As an electrical engineer and a fellow aviation fanatic, I must say awesome job so far. Helicopters are tricky to master in a perfect world, but I'm sure with the methodical and safety first mindset you have you will tame the machine with a little time. Best of luck, and God bless
I hadn't thought of it, but, as you said, the downwash into the rudder plates and tail will induce a behaviour similar to tail heaviness. But, fortunately, It seems the 5.5kg weight at the front balanced it out. Looks good! Keep up the good work!
Sweet looking build. Best wishes for success! I have one question... With the rotor tips at 400 mph or so and no pitch changing collective, can this design autorotate? I’m a fixed wing commercially licensed pilot in the US with experience in a Hughes 269 with just enough time to have learned to hover and do pirouettes along the 1000 ft markers... Flying models helped me learn, but with the slower responses of the Hughes, I had to hold the cyclic almost loosely like a pencil and anticipate each movement with the the resulting motion of the bird. Exaggerate and back off. Exaggerate and back off. And repeat. I smoothed out my control movements by the data collected and that did the trick. LOADS OF FUN!
Thanks very much for the comment, it can't autorotate so must not be flown more than a few feet. If I went to dual engines or added collective I think it would be safe to go higher. I also fly models and tried an R44 and R22 I got on better with the 44 but couldn't control the 22, I shall remember your advice on cyclic input and try it. How long would you say it took you to get used to the cyclic ?
@@Ben-Dixey Thanks! I cheated a little... I used X plane and then flew models which required exponentially smaller movements. Then I got to fly the real thing courtesy of a good friend of mine (who happens to be English) and I used the same strategy that helped me get my tailwheel endorsement years ago... Treat the cyclic like an out of balance wet mop in the palm of your hand whilst theoretically sitting on a clothes washing machine, and that makes a difference. Exaggerate within the known envelope and back off to the known center. Repeat. Once one feels out the delays and the results, try again... Kind of like pushing a shopping cart backwards... Most people hate the idea of a shopping cart moving backwards, but that really helps. It took probably about 5 minutes on the Hughes to get used to the cyclic... I have heard that the 22 is about 4 or more times harder than the 44 to learn. BTW, a slightly heavy nose feels better in the controls. Just natural if you ask me. Cheers!!!
Thank you for the advice, great stuff, makes sense. In the R44 it had hydraulic assist and I was able to use similar quick, short, sharp movements as in the models. It seemed to work but in the R22 I couldn't do that as there wasn't any hydraulics, quick movements weren't so easy. Your point about making an exaggerated input and then quickly returning sounds good. There seems to be a much more delayed response when compared to the models and the timing and magnitude needs to be learnt. Cheers
@@Ben-Dixey Cool thanks! Just be careful, and never forget that that the word “Impossible” is just “Valuable negative information” according to Robert H. Goddard... Never give up!!!
@@nagjrcjasonbower No, less is more! One of my more eye-opening lessons was during hover exercises, the instructor put both hands on the cyclic and 'froze' it...and lo and behold, the helicopter stopped moving around. Tiny, tiny finger tip adjustments is all you need.
Having a slight head-wind will actually help you achieve and hold the hover as the weather cocking effect prevents too much yawing, therefore less input on the pedals are needed, so other controls don't need to be balanced. It's actually demonstrated to students when doing their PPL. The conditions are used as an aid to the student in achieving their first hover, and also demonstrating how much hard work cross wind hovering actually is. The only other thing I could suggest to help you hover is to get some lessons in an R22, only a couple of hours worth, to help you get the feel of what control inputs are actually required. I had over 7 years of gliding experience and 1000+ hours of fixed wing before I stepped into a rotary, even though I 'knew' how to hover a helicopter, It still took be 5+ hours of practice to really be any good. I have never heard of anyone self teaching themselves how to hover, so I don't really know how much insight I can give you. But, I would say preventing dynamic rollover is your 100% PRIORITY. There have been people killed in the past in ultralights that have been cut in half from disintegrating rotor blades. If I were you I would build a light frame around the base of the aircraft that would mean that tipping is virtually impossible. This will also give you much less reticence about actually achieving a hover, because you know that whatever happens you'll land upright. Best of luck. Oliver. Commerial Pilot. 4000h fixed wing, 9500h rotary. ATPLH+A IR FI
Thanks for this Oliver, completely agree about the dynamic roll over and it's particularly a problem with fixed pitch as it takes a second for lowering the throttle to take effect. I've had half an hour in an R22 trying to hover and didn't make much progress which is to be expected in that time. If I don't feel it's safe advance past the tether stage I won't do it, making some sort of supporting frame might well be the thing to do but it's got to replicate free flight conditions to be of use. Cicare helicopters developed a gimbal type frame work which is fine for learning the reaction of pedals and collective but I can't imagine the cyclic being anything like real life which is the hardest control to master. There will be a way to do this safely. Cheers
Fuel injection gives a quicker response to throttle than standard aspiration from what I have seen on land-based vehicles. Moreso if you are using an alt fuel like propane.
To comply with the Golden Rule, the lowest rotor should be raised at least 10cm, the tilt control arms of the 'U-shaped' rotors should be spaced at least 10cm each from the center. if it also raised the upper rotor it would be even better. Already this should greatly increase the stability in my opinion
exciting, when i was a kid in the 60's there was an arcade helicopter game, it was in a large plastic bubble and the helicopter was tethered in the center, you flew around in a circle and had to touch small rods the turn lights on, you only controlled up and down, left and right, and forward and backwards, i spent all my allowance on that game lol of course you didn't die if you got it wrong.
You need some reference point in your line of forward vision, preferably near to the horizon - use this to keep the helicopter level at all times. Strongly recommend some tortional vibration monitoring with those really unforgiving belts..
