Collective Pitch Thrust Vectoring on a RC Plane

ScreenShot066

The RC plane shown above is hovering in that position. And that’s about the least impressive thing it can do. This is the power of Collective Pitch Thrust Vectoring… on a plane.

So what exactly is Collective Pitch Thrust Vectoring anyway? Put simply, it’s like strapping a helicopter rotor to the front of a plane. We think the basic mechanism behind this is called a Swashplate (as found on a helicopter rotor), which allows for thrust vectoring, meaning the propeller blades can actually change their pitch cyclically, while still spinning at high speeds! This is what allows helicopters to do crazy tricks like barrel rolls.

A normal RC plane can only increase or decrease thrust with the speed of the engine. But with this, the thrust can be changed cyclically as the blades spin allowing for thrust vectoring (advanced steering). Couple that with some huge control surfaces and wing stabilizers and that means some seriously crazy aerodynamic feats.

Watch the video after the break, it’s amazing.

Comments

  1. Mike says:

    this looks really really good, kudos! love the idea.

  2. rotceh_dnih says:

    not bad , i seen a video back in 2005 where a guy had a cp plane setup without Thrust Vectoring and it worked pretty good , no gyros back then though

  3. sparkygsx says:

    While it’s certainly impressive, I think the “plane” classification is somewhat debatable; I think you could also consider it to be a helicopter with auxiliary fixed wings. I wonder how he manages to control that many control variables though; does it come with an extra pair of thumbs?

    • oodain says:

      i would imagine using modifiers,
      a single button plus the sticks would control one thing where the sticks themselves control another, only a guess though.

      • Lord Nothing says:

        he probibly has a separate thumb stick to control the xy thrust vector. normally with the chopper the motor control is mixed into the collective pitch to give an optimal power curve, if that is the case then you would only need an additional 4 axes of control. if a 3 axis stick is used to manipulate the control surfaces, and a 2 axis for the thrust vector, and a third slider or knob for collective pitch and thrust. at least thats how i would do it. probibly with an optional switch to mix in the thrust vectoring with the control surfaces.

        • NickB says:

          I think the throttle is mixed with the collective pitch on one axis of a stick.
          Stick Forward: positive pitch + throttle
          Stick Backwards: negative pitch + throttle
          Extra buttons and sliders are difficult with this kind of flying.

        • hat says:

          I wonder if anyone has thought to steal ideas from full-scale helicopters? It would be pretty easy to use a microcontroller to build a governor: Measure engine speed and the PWM signal going to the collective servo and then generate a PWM signal to control the throttle servo. It might take a little work to get the right PID constants, but it you would save one channel on the radio.

          That plus mixing the cyclic with the elevator and rudder controls could save you from needing anything more than a four-channel radio (I’m sure *Team FUTABA* isn’t going to want to go that route :-)

    • AllenKll says:

      Agreed.. Just because it looks like a plane, does not mean it is a plane. Airplanes are defined by the requirement of getting most if not all of its lift from a fixed wing or wings. The body of that helicopter is used for aux maneuvering, not lift.

      Honestly, it drive me crazy that people think that any piece of garbage with a big enough propeller to cause it to get off the ground is an airplane. It’s almost as bad as the, “because it doesn’t look like an RC car, it must be a robot” argument.

      These misnomers really damage the credibility of the craftsmen that can actually create a working airplane or a robot. And only serve to pump the ego of those who just slap a giant prop on a toaster, or give it wheels to drive around with.

      • lwatcdr says:

        No this is a plane folks. It can hover but it lacks the rotor hinge to deal with the leading blade issues that a helicopter has to deal with. It can hover and go forward slowly but would be much more speed limited than a helicopter. The model is one of many classified as a 3D airplane. Lots of power and low weight so they have a better than a 1 to 1 thrust ratio. Adding cyclic pitch is a new twist but it is still a plane.

        • Lord Nothing says:

          i have to agree here. just because the lifting surfaces have insanely large control surfaces, does not mean that they do not produce lift (anything can produce lift). you would have no problem flying straight and level using the wings for lift. it would be easier to fly as a plane, it would not handle like a helicopter at cruise very well at all.

      • PedantioReguloso says:

        “damage the credibility”

        In whose eyes?

      • Blue Footed Booby says:

        @AllenKll
        So do harriers cease to be airplanes when they’re covering? Does an F22 stop being a plane when it’s using raw thrust to go straight up and thrust vectoring to control angle?

        At first I thought you had some kind of word fetish and wanted to make distinctions for distinction’s sake, but then I got to “any piece of garbage with a big enough propeller.” Now I just think you’re getting pissy because someone dared to speak on the subject without showing the True Art due deference. Chill the hell out.

