Design is really coming together. Create, build, test, iterate, iterate. iterate. Nice to watch engineers that know the value of exercising due diligence. Your attention to detail really shows. A pleasure to watch.
Its really impressive to see what modern engineering theory and manufacturing techniques can do to modernize a more traditional aircraft design. Very nice work all around.
1) Rev. Nose Wheel Centering Cam so Nose Wheel aligns during operation. 2) You have a fast aircraft... add Steering Damper (anti shimmy) Great job brothers fast!!!
It appears the nose wheel is a fully caster type, without any steering inputs. A shimmy damper would prevent the nose wheel from swiveling. A properly designed castering wheel will always trail behind without wobble. Riding a super bike no-handed at 160mph is a prime example of perfect front fork rake/angle. Most GA airplanes don't have enough steering castor to remain stable, because castor requires more effort and larger loads on steering components and pilot legs. But that's the case where you have steering linkages to the nose wheel. This airplane appears that it doesn't have those linkages. So I suppose it's steering by differential braking. Very simple, reliable, and works well if properly designed. (But this overall design seems to be utilizing multiple control concepts that are less than ideal for yaw control, both in the skr and on the ground, at least from the standpoint of this rudder-loving pilot).
So I love following along with you guys, and challenging myself to think about your designs, and how something might be improved. The opening scene with the linkage drove the same concerns as I later discovered you had, and I even came up with the same solution (Gear driven), for a better, more consistent actuation. So cool to see you guys take that path at the end!! I love what you guys are doing. Your attention to detail a second to none. There is so much pride contained in the form of your work. You guys are world class! 🌎 ✈️
It seems nose gear is always blasted with grit / bugs / crap and such from the prop, your work here is so nice - I'd suggest a small carbon fairing (similar to dirt bike fork guard) to protect that dandy design as well as make the post flight clean up duty a bit easier.
If a fairing had a definate aerodynamic advantage that may be the way to go but just to keep insects and minor dirt off the leg?? Depending on where you live you're going to get bugs all over the craft. Just give the aircraft a quick clean after every couple of flights. It has to be a working aircraft so it's going to get a bit of rash here and there! These people seem to know what they are doing!
You are doing super work as you are challenging yourselves and not letting overconfidence to have second best designs for DarkAero systems and components.
Another great episode, I love it! It's really liberating to see that great design does not mean that everything is working out just perfect for the first time, but the end product of continous iteration and perserverance. It is a point easy to miss by daily engineering work when all seen is higher costs and additional work hours. You make it look like fun, however it must have been kind of frustrating at some level. It would be nice to see a static or dynamic FEA comparison of the original and new design. Keep up, it is going to fly like a dream! :)
The linear actuator is fragile at the gear box, i have over 100 hrs on my wheel skis and one of it fail. The speed for retraction is`t important,.Any back up sys for the ldg ?
I like the the second design. Having the actuator act in the same axis and direction as the front gear assembly will remove the cantilever force on the slide rail all together, it wouldn't hold up well on the carbon cause it would eventually rub wear. The only issue I see now is getting enough leverage on the nose gear to not stress the actuator. Knowing that adding a relief rod with lose bolt ends would add height to the location of the actuator. And thats a nice main wiring harness.
How will the heat from the engine compartment affect the electric actuator? Will the gear have an emergency free-fall lock into position ability incase of actuator or electric malfunction? Great work love following the progress.
Nah. In case of gear malfunction during flying... Like everybody else... you will go to their website, fill out a long form and draw a support ticket. Aero India call center will get to you within 24h and provide a solution plan. It's the least we can do!!
Use of a worm gear drive occurred to me for this application. In emergency extension the worm could be disengaged from its driven spur gear and the air strut provide the extension energy as you've planned. I'm sure you've kept in mind keeping the gears clean; wheels kick up a lot of dirt. I admire your work and very much enjoy (and intellectually profit from) your reports. Thank you, thank you.
Down lock system? Emergency extension system? All the forces are going to go against the gear teeth? Ever land a plane that had nose gear shimmy problems, even with a damper installed? Lots of forces at work there. If you want to emphasize light weight, look into an early Mooney with a lever system activated by muscle power. Also the little BD-5s had the same idea.
Honest questions: 1)Using a gear drive, have you given thought to teeth breakage or binding due to stress and wear over time. Of course you are aware that aircraft landing produce a great deal of force and that force would be transferred to the teeth of a gear. And specifically the few actual teeth in contact with each other at time of landing. And it being a gear driven system and the same teeth ending up in the same spot at full extension of the landing gear every time means that those same teeth would bear the weight of every landing. This could cause shearing after fatigue over time which would be bad. It could also cause binding of landing gear during take off and or deployment of gear during landing. Over time gear wear because of load from landing with cause "slop" or space between teeth which can cause binding and complete failure. I'm a former aviation mechanic for the Marine Corps and even though it's not an engine part, landing gear is still critical. I am also a car guy and when I think gears, I think timing gears, differential gears and transmission gears and all of these share the same potential failures. Breakage and mesh loss over time due to either wear, torque or both and when the fail, the fail bad.
The airframe is designed to the weight and center of mass of the UL Power engine. The equivalent Lycoming is 80 pounds heavier and physically larger. Not only would it not fit, it would make the plane unacceptably nose heavy.
You did a nice job on the machining of that landing gear housing, you guys are into great details these two watchmaker's appreciate watching. Keep up the great work, from two guys at the Yucca Valley Airport in the California high-desert. Lance & Patrick
Seems like the self steering nose fork would work best at a 90 degree angle. Having the nose gear raked forward will lessen the ability to fight unintended nose wheel wobbling. Like a shopping cart with a bad wheel. I would fabricate a trailer hitch jig for it and go drive it around and see if it works over bumps, similar to centerline lighting, and is stable. Very cool build. Can’t wait to see it fly.