@@Ben-Dixey No, it's needed because of the very rigid drive mechanism - the more rigid, the higher the resonant Q and the more violent the torque spikes. Any engine and drive type no matter how smooth will have some resonant rpm - it behooves you to find it before it finds you! If there was some very bad resonant point it will blow your false teeth out, but you will still be able to feel it through your body, it will be a mild hum building to a strong buzz or worse as you pass through it's range - you may wish to dodge through these rev ranges promptly. The only real badness can happen when it is resonant at your actual continuous operating rpm and you assume that the vibration you believe to be normal operation is actually some badly resonant mode. You might like to add some vibration monitoring gear, but likely you can see and feel it through the airframe if you are mindful of it.
Looks like the controls are loose from the cyclic to the mast assy. Look at 3:35 when you come down the mast wobbles side to side and no control input is noticed in your hand.
There is some very slight play where the rose joints are on the threaded part of the bolts rather than the shank of the bolts. I'll sort this for the next test and get all the play out. Thanks for the reminder. 👍
Could you just mount it to some swivel wheels and roll it around on a hard surface like an office chair? It might be easier to find the center that way because with the tethers you have a very narrow space to hover.
The Helitrike on TH-cam tried this and I think there was some benefit but they said the reaction was too sluggish to imitate real flight conditions. I think if I was to incorporate linear rails instead of wheels then it would work. Certainly an option to consider anyway.
You need to hold the cyclic gently, so that you can make tiny small "jab" types of continuous inputs, vs holding it firmly. Example: When the helicopter drifts to the left, you make little "jabs" on the cyclic to the right. Like you would make in punching a punching bag - moving the cyclic to the right a very slight bit and then back to the left a very little. Hovering required a continuous movement or jabs in all directions. So much so, that when you acquire the "feel", it happens without you thinking about it. If you don't, then you get into the pendulum motion which just gets worse. So, hold your cyclic very lightly almost with two or three fingers.
Question if I may? Shaft holding top rotor looks very thin in diameter? Is there so much more advantage for all the extras in dual sets of rotors? Spinning in different directions, or better for one bigger set of rotors, with calculated lift proportions?
The biggest benefit of coaxial's is that you don't need a tail rotor. Tail rotors are wasted energy that could be used for lift instead. The most efficient use of dual rotors is the chinook with minimal rotor Interference. Coaxial's are the worst for rotor Interference but they are still more efficient than a main rotor tail rotor configuration.
Great improvement in this video! Is the engine running in its rated rev range? I heard you say you had 10 to 15% power remaining at breaking ground. If it is not loaded up, is it worthwhile adjusting the pitch to generate the same lift with a greater reserve? It will be interest if the overheating is now fixed. By the way the tie downs are great but have you had a look around for some poles, preferably rigid and light such as fibreglass ? We used to do that with added foam balls on the end of the poles. One horizontally strapped to the landing gear and about 1 meter longer than the rotor arc either side and a second pole fore and aft rigged to the undercarriage. As you sort out the balance and stability of your helicopter, it prevents the poles digging into the grass and prevent pitch over whilst learning in ground effect. If you are developing only enough lift to marginally break away from the ground, remember it is like trying to balance on a soap bubble! It will tend to attempt to go in any direction if you don’t have positive control. Can you please next time run a video with the camera in line with the rotor hub from the side. I noted the left and right cyclic in this video was a bit strange and wonder if it is also affecting the fore aft pitching moment. Keep up the safety and good work. Look forward to the next one.
Hi, the engine is running around 5500rpm at lift off, it can go up to around 6500. I could increase pitch and I think it will lift more up to 7 degrees. the top rotor is at 5.3 degrees and the bottom is at 6.3 degrees. I'm not sure if increasing the pitch would make throttle response less or more sensitive. possibly less which is what might be handy so it's something I could try. The overheating won't be fixed but should allow a longer run, it's going to be a lot of modifications to get the engine cooling system up to scratch. The extended skids is certainly an option and I might go down this route. What helicopter were you testing ? Yes I will be filming a side on view next time for sure, would be interested in your thoughts. New video coming soon. 👍👍
So throttle controls engine rpm, which controls lift. I think that is what a lot of RC Helicopters do. Whereas Helicopters, R22 included, maintain a constant engine RPM and vary the pitch of the blades. Watching your video it looks like you need a course throttle to spin up the blades to 90% then a finer one for hovering and flight.
Hi, that's correct altitude is controlled by engine rpm, I did that for simplicity but at the cost of precision. A finer throttle control might be needed., and your idea of fine control of just the hovering stage would be great, I'm sure there is a way to do this.
Hi, Autorotation is not possible in this current configuration, if I added collective pitch or dual engines then it could be flown higher than the few feet I'm aiming for currently.
I would be tempted to mount a vertical T bar between the rudder pedals and tall enough to be in your line of sight which would give you a visual reference to the horizon be it the bushes or whatever is in front of you.
its gonna be tough finding the cyclic center line on the ground , but you have no choice i guess. The tethers themselves will bias the behavior as you max one out , but not the other. Be nice to have a large central tether connected to a post 5 feet into the ground..if it were center to the CG , the heli would behave as expected when in the air. ( if that makes sense
Thanks Rob, I would be quite happy to try the single central tether, I will give this some serious thought. The creator of the Helitrike on youtube said the same thing, so I'm very tempted.
