Arducopter Flies Gas Powered Helicopter


Now we're cooking with gas!

I have just completed a project to build a helicopter with a gasoline engine, controlled by Arducopter (of course!)  This helicopter serves as a test bed for future gas heli development work for a client of mine.  The goal was to prove out that it could be done.  Gas engines pose a unique challenge for Arducopter due to the heavy vibration they produce.  But they also present a lot of promise for UAV applications as it can allow heavy payloads, long duration flight, and high speeds.


The heli is based on a Helix Heli conversion of a Trex 700.  However I stretched it to 800, used many aftermarket upgrades such as from KDE, and machined a number of custom parts myself.  The machine required quite a bit of customization in order to increase frame stiffness which is important for vibration reduction.  The engine is a Zenoah G29RC engine with pull start.  This is an increased displacement 23cc engine, which makes more power but creates more vibration than the G23.  I could have purchased an aftermarket balanced engine, but I wanted to use COTS parts and also prove the Pixhawk can survive with a worst-case engine.  

Last night I performed the first check flights of the new machine and began PID tuning.  This is one segment of that flight where I was working on the PIDs.

Today I finished the PID tuning, and it is flying very well indeed.  After increasing rotor speed to ~1600rpm and tracking in the blades, the vibrations on the Pixhawk are quite good, better than both of my quads:


I flew it around a bit in Stabilize, and hit 30 m/s without really trying.  It should easily be capable of 40 m/s flight speeds.  I'm hoping for a 10 kg payload capacity. Flight time is currently better than 20 minutes with plenty of reserve on a 630cc tank.  I will probably begin development on a larger fuel tank system on the order of about 2L which should allow for 1 hour of flight time with payload.  Currently the 2S 4400mAH avionics battery lasts for at least an hour, but will be supplemented with an on-board generator.

Later today, I will start working on auto missions and will shoot another video.  

The success of this project opens up an entirely new world of possibilities for affordable UAVs.  It will be possible to perform realistic crop spraying.  Aerial imaging with the best quality cameras available.  And extended flight ranges in a large aircraft with VTOL capability for usage in areas without a prepared landing strip.  Obviously this is not the type machine that would be used anywhere near people. But remote areas, or secured industrial lands would be suitable operational areas.

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  • I also have a helix conversion and will be setting it up with pixhawk and arducopter once I have my test bed (500 clone) working well.  I am in the process of laying out the helix side frames in CAD.  I am planning on extending the frames to accept a second trex 700N tank behind the current location.  I may investigate other tanks to see if I can wedge an even larger one in.  I have a 3 axis mill and will be cutting them out of 2 or 3mm carbon fiber.  Thank you Rob for blazing the path!  I hope you are still marching forward.




  • Hi guys,

    I love this build. @Rob; sorry to hear about the crash. Quick question to anyone; Should one use a Governor with the PixHawk when it's running a gas engine?, Or can the throttle servo be plugged into the PixHawk directly?

  • Rob, is ur gas heli still alive ?

  • @ John,

    Grreat point, Liquid tape is cool stuff and even has some vibration damping qualities, essentially an insulating plastisol.

    Excellent product for all kinds of uses.

    Silicone is stronger, denser and more durable than liquid tape and, if you put on a thin-ish layer of it, it can be removed with a bit of scraping.

    And like you said if you want it permanent Epoxy is the way to go and you can get high thermal conductivity potting Epoxy's.

    One of these days it might be worth putting together a good reference page for glues, adhesives, thermal compounds and other chemicals and what they are good for.

    Best Regards,


  • Developer

    When hot glue is not enough but I still want the possibility to remove it later. I use liquid tape.

    For a permanent fix, nothing beats epoxy.

  • Just a small thought, hot melt glue is probably not the optimal solution.

    Hot melt glue has a very limited bonding strength which is itself subject to breakdown from vibration, it also undergoes reduced bonding strength as it ages.

    And of course it becomes significantly weaker as it warms up.

    Silicone can work well for this (and is still removable) but you need a clean bonding surface.

    Most other glues will make it very hard to remove if you want to.

    Hot melt glue is definitely not ideal for high vibration applications.

  • Pleasee... Keep on going Rob... 

    Your achievement open so many opportunities ahead.. Good Job!!

  • Beautiful machine.  Thanks for the tip with on board batteries. 

  • @Rob_L so glad you posted this! I have a colleague locally that I was discussing this possibility. He has several traditional large Heli's that I feel could really benefit from a Pixhawk... Thank you for posting! 

  • Rob,  Sorry to read about the crash.  I had thought about the battery popping out of the GPS but never thought about it shorting things out.  Makes me look at everything closer and a little different. Again, sorry for the set back.


    David R. Boulanger

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