Good questions! We're following the guidelines per FAR 23.729 for extension and retraction for airspeeds of 1.6*V_s1. Yes, the motor and gears can generate enough torque to fully retract and extend the gear. Thanks for watching!
It never really dawned on me until now when you mentioned the target weight of the aircraft but 750lbs empty? There are dudes that could lift that on their own!
I've been watching a lot of Mike Patey and one of his videos he increased the size of the vertical stabilizer for more stability at speed (his low-wing orange plane). It'll be interesting to see how your small stabilizer plays out with stability at speed, especially given the low weight.
As a mechanical engineering student and a mechanical designer i really enjoy watching your videos. Please explain more about the tolerances that you consider for designing parts. Do you use standard tolerances for fits or not?
0:14. I see it now, there is some provision for emergency gear extension. Only now catching up on all the videos. Looking at the panel layout, I would like to have a 750. I currently have a 650 and it's comparative limitations are noticeable. To make room for it, the gear handle could be moved to below the emergency handle, on that vertical pedestal. Typically, you reach down from the throttle to grab the gear handle, at least on a lot of planes I have flown.. This would make it more natural and free some space on the top of the stack. The gear lights are small enough to be place in the sight line between the G3X and the cowl. the remaining light switches could be placed along that line too. Then you have the additional "single DIN" space for a 750. Plus, the center stack can be stacked together in a single cage. The 750 with the AutoPilot control head nestled above it. Plus it saves a little complexity and weight over two individual/separated cages.
is the front wheel free castering ? if so, how do you stop it from flopping over ,or getting stuck ,when it retracts, as the bay is not big enough ? if the wheel is sideways ?
I was going to ask the same question, what centers the nose wheel prior to retraction? Does not appear to be a lot of clearance considering the cutouts for the axial tips.
Honest questions: 2) Is there a way to use both gear driven and actuated movement for the landing gear Pardon my ignorance in these questions. They are genuine questions and following your build, I'd like to give you some thought from the outside looking in and I can learn a little from you guys (or anybody that chose to answer my questions. Be easy on me.) The reason I ask if using both is possible is because it gives you a contingency if either should fail. I realize this means more parts which possibly equals more weight, complexity, PARTS and so on but in my feeble mind landing gear is almost as important as power and wings on an aircraft. Also with a gear system backup it give you and option of manual or hand driven deployment of landing gear should you lose electric power which I just watched a video on. The aircraft's alternator failed due to wire abrasion and the pilot had to land without power. His landing gear was fixed though.
That linear actuator would have worked without deflection if it had only been supported at the motor end. Get rid of that forward attachment near the gland end. Attach the tip of the rod directly to the retract /extend arm. Get rid of the travel slot and the big roller bearing, and also get rid of the dogbone link. If the actuator allows for only being anchored at the motor end without pulling the guts out of it, then the actuator pivots to stay in line with the pull / push on the retract / extend link no matter where they are in the cycle. No deflection, constant alignment, fewer parts, joints, fasteners. That all said, you've moved on to geared.
Awesome as always! Question: what’s to stop the nose wheel from spinning upside down (or back to front) during retract? It looks like it would want to do a 180 turn once it gets close to the gear well.
@@DarkAeroInc I defer to your experience and vision. By my eye from what little I have seen, just looks a tad but under. Again, just around the top of the eyelets. ;P Love the videos guys.
That's one hell of a custom harness. I don't know much about making harnesses other than videos I've seen on HP Academy, but were there thoughts of doing concentrically twisting the harness to make it more workable, or due to the distance was it not necessary? Either way I love the work you guys are doing.
I love your development. I wouldn't be to happy with the gear being attached to the electrical system. Electrical failure seems to be one of the most common failures in an ac. And the stress starts multiplying if my "safe exit", the landing requires additional work. Have you checked how many cycles such a gear can do in a row before failing?
Great progress!!! Can you PLEASE make the audio output louder...PLEASE?!?!? A concern is that you have placed all of your electrical eggs in one "box-ket" and that could lead to a really bad day. Don't fly south over Chicago...one stray bullet will be no bueno.
Ah yeah. Here something. Are you making the whole plane around the idea of having a parachute system for it? I know myself I would be buying a plane with it rather than one without.
The tolerances of the tire bracket in relation to the tire seem very close in the video. Any worries of a bind happening on landing via deflection of the tire or a rock or debris getting between the tire and the bracket?
Great work guys, as a pilot my thought is what kind of system will you have in case that auto extension doesn’t work? Will it be a crank type alternate gear extension or something like that since gravity extension won’t work on that? Or a combo of both?
Regarding the nose gear, I did not notice any mechanical stop the wheel will be sitting on when under load. I hope you guys have some there so the whole weight of the plane does not sit on the actuator.
Quite a lot of torque is gong to be on that gear driven pivot point when the nose gear touches the runway while landing. you need some sort of cross member to absorb that.
John, thanks for watching and the comment! You're correct that a lot of force would be transferred to the gears w/o drag links. We should have mentioned this during the video but the drag links weren't made visible in the CAD for the new design. If you watch back during the clips where we show the linear actuator design you'll see them visible there. Drag links are still planned for the new design. You can see the mount point for where they'd connect midway up on the aft trunnion of the new design.
What straightens the wheel if it isn't straight when it retracts. With no brakes precession might be a problem with a spinning wheel and a turn?. Might need some guides. How about spinning the wheel up and retracting it in your test stand? How about an out of balance wheel turning sideways? Does the wheel wheel need guides to help it get straight and not hit the doors? Can it go in backwards or are there stops at 90 degrees of turn? Is there any safety/fail safe if there is pressure/weight on it to not retract?