Hello again btd1982. Now I'm no helicopter engineer or even any kind of engineer but I can't help thinking about how gyroscopic precession may make this coaxial helicopter without cyclic impossible. As you should well know, gyroscopic precession in simple turns delays an input 90 degrees. If you had a single rotor turning CW, you would give input to turn the mast left to go forward, forward to roll right, right to go back and back to roll left. This would apply both in the case of tilting the mask or controlling cyclic through a swash plate. Since you have two counter rotating rotors, tilting the mast forward may actually have the effect of one rotor tilting right and the other tilting left. This would also give you the feeling of unresponsiveness of the wanted effect. If sticking to fixed blades design you may have to go to twin slightly tilted intermeshing rotors to make this work.
Hi, it's something I thought too but found gyroscopic precession is cancelled out in a counter rotating system. I did a video on it. th-cam.com/video/bjbEw8VItoU/w-d-xo.html
@@Ben-Dixey The difference between your test with the wheels and your helicopter is that you're holding and applying a force to the wheels between them, whereas on your helicopter you're applying the force below both rotor discs. I also suspect that you may mistake gyroscopic stability for gyroscopic precession. If you look at all the cheap model helicopters flying on the same principle as yours, they ALL have a Bell-Hiller style flybar 45 degrees off and controlling the top rotor AOA. I will bet my farm, if I had one, that the extra cost of this flybar is not for looks but is NEEDED for this principle to work. As a final note ask yourself why there are no other helicopters, even models, flying on this simple principle. It's not because people and engineers haven't tried.
Interesting comments, thanks for bringing it up. If I understand correctly gyroscopic stability would be what keeps those gyroscopic toys from falling over when spinning and precession is the direction it moves when applying a force. Neither of these apply to my rotor it behaves as if it wasn't spinning at all. The coaxial models with a stabiliser bar I believe is like the Bell 47 and provides extra stability but isn't always necessary. Have a look at the air scooter it's very similar to mine but not like the Bensen B9. th-cam.com/video/V8zqG4LRnrE/w-d-xo.html
@@Ben-Dixey Saying that gyroscopic precession doesn't apply to your rotors is a rather large statement to make. I am simply questioning your principle from what I know about helicopters (RC control), what I see is available on the market (RC, kits and commercial) and none using your simple controls exist. AirScooter didn't amount to anything and I'm pretty sure there'd be a market for such a simple vehicle if it actually worked. Just trying to possibly save you a bunch of headache, time and money unless you can actually find proof that this principle works.
I believe it will work, the money is spent, and soon I will have the answer. I don't know but I would think the airscooter wasn't made available to the public due to not having any redundancy. No back up power plant and no collective pitch for autorotation. The main objective for this project was to test myself, see if I could make a helicopter and learn new skills ect. I haven't been able to speak to anyone involved in the projects from the past so haven't had and still don't have all the answers. Good point about the models, there is a guy who built one. th-cam.com/video/X2gcgRWOAOw/w-d-xo.html
Hi, I have a blade 400 RC helicopter and haven't really thought about how the ground effect, affects it, but it does require less power close to the ground.
@@Ben-Dixey I was with an engineer for hours one day who was trying to balance new rotor blades that he'd just adjusted on a Hughes 300 using a strobe light. Little washer weights were then put in place until they were perfectly balanced. Ironically, the tail rotor bearing then was noticed to be untrue so we shut down and found the bearing was on its way out. I jumped into it with the engine and rotors running and not doing my own walkaround check and noticed it twitching in flight so this resulted in another night out until a new bearing could be sourced
@@Ben-Dixey Yes, with the strobe light he could stop the rotors so he could see exactly how the rotors were behaving and added little washers for weight counterbalance. No vibrations at all when he had finished, just a massive bill. With a contrarotating helicopter, are the pedals controlling the upper and lower rotors separately to get the turn?
@@Ben-Dixey I’m not sure either, but it seems your method of checking CofG assumes the shaft is perfectly vertical. The horizontal bar you measure the inclination of could be horizontal and the main shaft not vertical, because of the hinge.
Let me mention one more thing In my opinion, place the water radiator cooler vertically !! The rotor wind currents hit the radiator cooler, producing torque and raising the nose.
Thanks, I do think the downwash is pushing down the tail. I wonder though if the radiator is in a high enough airflow region and if it's got enough leverage where it is to have that effect ? It wouldn't take much to move it and try.
excellent Piloting a helicopter is very difficult. You have to practice a lot and follow the safety tips Once you have the experience, piloting will be comfortable
The R22 is going to be quite a different animal to your machine, but I bet you already knew that. Lacking any collective and cyclic, I’d want my CG directly beneath the center of lift since cyclic control is to be achieved by shifting CG. It’s going to be tedious, but you’re already so close to a perfect vertical liftoff I bet we see you buzzing around your field by part 4 ;)
Please verify all your key joints are properly secured (wired, glued or something like that) and make sure your key parts are strong enough, I don't think I have seen welding applied on aircraft. The point is you want to have a vibration proof machine that's not going to come apart in the middle of the flight. Also, I think your controls are pulling too much towards the back. I read somewhere that the force applied on one quadrant of the rotor is actually shifted 90 degrees in the direction of rotation (gyroscopic effect or something) Please be careful. Good luck 👍
Thanks for this. 👍 controls are sorted now, all feeling good. I agree welding isn't often used on aircraft. Ok for a prototype I think but still not on critical parts.
I am a licensed helicopter pilot for what that’s worth. Rest your cyclic arm on your leg. Every student over controls when they are learning. The cyclic should be loose in your hand. When the muscles in your arm are tense you can’t make the fine motor movements necessary to control your beast. Do you have a throttle correlator connected to your collective? Do you have a governor to maintain constant rotor rpm? Every modern helicopter has at least one and in the case of Robinson both. It would be really helpful to get someone that knows how to fly to try to hover your baby. Good luck, be safe.
