wing has to carry a substantial portion of the weight. Because an aircraft such as this, must have positive static stability. The center of gravity must be a certain distance in front of the aerodynamic center (of lift). The aerodynamic center in a canard is near the leading edge of the rear wing, or slightly in front of it. So the center of gravity has to be moved forward of that point to remain stable. This means the weight of the aircraft has a lever-arm nose down from the main wing. The canard must lift this to remain level or climb. So it must generate lift at all times.
Why can't you have flaps? Is this because of how it comes, cause I would just add them myself 😅or is the canards supposed to do this job? Love to hear your input cause a lot of videos don't cater to the layman
If you add flaps to the main wing, it increases the lift generated (and drag). In order to keep the airplane balanced, you now need flaps on the canard as well. You can't really do that, so the only alternative is to increase the size of the canard and authority of the elevator. But in doing that, you increase the lift generated by the canard in all phases of flight, which means you could now stall the main wing before the canard.
The Flaps would be so far behind the Center of Gravity, and Aerodynamic Center, that they would create an enormous nose-down moment. Because the main wing would effectively become an elevator with down deflection.
You are forgetting that induced drag (if you know what that is) is proportional to the square of span loading (L/sp)² Increase span 10% that reduces the ID by 20% The parasite drag is proportional to wetted area. The higher lift on the short canard produces a large drag. On the other hand the tailplane can also lift. As long as the incidence angle of the forward wing is higher by a little bit than the incidence angle of the rear wing the aircraft is stable. No down force REQUIRED So you are mostly wrong! when your CG is at the rear point in the stability envelope
Not to be nitpicking, but there is a little something wrong with the explanation about rotating during takeoff when comparing this canard design to a conventional design with a tail. What first and foremost matter here are the position of the center of gravity/ center of mass versus the position of the landing gear and the center of lift, combined with the momentum generated by the tail or the canards. Having to 'lift the entire front section of the airplane up' to rotate the aircraft for takeoff is NOT what the issue here is (simply because that already factors into the position of the center of gravity/ center of mass). The other factors mentioned however do come into play of course. I much rather suspect that the main part of explaining this 'phenomenon' is simply a natural result of the required high wing-loading of the canards to assure nose down stall behavior of the aircraft. In other words: Because the canards must (always) stall (much) 'earlier' than the main wing stalls, they will naturally also only be able to produce the lift required to rotate the aircraft for takeoff at respectively higher speeds as well (Because by design the wing must 'start flying' first, before the canards 'can be allowed to start flying'). My explanation is that it's basically just a result of the required safety feature of the overall canard design requiring a nose down stall behavior to be assured at all times, whereas conventional aircraft naturally and inherently have a nose down stall tendency (and can thus simply - and safely have larger tail surfaces allowing them to rotate at slower speeds). Or to put it even another way: Would the canards be modified and would simply be made larger in order to enable rotating the aircraft during takeoff at slower speeds, then it would no longer have a nose down stall behavior and as a result it would then no longer be safe to fly.
You're correct, and that is done by ensuring the load factor and angle of attack of the canard is greater than that of the main wing. Until the canard begins to fly and elevates the deck angle, the main wing doesn't have sufficient AoA to fly - so you really are rotating to get the main wing to fly.
Boeing leased an airplane to Dutch royalty who then leased it back to Boeing so they could come up with a mod to add winglets to the 737- 200. When they conducted the first flight test it's climb rate was so great it bordered on being uncontrollable. So they dialed out some of the lift and she flew fine after that.
Another issue with canard aircraft is icing. If the canard stalls due to icing it's game over. The wing loading on the canard is high to ensure the canard stalls first. This makes it imperative that the canard is kept free of ice.
Very true. Icing on a canard can turn your airplane into a lawn dart. Some people install heated pitot tubes on their canards - I simply never fly when there is a possibility of icing.
OK . . . l am just learning the rudiments about canards, and flying in general. Not sure if l ever will fly, due to chronic vertigo. Hoeever, it doesn't hurt to do cerebral gymnastics. Question that comes to mind is (drumroll) . . . why is/are there no wing flaps? -- iz this a buggerment regulation? -- or is there some sort of aerodynamic reason? Thanks in advance.
Making the canard bigger means it will generate more lift - and that means that you now have the problem where the main wing can stall before the canard does, particularly at aft C/G. Everything affects everything else.
@@CanardBoulevard so glad you got back to me, so is it always the aim to have the front of the plane stall/drop first? Is that easier to feel/predict than having the back drop first?
@@CanardBoulevard you are the first person to give me real world experience on just how delicate the balance is of staying 'up' in an advanced aircraft 😅lol
Yes. A stall is caused by a wing exceeding its critical angle of attack (around +15 degrees). Ideally, an aircraft that stalls, should automatically lower its angle of attack (its nose) to recover from this condition. You don't want it to diverge into a nose-up maneuver, as this would make the wing stall deeper into the less lift/ more drag regime. (I.e. result in going downward at lethal velocity). Suggested reading: Stick and Rudder, an Explanation of the Air of Flying. - By Wolfgang Langweische.
hey.. you are trying hard and doing a good job explaining canard stability but you know the front wing doesnt have to stall to create stability. its the lift curve slope and zero lift angle. the lift curve slope is bigger for the big wing because its big so the plane is stable. the stable point is a positive angle because of the incidence of the front is greater. you fly the plane in pitch axis by adjusting the pitch stable point by changing the canard control surface. you should play around with xflr5 or AVL and see the numbers and stability love your discussion though
I just love this video so much, you really taught me so much from your pilot based experience for want of a better explanation 😅 am so glad I found you, by the way my goal is to make my own jet pack, or even jump jets, so I value your experience and way with words 😮
Love this kind of content! Plenty of learning going on. I suggest watching talks given by the late John Ronz for aerodynamic concepts. He was brilliant.
Merry Christmas and a prosperous New Year However the plain in question did claim the life of a well known musician and that is the only reason why I will always look past them
At 18:03, my experience flying this plane would not lead me to the conclusion you stated.
As soon as you start your takeoff roll, you should hold the stick full aft. As your air speed increases the canard will start flying quite soon and lift the nose. When this happens, move the stick forward and hold the canard approximately on the horizon, which will keep the nosewheel off the ground for the remainder of the takeoff roll. Once enough speed is obtained, the main wing will start flying and the aircraft will leave the ground.
This method is not unlike a tailwheel pilot lifting the tail of the plane as soon as the tail starts flying, and continuing the takeoff roll using the main gear only.
No need to worry about the nosewheel bouncing and reducing the angle of attack. You can easily control the pitch attitude of this aircraft with the nosewheel off the ground.
Another advantage in doing it this way is that with the nosewheel off the ground, you are less likely to throw debris or foreign objects into your prop, which is something you should try and avoid with any pusher aircraft.
Interesting video. My buddy in an early Velocity during testing did stall the rear wing. He went to full right aileron, full right rudder, full nose down, and full power. Eventually the plane started dropping off to the right and into a knife edge, gained speed and started flying again. Took 5000 feet tho. But even with the rear wing stalled the plane is dropping at a slow decent rate and likely survivable.
Yes. I don't recall if I mentioned that in this video or the previous one, but several people have stalled the main wing on a Cozy, rode it down, and survived - it comes down at about 40-45 mph, so it's not going to be nice, but it can be survivable.
How about elevons on the front wing, they should allow faster roll-dive recovery?
@@tymoteuszkazubski2755 at that point I’d make the canards movable it would be more economical both cost and amount of lift, but then you’d have to make them be constantly adjusted and monitored by computer which in turn would make this too expensive for private use? Reason: it would provably be too dangerous / difficult to fly otherwise.
@@tymoteuszkazubski2755too short to produce a meaningful roll moment.
@tymoteuszkazubski2755 excellent idea, but how effective will it be. Hooked up to each rudder pedal? Or independent.
