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New VTOL concept - Hybrid Airplane/tricopter

#1
Hi guys,

I think I invented a new model of VTOL airplane. Correct me if I'm wrong!

It's made of blue insulation foam with the hot wire cutting technic.

2013-09-28 08.56.56.jpg

My main goal was to create a model easy to fly without any tilting parts (wings and/or rotors) like are the "Osprey", "AW609" and many others. These are heavier and very delicate to control.

My configuration brings the air flows of the props away from the wing and elevator to not create turbulence and therby a lost of lift.

pogl018small.jpg

On horizontal flight, at about 20-25 km/h, the vertical thrust vector is not needed anymore and the motors slows. Wich is the opposite with a standard multicopter. Giving my model a much better autonomy.

I don't like the way helicopters and multicopters flies and I prefer a lot to glide like a bird. But I was facinated since a long time about the possibility to takeoff and land verticaly. I did it !

I'm now tuning it. Only 4 flights done but great feeling yet. I cannot wait to put my FPV system on it...

You can see it fly in this video.

https://www.youtube.com/watch?v=5qKHUme6ZVY

Pat
 
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Craftydan

Hostage Taker of Quads
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#2
Interesting design!

How do your flight times and throttle levels compare (hover vs. forward flight)?
 
#3
I'm a little over 50% for hovering and about 25% in forward flight. I flew only at 4 occasions because of the bad weather... I will post more infos when I'll have it.
 

Craftydan

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#4
Most Vtols I've seen tilt the rotors. This is the first I've seen someone tilt the plane. A very elegant solution!

What angle of incidence are you using?
 
#5
By looking at multicopter videos, like David's first tricopter, I estimated that 25 deg. would be a good guess. I needed as much of the horizontal thrust vector as possible once forward flight.

Like an helicopter, it's needless to bring the rotors completly down. I also understood that the flight speed would be limited.
 

Craftydan

Hostage Taker of Quads
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#6
I'm wondering, if you mounted a flying wing at 90 degrees to a quad, and switched to acro would you need any control surfaces at all? once the platform is rotated, pitch, elevator and rudder can be accomplished by thrust vectoring built into the quad.

The only issue is after the transition, the rudder and elevator functions would be swapped -- in "forward", rudder would be run by left/right and roll by torque differential. I imagine that swaping channels could be automated in a nasty set of mixes, or a custom rom like openaero. you'd now have to balance CG in three diminsions, but that's doable.

Of course then you'd have no control in a glide . . .

If nothing else, Pat, you've got me thinking in different directions!
 

themajik1

Monkey/Bear Poker
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#7
Very cool concept! From what I could see in the video, it appears to fly very well. Looking forward to update on this one for sure!

Nice work!!!
 
#8
Your idea is very close to the "Quadshot" from Transition Robotic and also remind me those tail siter models. Transitions are for those very tricky and makes cameras and FPVs system complicated to mount (also need to tilt 90deg.).

My configuration give very smooth transitions. You fly around, sneaking the paysage and by a flip of a switch (engaging self-level mode) you stop slowly, take a pic, switch again and continue your way.

In my video, when I switch back to self-level, I lose a lot of altitude because I didn't had the reflex to gain up my throttle. Since it was slowed in forward flight...
 

Craftydan

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#9
Now that you mention it , I suppose you're right. Didn't particularly care for the quadshot's lines anyhow -- too much of the worst of each, even if it can fly well.

I agree ths appears to be a much more fluid in the transitions becasue it's not really changing flight modes as much as trading between wing and rotor lift.

I wonder if you could tie the throttle scaling to the mode change. Switch off SL and the craft would be allowed to lean forward, but the throttle scaling would slowly drop by 1/2. Switch back, it automatically pulls back but the thrust slowly scales back up to compensate. Tricky to program smooth mode changes though -- easier just to move the sticks.
 
#12
I'm been thinking about building something like this but have been puzzling over the controls. My ideal solution would be an onboard system that transitions from quadcopter control to airplane control once a certain airspeed is achieved. Anyone know how this one works?