Hi, thanks for the comment and great advice I will try that next time👍 You might be surprised to hear that this helicopter hasn't got collective pitch, the blades are fixed and altitude is controlled by rotor speed. There is still what's considered cyclic pitch control but this isn't achieved by cyclic feathering, the mast tilts as a whole instead. I've considered getting a helicopter Pilot to try it but this is not a conventional setup and it might handle quite differently. There's certainly a time delay when reducing rotor speed in order to reduce lift which I don't believe is similar to collective pitch control.
It's not the cc that matters, it's the Hp. However my engine is 737cc and 60hp , your 300cc engine is likely to be around 25-30hp. It's possible to get airborne in an ultralight helicopter with 40hp but any less and it's increasingly unlikely.
I would suggest making a smaller model. You can do this with very little money and learn an awful lot. Then when you are financially ready make a full size version. I would suggest using a 60hp engine for a full scale helicopter.
no actual knowledge in aviation or engineering.. i wonder if a small counter weight on the rotors might act as a gyro and keep the blades level while giving you move feedback in the control stick? watching with interest! Brad
Interesting thought. I think what might happen is if the rotor had some gyroscopic stability the machine would become a weight shift design. The rotor stays still and frame moves on the hinges. At the moment i believe it's more of a tilt rotor but it could be a combination of the two. All gets a bit confusing, I'm looking forward to coming to some conclusions over the testing period.
Hi, have a look at part 2, I think it's the downwash of the rotor pushing down on the tail more than the nose? th-cam.com/video/4JNiHFk0qdg/w-d-xo.html
I decided to keep things simple. collective or dual engines could be a future addition. In the current configuration it won't be flown higher than a few feet.
@@Ben-Dixey but how you make thrust, there is some angle that blades hit air ? then how you change direction you change angle of craft similar to gyrocopter ?
@@Ben-Dixey just one thing, controlling movement by throttle is more difficult then with variable angle of blades, anyway I like the design, what engine you used ?
Holy crap it just dawned on me that you cant autorotate. No collective 😬. Doesn’t this mean the first time your engine hiccups (And it surely will as a human made machine) that you will lose some lift control and ball it up? I am admiring your work and i hate being a nancy but yeah this seems to be exceptionally risky.
you are correct, this machine must be used responsibly, hovering a few feet only. However collective might not save you at low altitudes with no forward speed. Helicopters must avoid operation in the dead mans curve.
@@Ben-Dixey Thank you for not biting my head off and I'm glad you understand this and it sounds like you have learned some of the Helicopter caveats. Some of your milled and machined parts sound look sooo good. I love seeing fresh machined parts. I can gawk for hours.
Cheers for that. 👍 it's quite nice working with aluminium, pretty quick to machine and it can be polished to a mirror finish if you wanted. Though I'm glad I built this before all the prices went up. I wanted some lighter tubing for extended skids and it was going to cost me £100 for two lengths. I haven't bought any aluminium for quite a while but reckon the price has doubled. ☹️
Furst of all you shoud take to long steel pipe inflation in a net underneath your skin just wait help preventing you from tipping sideways they do this on remote control helicopters when you're learning to fly and second maybe you need an adjustment on your linkages
Oh my god. Mate you need to watch the video of another homebuilt helo killing it’s would-be engineer/pilot. It’s not worth it, you’re wasting money and risking your life!
I've seen the video you're on about, he was vey unlucky to have that outcome, it was caused by a tail rotor separation. This sort of failure will not happen if the maths has been done on the centrifugal loads and adding a large safety factor. I have done my homework on this.
As an electrical engineer and a fellow aviation fanatic, I must say awesome job so far. Helicopters are tricky to master in a perfect world, but I'm sure with the methodical and safety first mindset you have you will tame the machine with a little time. Best of luck, and God bless
Thank you for the kind words 👍👍
Love your "let's do it!" attitude
Starting out with trying to hover an experimental aircraft, that does take a set of big balls 👍👍
I hadn't thought of it, but, as you said, the downwash into the rudder plates and tail will induce a behaviour similar to tail heaviness. But, fortunately, It seems the 5.5kg weight at the front balanced it out. Looks good! Keep up the good work!
Sweet looking build. Best wishes for success! I have one question... With the rotor tips at 400 mph or so and no pitch changing collective, can this design autorotate? I’m a fixed wing commercially licensed pilot in the US with experience in a Hughes 269 with just enough time to have learned to hover and do pirouettes along the 1000 ft markers... Flying models helped me learn, but with the slower responses of the Hughes, I had to hold the cyclic almost loosely like a pencil and anticipate each movement with the the resulting motion of the bird. Exaggerate and back off. Exaggerate and back off. And repeat. I smoothed out my control movements by the data collected and that did the trick. LOADS OF FUN!
Thanks very much for the comment, it can't autorotate so must not be flown more than a few feet. If I went to dual engines or added collective I think it would be safe to go higher. I also fly models and tried an R44 and R22 I got on better with the 44 but couldn't control the 22, I shall remember your advice on cyclic input and try it. How long would you say it took you to get used to the cyclic ?
@@Ben-Dixey Thanks! I cheated a little... I used X plane and then flew models which required exponentially smaller movements. Then I got to fly the real thing courtesy of a good friend of mine (who happens to be English) and I used the same strategy that helped me get my tailwheel endorsement years ago... Treat the cyclic like an out of balance wet mop in the palm of your hand whilst theoretically sitting on a clothes washing machine, and that makes a difference. Exaggerate within the known envelope and back off to the known center. Repeat. Once one feels out the delays and the results, try again... Kind of like pushing a shopping cart backwards... Most people hate the idea of a shopping cart moving backwards, but that really helps. It took probably about 5 minutes on the Hughes to get used to the cyclic... I have heard that the 22 is about 4 or more times harder than the 44 to learn. BTW, a slightly heavy nose feels better in the controls. Just natural if you ask me. Cheers!!!