Is that a Vex BAG motor and planetary I see? That shot at the end looks an awful lot like Vex motors and gears we used in FRC. Have you thought much about how you're going to handle emergency gear extension? Traditionally this is done by dumping hydraulic pressure and spring-loading the gear down, but since there are no hydraulics, how do you intend to extend the gear if the actuator fails? Those BAG motors are good, but we've popped a few in the past...
I still don't like all the instrument panel wiring coming through one connector, if that connector comes loose in flight? Would it be that difficult to split the wiring between 2 connectors so you have some redundancy.
When will she fly? Where can I learn about your Airventure booth, schedule, etc. I need to visit with you and sit in her, not sure 6’ 4.5” frame will fit?
Also...do you have a shimmy damper or are you just relying on the Bellevue washers? If no shimmy damper the washers will require a great deal of friction to prevent shimmy and that will require a great deal of differential braking and that is not vey pilot pleasing.
Will you implement some kind of emergency gear drop ( Gravity drop? ) I´m starting to fancy your plane, looks great and not to expensive as what I understand.
Great question! Yes, both designs we showed incorporated a backup provision for extending the gear. The pilot pulls a handle that disengages the actuation system and a passive gas spring drives the gear down to overcome aerodynamic loads and into the down locked position. We will have more to show on how this works in upcoming videos.
@@DarkAeroInc Sounds nice. I was thinking about building the sling TSI... but now I´m starting to think "Hmm.. maybe I can live with a 2 seat plane" :D Keep it up.
@@DarkAeroInc Oh.. sorry. One more thing. Can you please update your website so international ppl (rest of the world basically) understands ( Metrics please :) ) I have no idea of how far 1700 sm is withou google... Nm (aviation) or Km (standard) would be nice. Same goes for pounds and kilos.
@@DarkAeroInc is there an overcenter linkage to hold them down? I'd trust the gas strut to drop the gear against aerodynamic loads but not against runway loads. Also I hope you have some sort of open house after the pandemic ends. I'm also on the south ramp and it takes all my willpower to not go over and bother you guys
Why not making the landing gear the other way around, using the air flow to help opening it. The way you have it set up is against the wind when opening.
Good question! This approach would have required a pivoting point further aft thus increasing the length of the strut leg and the length of the retract cavity required. Additionally, there is very limited space firewall forward to tuck the tire away to with the engine taking up the majority of that space. Thanks for watching!
Is there some sort of seperate locking mechanism not shown in the CAD? The shear load of a hard landing on those gear teeth could be rather high. I’d want the mechanical advantage of the lock’s mount being halfway down the landing gear, as opposed to being up at the top with the gear segment.
Correct. It wasn’t shown in the video but the second design also has drag links to react against the drag loads. There is an “eye” on the back of the trunnion to interface with the drag links which is shown though. Gear teeth are not used to hold the position of the nose gear in the up or down position, just to actuate the gear up or down.
Okay, oddball question. You've got electric gear with local actuators, and the nose gear extends forward. How to handle emergency extension? I otherwise love the design - trailing link or the equivalent without a lot of excess material to make it work right...
Thanks for watching and the question! Great question! We didn't have it mocked up on the test stand, but we do have a backup provision for extending the gear. The pilot pulls a handle that disengages the actuation system and a passive gas spring drives the gear down to overcome aerodynamic loads and into the down locked position. We will have more to show on how this works in upcoming videos.
I love that you are using components meant for FIRST robotics on this project. Tip if you are not in the FIRST community: look into these gears: wcproducts.com/products/pocketed-gears. They are the same as the Vex pro components you show but have been pocketed to drop the weight in unnecessary areas. I have used those gearboxes quite a bit and have been mostly happy with them, but they have some real failure modes associated with them. Send me a PM and we can have a quick chat.
Good eye! One of our interns, Michael, introduced us to them since he had a lot of experience with robotics. Still determining the production solution, but for initial testing of the design, the VEX parts are awesome because they are readily available, cost effective, and are backed by a lot of engineering data and testing.
@@DarkAeroInc Honestly, there are a lot of analogs between the competition robots and Aviation. Both are trying to cram peak performance with minimal weight. The biggest difference is in reliability and failure tolerance. There are even some items in the competition robot world that I think would be acceptable for use in landing gear...
Hi Gents, I'm new on your channel but very interested about this project so I'going to watch all previous episodes, your work is amazing for me:) One question, have you consider winglet or sharklet?
Pawel, thank you for watching and checking out some of our previous videos! We answered the winglet question in this video here: th-cam.com/video/GrlM3OFhKyM/w-d-xo.html
A manual system would be awesome! That would be the ultimate in simplicity! We did consider manual but the constraints of our design end up making a manual lever or crank system less appealing than an electrically actuated system.
Since our airplane is experimental category, there are a lot of options for what we can use. The biggest requirement for the gears is strength but beyond that we want to keep the weight down too. We have sourced some prototype parts from McMaster but there are a lot of places to get gears since they are a common mechanical component.
Josh, thanks for the question! The self steering nose wheel design follows a similar design principle of other proven, self steering nose wheel aircraft. Pre-tension on the front pivot pin is adjusted to provide sufficient damping and tension to prevent the nose wheel from flopping over during retract or spin during heavy cross wind. We have played around testing this. A good example of self steering, retractable gear can be found on the Rutan style canard aircraft. For retract, if there is an event where the gear is slightly cocked to one side there will be a self aligning feature incorporated into the gear doors and wheel fork to help correct - this hasn't been installed yet. Thanks for watching!