Just like with your montage clarification video I have huge respect for you Scott that you strive to rather have the correct info out rather than ego boost. Kudos
Your videos are just way more interesting bro...easier to watch.. it doesnt feel like a classroom
Bruce McCandless flying the manned maneuvering unit❤
The whole thing with the swept wing and aspect ratio comes down to one simple concept...spanwise flow is inefficient so avoid it if at all possible. Higher aspect ratio wings have less chord so spanwise flow is reduced and thus provides a higher lift:drag ratio. Sweeping the wings back increases spanwise flow because even at zero AOA, there is spanwise flow equivalent to the angle of the sweep. The more sweep or AOA you give it, the more spanwise flow you'll get. Take it to the extreme and imagine a 100% swept wing, basically folded all the way back like a kitfox in transit. In that configuration, you have 100% spanwise flow and your wings are almost useless (they'll still make some lift, but not much). The other extreme is AOA with a low aspect ratio (imagine a wing with the same chord as its span), keep increasing AOA of this wing all the way to 90deg, the air will hit the center of the wing and flow in all directions....forward to the leading edge, back to the trailing edge, and out to the wingtip all at the same time, this could also be considered 100% spanwise flow as the air simply radiates outward from the center of the wing. Your wing is useless as anything but an airbrake at this point. Decrease the AOA of this wing to say 45deg and you'll notice that all the air is flowing rearward and spanwise at around 45deg, tons of air spilling over the wingtip which is very inefficient but making some lift. Swap that wing with a high aspect glider wing at 45deg and you'll see that the air is still traveling out at 45deg but very little of it is actually able to spill over the wingtip, now you're making the same lift but with far less drag. This is how aspect ratio and swept wings affect aerodynamic efficiency. Swept wings are only an efficient gambit when you're talking transonic and supersonic flight regimes, and it's not because spanwise flow reduces at those speeds, it's because the shape delays transonic flow and shock waves from being created. It becomes less important to gain efficiency from aspect ratio and more important to gain efficiency by reducing shockwave buildup the faster you go. As you mentioned, swept wings in slower speed canard aircraft are only there to get the vertical and rudder far enough back to effect a positive change and inherent stability in that axis.
As for canards not being able to use flaps...well that's not entirely true. If you could aerodynamically balance the flaps with leading edge slats then there would be no change in pitch moment and no need for elevator input. You'd gain considerable lift and the flaps wouldn't act like elevators that pushed the nose down, giving you either slower stall speeds or more efficiency by not needing as big of a wing.
Excellent summary. I actually meant to mention the use of swept wing in higher speed aircraft for transonic flow purposes. Interesting thought about flaps being balanced with slats - it would work, if you could make sure that they would be balanced at all angles of attack and speeds. Other, larger canards either add simultaneous flaps on the canard (adding droop to both elevators), or like the Beech Starship, reduce the efficiency (and hence lift) of the canard in cruise by sweeping it back.
Thanks for explaining why there aren't flaps, I was going through the comments before asking. As soon as I saw your comment I realised I should have been able to work out the reason. On seeing the plane, I haven't seen this plane before, this video just turned up as a TH-cam recommendation, I didn't think about the swept wing, which as you say is really only required for transonic and supersonic flight, so the fact it is used to get the rudder further back is interesting. The two planes of similar performance are both straight wings, showing that the sweep isn't required for aerodynamic reasons.
That's a lot in a short span of written verbage. He would need actually several class hours and a whiteboard to demonstrate all this in detail.
Forward half slats need to go to testing. Call Mike patey
@@martinhiner2059 Most of the newer airliners with slats and multi-segment flaps take this principle into account and sequence the slats to deploy as a function of flap position. This minimizes the pitch effect and takes some of the workload off the pilot so they can focus on the landing instead. I'm sure it's well documented, the only caveat is that with conventional aircraft it doesn't have to be perfectly balanced aerodynamically, they can get away with some pitching moment because just a bit of trimming will take care of it. With a canard, this would require a lot more attention to aerodynamic balancing of those forces, as the resulting pitching moment could easily overpower the elevator's effectiveness at slow speed. Assuming you were able to get the finished product close to correct from simulations, having infinitely adjustable flaps and slats operating independently during test flights would allow you to find the perfect settings to effect hands off level flight, just a matter of deploying a bit of flaps and then adding some slat deployment until you no longer needed elevator input to counter the flaps. Mark those positions, then move to the next flap position and repeat. Eventually you'll have enough data points to graph out a flap to slat movement ratio throughout their entire deflection and lock those in with either mechanical linkages or sequencing them electronically/hydraulically. And just like that, you'd have effective and predictable flaps, which would alleviate one of the biggest downsides to a canard aircraft. Someone could make a hell of an airplane utilizing this design.
You may not want a Canard Airplane because it will spoil you. Your C182 flying friends will ask what your fuel burn and cruise speed is and say the F bomb.
100%!! I see the envy in the eyes of my hangar neighbors every time I mention my cruise speed and fuel consumption!! :)
@@CanardBoulevarddoes that come mostly from the efficiency of lifting the nose instead of pushing the tail down? Or something else?
@@PetesGuide It's a combination of things - I go over them all in my first video: th-cam.com/video/ycLQaiX4ylE/w-d-xo.html
@@PetesGuide Small wetted area. Due to compact design. No rear fuselage. Seats on the floor, reclined passengers. Little to no baggage space. Etc, etc. This reduced flat-plate drag area.
Leas drag, means more speed for the same power. Or leas power for the same speed. Less power means less fuel consumption.
Yes but 182 can take a full cooler, camping gear, bicycle, dog and girlfriend/wife in to a Idaho back country strip. I love my 182 and want a longez/cozy very much. Everyone needs 2 airplanes 😂 nice video
I had a Varieze and sold it and I have been kicking myself ever since. Perhaps a velocity or a standard cozy is in my future. Canards aren’t popular because of its configuration but if a standard pilot could fly one for 5-10 hours opinions would change. Very safe efficient airframe.
I know exactly what you mean.. sold my long ez in a divorce… kick myself every day…
Pusher Canards require a paved, Asphalt or Concrete Airstrip, otherwise, Stones rised by front wheel will hit the Propeller, even more, it's TO and landing Speed is high.
Canards do Stall, after a Propeller Blade loss, Pilot on a Velocity pulled stick instead of pulling it to gain airspeed, machine entered a flat, Impossible to recover, high speed fall, killing pilot.
See 'Des couacs chez les canards', 'Kwaks among ducks' , in Homebuilt Aircraft & Kitplanes Site.
Blessings +
I was reading comments and I slowly got angry because NOBODY even mentioned Burton. Finally here is one, and spot on: regrets selling one. Burton designs are great, and pilots who don't understand that, well, maybe it simply is not the plane they are used to. I understood high landing speeds is a big deal, not everybody likes this. And that is just one detail. But don't they want the advantages? Don't aerobatic specs make them think again? Ten times more pilot fun, what is WRONG with that? Do they prefer twin turboprop monsters, doing 300 knots cruising speed, weighing ten times a Long EZ? Why? Proud of spending fortunes each year? What is it, why pilots say no thank you, seeing those Burton canards? Their are business jet size canards, as well. Amazing that people can focus on the disadvantages only, for these planes are great, or what?
@@voornaam3191
‘Burton’ = Burt Rutan?
I own a canard and I think that every airplane is a compromise in design. These aircraft are designed to optimize for good cruise performance, that pilots really like. This optimization results in choices that reduce drag like less wing area and less frontal area. I think if they had more wing area the takeoff and landing speed they could be more comparable to other light aircraft but that would also increase weight and drag and also reduce cruise speed. Another factor is weight growth. Since these are homebuilt people can add items that add weight like avionics and upholstery and really nice paints that can make them heavier also reducing their takeoff performance. One plus of these is the overall simplicity of the design. I had a instructor once show me how you can make a steeper final approach at a slightly reduced power and on landing flair the speed can be bleed off faster making a shorter landing distance. It works but you have to make sure you keep your speed up to a safe level to avoid a hard landing. Overall the increased speed is very impressive and perhaps worth the tradeoffs.
Eye opening! My criteria for a safe airplane is one that can land at a very slow airspeed -- as in an emergency landing off-airport. The canard offers some advantages in efficiency and high speed, but not in low landing speed -- and that's because there are no flaps or leading edge configurations on the main wing.
In my case you are talking to a non-pilot of limited technical background. I found it to be informative in a manner I was able to follow. Anytime you have alternatives you will find people telling everyone why this new idea is the greatest thing since sliced bread. Probably the most significant thing you said in the whole video is "there is no free lunch." I want speed and efficient fuel use. You pointed out where the lunch is paid for, higher takeoff and landing speeds and a longer runway needed. I am not going to be trying to land in little back-country meadows. I also liked how you mentioned to not try to compare this plane with a Cessna 172. All in all, a great presentation.