Thank you for the advice, great stuff, makes sense. In the R44 it had hydraulic assist and I was able to use similar quick, short, sharp movements as in the models. It seemed to work but in the R22 I couldn't do that as there wasn't any hydraulics, quick movements weren't so easy. Your point about making an exaggerated input and then quickly returning sounds good. There seems to be a much more delayed response when compared to the models and the timing and magnitude needs to be learnt. Cheers
@@Ben-Dixey Cool thanks! Just be careful, and never forget that that the word “Impossible” is just “Valuable negative information” according to Robert H. Goddard... Never give up!!!
@@nagjrcjasonbower No, less is more! One of my more eye-opening lessons was during hover exercises, the instructor put both hands on the cyclic and 'froze' it...and lo and behold, the helicopter stopped moving around. Tiny, tiny finger tip adjustments is all you need.
Having a slight head-wind will actually help you achieve and hold the hover as the weather cocking effect prevents too much yawing, therefore less input on the pedals are needed, so other controls don't need to be balanced. It's actually demonstrated to students when doing their PPL. The conditions are used as an aid to the student in achieving their first hover, and also demonstrating how much hard work cross wind hovering actually is.
The only other thing I could suggest to help you hover is to get some lessons in an R22, only a couple of hours worth, to help you get the feel of what control inputs are actually required. I had over 7 years of gliding experience and 1000+ hours of fixed wing before I stepped into a rotary, even though I 'knew' how to hover a helicopter, It still took be 5+ hours of practice to really be any good.
I have never heard of anyone self teaching themselves how to hover, so I don't really know how much insight I can give you. But, I would say preventing dynamic rollover is your 100% PRIORITY. There have been people killed in the past in ultralights that have been cut in half from disintegrating rotor blades. If I were you I would build a light frame around the base of the aircraft that would mean that tipping is virtually impossible. This will also give you much less reticence about actually achieving a hover, because you know that whatever happens you'll land upright. Best of luck. Oliver. Commerial Pilot. 4000h fixed wing, 9500h rotary. ATPLH+A IR FI
Thanks for this Oliver, completely agree about the dynamic roll over and it's particularly a problem with fixed pitch as it takes a second for lowering the throttle to take effect. I've had half an hour in an R22 trying to hover and didn't make much progress which is to be expected in that time. If I don't feel it's safe advance past the tether stage I won't do it, making some sort of supporting frame might well be the thing to do but it's got to replicate free flight conditions to be of use. Cicare helicopters developed a gimbal type frame work which is fine for learning the reaction of pedals and collective but I can't imagine the cyclic being anything like real life which is the hardest control to master. There will be a way to do this safely. Cheers
Fuel injection gives a quicker response to throttle than standard aspiration from what I have seen on land-based vehicles. Moreso if you are using an alt fuel like propane.
Nice to see someone applying logic, incremental steps, and gaining knowledge along the way.
Thank you 👍
To comply with the Golden Rule, the lowest rotor should be raised at least 10cm, the tilt control arms of the 'U-shaped' rotors should be spaced at least 10cm each from the center. if it also raised the upper rotor it would be even better. Already this should greatly increase the stability in my opinion
🔎🤔انو ممتاز ياصديق انكم تشجعون الشخص عكس العرب انهم يدمرون فقط
exciting, when i was a kid in the 60's there was an arcade helicopter game, it was in a large plastic bubble and the helicopter was tethered in the center, you flew around in a circle and had to touch small rods the turn lights on, you only controlled up and down, left and right, and forward and backwards, i spent all my allowance on that game lol of course you didn't die if you got it wrong.
I can fly an Apache all day long in the sim. IRL though, I'd sht myself long before that!
Midways Whirleybird. Spent many quarters on that game
You need some reference point in your line of forward vision, preferably near to the horizon - use this to keep the helicopter level at all times. Strongly recommend some tortional vibration monitoring with those really unforgiving belts..
The torsional vibration monitoring is needed because of the engine torque spikes ? What's the best method of measurement ?
@@Ben-Dixey No, it's needed because of the very rigid drive mechanism - the more rigid, the higher the resonant Q and the more violent the torque spikes. Any engine and drive type no matter how smooth will have some resonant rpm - it behooves you to find it before it finds you! If there was some very bad resonant point it will blow your false teeth out, but you will still be able to feel it through your body, it will be a mild hum building to a strong buzz or worse as you pass through it's range - you may wish to dodge through these rev ranges promptly. The only real badness can happen when it is resonant at your actual continuous operating rpm and you assume that the vibration you believe to be normal operation is actually some badly resonant mode. You might like to add some vibration monitoring gear, but likely you can see and feel it through the airframe if you are mindful of it.
Thanks for the information I wasn't aware of resonance in belt drives. I'm glad I installed the flexible drive coupling I'm sure it is helping.
Looks like the controls are loose from the cyclic to the mast assy. Look at 3:35 when you come down the mast wobbles side to side and no control input is noticed in your hand.
There is some very slight play where the rose joints are on the threaded part of the bolts rather than the shank of the bolts. I'll sort this for the next test and get all the play out. Thanks for the reminder. 👍
Hello from Mauritius! That is awesome! Looking forward to watching you take flight successfully! All the best! #subbed
Thank you 👍
Could you just mount it to some swivel wheels and roll it around on a hard surface like an office chair? It might be easier to find the center that way because with the tethers you have a very narrow space to hover.
The Helitrike on TH-cam tried this and I think there was some benefit but they said the reaction was too sluggish to imitate real flight conditions. I think if I was to incorporate linear rails instead of wheels then it would work. Certainly an option to consider anyway.