Glad to hear there is a mechanical feature to center the nose gear during retraction. I just need to finish watching all the videos. It appears every time I have a question or concern-you’ve answered it.
Kevin, thanks for the question! The takeoff and landing roll at sea level on pavement is projected to be around 1000ft. Minimum runway length would be much longer than this though to provide safe stopping distance for an aborted takeoff or for misjudged approach on landing.
Jeff, thanks for the question! The self steering nose wheel design follows a similar design principle of other proven, self steering nose wheel aircraft. Pre-tension on the front pivot pin is adjusted to provide sufficient damping and tension to prevent the nose wheel from flopping over during retract or spin during heavy cross wind. We have played around testing this. A good example of self steering, retractable gear can be found on the Rutan style canard aircraft. For retract, if there is an event where the gear is slightly cocked to one side there will be a self aligning feature incorporated into the gear doors and wheel fork to help correct - this hasn't been installed yet. Thanks for watching!
Seeing that fat bundle of wires causes me to wonder: CAN Bus technology/implementation? Is it it possible and or desirable for your application? Great job in creating a modular box-style plug and play solution, but surely a one wire set up would be more desirable, or am I missing something? And while you’ve created a gorgeous chunk of CNC aluminum gear strut there, why not craft it from carbon fiber too?
Hey David, we do have CAN bus for most of our Garmin avionics and gear logic, but there are still a few devices that get controlled through the panel running on separate data protocols. The modular setup came about somewhat out of necessity because our instrument panel is integrated into the canopy and needed to be able to separate from the rest of the harness. The modular setup is an interesting work tradeoff since it does require extra effort to construct the connectors that run into each module, but it makes it easier to break up the work of creating the harness and allows it to be done outside the cramped spaces of the aircraft. We are going with carbon fiber struts for our main gear, but for the nose gear it would be difficult to use the same approach. There is less space for the nose gear to fit both the strut and the shock into the same area without integrating the shock inside the strut, which led us to the design you see in the video. For the current strut design, carbon fiber is less ideal from a manufacturing standpoint since it involves parts like the trunnion that have complex geometries.
I envisioned a hybrid approach for the nose strut, that is, trunnion and upper pivot of aluminum, main strut in CF. It just seems that carving that piece out of aluminum is super expensive, time consuming, and is an exercise in re-inventing the wheel, so to speak. The cartridge design for the suspension action is very clever though.
@@DarkAeroInc I know your engine for the prototype does not have CAN Bus, but the latest version of the engine does have it. It may or may not be of use to your electrical design.
I like gears but wont you need a mechanical lock of sort to carry the torque load on ground impact. Alternatively make the gears large diameter and wide teeth, maybe symmetric in both sides so it's strong enough to carry the shocks. And how do other simple planes do this? like lancair IV
Both designs we showed have hardware to lock the gear down and react against the drag loads. The second design did not have the drag links or torque links shown in the CAD model we shared but you could see the “eyelets” on the back face of the trunnion where they interface. Lancair uses hydraulic actuation on their designs but our gear retract design and geometry is much different from a Lancair so we couldn’t reference their work.
@@DarkAeroInc ok, thanks for the answer. I prefer direct electric over hydraulic. Have you considered angling the suspension forward a bit to absorb the backward compression component? so it doesn't turn into a locking force on the sliding link.
Design is really coming together. Create, build, test, iterate, iterate. iterate. Nice to watch engineers that know the value of exercising due diligence. Your attention to detail really shows. A pleasure to watch.
This channel is the best example for living vicariously :-)
Thank you for sharing
That wiring harness update is no simple task! What amazing organization, and love the nose gear retract animations. Thanks for the update!
Its really impressive to see what modern engineering theory and manufacturing techniques can do to modernize a more traditional aircraft design. Very nice work all around.
1) Rev. Nose Wheel Centering Cam so Nose Wheel aligns during operation. 2) You have a fast aircraft... add Steering Damper (anti shimmy) Great job brothers fast!!!
It appears the nose wheel is a fully caster type, without any steering inputs.
A shimmy damper would prevent the nose wheel from swiveling.
A properly designed castering wheel will always trail behind without wobble. Riding a super bike no-handed at 160mph is a prime example of perfect front fork rake/angle.
Most GA airplanes don't have enough steering castor to remain stable, because castor requires more effort and larger loads on steering components and pilot legs.
But that's the case where you have steering linkages to the nose wheel. This airplane appears that it doesn't have those linkages.
So I suppose it's steering by differential braking. Very simple, reliable, and works well if properly designed.
(But this overall design seems to be utilizing multiple control concepts that are less than ideal for yaw control, both in the skr and on the ground, at least from the standpoint of this rudder-loving pilot).
So I love following along with you guys, and challenging myself to think about your designs, and how something might be improved. The opening scene with the linkage drove the same concerns as I later discovered you had, and I even came up with the same solution (Gear driven), for a better, more consistent actuation. So cool to see you guys take that path at the end!!
I love what you guys are doing. Your attention to detail a second to none. There is so much pride contained in the form of your work. You guys are world class! 🌎 ✈️
Terrific work, gentlemen!
It’s very exciting watching all of you brothers build your airplane. Can’t wait to see it fly.
From Missouri
It seems nose gear is always blasted with grit / bugs / crap and such from the prop, your work here is so nice - I'd suggest a small carbon fairing (similar to dirt bike fork guard) to protect that dandy design as well as make the post flight clean up duty a bit easier.
If a fairing had a definate aerodynamic advantage that may be the way to go but just to keep insects and minor dirt off the leg?? Depending on where you live you're going to get bugs all over the craft.
Just give the aircraft a quick clean after every couple of flights. It has to be a working aircraft so it's going to get a bit of rash here and there! These people seem to know what they are doing!
