I wanted to bring attention to the work that Tridge and the rest of the CUAV team have done to demonstrate the possibility of flying a Helicopter with a standard FBL controller handling the rate control duties.  They have been testing gas powered helicopter for next round of the Outback Challenge which will require a long-range VTOL aircraft.  Helicopters are a natural target for this mission of course.

Several of the CUAV team are experienced RC helicopter pilots, but not as familiar with installing a Pixhawk on a helicopter which can be difficult, especially in the case of gas engine helis.  As such, they were more comfortable having a normal Flybarless Controller handling rate control. In this case, the Skookum Robotics 540.   Tridge has made changes to the code which allow for a pure control pass-through from the RC Rx, through the Pixhawk, and straight to the FBL controller. This pass-through occurs in Acro mode, whereby the Pixhawk running ArduCopter has no effect on the flight control, so even if the Pixhawk should have a major AHRS/EKF failure, the helicopter is still controllable. 


Of course, the Pixhawk is capable of controlling a Helicopter without any FBL system, and this is the most common arrangement.  But the possibility of running an FBL controller in series with the Pixhawk helps lower the barrier to entry for many existing RC Helicopter pilots.  And also offers helicopters similar failsafe-function to airplanes, where they can survive the loss of the autopilot.

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  • Thanks for this Rob. Thought I'd mention that the two CUAV team members pictured are Jack Pittar on the left and Greg Oakes on the right. Both amazing pilots who along with Tridge and the rest of the team have put in countless hours in the pursuit to find Outback Joe

  • @JB I think the biggest safety issue with gas powered traditional helicopters are that they tend to be larger, and therefore as you mentioned, the blades have substantially higher inertia - particularly compared to average sized multi-copters.  I'm not aware of any deaths or many life threatening injuries caused by multi-rotor accidents, but there's been a few high profile deaths caused by traditional helicopters (both gas and electric).

    On this point, let's be clear.  The deaths that occurred with hobby helicopters, all happened to pilots who were flying extremely aggressive, close-in stunts.  There's a weird trend in helicopters where the thing to do, is fly closer and closer to yourself at high speeds, for the thrill of risking death, I assume.

  • I second Pascal's question about camera vibrations on a gas heli impeding mapping or video work.  Do the same dampening techniques used on a multirotor work for a heli?  Or does it need to be a different kind of dampening to beat the lower frequency vibrations of the larger rotor? 

    It's definitely more difficult to get vibration free camera operation on a helicopter, but it can be done.

    I have seen some professional companies using helicopters for aerial video as well, but that's going to be even more difficult.  I hope to start testing still pictures from the gas heli soon however, and I think that can work well with the right setup.

  • Thomas

    From my understanding a gasser or electric heli typically both experience more vibrations than a multi. Every application has it's own merits, helis can lift lots for longer.



    It's cool that you're doing such extensive testing and I get where you coming from with customer perceptions. I'm wondering if you think that replacing components frequently might increase you chances of hitting a faulty one?

  • I second Pascal's question about camera vibrations on a gas heli impeding mapping or video work.  Do the same dampening techniques used on a multirotor work for a heli?  Or does it need to be a different kind of dampening to beat the lower frequency vibrations of the larger rotor? 

    Could I go out and get a 150 size heli with a FBL controller and strap a Pixhawk with telemetry to the bottom and get the same results?  Learn to fly a heli with this setup and then move up to something that can carry a payload at a later date?

  • Guy, thanks for sharing, very interesting

  • T3
    It seems to me that *in general* when people use gas powered (insert favorite device here), people exercise more caution than when they use batteries. Those with knowledge of the potential danger in LiPos treat them with the respect they deserve but in general, especially with the recent drone boom, most people treat it as another battery, not the potentially hazardous item that it is.
    We've known for decades that gas is highly flammable and in general, act appropriately and take proper precautions. That isn't the case with LiPos as we haven't had the time to have had it beat into our heads yet. Both are safe if you are aware of the risks and are appropriately cautious but the flip side is also just as true for both. You can argue that one is more safe/dangerous 'til the cows come home and you would be right in both cases.
  • Lots of smoke not much fire.... ;-)

    Evidence should be used to make informed decisions, and evidence needs to take the form of facts.

    For consequences of gasoline fires do a google image search of  "gasoline fire injuries" (be advised horrifically graphic content), in comparison image search "lithium polymer battery fire injury" to find nothing....

    The definition of safesecure from liability to harm, injury, danger, or risk

    The consequence of being burnt by even a small amount of gasoline is severe, in comparison to a lipo fire where it's not, let alone nearly undocumented despite the prolific update of lipos, even by yourself to fly multicopters etc.

    I'm not saying at all lipos are without risk, but I am saying i don't agree with you at all when you say "gasoline is safer then lipos". It's not.

    Can you rebut the arguments I make in my original post to persuade me otherwise? Maybe we should start our own thread to discuss the merits of each in detail. I think safety warrants it's own discussion.


  • If lipos where so "dangerous" what batteries are you using onboard your gasser to run the pixhawk? Nicds? ;-)

    Actually, I am using NiMh.  Safe and reliable.  Can leave them charged with no problems. Fill up the gas, pull the cord, and go.  Very liberating.

    My being ridiculous was only provoked by you saying gas was safer than lipo. I can't see it being so and I simply pointed out my position, along with a request of some facts to prove it was in fact so. Further gas storage wasn't the subject, use in RC aircraft was. The points I made were valid and videos posted to demonstrator the intentional ignition of them. (it takes a awful long time to wait until they blow up of their on accord!)


    Check 0:28 here:

    Almost every electric helicopter crash ends like this:


  • Talking of gas vs lipos : greater vibrations due to gas engine is really a show stopper for a good video or mapping helicopter solution ?

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