You need to hold the cyclic gently, so that you can make tiny small "jab" types of continuous inputs, vs holding it firmly. Example: When the helicopter drifts to the left, you make little "jabs" on the cyclic to the right. Like you would make in punching a punching bag - moving the cyclic to the right a very slight bit and then back to the left a very little. Hovering required a continuous movement or jabs in all directions. So much so, that when you acquire the "feel", it happens without you thinking about it. If you don't, then you get into the pendulum motion which just gets worse. So, hold your cyclic very lightly almost with two or three fingers.
Thanks and I agree. Here is an up to date video.
th-cam.com/video/4wNnU3swb94/w-d-xo.html
Question if I may? Shaft holding top rotor looks very thin in diameter? Is there so much more advantage for all the extras in dual sets of rotors? Spinning in different directions, or better for one bigger set of rotors, with calculated lift proportions?
The biggest benefit of coaxial's is that you don't need a tail rotor. Tail rotors are wasted energy that could be used for lift instead. The most efficient use of dual rotors is the chinook with minimal rotor Interference. Coaxial's are the worst for rotor Interference but they are still more efficient than a main rotor tail rotor configuration.
Not only are you building a complex flying machine your learning to fly it at the same time, not an easy task to say the least. Stay safe..
10 seconds into your video my wife reads the title and says “No.” Good luck and stay safe as I live vicariously through you.
😂
Great improvement in this video! Is the engine running in its rated rev range? I heard you say you had 10 to 15% power remaining at breaking ground. If it is not loaded up, is it worthwhile adjusting the pitch to generate the same lift with a greater reserve? It will be interest if the overheating is now fixed. By the way the tie downs are great but have you had a look around for some poles, preferably rigid and light such as fibreglass ? We used to do that with added foam balls on the end of the poles. One horizontally strapped to the landing gear and about 1 meter longer than the rotor arc either side and a second pole fore and aft rigged to the undercarriage. As you sort out the balance and stability of your helicopter, it prevents the poles digging into the grass and prevent pitch over whilst learning in ground effect. If you are developing only enough lift to marginally break away from the ground, remember it is like trying to balance on a soap bubble! It will tend to attempt to go in any direction if you don’t have positive control. Can you please next time run a video with the camera in line with the rotor hub from the side. I noted the left and right cyclic in this video was a bit strange and wonder if it is also affecting the fore aft pitching moment. Keep up the safety and good work. Look forward to the next one.
Hi, the engine is running around 5500rpm at lift off, it can go up to around 6500. I could increase pitch and I think it will lift more up to 7 degrees. the top rotor is at 5.3 degrees and the bottom is at 6.3 degrees. I'm not sure if increasing the pitch would make throttle response less or more sensitive. possibly less which is what might be handy so it's something I could try. The overheating won't be fixed but should allow a longer run, it's going to be a lot of modifications to get the engine cooling system up to scratch. The extended skids is certainly an option and I might go down this route. What helicopter were you testing ? Yes I will be filming a side on view next time for sure, would be interested in your thoughts. New video coming soon. 👍👍
So throttle controls engine rpm, which controls lift. I think that is what a lot of RC Helicopters do. Whereas Helicopters, R22 included, maintain a constant engine RPM and vary the pitch of the blades.
Watching your video it looks like you need a course throttle to spin up the blades to 90% then a finer one for hovering and flight.
Hi, that's correct altitude is controlled by engine rpm, I did that for simplicity but at the cost of precision. A finer throttle control might be needed., and your idea of fine control of just the hovering stage would be great, I'm sure there is a way to do this.
Is an autorotation possible with this craft? If not, what are the procedures in an engine out emergancy?
Hi, Autorotation is not possible in this current configuration, if I added collective pitch or dual engines then it could be flown higher than the few feet I'm aiming for currently.
I would be tempted to mount a vertical T bar between the rudder pedals and tall enough to be in your line of sight which would give you a visual reference to the horizon be it the bushes or whatever is in front of you.
Good idea 👍 thanks
its gonna be tough finding the cyclic center line on the ground , but you have no choice i guess. The tethers themselves will bias the behavior as you max one out , but not the other. Be nice to have a large central tether connected to a post 5 feet into the ground..if it were center to the CG , the heli would behave as expected when in the air. ( if that makes sense
Thanks Rob, I would be quite happy to try the single central tether, I will give this some serious thought. The creator of the Helitrike on youtube said the same thing, so I'm very tempted.
Looks like you turned over the cooling fan....wont that make the fan inefficient?
I've read that a fan pulling through the radiator is more efficient until you have more than a two core radiator, then you need to push air through.
It could be that the weight of the rotor drive mechanism is making the rotor tilt backwards?
Not something I had thought of, certainly worth investigating. Cheers
Hello again btd1982. Now I'm no helicopter engineer or even any kind of engineer but I can't help thinking about how gyroscopic precession may make this coaxial helicopter without cyclic impossible. As you should well know, gyroscopic precession in simple turns delays an input 90 degrees. If you had a single rotor turning CW, you would give input to turn the mast left to go forward, forward to roll right, right to go back and back to roll left. This would apply both in the case of tilting the mask or controlling cyclic through a swash plate. Since you have two counter rotating rotors, tilting the mast forward may actually have the effect of one rotor tilting right and the other tilting left. This would also give you the feeling of unresponsiveness of the wanted effect. If sticking to fixed blades design you may have to go to twin slightly tilted intermeshing rotors to make this work.