Your team and Mike Patey team are advancing aviation to a new level. You guys are awesome!!!
You are doing super work as you are challenging yourselves and not letting overconfidence to have second best designs for DarkAero systems and components.
Love your videos! A dream workplace to challenge, learn and apply the ideas, and see it materialise !
Another great episode, I love it!
It's really liberating to see that great design does not mean that everything is working out just perfect for the first time, but the end product of continous iteration and perserverance. It is a point easy to miss by daily engineering work when all seen is higher costs and additional work hours. You make it look like fun, however it must have been kind of frustrating at some level.
It would be nice to see a static or dynamic FEA comparison of the original and new design.
Keep up, it is going to fly like a dream! :)
Love seeing those FRC parts!
The linear actuator is fragile at the gear box, i have over 100 hrs on my wheel skis and one of it fail. The speed for retraction is`t important,.Any back up sys for the ldg ?
I like the the second design. Having the actuator act in the same axis and direction as the front gear assembly will remove the cantilever force on the slide rail all together, it wouldn't hold up well on the carbon cause it would eventually rub wear.
The only issue I see now is getting enough leverage on the nose gear to not stress the actuator. Knowing that adding a relief rod with lose bolt ends would add height to the location of the actuator.
And thats a nice main wiring harness.
Very cool. Cant wait to see her in the air!
How will the heat from the engine compartment affect the electric actuator? Will the gear have an emergency free-fall lock into position ability incase of actuator or electric malfunction? Great work love following the progress.
Nah. In case of gear malfunction during flying... Like everybody else... you will go to their website, fill out a long form and draw a support ticket. Aero India call center will get to you within 24h and provide a solution plan. It's the least we can do!!
You guys are BRILLIANT!
I think what you guys are doing is amazing!
Use of a worm gear drive occurred to me for this application. In emergency extension the worm could be disengaged from its driven spur gear and the air strut provide the extension energy as you've planned. I'm sure you've kept in mind keeping the gears clean; wheels kick up a lot of dirt. I admire your work and very much enjoy (and intellectually profit from) your reports. Thank you, thank you.
You could incorporate a Geneva mechanism as a positive-lock in the down position.
Really love the evolution of the nose gear.
Down lock system? Emergency extension system? All the forces are going to go against the gear teeth? Ever land a plane that had nose gear shimmy problems, even with a damper installed? Lots of forces at work there. If you want to emphasize light weight, look into an early Mooney with a lever system activated by muscle power. Also the little BD-5s had the same idea.
These videos are cool to watch.
Honest questions:
1)Using a gear drive, have you given thought to teeth breakage or binding due to stress and wear over time. Of course you are aware that aircraft landing produce a great deal of force and that force would be transferred to the teeth of a gear. And specifically the few actual teeth in contact with each other at time of landing. And it being a gear driven system and the same teeth ending up in the same spot at full extension of the landing gear every time means that those same teeth would bear the weight of every landing. This could cause shearing after fatigue over time which would be bad. It could also cause binding of landing gear during take off and or deployment of gear during landing. Over time gear wear because of load from landing with cause "slop" or space between teeth which can cause binding and complete failure. I'm a former aviation mechanic for the Marine Corps and even though it's not an engine part, landing gear is still critical. I am also a car guy and when I think gears, I think timing gears, differential gears and transmission gears and all of these share the same potential failures. Breakage and mesh loss over time due to either wear, torque or both and when the fail, the fail bad.
Thanks for sharing guys... Outstanding combined works of aviation art... Cheers
Always Fun to see the cool stuff you guys are doing.
Thanks Creighton!
New arrangement makes it easier to fit a lycoming which is good to see!
The airframe is designed to the weight and center of mass of the UL Power engine. The equivalent Lycoming is 80 pounds heavier and physically larger. Not only would it not fit, it would make the plane unacceptably nose heavy.
I see so much love in those bundles.
This a very interesting and well put together you tube channel. One of if not the best out here.
Looking good!
look at 3:51 the Dell dude is back! Please say "Dude you're getting a Dell!"
Боже как, круто получается! Молодцы команда на высоте, все четко, продумано так и продолжать)
You did a nice job on the machining of that landing gear housing, you guys are into great details these two watchmaker's appreciate watching. Keep up the great work, from two guys at the Yucca Valley Airport in the California high-desert. Lance & Patrick
Seems like the self steering nose fork would work best at a 90 degree angle. Having the nose gear raked forward will lessen the ability to fight unintended nose wheel wobbling. Like a shopping cart with a bad wheel. I would fabricate a trailer hitch jig for it and go drive it around and see if it works over bumps, similar to centerline lighting, and is stable. Very cool build. Can’t wait to see it fly.
Wondering what airspeeds the nose gear be able to handle... and if the electric motor is strong enough.
Good questions! We're following the guidelines per FAR 23.729 for extension and retraction for airspeeds of 1.6*V_s1. Yes, the motor and gears can generate enough torque to fully retract and extend the gear. Thanks for watching!
@@DarkAeroInc I want a marshmallow man spec.
Many Aircraft like the light cessna things are electric.
I admire you guys 👍🏻
It never really dawned on me until now when you mentioned the target weight of the aircraft but 750lbs empty? There are dudes that could lift that on their own!
I've been watching a lot of Mike Patey and one of his videos he increased the size of the vertical stabilizer for more stability at speed (his low-wing orange plane). It'll be interesting to see how your small stabilizer plays out with stability at speed, especially given the low weight.
Thanks for sharing!
nice job guys 👍
As a mechanical engineering student and a mechanical designer i really enjoy watching your videos.
Please explain more about the tolerances that you consider for designing parts.
Do you use standard tolerances for fits or not?