Thanks for your very kind comments. Yes, when it comes to engineering, everything is a compromise. You can have more of THIS, but you'll pay for it in THAT.
@@CanardBoulevardUnless it's a comparison after decades of progress, for example a computer from the late 90's with a current smartphone, laptop or PC. Still it is more complex, less tolerant to EMF interference, ... so there is a (reasonable) tradeoff.
How can I get a ride in a Piaggio P180 in the US?
Because you seem to like the technical details - that 'optimal wing shape is an ellipse' thing has a whole lot of assumptions baked in, its not merely an aerodynamic argument, its how to maximise efficiency with a mechanical spar with weight and stress limitations such that the extra lift at tips doesnt disproportionately add to bending moments at the root. Different spar designs and overall weight distributions have very different optimal wing shapes.
100% correct. I didn't want to start talking about structural design (although I guess I did a bit with talking about winglets - or perhaps that was my first video? I don't recall which, but I did). You could have the wing make full lift out to the tip, but you need a ton of structure at the root to support that, and now you have more wingtip vortices...one thing leads to another. Like I said, there's no free lunch! :)
Elliptical wing shape has the lowest induced drag possible.
@@peceed Elliptical LIFT DISTRIBUTION has the lowest induced drag, for a given wingspan (aspect ratio, if you factor in a fixed wing area).
You can obtain an elliptical loading with any wing planform shape. But it will be elliptical lift distribution at one angle of attack and lift coefficient.
An elliptical wing shape, without twist, will have an elliptical lift distribution at all angle of attack. (Negating Reynolds number effects).
@@CanardBoulevard
Yes, your comment on structure was in this video, and was a consideration I didn’t get from another respected TH-camr’s video on the true nature of winglets on commercial aircraft.
Thanks.
The rear stabilizer in a conventionally configured aircraft is an upside-down wing. Inverted. It's lift component is downwards. It counteracts the CofG which is forward of the Main wings centre of pressure.
I go through that in my first video in this series: th-cam.com/video/ycLQaiX4ylE/w-d-xo.html
My thoughts:
It's not technically a Canard; it's a twin-wing configuration, meaning there's another set of wings contributing to lift. Canards usually function similar to elevators but positioned in front, making the aircraft inherently unstable. That's why they're often seen in jets designed for agility (requiring fly-by-wire systems).
The horizontal tail (HT) generally provides a moment arm, not necessarily 'better lift' than the main wing. For instance, in stable trimmed flight, when a gust upsets the plane, the change in angle (AoA) on the HT generates lift (a moment arm) to stabilize the plane.
The center of gravity (C.G) doesn't need to be ahead of the center of lift for the wing (not considering the entire plane's aerodynamics center of lift), it is also known as the center of pressure (CP). In this case of a twin-wing setup, yes, it MUST be ahead because of the additional set of lift-generating wings in front (which is why it's not called a canard). However, the model plane you're using is not a twin-wing but a typical tailed airplane. Thus, the C.G can fall within a certain range, depending on the size of the plane's tail. For instance, in a typical configuration like the model you're holding, the CP might be around 25% from the leading edge (LE). Depending on the tail size and distance, the C.G typically ranges from around 20% to 35% LE. Moving the C.G further forward enhances stability but also makes it more prone to being head-heavy and challenging to pitch up.
Thankyou for your words 😅it helped
Way too many words. I have built both a varieze and a Defiant. Both. Canards. They are called loaded canards. You were wrong calling them twin wings. NOBODY calls them that. I considered the Defiant to be a Tandem wing aircraft because of the size of the Canard. It was still a Canard however. I have over 2000 hours flying these aircraft. They were both awesome aircraft.
Great job on making such a detailed follow up video with multiple rounds of corrections. The world would be a far better place if more people were a like you.
As long as the area loading is higher on the canard and a decalage is present the configuration is stable in pitch.
With a tailplane configuration the taiplane must push down, effectively increasing the wing lift and the induced drag
Dind = (lift/span)² /(q π)
A well designed canard AC must be more efficient. Proof is the round the world Dick Rutan's flight.
BTW if the sailplane you showed is a Diamant, well I designed the first prototype.
For your information Max L/D = span/2√(π e/CDA)
CDA is drag area ~ 1 ft²
Span is dominant
e is span loading efficiency
The high canard load is partly absorbed by the wing inner span.
"The high canard load is partly absorbed by the wing inner span." - you got it, this is the fact that escapes most canard pilots. The canard causes reduced efficiency of the inner portion of the main wing, requiring a larger overall main wing to compensate, with a corresponding increase in drag.
As a total fan of the canard design airplanes I appreciate this video 📸 excellent work ty 🛬🛬🛬
A minor contribution to the swept wing discussion. Swept wings provide some degree of yaw stability. When a swept wing aircraft yaws to the left, the right wing essentially becomes longer and the left shorter relative to airflow. The right wing increases its frontal cross section section creating greater drag. Conversely, the left wing decreases it's frontal area decreasing drag. The increasing drag on the right and drecreasing drag on the left pulls the aircraft back toward a neutral yaw position. As least that's what I remember from my education from four decades ago.
Yup, but you need the initial engineering to dampen that yaw correction, or else you end up with annoying dutch roll at some speeds. The frontal area does increase, but a lot of the increased drag is also because you reduce spanwise flow on the forward wing, increasing lift, which increases drag.
You over control on the first take off. That is what newbies remember. After the first take off you never think about it again.
I respect that you admit your mistakes. I think others would go on the defensive and get into attack mode.
A pilot who thinks they know everything and refuses to learn from others is a pilot with a very short expected lifespan.
Unfortunately the propeller is also flying through disturbed air causing a lot of stress and inefficiency. It's also prone to damage from rocks and debris.
Yes, I mentioned this in the first video. It does make the plane sound really cool when it flies past, though! :)
@@CanardBoulevard The rear mounted prop is not in a disturbed airflow, its centered on the fueselage. The XL-RG is a 230ktas plane in cruise with a TSIO-550-C 310hp engine, if there is prop inefficiency then its a nit given the performance of the aircraft.
@@speedomars
How is it not in disturbed airflow?
It is in the air stream which has generated lift at the canard and the main wing root, passed over and around the non-cylindrical, non-concentric fuselage, has been over or through the engine cowling…. It was not stated that it was necessarily turbulent, just disturbed.
At best, each blade is cutting through a varying velocity vector field of airflow, in effect producing a cyclically varying angle of attack and hence varying bending moment of the prop disk on the prop shaft. This would seem to me* to induce a sort of high frequency p-factor, among other effects of assorted (and quite possibly negligible) magnitudes.
Re XL-RG: Prop inefficiency is a quantitative matter, it is not qualitatively prop ineffectiveness.
* Your cue that this has not been tested in the heat of battle, just my best analysis from much reading and thinking, and a lifetime of curios observation.
@@For_What_It-s_Worth What some are leaving out of the conversation is the swept wing design of the Velocity. When a swept wing travels at high speed, the airflow has little time to react and simply flows over the wing almost straight from front to back. At lower speeds the air does have time to react, and is pushed spanwise by the angled leading edge, towards the wing tip. Either way, the airflow behind this wing does not produce the kind of dirty air some are assuming on this particular pusher aircraft design.
@@speedomarsthe prop has to chop through different airflow, versus if on the front , get clean air.
The swept wing design is to reduce drag and give the aircraft better handling in slow flight. The performance is best in class. If there is a complaint about this aircraft (Velocity XL-RG) it is that pilots with experience in Cessnas, Pipers or even Mooneys and Cirrus have to deal with far higher performance specs. And no-flap, flat landings requiring longer, paved runways.
Very interesting to hear your corrections, thanks for including the original takes. Hearing the misconceptions said out loud and then the explanation of why they're incorrect is actually a lot more information than just hearing correct facts
At 18:30, what you say is true for conventional propeller aircraft, but not for jet aircraft. To some extent, this is not even true for conventional aircraft with T-tails.
This is one reason why many flight instructors felt that the Piper Tomahawk made a better trainer when compared to the Cessna 152, for those eventually wanting to fly jets. With any pusher aircraft, jet aircraft, and conventional aircraft with T-tails, one cannot simply just blast the throttle and get pitch authority back. This forces the pilot to learn the proper technique of a stabilized approach, so that these types of aggressive antics are not required to maintain pitch control.