Hi, it's something I thought too but found gyroscopic precession is cancelled out in a counter rotating system. I did a video on it.
th-cam.com/video/bjbEw8VItoU/w-d-xo.html
@@Ben-Dixey The difference between your test with the wheels and your helicopter is that you're holding and applying a force to the wheels between them, whereas on your helicopter you're applying the force below both rotor discs. I also suspect that you may mistake gyroscopic stability for gyroscopic precession. If you look at all the cheap model helicopters flying on the same principle as yours, they ALL have a Bell-Hiller style flybar 45 degrees off and controlling the top rotor AOA. I will bet my farm, if I had one, that the extra cost of this flybar is not for looks but is NEEDED for this principle to work. As a final note ask yourself why there are no other helicopters, even models, flying on this simple principle. It's not because people and engineers haven't tried.
Interesting comments, thanks for bringing it up. If I understand correctly gyroscopic stability would be what keeps those gyroscopic toys from falling over when spinning and precession is the direction it moves when applying a force. Neither of these apply to my rotor it behaves as if it wasn't spinning at all. The coaxial models with a stabiliser bar I believe is like the Bell 47 and provides extra stability but isn't always necessary. Have a look at the air scooter it's very similar to mine but not like the Bensen B9. th-cam.com/video/V8zqG4LRnrE/w-d-xo.html
@@Ben-Dixey Saying that gyroscopic precession doesn't apply to your rotors is a rather large statement to make. I am simply questioning your principle from what I know about helicopters (RC control), what I see is available on the market (RC, kits and commercial) and none using your simple controls exist. AirScooter didn't amount to anything and I'm pretty sure there'd be a market for such a simple vehicle if it actually worked. Just trying to possibly save you a bunch of headache, time and money unless you can actually find proof that this principle works.
I believe it will work, the money is spent, and soon I will have the answer. I don't know but I would think the airscooter wasn't made available to the public due to not having any redundancy. No back up power plant and no collective pitch for autorotation. The main objective for this project was to test myself, see if I could make a helicopter and learn new skills ect. I haven't been able to speak to anyone involved in the projects from the past so haven't had and still don't have all the answers. Good point about the models, there is a guy who built one.
th-cam.com/video/X2gcgRWOAOw/w-d-xo.html
Things are going to change again once you get the helicopter out of ground effect. Do you have any time with a model helicopter?
Hi, I have a blade 400 RC helicopter and haven't really thought about how the ground effect, affects it, but it does require less power close to the ground.
The whole rotor head looks like it could do with a better bearing as its all moving
The whole mast tilts for control not like a conventional helicopter.
@@Ben-Dixey Have a look at this one. th-cam.com/video/nfvm_77JeOA/w-d-xo.html
@@Ben-Dixey I was with an engineer for hours one day who was trying to balance new rotor blades that he'd just adjusted on a Hughes 300 using a strobe light. Little washer weights were then put in place until they were perfectly balanced. Ironically, the tail rotor bearing then was noticed to be untrue so we shut down and found the bearing was on its way out. I jumped into it with the engine and rotors running and not doing my own walkaround check and noticed it twitching in flight so this resulted in another night out until a new bearing could be sourced
Interesting, was the strobe being used for tracking ? Then dynamic balancing equipment?
@@Ben-Dixey Yes, with the strobe light he could stop the rotors so he could see exactly how the rotors were behaving and added little washers for weight counterbalance. No vibrations at all when he had finished, just a massive bill. With a contrarotating helicopter, are the pedals controlling the upper and lower rotors separately to get the turn?
if you look at other home build ultralight helis they always seem to have trouble with tail rotor authority, maybe this is the way to go.
Yes I really don't like tail rotors, they are trouble. Yaw authority on this machine seems good so far.
When you hang the helicopter as you showed, is the main shaft perfectly vertical?
umm Not sure, I'll check next time. I would assume it would always be vertical as it's hinged?
@@Ben-Dixey I’m not sure either, but it seems your method of checking CofG assumes the shaft is perfectly vertical. The horizontal bar you measure the inclination of could be horizontal and the main shaft not vertical, because of the hinge.
I'll put the inclinometer on the shaft next and check what it's doing. Thanks 👍
Yoo you was born in 82? we are the 2nd year millennials what month was you born and sweet copter though ultralight?
Let me mention one more thing
In my opinion, place the water radiator cooler vertically !!
The rotor wind currents hit the radiator cooler, producing torque and raising the nose.
Thanks, I do think the downwash is pushing down the tail. I wonder though if the radiator is in a high enough airflow region and if it's got enough leverage where it is to have that effect ? It wouldn't take much to move it and try.
@@Ben-Dixey Practice now to find out the features and drawbacks of the helicopter over time
It sould be install a swash plat to control siclic and colectiv control
Hi, It doesn't need a swash plate.
Can't wait for part 3, stay safe 👍
Looks to me that the rotors are to short
excellent
Piloting a helicopter is very difficult.
You have to practice a lot and follow the safety tips
Once you have the experience, piloting will be comfortable
The R22 is going to be quite a different animal to your machine, but I bet you already knew that. Lacking any collective and cyclic, I’d want my CG directly beneath the center of lift since cyclic control is to be achieved by shifting CG. It’s going to be tedious, but you’re already so close to a perfect vertical liftoff I bet we see you buzzing around your field by part 4 ;)
Great points thanks, Love the optimism 👍
Please verify all your key joints are properly secured (wired, glued or something like that) and make sure your key parts are strong enough, I don't think I have seen welding applied on aircraft. The point is you want to have a vibration proof machine that's not going to come apart in the middle of the flight.
Also, I think your controls are pulling too much towards the back. I read somewhere that the force applied on one quadrant of the rotor is actually shifted 90 degrees in the direction of rotation (gyroscopic effect or something)
Please be careful.
Good luck 👍
Thanks for this. 👍 controls are sorted now, all feeling good. I agree welding isn't often used on aircraft. Ok for a prototype I think but still not on critical parts.