0:14. I see it now, there is some provision for emergency gear extension. Only now catching up on all the videos.
Looking at the panel layout, I would like to have a 750. I currently have a 650 and it's comparative limitations are noticeable.
To make room for it, the gear handle could be moved to below the emergency handle, on that vertical pedestal.
Typically, you reach down from the throttle to grab the gear handle, at least on a lot of planes I have flown.. This would make it more natural and free some space on the top of the stack.
The gear lights are small enough to be place in the sight line between the G3X and the cowl. the remaining light switches could be placed along that line too.
Then you have the additional "single DIN" space for a 750.
Plus, the center stack can be stacked together in a single cage. The 750 with the AutoPilot control head nestled above it. Plus it saves a little complexity and weight over two individual/separated cages.
I'm impressed😁
What are your plans for an emergency gear extension, seeing that the gear extends more than 90 degrees. May be hard to fight against that airflow
is the front wheel free castering ? if so, how do you stop it from flopping over ,or getting stuck ,when it retracts, as the bay is not big enough ? if the wheel is sideways ?
I was going to ask the same question, what centers the nose wheel prior to retraction? Does not appear to be a lot of clearance considering the cutouts for the axial tips.
Honest questions:
2) Is there a way to use both gear driven and actuated movement for the landing gear Pardon my ignorance in these questions. They are genuine questions and following your build, I'd like to give you some thought from the outside looking in and I can learn a little from you guys (or anybody that chose to answer my questions. Be easy on me.) The reason I ask if using both is possible is because it gives you a contingency if either should fail. I realize this means more parts which possibly equals more weight, complexity, PARTS and so on but in my feeble mind landing gear is almost as important as power and wings on an aircraft. Also with a gear system backup it give you and option of manual or hand driven deployment of landing gear should you lose electric power which I just watched a video on. The aircraft's alternator failed due to wire abrasion and the pilot had to land without power. His landing gear was fixed though.
That linear actuator would have worked without deflection if it had only been supported at the motor end. Get rid of that forward attachment near the gland end. Attach the tip of the rod directly to the retract /extend arm.
Get rid of the travel slot and the big roller bearing, and also get rid of the dogbone link. If the actuator allows for only being anchored at the motor end without pulling the guts out of it, then the actuator pivots to stay in line with the pull / push on the retract / extend link no matter where they are in the cycle. No deflection, constant alignment, fewer parts, joints, fasteners.
That all said, you've moved on to geared.
0:19 OH NO DUDE, YOUR ANGLE GRINDER DISK IS BROKEN...wait, what?
It's an oscillating saw
Much gentler than an angle grinder, and it can't throw the blade at you.
Who is their right mind can dislike these videos?!?
Everytime I look at the canopy, I wonder how much visibility you have looking down.
probably not much once the wings are installed
Great work, but why not a second linear actuator in parallel just for some good redundancy ?
Awesome as always! Question: what’s to stop the nose wheel from spinning upside down (or back to front) during retract? It looks like it would want to do a 180 turn once it gets close to the gear well.
I would consider having more 'meat' around the eyelets where the bolt attaches the nose gear to your two ears. I like it though!
It’s a fine line to walk between adding more meat and getting too beefy.
@@DarkAeroInc I defer to your experience and vision. By my eye from what little I have seen, just looks a tad but under. Again, just around the top of the eyelets. ;P Love the videos guys.
Do you have some kind of slip or flexible coupling between the gear wheel and the landing strut?
That's one hell of a custom harness. I don't know much about making harnesses other than videos I've seen on HP Academy, but were there thoughts of doing concentrically twisting the harness to make it more workable, or due to the distance was it not necessary? Either way I love the work you guys are doing.
I love your development. I wouldn't be to happy with the gear being attached to the electrical system. Electrical failure seems to be one of the most common failures in an ac. And the stress starts multiplying if my "safe exit", the landing requires additional work.
Have you checked how many cycles such a gear can do in a row before failing?
Great progress!!!
Can you PLEASE make the audio output louder...PLEASE?!?!?
A concern is that you have placed all of your electrical eggs in one "box-ket" and that could lead to a really bad day. Don't fly south over Chicago...one stray bullet will be no bueno.
AWESOME
maybe try a generative design; and use the layout created by the AI as inspiration to convert it into something machinable?
Like new projects 🤩🇧🇷
Ah yeah. Here something. Are you making the whole plane around the idea of having a parachute system for it? I know myself I would be buying a plane with it rather than one without.
Good job great video
At 1.35 u forgot to heat up the pink heat shrink connector. Otherwise great work.
The tolerances of the tire bracket in relation to the tire seem very close in the video. Any worries of a bind happening on landing via deflection of the tire or a rock or debris getting between the tire and the bracket?
Or getting grass in between?
Great work guys, as a pilot my thought is what kind of system will you have in case that auto extension doesn’t work? Will it be a crank type alternate gear extension or something like that since gravity extension won’t work on that? Or a combo of both?
Regarding the nose gear, I did not notice any mechanical stop the wheel will be sitting on when under load. I hope you guys have some there so the whole weight of the plane does not sit on the actuator.
Quite a lot of torque is gong to be on that gear driven pivot point when the nose gear touches the runway while landing. you need some sort of cross member to absorb that.
John, thanks for watching and the comment! You're correct that a lot of force would be transferred to the gears w/o drag links. We should have mentioned this during the video but the drag links weren't made visible in the CAD for the new design. If you watch back during the clips where we show the linear actuator design you'll see them visible there. Drag links are still planned for the new design. You can see the mount point for where they'd connect midway up on the aft trunnion of the new design.