Forces, Leaver Arms, Moments, Mass, Moment of Inertia, Center of Gravity, Aerodynamic Center, Angle of Attack, Angle of Sideslip, Angle of Incidence, Wing Twist, Wing Strakes, Vortex Generators....and Trailers? Your talk is just all over the place, bouncing around, focusing various things, glossing over...some true, some not so much, like a stream of consciousness video about Burt Ratans radically different design. Grade=C
Maybe scripting out your stream of consciousness to stay focused oh smaller chunks of the many unique design features of Burt's creation.
Great TH-cam Video, have fun flying
Has anyone tried forward swept wings like X29
1. This video would apply only to Eze and derivatives. These were designed to a set of requirements. C172 were designed to other requirements. Some of the requirements overlap, and many don’t. The pilot has to decide which plane’s requirements best match his needs. No plane does all.
2. Landing Speed/flaps. Canards can and do have flaps. Clever is the Rutan/Beech Starship. Here the flaps and canard are linked. Flaps deployed-canard straight; flaps up-canard swept. Sweeping the canard flattened its lift curve slope obeying the “canard stall first rule”.
3. An Eze main wing sweep moves the Aerodynamic center further back. If Rutan had used a straight wing, the engine would be further forward relative to the AC. It would have needed a driveshaft. The wing vortillon (?) are aerodynamic fix that came some years after the Eze debut. Aerodynamic bandaids are hardly new or unique to canards.
4. A swept wing provides dihedral effect. The EZEs rudder winglets an added bonus..
5. The canard wake affecting the wing is not necessarily bad. Rutan’s location may have improved pitch stability by increasing the wings stall AoA.
6. Modern fly by wire jets have all surfaces lifting..like a canard. The only plane to circumnavigate the planet was a canard. So canards have a few virtues.
Well . . . I still want one. A canard configuration is still the coolest looking airplane!
I agree! I love it, and I do not regret my purchase!
So, the horizontal stabilizer of a conventionally-tailed aircraft can generate lift. It depends on how stable the vehicle is. In unstable designs like an F-16, the deflection on the all moving tail will actually be greater than the angle of attack during straight and level flight. On very stable aircraft like a Cessna 172, this is correct. In between, you can have situations where the tail generates net lift but the elevator itself does not.
Great information!!!! I enjoy still learning new things about things thought i thoroughly understood. I work on my friends velocity from time to time and i have a never ending joke of "It goes through the prop." Loose cowling screw?... "It goes the prop". FOD? "it goes through the prop". Money? "it goes through the prop". I have seen some battle scars of canard planes and things pinging off the props too. Anyways, nice videos thanks for another one.
It's absolutely true. If it's loose, it will go through the prop, every time!
Seems to me flaps are doable but you would need to trim the canard for them , in effect having flaps on the canard. Or something like that. I remember building an RC aircraft like that
and it cam in a a steep angle of attack.
Every airplane is a compromise, interesting points about the canard airframe. I don't think there is any one design that checks all the boxes that we all seem to want in an aircraft. And even if there was, it still would not fit everyone's idea of the mission they want an airplane to fly.
You're right. It really depends on what your mission is - and you really have to know this in advance in order to make an informed decision on the type of aircraft that will suit those missions.
in regards to a conventional C.L.T. S.E. tractor prop- cruciform aircraft configuration, there are usually a built in nose down incidence on the horizontal stab of those with a fixed horizontal stab, the main wing usually has a nose up incidence, of which, both are based off the level line along the aircraft's fuselage.. So therefore when you apply engine power you have to add forward trim or aft trim as you decrease power in order to maintain level flight during power changes.
I'm no expert on aerodynamics but please check me on this. There are some disadvantages from having prop wash over lifting surfaces as it would be in a conventional engine-in-front airplane. As the prop wash flows over lifting surfaces it causes an increase in dynamic pressure and changes the local angle of attack. This can result in many different effects including an altered lift distribution, increased control surface authority, and changes in the aircraft stability. If the vertical stabilizer is directly behind the prop as in many conventional airplanes, it also creates some yaw torque from the spiraling air generated by the prop. We don't have that problem in our canards. No prop wash over vertical stabilizers and wings means only clean air over those surfaces making for a much smoother ride on the ground (where it's most noticeable) and in the air. Canardists are not very concerned about adverse yaw, P-factor, or Torque effects. During transition training we pretty much forget all about that nonsense. TGFT
You got it! I never thought to talk about that vortex around the vertical stab on conventional aircraft. But you're right, we hardly have to use our feet. :)
But there are advantages AND disadvantages to having propwash over control surfaces. You get instant response on a conventional aircraft - you add power, you can instantly make pitch adjustments with that power because of the added airflow over the horizontal stabilizer (unless it's a T-tail, which is just dumb on propeller aircraft, in my opinion and experience). Canards you have to increase airspeed first, so you have to fly it more like a jet - increase power, wait for airspeed increase to get added effectiveness.
@@CanardBoulevard Had never thought much about it till now but I think you're right. I've learned something new. I subscribed to your channel as there aren't many on Canards and I learn from your work on the Cozy because, just like you, I bought mine (Long-EZ). Good interacting with you!
I have always thought that a canard was more efficient. When you pull back the stick in a conventional aircraft you push the tail down - the reverse of your desire to increase altitude. With a canard the control causes the nose to rise - the very direction you desire.
I talk about this a lot more in this video: th-cam.com/video/ycLQaiX4ylE/w-d-xo.html
At first glance this is correct. But when the forward wing lifts up, it generates a downwash. The rear wing flies in the constantly generated downwash. And it has to constantly "climb" in the downwash wherever is goes. Even when flying level.
@@Triple_J.1 thank you.
Thank you for uploading this. I was excited to hear what he shared with you!
Great breakdown. You even threw in things that I wasn't aware of as well. I love the physics of it all! When you spoke about CG I've in the past talked about that to some folks when it comes to driving a car. It's more like CP (center point) they way I explain it. Heh See, some have formed the habit of if they have to turn they go slightly the opposite way (if they have to make a right turn they go slightly left then right) then make the turn. If they knew the CP then they'd realize that's not necessary. Especially since the wheelbase length isn't like some long van or truck that has to do things like that. If you're in a regular size car, just setup for the turn. And realize your CP is before the rear wheel. I know none of that has to do with flying but when you were talking about that it just all seemed the same, but different. I hope that all made sense.
Still, I wonder if this plane isn't as popular because of the maybe "conditioning" of what regular flight is known to be. I find it interesting that the Wright Brothers basically flew a Canard. But, somewhere in there things got changed to what we know as flight now. I wonder why.
Anyhoo, as I typed on the intro video before this, I'm a simmer. I will get my license eventually. So, I like to look at planes that would fit what I'm trying to accomplish. Which is a lot of personal flights. That includes Experimental planes.
Thanks a lot for this video! It was a lot of fun for me. I'll be checking out more of your videos in the future.
Cheers! ✌🏾
As a truck driver, I hate when people counter steer before a corner. Increases the likelihood that they will get killed by an inattentive truck driver. The more critical thing to consider in turning an automobile is that the point of rotation is the rear wheels. (Especially noticeable when backing)
I’ve always been curious about the CP of a canard aircraft, and about the CG range. I’m not sure I understood his explanation.
Wright Flyer was a forward all-flying control surface like a backward Cub. (Reportedly pretty longitudinally unstable, increasing with speed.) That’s often excepted from canard lists because it was not intended to function as a lifting surface.
I love what you just said😅all of it, I might not be a pilot but I am a sheetmetal worker/engineer and I love hearing from people that can teach me
I love the authenticity of honouring information
Longitudinal stability is NOT about stalling one of the aerodynamic surfaces! It is the ability of the airplane to return to level flight after a disturbance, e.g. a gust. This happens at small AoAs; you don’t stall the canard every time you encounter a small gust.
If the overall AoA is increased by a gust, both the canard’s and the main wing’s list are increased. This results in a pitching moment around the aircraft’s center of gravity which is it’s mechanical center of motion. In order to return to level flight, this pitching moment needs to counter the initial disturbance, hence be nose down. This is the case if the sum of the added lift acts aft of the center of gravity. The point where this combined lift acts upon is the airplane’s neutral point. (This is valid not only for canard airplanes)
Static longitudinal stability is when the airplane returns to level flight after a disturbance with the elevator fixed. Dynamic longitudinal stability is with the elevator free.