This one is my favorite. And not JUST because it uses the Bixler.

 
#13
Hi ST,

You are at the right place. This model "a largely modify Bixler" is a very nice and working model made by Ran D. St-Clair. Here is another link to see more,

https://www.youtube.com/watch?v=UyVF0xCNMos#t=46

Using "Y" arness, between the Rx an the KK2 flight controler board, you can send the signals both to the flight controler for hovering assistance and to the flight control surfaces for horizontal flight. There is many different firmware for the KK2 board. I suppose that this Bixler was flying with the OpenAero2.

The actual problem is to be able to disengage the stabilisation inputs from the flight controler (kk2) once in horizontal flight. I'm not a pro in this but this is where I am now. HappySundays (the OpenAero firmware father) is now working on an evoluted version of the OpenAero firmware specialy for VTOL models, the "OpenAero VTOL".

See this tread for more infos.

http://www.rcgroups.com/forums/showthread.php?t=1972686&highlight=openaero+vtol
 

Cyberdactyl

Misfit Multirotor Monkey
#15
Very cool Pat. :D

I'm curious, are the front wings fixed and pitched up to provide lift for a predetermined forward speed? Or can the wing change pitch? It's hard to tell from the video?
 
#16
Very cool Pat. :D

I'm curious, are the front wings fixed and pitched up to provide lift for a predetermined forward speed? Or can the wing change pitch? It's hard to tell from the video?
Thanks Cyberdactyl,

Wing tips and the tail are fixed at about 15 deg. Of course this is a limitation in speed but my main goal was to stabilyse the model and to give it a certain plane like behavior. It's working pretty well. Easy to build, to fly and lite. One of my best untill now ;)
 
#17
I really liked your first concept with the full wings. I am inspired to build something like your first concept, but was curious why you decided to cut away the wings? Is there an advantage to the cut away design (wing tips only) over the original full wing design? I love flying the tricopter and I like slow flying airplanes and having been dreaming how to merge the two.
 

stay-fun

Helicopter addict
#18
Wow this is an interesting concept! I wonder if you now added a 'glide slope' to your multirotor! That means, what if you have forward speed, kill the motors and see if you can land it in a glide. That'd be awesome!
 
#19
POGL 019 - to be built

Hi gsgraber92,

I've been doing the same dream and I'm close to it. My first full wing (pogl 018) was great but I had two power failures (because of my cheap RCtTimer motors I suspected) and the second failure destroyed it. I tried a free fall (to glide) and it did it but the motors never restart and I landed to roughly in a crusty snow bank... It glided heavily like a full loaded war bird.

Why did I cut away the wings? Because the global behaviour was not perfect at all. It was more than good in hovering mode (super stable and easy to fly) but very very limited in horizontal flight. Limited by the fixed angle of the flight surfaces (at about 15°). It was very easy to do the transitions but once in horizontal flight it was for example not easy to gain altitude. The flight controler (kk2 v1.2) was by itself working against the wings, leveling the model. This problem could have certainly been resolved with a better FC settings but I didn't had the time to try any more configurations.

So, before to rebuilt a new full wing design, I decided to experiment a less agressive one closer to the tricopter with a small wing (wing tips and small tail) for stability and it works very well. Forget about gliding with this config but what a feeling. It's softening all the throttle input making you feel like being hook to a rubber band. This model is a hit every where I flew it.

Finally, I draw a second full wing model because I realy want to accomplish my dream and do a perfect glide "with" a VTOL. My wings are still at 15° to soften the transitions but one of the motor (aft one) will have to tilt to become a pusher and the two front motors will have to stop in horizontal flight. I'll certainly flash my KK2 with the Openaero VTOL software to accomplish this. A lot of settings to come. Here are the drawings:

019 plan.JPG 019 prof.JPG

I hope this help and answers your questionings. My strange syntax is my french heritage :)