What straightens the wheel if it isn't straight when it retracts. With no brakes precession might be a problem with a spinning wheel and a turn?. Might need some guides. How about spinning the wheel up and retracting it in your test stand? How about an out of balance wheel turning sideways? Does the wheel wheel need guides to help it get straight and not hit the doors? Can it go in backwards or are there stops at 90 degrees of turn? Is there any safety/fail safe if there is pressure/weight on it to not retract?
Those were my thoughts too...
Is that a Vex BAG motor and planetary I see? That shot at the end looks an awful lot like Vex motors and gears we used in FRC. Have you thought much about how you're going to handle emergency gear extension? Traditionally this is done by dumping hydraulic pressure and spring-loading the gear down, but since there are no hydraulics, how do you intend to extend the gear if the actuator fails? Those BAG motors are good, but we've popped a few in the past...
Do you have a list of connectors you used to build the wiring harness? I am always looking for connectors to help speed up avionics installs.
Hello Dark Arrow project from Sydney, Australia.
*was the speed of the actuator considered?
* drag reduction
* for return in the down position.
🌏🇭🇲
those actuators can be back driven if enough force is applied.
It’s a good thing the gear strut extends beyond 90° then
4:32 the airshock's shaft in the middle between two parts doesn't looks to me right.
I still don't like all the instrument panel wiring coming through one connector, if that connector comes loose in flight? Would it be that difficult to split the wiring between 2 connectors so you have some redundancy.
The connectors can be safety wired.
When will she fly? Where can I learn about your Airventure booth, schedule, etc. I need to visit with you and sit in her, not sure 6’ 4.5” frame will fit?
Also...do you have a shimmy damper or are you just relying on the Bellevue washers? If no shimmy damper the washers will require a great deal of friction to prevent shimmy and that will require a great deal of differential braking and that is not vey pilot pleasing.
Will you implement some kind of emergency gear drop ( Gravity drop? )
I´m starting to fancy your plane, looks great and not to expensive as what I understand.
Great question! Yes, both designs we showed incorporated a backup provision for extending the gear. The pilot pulls a handle that disengages the actuation system and a passive gas spring drives the gear down to overcome aerodynamic loads and into the down locked position. We will have more to show on how this works in upcoming videos.
@@DarkAeroInc Sounds nice. I was thinking about building the sling TSI... but now I´m starting to think "Hmm.. maybe I can live with a 2 seat plane" :D Keep it up.
@@DarkAeroInc Oh.. sorry. One more thing.
Can you please update your website so international ppl (rest of the world basically) understands ( Metrics please :) )
I have no idea of how far 1700 sm is withou google... Nm (aviation) or Km (standard) would be nice. Same goes for pounds and kilos.
@@Maviation 2.2 pounds per kilo and all sorts of converters available on line.
@@DarkAeroInc is there an overcenter linkage to hold them down? I'd trust the gas strut to drop the gear against aerodynamic loads but not against runway loads. Also I hope you have some sort of open house after the pandemic ends. I'm also on the south ramp and it takes all my willpower to not go over and bother you guys
Why not making the landing gear the other way around, using the air flow to help opening it. The way you have it set up is against the wind when opening.
Good question! This approach would have required a pivoting point further aft thus increasing the length of the strut leg and the length of the retract cavity required. Additionally, there is very limited space firewall forward to tuck the tire away to with the engine taking up the majority of that space. Thanks for watching!
Is there some sort of seperate locking mechanism not shown in the CAD? The shear load of a hard landing on those gear teeth could be rather high. I’d want the mechanical advantage of the lock’s mount being halfway down the landing gear, as opposed to being up at the top with the gear segment.
Correct. It wasn’t shown in the video but the second design also has drag links to react against the drag loads. There is an “eye” on the back of the trunnion to interface with the drag links which is shown though. Gear teeth are not used to hold the position of the nose gear in the up or down position, just to actuate the gear up or down.
Okay, oddball question. You've got electric gear with local actuators, and the nose gear extends forward. How to handle emergency extension? I otherwise love the design - trailing link or the equivalent without a lot of excess material to make it work right...
Thanks for watching and the question! Great question! We didn't have it mocked up on the test stand, but we do have a backup provision for extending the gear. The pilot pulls a handle that disengages the actuation system and a passive gas spring drives the gear down to overcome aerodynamic loads and into the down locked position. We will have more to show on how this works in upcoming videos.
@@DarkAeroInc a *gas* spring! Cool! Looking forward to it.
What centers the nosewheel when it goes up into the well.
@darkarrow Do you really mean flex in the linkage or play?
Bought a shirt! Keep up the amazing work!
Thank you! We appreciate the support!
Make sure mice don't like to eat that brand of heat shrink tubing. I had that problem in my motorhome!
Never leave food in your plane when it is storage.
@@i.r.wayright1457
Sometimes they are just looking for a place to nest.. then they eat the wires...
I love that you are using components meant for FIRST robotics on this project. Tip if you are not in the FIRST community: look into these gears: wcproducts.com/products/pocketed-gears. They are the same as the Vex pro components you show but have been pocketed to drop the weight in unnecessary areas. I have used those gearboxes quite a bit and have been mostly happy with them, but they have some real failure modes associated with them. Send me a PM and we can have a quick chat.
Good eye! One of our interns, Michael, introduced us to them since he had a lot of experience with robotics. Still determining the production solution, but for initial testing of the design, the VEX parts are awesome because they are readily available, cost effective, and are backed by a lot of engineering data and testing.
@@DarkAeroInc Honestly, there are a lot of analogs between the competition robots and Aviation. Both are trying to cram peak performance with minimal weight. The biggest difference is in reliability and failure tolerance. There are even some items in the competition robot world that I think would be acceptable for use in landing gear...