My internal little boy really wants that red model plane.
I gave it to my nephew, he loves it! :)
1 point you missed is that the canard design looks f-ing cool, do the disadvantages don't really matter
Indeed, the swept wings in airliners are about increasing critical mach number, so if your aircraft had swept wings for the same reason, you would have an heck of a fast canard! 😎
Next one. :)
Actually, you can add fowler flaps to a canard aircraft, but you will have to add them to both the main wing and to the canard itself. The size of the flaps will have to be around 20% larger for the canard than for the main wing due to the fact that the flaps will tend to move the center of lift rearward as they extend.
I go through that in my first video in this series: th-cam.com/video/ycLQaiX4ylE/w-d-xo.html
Scott
I still love the Cozy and the Long EZ, despite your warning...hahaha. I do have one question, why can't you put flaps on that type of wing design?
Great video!!!
Check out the first video I did on this topic, I talk about this extensively: th-cam.com/video/ycLQaiX4ylE/w-d-xo.html
The most interesting question I've heard in a Helluva long time!
@@CanardBoulevard I did just check out that video, I had already watched it, but I didn't correlate what you said about the flaps in that video with this video. Thanks for directing me over there. I still stand with my original statement that I love the cozy and Long EZ. Cheers from Texas.
A senior (possibly retired by now) MIT aerodynamics prof listed the three rules of aircraft design as "No canards, no canards, and no canards".
Depends on the intent of Your design.
If great stall resistance for inexperienced private pilots, who might not fly for extended periods of time while building, if that is Your goal. Canard is the solution.
@@Triple_J.1 True. I should have been more specific that the subject was aerodynamic efficiency. People hear that both surfaces lift and assume it's more efficient than a conventional layout.
@@Triple_J.1
Not having exhaustive knowledge, I would only have been comfortable claiming it as A solution.
(No, not solution A…)
Rutan's number one reason for the canard design was to reduce low speed stall/spin accidents in the landing pattern.
The canard stalls before the main wing and pushes the nose down, which is what you want.
Unfortunately many fatal accidents in the landing pattern are caused when the pilot pulls back on the stick when the plane starts to stall in a turn.....this increases the stall, which turns into a spin with fatal results.
I built and fly a Cozy IV I love the plane the way it flys and I enjoy blowing the doors off Cessnas It does have its limitations but all in all it is a great plane. I liked my first plane a Longeze better it was more of a pilots plane. It had an 0235 which limited it a bit. Thanks for your video.
When it all comes down to it, I do love the Cozy - obviously!
0235? Can you tell me what this means?
@@CraigLandsberg-lk1ep O-235 is an aircraft engine with 235 cubic inches of displacement. It makes significantly less power than for instance the IO-360 in my airplane.
5:27 The induced drag is a result of span loading, not at all related to the aspect ratio, defined as span²/wing area.
Great audio for being in a hanger during a windy rainstorm.
I used a spectral audio tool to try to fix it as best I could.
@@CanardBoulevard
I wondered! It was very effective.
IDK how I came across this vid, but glad I did. Absolutely fascinating comparisons. I'm not a pilot (wish I was) but have a keen interest in fluid dynamics & aviation. Can't wait to watch ur other vids!
Love canards, but they require lots of runway. That's the biggest shortcoming IMO. After test flying several I went with an RV8 for my mission.
RV-8 is a great airplane. "Conventional" is just that. Because it works better for most applications.
I appreciate the effort you put into making sure your facts were right.
High Scott! Very ilustrative explanation you gave. On detail that you mentioned in conventional planes does not entirely true.. but is valid for your explanation.
The vertical force in a Tail horizontal surface in a conventional configuration plane could be upward, cero or downward..
For example when take of at high CLift the main wing moment ia very high and nose-up so a tail will probably will get a upward force specially is cg is at rear limits.
Also depending of the position of the cg related to the main wing lift. In a case that the plane has a very effective tail volume and neutral point is at the very rear, then the cg can be behind the main wing line of lift and in this case the tail hirizotal will trim the plane with an upward force
From my limited knowledge Burt Rutan is the real guru of canard craft😅 haven't finished your video yet but am sure it will teach me something lol
Burt Rutan is a Stability and Control. Structures. And Performance expert. He is a genius, not due to wacky designs, that comes from insanity. But due to the simplicity in his designs. Form follows function. And everything is simple. Look at SpaceShipOne. Its engine had only one moving part. Its cabin pressurization and reaction controlla used: Air. Compressed air. That is all.
Enjoyed this thanks. Unfortunately your explanation of the rotation forces about the main gear is incorrect. The part you got right: blown horizontal tail is more effective than canard. If you calculate the CG location relative to the main gear (moment arm) it is similar to a conventional aircraft, and is not why the rotation requires more speed .
OK lets draw triangles here.
Where the body is one side (A) and the tip to tip of the wings form 2 triangles, so one tip to the body is (B) as the leading edge of the wing is the hypotenuse of each (C).
If a straight wing has the same length as the (C) then yes the swept wing has less lift.
But if we take a straight wing that is the same length as (B) then slice it up and set the slices off set to each other to create
a chunky type of swept wing (as though it where made with building blocks)
then do we have a similar lift ratio ? but with the swept dynamically stable behavior your talking about here ( 6:10 ) ?
I think is how the lift expectation of a swept wing is miss understood as (B) is actually the angle of attack Hens the use of Vortilons
and so the wing should be considered in size as the length of (B) not the length of the leading edge ?
Kudos for correcting your correction video. Few creators do that.
Now I am off to Marc's channel in search of his treatment (if any) of "three lifting surfaces" design, that is, Piaggio P.180.
Scott
Hey, Jeff here! I just had to make a comment because the two major things I love right now is aviation, for years I've been a pilot for a while and my Honda goldwing! And I was watching your video and I was thinking I know that voice!..... And I think I finally figured it out did you host goldwingdocs?
If so, I never realized you were into aviation also!
Your Gold Wing and mine I think are almost exactly the same! Glacier white!
Well, I just wanted to say hi and I'll keep watching your video and I always had a love for kennard aircraft also. I know it's someday here I do want to build a kit I just find out that life gets in the way LOL
Yes, I have run GoldwingDocs for maaany years. This video might explain more: th-cam.com/video/uoZV80IXF00/w-d-xo.html
Double bonus points for putting out a correction video! But now you have to make another one.
You can have a vortex or vorticies, but not a vorticie :(
(16:50) _“We can´t have flaps in this design.“_
By “this design“, do you mean (just) the Cozy? The Cessna Starship, a canard design, has flaps, made possible because the canard wings translate forward, thus compensating for the change of the center of lift of the main wing when they are actuated.
Correct, but this type of mechanism is not practical in a small canard such as this. The weight (and complexity of fail-safe interlocks) would be prohibitive.
6:45 wrong. tail produce lift but direction of that lift is down. when AoA increse lift produced by tail DECRISED, and that allows center of mass pitch down because is before point of lift.
effect is: to be airborn you need 1000kN of lift but in conventical airplane you generate 1100kN of lift on main wings and 100kN of down lift on the tail.
Total drag is generated from 1200kN of generated lift.
in canard you generate 100kN on canard an 900kN on main wing
Total drag is generated from 1000kN of generated lift.
that is why canard is more fuel efficient.
danger of canard is if main wing stall first AoA increase making situation verry bad. because you don't have natural "anatomy" for recovery.
yeah the config looks cool but I don't like the configuration over conventional because it's more complex for little to no benefit. If we look at the really high performance designs that gliders are, they are very conventional. As for the elegance of rear propulsion, that's one of several reasons why I'm advocating for getting small turbofan jet engines in GA. For light planes they can be so small that they can be very cheap and a big surprise to many is that if you take them to altitude they will give you both extreme speed and fuel efficiency that you can't beat with piston props.
World distance record belongs to rutan's global flyer which is a glider design with an off the shelf Williams FJ44-4 jet engine and it did 40000km at 500km/h without refueling. Try that in a Cessna 172 :) Light GA planes with great aero and tiny turbofan jet engines can just have borderline magical performance. Fighter jet agility, private jet freedom but LSA fuel economy.