Great video, just need a tad longer!
Thanks 👍
I am a licensed helicopter pilot for what that’s worth. Rest your cyclic arm on your leg. Every student over controls when they are learning. The cyclic should be loose in your hand. When the muscles in your arm are tense you can’t make the fine motor movements necessary to control your beast. Do you have a throttle correlator connected to your collective? Do you have a governor to maintain constant rotor rpm? Every modern helicopter has at least one and in the case of Robinson both. It would be really helpful to get someone that knows how to fly to try to hover your baby. Good luck, be safe.
Hi, thanks for the comment and great advice I will try that next time👍
You might be surprised to hear that this helicopter hasn't got collective pitch, the blades are fixed and altitude is controlled by rotor speed. There is still what's considered cyclic pitch control but this isn't achieved by cyclic feathering, the mast tilts as a whole instead. I've considered getting a helicopter Pilot to try it but this is not a conventional setup and it might handle quite differently. There's certainly a time delay when reducing rotor speed in order to reduce lift which I don't believe is similar to collective pitch control.
Eager to see how it all goes SUBBED 👍
Great Job.
Can a 300cc motorcycle engine work on a ultralight helcopter.
It's not the cc that matters, it's the Hp. However my engine is 737cc and 60hp , your 300cc engine is likely to be around 25-30hp. It's possible to get airborne in an ultralight helicopter with 40hp but any less and it's increasingly unlikely.
Can a 40 HP motorcycle engine lift an ultralight helcopter.
Iam very much interested in making my homemade ultralight helcopter but I don't have money right now.
I would suggest making a smaller model. You can do this with very little money and learn an awful lot. Then when you are financially ready make a full size version. I would suggest using a 60hp engine for a full scale helicopter.
Good luck 👍
no actual knowledge in aviation or engineering.. i wonder if a small counter weight on the rotors might act as a gyro and keep the blades level while giving you move feedback in the control stick? watching with interest! Brad
Interesting thought. I think what might happen is if the rotor had some gyroscopic stability the machine would become a weight shift design. The rotor stays still and frame moves on the hinges. At the moment i believe it's more of a tilt rotor but it could be a combination of the two. All gets a bit confusing, I'm looking forward to coming to some conclusions over the testing period.
@@Ben-Dixey keep it up! coming along great
Thx for share
your right arm needs to rest on your right thigh,,, a pivot point for small changes,,,,, ultimately just alot of wrist movements
Thanks, I've put this into practise on the latest video and agree it certainly helps. 👍
Mmmm me parece que tienes un problema con el centro de gravedad
Hi, have a look at part 2, I think it's the downwash of the rotor pushing down on the tail more than the nose?
th-cam.com/video/4JNiHFk0qdg/w-d-xo.html
you must have collective meaning angle of propeller blades must be adjustable to fly ....
I decided to keep things simple. collective or dual engines could be a future addition. In the current configuration it won't be flown higher than a few feet.
@@Ben-Dixey but how you make thrust, there is some angle that blades hit air ? then how you change direction you change angle of craft similar to gyrocopter ?
That's correct. The mast tilts like a gyro copter. The blades are set at the correct lift angle and the speed is increased until it lifts off.
@@Ben-Dixey just one thing, controlling movement by throttle is more difficult then with variable angle of blades, anyway I like the design, what engine you used ?
Yes, I think that's true, I used a Johnson 60hp 2 stroke outboard engine.
Holy crap it just dawned on me that you cant autorotate. No collective 😬. Doesn’t this mean the first time your engine hiccups (And it surely will as a human made machine) that you will lose some lift control and ball it up? I am admiring your work and i hate being a nancy but yeah this seems to be exceptionally risky.
you are correct, this machine must be used responsibly, hovering a few feet only. However collective might not save you at low altitudes with no forward speed. Helicopters must avoid operation in the dead mans curve.
@@Ben-Dixey Thank you for not biting my head off and I'm glad you understand this and it sounds like you have learned some of the Helicopter caveats. Some of your milled and machined parts sound look sooo good. I love seeing fresh machined parts. I can gawk for hours.
Cheers for that. 👍 it's quite nice working with aluminium, pretty quick to machine and it can be polished to a mirror finish if you wanted. Though I'm glad I built this before all the prices went up. I wanted some lighter tubing for extended skids and it was going to cost me £100 for two lengths. I haven't bought any aluminium for quite a while but reckon the price has doubled. ☹️
You need to rest your forearm on the top of your leg. Using a stiff arm will make you move the control to much.
Ahh yes, I remember reading that advice, thanks 👍
جيد
Please don't blast the music louder than your voice. It almost blew my eardrums out 😛.
My apologies. Was it the music at the end?
Checkout Donny watts generator, Patrick Kelly channel, heli s r ridiculous ly complicated, just build a gyrocopter
Gyro's are fine but need a runway. It was hovering that I wanted to do.
Furst of all you shoud take to long steel pipe inflation in a net underneath your skin just wait help preventing you from tipping sideways they do this on remote control helicopters when you're learning to fly and second maybe you need an adjustment on your linkages
Yes, extended skids is definitely an option and I will probably try it. 👍
Otra vez no te basto lok te emvie
Oh my god. Mate you need to watch the video of another homebuilt helo killing it’s would-be engineer/pilot. It’s not worth it, you’re wasting money and risking your life!
I've seen the video you're on about, he was vey unlucky to have that outcome, it was caused by a tail rotor separation. This sort of failure will not happen if the maths has been done on the centrifugal loads and adding a large safety factor. I have done my homework on this.
You're relaxing into this all now, great stuff!! 👍👌 Oh, and I'd say you have a mole problem in your garden!!! Ha ha!