Hi Gents, I'm new on your channel but very interested about this project so I'going to watch all previous episodes, your work is amazing for me:)
One question, have you consider winglet or sharklet?
Pawel, thank you for watching and checking out some of our previous videos! We answered the winglet question in this video here: th-cam.com/video/GrlM3OFhKyM/w-d-xo.html
Loose the weight of the liner actuator by omitting it entirety. Instead consider a manual drop and retracting mechanism of carbon tubes.
Like the BD-5
A manual system would be awesome! That would be the ultimate in simplicity! We did consider manual but the constraints of our design end up making a manual lever or crank system less appealing than an electrically actuated system.
Holy cow a VersaPlanetary gearbox in an airplane?
can you buy your spur gears from mcmaster-carr or is the aero quality contraint preventing that?
Since our airplane is experimental category, there are a lot of options for what we can use. The biggest requirement for the gears is strength but beyond that we want to keep the weight down too. We have sourced some prototype parts from McMaster but there are a lot of places to get gears since they are a common mechanical component.
Was your plane designed in metric or imperial units?
I'm hoping you can show how you are able to make sure that the tire is rotated to the. Correct position during retraction or if that doesn't matter?
Josh, thanks for the question! The self steering nose wheel design follows a similar design principle of other proven, self steering nose wheel aircraft. Pre-tension on the front pivot pin is adjusted to provide sufficient damping and tension to prevent the nose wheel from flopping over during retract or spin during heavy cross wind. We have played around testing this. A good example of self steering, retractable gear can be found on the Rutan style canard aircraft.
For retract, if there is an event where the gear is slightly cocked to one side there will be a self aligning feature incorporated into the gear doors and wheel fork to help correct - this hasn't been installed yet. Thanks for watching!
@@DarkAeroInc that's freaking cool stuff right there! Thanks for taking the time to explain that to me.
Glad to hear there is a mechanical feature to center the nose gear during retraction. I just need to finish watching all the videos. It appears every time I have a question or concern-you’ve answered it.
What's the minimum runway length for take-off and landing?
Kevin, thanks for the question! The takeoff and landing roll at sea level on pavement is projected to be around 1000ft. Minimum runway length would be much longer than this though to provide safe stopping distance for an aborted takeoff or for misjudged approach on landing.
Wow I hadn't seen updates from your channel in a long time and I must say that plane looks almost done and ready to fly
when do you think the whole project will be finished?
Vanni, thank you for watching and the question! We are working toward taxi testing and first flights this year.
What would keep the wheel from flopping to the left or right while the gear is being retracted?
Jeff, thanks for the question! The self steering nose wheel design follows a similar design principle of other proven, self steering nose wheel aircraft. Pre-tension on the front pivot pin is adjusted to provide sufficient damping and tension to prevent the nose wheel from flopping over during retract or spin during heavy cross wind. We have played around testing this. A good example of self steering, retractable gear can be found on the Rutan style canard aircraft.
For retract, if there is an event where the gear is slightly cocked to one side there will be a self aligning feature incorporated into the gear doors and wheel fork to help correct - this hasn't been installed yet. Thanks for watching!
@@DarkAeroInc Thank you for the great reply. I figured you had a trick up your sleeve.
Can i know the vendor for electro mechanical actuator for landing gear actuator
Seeing that fat bundle of wires causes me to wonder: CAN Bus technology/implementation? Is it it possible and or desirable for your application?
Great job in creating a modular box-style plug and play solution, but surely a one wire set up would be more desirable, or am I missing something?
And while you’ve created a gorgeous chunk of CNC aluminum gear strut there, why not craft it from carbon fiber too?
Hey David, we do have CAN bus for most of our Garmin avionics and gear logic, but there are still a few devices that get controlled through the panel running on separate data protocols. The modular setup came about somewhat out of necessity because our instrument panel is integrated into the canopy and needed to be able to separate from the rest of the harness. The modular setup is an interesting work tradeoff since it does require extra effort to construct the connectors that run into each module, but it makes it easier to break up the work of creating the harness and allows it to be done outside the cramped spaces of the aircraft.
We are going with carbon fiber struts for our main gear, but for the nose gear it would be difficult to use the same approach. There is less space for the nose gear to fit both the strut and the shock into the same area without integrating the shock inside the strut, which led us to the design you see in the video. For the current strut design, carbon fiber is less ideal from a manufacturing standpoint since it involves parts like the trunnion that have complex geometries.
I envisioned a hybrid approach for the nose strut, that is, trunnion and upper pivot of aluminum, main strut in CF. It just seems that carving that piece out of aluminum is super expensive, time consuming, and is an exercise in re-inventing the wheel, so to speak. The cartridge design for the suspension action is very clever though.
@@DarkAeroInc I know your engine for the prototype does not have CAN Bus, but the latest version of the engine does have it. It may or may not be of use to your electrical design.
I like gears but wont you need a mechanical lock of sort to carry the torque load on ground impact. Alternatively make the gears large diameter and wide teeth, maybe symmetric in both sides so it's strong enough to carry the shocks. And how do other simple planes do this? like lancair IV
Both designs we showed have hardware to lock the gear down and react against the drag loads. The second design did not have the drag links or torque links shown in the CAD model we shared but you could see the “eyelets” on the back face of the trunnion where they interface. Lancair uses hydraulic actuation on their designs but our gear retract design and geometry is much different from a Lancair so we couldn’t reference their work.
@@DarkAeroInc ok, thanks for the answer. I prefer direct electric over hydraulic. Have you considered angling the suspension forward a bit to absorb the backward compression component? so it doesn't turn into a locking force on the sliding link.
@@DarkAeroInc or a spring steel tube gear without suspension angled backwards a bit.