A polish carbon fiber glider plane called Gekon weighs 69kg with gear and avionics. That means a personal jet doesn't need to weigh the 3300kg that a Phenom 100 does. Or even the 1600kg of an Eclipse 500. Low weight and high glide directly translates to fuel efficiency. An Eclipse actually beats a Baron 58 for fuel economy so imagine how great a light tandem 2 seater could be.
And when designed for high speed it can actually have quite a small wing. So it can actually be cheaper to make.
Trouble is, to get a jet efficient, you need to take advantage of air compressability. That requires lots of altitude. So… high altitude, advantage of speed, pressurized cabin, we’re edging closer to that Eclipse. Also, takes production volume to bring costs down.
@@russbell6418 true that a jet shines best at FL600 at mach 3 but an Eclipse already has better fuel economy than a Baron 58 and Eclipse is bigger so if you cut the weight down by 75% which is very possible and engines too then I thrust you can see the fuel economy of a jet can easily be in the workable range, even much below FL400. Say 15000feet.
The cleanliness, the lightness, the silence and the coolness and safety of twin jet just sweeps everything else off the floor. Piston props need not apply.
I did the math on a 4 seater and the jet engines only need to weigh 15kg each. That really helps lighten the bird. And 400kg empty weight is a conservative estimate. If pushed it could be lower still. A carbon fiber bubble can be very light. What's possible with carbon and turbofans as a replacement for a bonanza would blow you away.
Hello Scott, I have enjoyed your videos and have learned alot. You said you have lead shot in the front. Does that mean the Cozy was designed for a person of a certain weight? Or is there something missing from yours? Also, is a cozy designed for an optimal flight characteristic? Has anyone tried to put large tires on it for rough field conditions and soft surface? Thanks
The C/G in a canard is narrower, such that if you are alone in the front, you will require ballast in order for the aircraft to be inside its C/G window. The gear of these aircraft is designed for hard surfaces - the nosegear in particular would not survive bush use, and a larger tire on it would prevent it from being retracted.
I 'love' the way you talk! I am a sheetmetal worker/engineer and you have told me so much in a short space 😅
Why has no one put leading edge flaps on the Canard wing to increase lift on takeoff and landing?
Hi Scott. Many thanks for a fascinating video. Wonderful to get the aerodynamic perspective. What I still don’t quite understand is why the Canard doesn’t have flaps. The rear wing needs to have more lift than the front stabilisers at low speeds to give a nose down configuration to land. Surely flaps would give the main (rear) wing more lift and hence the required nose-down configuration - or am I missing something?
Deploying flaps moves the center of lift of the main wing rearward. This means there is more area between the center of lift and the center of gravity, causing a pitch-down moment. The canard will have to generate more lift to compensate for this, without exceeding its critical angle of attack. You don't want the canard capable of generating more lift without exceeding critical AOA, because it MUST stall first in order to protect the main wing. So the only way to get around this is to also add flaps to the canard so that it can generate more lift when the main wing flaps deploy. You would need a mechanism that absolutely, positively prevents one system from actuating without the other actuating simultaneously - if that were to happen, it would be absolutely disastrous. Something like that would add a LOT of weight, comparably, to a small airplane like this.
Thank you for this video I learned a lot from your presentation !!
Amazing aircraft out of the mind of one man , Burt Rutan - yes the aerodynamics on the Rutan Canard are hard to explain - another really complex one is Piaggio Avanati with the same engines can cruise 100KTAS ( 25% )faster than the Starship with similar power plants but to many the Boomarang was the one Rutan actually wanted to commercialize - great discussion
Rutan likes all of the credit but none of the blame. Starship is inferior to King Air in nearly all specs. There's a two word reason: Burt Rutan.
@@arcanondrum6543 The weight was the main problem, and not having a conventional tail (like the Avanti) is another problem. And the FAA wanted a wing that was very beefy, making the certified version much heavier than the proof-of-concept made by Rutan.
@@ErikssonTord_2 Everyone has to obey the same laws of physics and the FAA. Starship and the Adam A500 are, according to Rutan; "someone else's fault". Two big, very expensive flops with two words in common; Burt Rutan.
Great explanation of the pros and cons of a canard.
The SAAB Viggen has flaps on the canard, and a conventional elevator on the trailing edge of the main wing.
About the Downwash from Canard over Main Wing, any comment about the Saab Viggen approach, Canard located well higher than Main wing?
A chart is in Homebuilt Aircraft Site.
Blessings +
I love you man anybody inviting a critique or a comment or a correction especially is the top of the mountain to me. I love to watch people with money that have a disaster from being stupid because I'm poor from being stupid and my whole life is a disaster to look up from for a minute when someone buys an airplane. How does the kennard airplane respond to being overloaded? Most airplanes will fly straight overloaded and if you turn them even a little bit it's too much and they crash easy spin in. How does the kennard Wing respond to this pilot error have taken off with too much weight
The answer is...it depends. If you load outside of C/G, all bets are off. You could turn into a lawn dart if too far forward, or fall in an unrecoverable stall if too far aft. But when it just comes to overloading it while remaining in C/G - it's just an airplane, so it does what most airplanes do: climb poorly, stall at a higher airspeed. In a conventional airplane, if you overload it so you're using all your lift to just keep the thing in the air, if you then turn (which uses some of your lift to change the direction of the aircraft) it no longer has enough lift to fly - so either you descend, or you stall.
@@CanardBoulevard well I had a slightly more sophisticated view of it mathematically when you look at that extra weight and you had add bank angle, and a reduction of efficiency you might be looking at a situation where you will never have enough control authority to pull it out of the spiral. All of these things are nonlinear geometric changes so if you get very far in the direction of this geometry with the extra weight, it hits a "tipping point". Not physically tipping the airplane but just these things have lined up to hold you locked into something and you don't have enough control authority to restore to normal flight.
Re: aspect ratio, efficiency and lift and stall-resistance.
Efficient sleek planes that are stall-proof and super STOL have been proven. They are not used solely because they violate "If it looks right, it'll fly right" (even more than a canard). They look funny.
Aspect ratio is not a simple comparison between span & chord. It is span^2 divided by area. Expressed as an integer, not a ratio.
There have been very many very-low aspect-ratio planform planes that have done very well.
First, see the Arup planes from Indiana in the '30s. Aspect ratio under 2 ("Air"+"Up")
The trick they have is that at such low aspect-ratio, when flown very slowly with very high "A" (above 25° has been demonstrated), the wing-tip vortices wrap around above it capturing a "bubble" of low pressure above the wing, amplifying the lift they get at such slow speeds. At the same time, it traps air from the front over the top of the wing, keeping it from separating and giving strong smooth flow to the trailing edge controls. Such wings do not stall, as in losing all lift due to separation of flow and losing control surface effectiveness. They'll "mush" down if they're kept flying in such a way, but they don't depart.
They are not always burdened with carrying around all this extra drag: The vortex-driven "parachute lift" is elective and temporary, in order to fly slowly and not stall. Many of the type have proven to be sleek and quick on available power when flown normally.
If these very-low aspect-ratio planes are supposed to be inefficient and have lots of induced drag, what is this supposed inefficiency, if it does not manifest in power vs speed or fuel vs range? Because many of the sort have been excellent.
Charles Zimmerman worked for NACA in the '30s, saw the Arup S-2 fly for NACA, and later copied the very-low aspect-ratio and it's ability to be stall proof at very slow speeds very high "A", as the starting pint for his work with Vought and the Navy into a VTOL tail-sitter. He wrote about the "parachute lift" effect for UAC and NACA. Barnaby Wainfan also wrote extensively about for NASA when they were looking at the Facetmobile.
The "Parachute lift" effect and stall-proof nature of it is a known phenomenon.
Arup S-2 and S-4
th-cam.com/video/Nxz1UF67EQI/w-d-xo.htmlsi=Vf_lHaIBwL200EMg
th-cam.com/video/_XrSFVDa3mY/w-d-xo.htmlsi=Ur6PD3w6fJKd2HrN
The S-2 from 1934 was 780 lbs, flew 85 knots on 37 hp, with landing speed under 18 kts. It would not stall. Video shows it to be nimble and yet stable, with 45° climb. The Arup S-4 was 1150 lbs, dual control side by side. flew 100 kts on 70 hp. Between the two, they flew several seasons at air shows, frequently carrying advertising because nobody but _nobody_ wanted to buy or invest. They flew on until the age of the airframes retired them. The only incident was a fuel leak and fire an fatal crash of the similar Hoffman/Younghusband plane, which had many successful flights, demonstrating the same sorts of performance.
Next, see the Nemeth "parachute plane" of the '30s. Built on the fuselage of an Alliance Argo biplane, with a 15' diameter circular wing parasol on struts. Faster than the original, stall-proof, super-STOL, 45° climb, 60° super-slow descent with practically zero landing roll with any wind.
th-cam.com/video/mw7hPbTSdME/w-d-xo.htmlsi=Z-EjTj-Yx6NvWBDN
th-cam.com/video/0lMik-MkUlE/w-d-xo.htmlsi=cegLX6BwghPZNtD7
Then there's the similar Farman 1020. Like the Nemeth, built on the fuselage of a known successful (monoplane) Stall-proof, faster than the original.
The '40s Eshelman, commonly known as the "flying flounder". Aspect ratio under 1. Super-STOL and stall-proof, 156kts on 110 hp.
th-cam.com/video/JpV68abt8uc/w-d-xo.htmlsi=zB734mtnraibffd0
th-cam.com/video/idsA1dUD9QA/w-d-xo.htmlsi=xTFn0X3ejIZmjd0f
In the '80s, The Hatfield "Little Bird" by one who flew the original Arup planes. Sleek and efficient, STOL, stall proof.
th-cam.com/video/zK63GJ0saBA/w-d-xo.htmlsi=uJQL3KF9-Wx_NqzY
and other videos. Hatfield openly challenges the "conventional wisdom" which says they glide poorly and are draggy and difficult.
since 2015, the Rowe "UFO" from Aus.
th-cam.com/video/_-u0Y7cDngM/w-d-xo.htmlsi=NkS0IO4he0hsRzl2
th-cam.com/video/_-u0Y7cDngM/w-d-xo.htmlsi=NkS0IO4he0hsRzl2
Next, the '90s Wainfan "Facetmobile".
Wainfan also challenges the status quo about such things. They're misunderstood, and much maligned, but fly very well and should be more accepted.
740lbs max weight, 100kts on 47hp, with 340 lb useful load. Won't stall.
th-cam.com/video/LK7FhK5eL70/w-d-xo.htmlsi=Z_Ebe3sLBXp1gDtZ
Oshkosh 2023 Airventure Low Aspect Ratio Forum on Low Aspect Ratio Sport Airplanes - Barnaby Wainfan
th-cam.com/video/tzokRT3rbB0/w-d-xo.htmlsi=8t4X1kX8OIT4XzQn
Jolly interesting, thanks very much.
I thought this was about canards because the title said so. However, most of the negative points mentioned only apply to his particular aircraft type.
10:22 that is NOT correct. Your span wise lift distribution is moved out and bending moment increases as if the winglets were folded down making the wing longer. NO free lunch. The winglet reduces induced drag but reducing the wasted energy form wing tip vortices. The reasons airliners use winglets are two fold. One is span of wing and gate area at terminal is limited. Two it is great for a logo. Some of the latest airliners do not use winglets and just use longer wings and accept their gate access at a terminal will be limited.
You mentioned downwash (or maybe largely turbulent air) at the main wing because of the canard - is that less an issue with the Q200 because of the greater vertical offset between the canard and main wings?
No. A wing created a huge amount of downwash. From wingtip to wingtip, in a large circles over and under the entire aircraft. And that downwash descends at a certain rate. And that creates a downwash angle behind the wing. The rear wing, or horizontal stabilizer, exist in this downwash. And must "climb" up it indefinitely. They effectively have to climb even when flying level. This makes tandem and Canard aircraft inherently less efficient in terms of Lift-Induced drag. (Drag due to rearward tilt of the lift vector. Due to flying at an angle of attack).
I’m going to watch the videos you suggested. This video was awesome. I would really like to talk to you and Mark about the design of the cozy I have taken on. The canard on mine has the ability to adjust the angle of sweep.
Really! Wow, was that done to try to allow for flaps? Which Cozy is that? Or is it not flying?
Not flying yet. I’d estimate it at 85% complete. It’s a project that got started in the mid 90’s by my grandfather, I spent a lot of hours as a child helping him on it. The Cozy plans were childhood reading to me. Now in his upper 90’s, although extremely spry, and in the best shape of anyone I have ever seen at that age, he can’t finish it. It has been a dream of mine to finish it, and get him some stick time. I’m at a point in my life now that I can take on the task, and so here I am with a hanger and a plane that needs completion. He modified the design some. Like I mentioned the sweeping canard, it also has a IO-540 mounted to it, retractable rear gears, and a widened fuselage, among a few others. I’ve heard his rationale for the sweeping canard, but I’d like to pick the brain of a few others.
Also it’s a cozy Mark IV
@@a.j.bradley6851 an IO-540 AND retractable mains. This will be a truly unique airplane. I'd love to hear more about the sweeping canard.
Have you joined the Cozy Builders mailing list? There is a TON of collective knowledge there as well. If not, I'd highly suggest jointing: www.cozybuilders.org/mail_list/
Is there any testing on a canard that would retract or blend into the fuselage at higher speeds and the benefits/disadvantages ? Thanks
I very much enjoy your videos! I have a question. I am 6’6” tall and was wondering if the seat is adjustable enough to accommodate a tall person?
Thank you so much!!
The seat is not adjustable...at all. You can modify the rudder pedals slightly. I am 6'0" and my head is reasonably close to the canopy. At 6'6" I think you would have a hard time.
7:35 i think you meant static stability. Dynamic is over time. Static is immediate first reaction.
Canard downwash - Dragonfly better?
Traditional airplane - to reduce loss due downward tail force, could you have moveable CG? Put more weight on the tail during cruise?
I'm no aircraft engineer, but I was wondering if an all-moving canard could help with the stall recovery. Having it rotate far enough to let the nose drop straight down when needed.
You're wondering correctly. That's one of the most important things about a canard - and without any new individual rotation of the foreplane. The difference in the angles of incidence [i.e., built into the airframe] means that, as the aircraft gradually rotates towards dangerous angles of attack [with the airflow] the foreplane should always get to the stall angle before the mainplane does. The nose then begins to drop, so that the angles of attack decrease, improving matters for both planes. Canard pilots can use this feature to make very rapid descents.
@@robwilde855 I understand how normal canard configurations avoid main wing stall. My question about an all-moving canard is aimed at an alternative solution: If the main wing does stall, rotating the canards to almost vertical should eliminate most of the drag that stalled canards generate, making the nose drop faster than the stalled main wing, letting the pilot recover.
Sorry, I didn't read carefully enough. I see what you mean now.
My feelings about that are:
1) You say "if the main wing does stall..." - Well, it shouldn't, ever, unless you do something to deliberately cause it. Because the foreplane will always be stalling before the main wing can, and so the main's increase of angle of attack always stops and then begins to reduce before it can get far enough to stall. [These relationships of angles of incidence between fore and aft planes, for ANY type of aircraft, are integral to basic design, by the way; they are essential for stability, and could not be done away with in any "alternative solution".]
2) The drag of the stalled foreplane is acting mostly in the rearward direction; so not much of that drag force is preventing downward movement. Also a normally-stalled nose already drops at a reasonable rate, certainly fast enough to give the mainplane no chance of getting to the stall. So, is a faster drop really needed?
3) Your extended rotation: Are you thinking of more rearward rotation, or a forward rotation, to get to the final 'vertical' position? In other words is the foreplane to continue to increase its angle of incidence, or is it to reverse its movement and decrease the angle? If it is to move forwards, it will unstall, and assuming that that doesn't momentarily lift the nose higher [!], then as it rotates forward it will naturally pull the nose down with some force. If on the other hand it is to move even further 'back' and increase the drag, that would produce a very large force, more than the pivots are designed at present to handle. And what this 'ninety-degree airbrake' would do to the airflow, shedding violent eddies up and down, is rather alarming to contemplate. Even if that were taken care of, then the aircraft would never be able to fly in any stable way for more than a moment or two with such a flat-on aerodynamic surface, so the foreplane's natural position would have to be restored very quickly, going back through all those same problems.
4) Without the benefit of a practical experiment I think your idea, though ostensibly sensible and promising, might be somewhat a 'solution searching for a problem'. If, however, experiment showed that it did make a difference in some way, then the mechanical problems of the design and operation of a suitable and safe system might be too much, I mean not worth the time and expenditure and complication required.
Cheers.@@matejlieskovsky9625
@@robwilde855 Fair enough. Thank you for your response! I might think some more about it, but alas, I am busy enough with my own area of expertise most of the time.
Just to clarify: I was thinking about the foreplanes rotating forward. The whole idea was probably somewhat like making the foreplanes closer to control-only canards, removing the drag caused by needing a highly loaded foreplane. But you are right that I failed to consider the passive stability of the airframe. While a stall should be recoverable with such canards, it would be too easy to enter for a non-fly-by-wire aircraft.
@@matejlieskovsky9625 You are correct.
With a Canard that can rotate downward nearly vertical, it will break the stall.
But a canard that pivots (all-flying) is a thing to be carefully engineered. It will need irreversible controls. Or a very finely tuned anti-servo tab.
14:00 - You could just put the canard a foot lower fairly easily and not interfere with the main wing. I higher back wing is very common in conventional designs. Even if the front canard didn't produce a net positive lift, at least it's not producing a negative lift like a conventional tail. So it's really not a wash at all.
^ This does not work in Theory or in Practice.
A wing generates downwash when it creates lift. The rear wing has to fly in this downward deflected air. So it always has to climb. The front wing has to carry a substantial portion of the weight. Because an aircraft such as this, must have positive static stability. The center of gravity must be a certain distance in front of the aerodynamic center (of lift). The aerodynamic center in a canard is near the leading edge of the rear wing, or slightly in front of it. So the center of gravity has to be moved forward of that point to remain stable. This means the weight of the aircraft has a lever-arm nose down from the main wing. The canard must lift this to remain level or climb. So it must generate lift at all times.
Why can't you have flaps? Is this because of how it comes, cause I would just add them myself 😅or is the canards supposed to do this job? Love to hear your input cause a lot of videos don't cater to the layman
If you add flaps to the main wing, it increases the lift generated (and drag). In order to keep the airplane balanced, you now need flaps on the canard as well. You can't really do that, so the only alternative is to increase the size of the canard and authority of the elevator. But in doing that, you increase the lift generated by the canard in all phases of flight, which means you could now stall the main wing before the canard.
The Flaps would be so far behind the Center of Gravity, and Aerodynamic Center, that they would create an enormous nose-down moment. Because the main wing would effectively become an elevator with down deflection.
Informative basic breakdown.
You are forgetting that induced drag (if you know what that is) is proportional to the square of span loading (L/sp)²
Increase span 10% that reduces the ID by 20%
The parasite drag is proportional to wetted area.
The higher lift on the short canard produces a large drag.
On the other hand the tailplane can also lift. As long as the incidence angle of the forward wing is higher by a little bit than the incidence angle of the rear wing the aircraft is stable.
No down force REQUIRED
So you are mostly wrong! when your CG is at the rear point in the stability envelope
Nicely done!
I watched your video again and probably answered my own questions😅 cheers for the knowledge
Not to be nitpicking, but there is a little something wrong with the explanation about rotating during takeoff when comparing this canard design to a conventional design with a tail.
What first and foremost matter here are the position of the center of gravity/ center of mass versus the position of the landing gear and the center of lift, combined with the momentum generated by the tail or the canards.
Having to 'lift the entire front section of the airplane up' to rotate the aircraft for takeoff is NOT what the issue here is (simply because that already factors into the position of the center of gravity/ center of mass).
The other factors mentioned however do come into play of course.
I much rather suspect that the main part of explaining this 'phenomenon' is simply a natural result of the required high wing-loading of the canards to assure nose down stall behavior of the aircraft.
In other words:
Because the canards must (always) stall (much) 'earlier' than the main wing stalls, they will naturally also only be able to produce the lift required to rotate the aircraft for takeoff at respectively higher speeds as well (Because by design the wing must 'start flying' first, before the canards 'can be allowed to start flying').
My explanation is that it's basically just a result of the required safety feature of the overall canard design requiring a nose down stall behavior to be assured at all times, whereas conventional aircraft naturally and inherently have a nose down stall tendency (and can thus simply - and safely have larger tail surfaces allowing them to rotate at slower speeds).
Or to put it even another way:
Would the canards be modified and would simply be made larger in order to enable rotating the aircraft during takeoff at slower speeds, then it would no longer have a nose down stall behavior and as a result it would then no longer be safe to fly.
You're correct, and that is done by ensuring the load factor and angle of attack of the canard is greater than that of the main wing. Until the canard begins to fly and elevates the deck angle, the main wing doesn't have sufficient AoA to fly - so you really are rotating to get the main wing to fly.
Boeing leased an airplane to Dutch royalty who then leased it back to Boeing so they could come up with a mod to add winglets to the 737- 200. When they conducted the first flight test it's climb rate was so great it bordered on being uncontrollable. So they dialed out some of the lift and she flew fine after that.
Thanks for the great video!
I think a follow-on video comparing the canard to the Piaigo Avanti aerodynamics.
All the best,
M-
Another issue with canard aircraft is icing. If the canard stalls due to icing it's game over. The wing loading on the canard is high to ensure the canard stalls first. This makes it imperative that the canard is kept free of ice.
Very true. Icing on a canard can turn your airplane into a lawn dart. Some people install heated pitot tubes on their canards - I simply never fly when there is a possibility of icing.
Maybe you should discuss this with Burt Rutan. After all, he designs very capable and efficient canard A/C.
You realize this airplane is derived from a Rutan design, right? And I have talked to him before. :)
😂
Question: should Boeing have added canards on nose heavy 747?
Who said the 747 is nose heavy? That would depend on 1: Where its fuselage is located on the wing. And 2: How its loaded.
OK . . . l am just learning the rudiments about canards, and flying in general. Not sure if l ever will fly, due to chronic vertigo. Hoeever, it doesn't hurt to do cerebral gymnastics.
Question that comes to mind is (drumroll) . . . why is/are there no wing flaps? -- iz this a buggerment regulation? -- or is there some sort of aerodynamic reason?
Thanks in advance.
Have a look at this video - I explain this in detail in it: th-cam.com/video/ycLQaiX4ylE/w-d-xo.html
To the Author, could making the canard bigger account for some of the lost lift you need?
Making the canard bigger means it will generate more lift - and that means that you now have the problem where the main wing can stall before the canard does, particularly at aft C/G. Everything affects everything else.
@@CanardBoulevard so glad you got back to me, so is it always the aim to have the front of the plane stall/drop first? Is that easier to feel/predict than having the back drop first?
@@CanardBoulevard you are the first person to give me real world experience on just how delicate the balance is of staying 'up' in an advanced aircraft 😅lol
Yes. A stall is caused by a wing exceeding its critical angle of attack (around +15 degrees). Ideally, an aircraft that stalls, should automatically lower its angle of attack (its nose) to recover from this condition.
You don't want it to diverge into a nose-up maneuver, as this would make the wing stall deeper into the less lift/ more drag regime. (I.e. result in going downward at lethal velocity). Suggested reading: Stick and Rudder, an Explanation of the Air of Flying. - By Wolfgang Langweische.
hey.. you are trying hard and doing a good job explaining canard stability but you know the front wing doesnt have to stall to create stability. its the lift curve slope and zero lift angle. the lift curve slope is bigger for the big wing because its big so the plane is stable. the stable point is a positive angle because of the incidence of the front is greater. you fly the plane in pitch axis by adjusting the pitch stable point by changing the canard control surface. you should play around with xflr5 or AVL and see the numbers and stability
love your discussion though
I just love this video so much, you really taught me so much from your pilot based experience for want of a better explanation 😅 am so glad I found you, by the way my goal is to make my own jet pack, or even jump jets, so I value your experience and way with words 😮
Love this kind of content!
Plenty of learning going on. I suggest watching talks given by the late John Ronz for aerodynamic concepts. He was brilliant.
You may like having a look at 'Canards, design with care' (Burns?), also, in french: 'Des couacs chez les canards', Blessings +
Pretty good teacher.
Merry Christmas and a prosperous New Year
However the plain in question
did claim the life of a well known musician and that is the only reason why I will always look past them
It wasn't the type of plane that caused the crash: th-cam.com/video/Q17uzUe0bAk/w-d-xo.html