        • I Fly Models says:

          I agree with you booby. Also with some of the people above you except Allen. Some real world planes utilize an asymmetrical airfoil that has zero lift. The lift is solely dependent on the angle of attack just like this plane. I fly model airplanes and built and flew what they call, “profile,” planes like this one. One of them was an aerobatic Extra 300 similar to the model above minus the collective pitch system. In order to keep it airborne the tail feathers had to dip ever so slightly below the main wing to force an angle of attack and create lift. In the end this plane adheres to the same laws of physics as a real plane aftering taking into account the scale factor.

  4. Ninthlamp says:

    I’m guessing the maneuveres might be stored routines in their RC remote. If not, then that’s superlative manual control.

  5. w says:

    If it doesn’t behave like an aeroplane then what’s the point in having it look like one?

    Lose the plane fuselage and replace it with something useful. Maybe a small mechanical grabber so you can transport small items around. Or a UFO LED blinker, because a UFO is definitely what it reminded me of, not an aeroplane.

  6. RJ Gritter says:

    Alllllright everyone…. first, thanks for the interest! This thing is a blast to fly.
    A few things:
    There is no swashplate or cyclic control. The entire motor with Variable-Pitch Propeller (only collective pitch control) is on a mount that rotates it in the yaw axis. It’s pure vectoring, not helicopter-like control. The vectoring is simply mixed to the rudder stick.
    As someone suggested, the collective pitch is mixed to the throttle, so the bottom of the throttle stick is high throttle with negative thrust and the top of the stick gives high throttle with forward thrust.
    There are no gyros whatsoever. Gyros are common on helicopters but this is pure manual control.
    Also, none of that is stored or otherwise automated. It’s all good old manual control and a lot of practice! Though extra thumbs would be nice.

    • Robot says:

      At times my fixed wing RC skills resembles your aerobatics. . . though I’m simply trying not to crash. I’m up to 30 whole seconds of flight time!

      Humor aside; would cyclic control allow you to do maneuvers that you cannot now do, or would it just add complexity with little additional capability?

      Thanks,
      Robot

    • lwatcdr says:

      I thought it had cyclic but it is still nice. Is the prop off the shelf or custom?

  7. Tom van Veen says:

    While I hate to say it, the movement of the plane seems too smooth. Also the way the camera moves makes me wan’t to scream “FAAAAAKKEEE”.

    • AllenKll says:

      The fact that it’s made of foam and so large gives it the ability to dampen quick erratic movements of the prop, producing a more fluid look. I don’t think it’s fake. I do think the guy flying it is very good.

      • StrangeKnight says:

        Agreed. I had the chance to see some of these guys fly as an exhibition at a hobby show one year, Some are not that good, but yes others ARE this good. They just have practiced enough to be that smooth….

    • dioxide says:

      nah, i have no problem believing its real. when you provide huge power to a high surface area but low mass, you can get some really impressive results. it has no inertia to fight against.

  8. Arron Bates says:

    well, so many of these comments are depressing… I thought that Hackaday peoples were meant to be generally enlightened. The text of the article misses all the points, I think whoever wrote it *thinks* they have insight, but they don’t really… it’s not a helicopter head at all, mechanically very different.

    Anyways, here’s the story… The prop changes its pitch, but along with that the motor rotates for thrust vectoring for improved yaw control both forward and back. The thrust vectoring is mixed to the rudder control by flipping a switch. Flipping a different switch changes throttle/pitch control to be all on the throttle control.

    As for why the plane is flying so smooth… the builder and pilot of this is a friend of mine, RJ Gritter… who is about the best there is in the USA for indoor aerobatics (specifically, flying this kind of aircraft). If anyone wants edumacation on this topic, hit the YouTubes with his name, along with Devin McGrath, “ETOC”, Donatas Pauzuolis, and Martin Muller as search terms… these guys have been working on this craft for many years now. IMO the stuff RJ and Devin are doing is the best (as seen in the Hackaday linked video).

  9. Wretch says:

    Please, please tell me that military drones can do this. (c:

    It can be like a killer clown act. Draw the intended target out with the dancing routine (i.e., “Oooh, look at the dancing airplane!”) and, once he’s positively identified, KABLOOIE! (c;

  10. mefornow says:

    Any pictures of the prop/collective head? I’d like to see how this thing works.

  11. twdarkflame says:

    With turns like that, all its missing is Tron-bike esq exhaust trails.

  12. t-bone says:

    Wow, that performance is amazing. I can’t imagine the practice and training it must take to control that thing.

  13. soopergooman says:

    wow, scale this up to a full size plane.

  14. mr.squishy says:

    Some people here are incredibly stupid. YES THIS IS A PLANE. How could it not be, being made from a kit used to build this exact type of stunt RC aircraft? It most certainly IS an airplane, and the only thing special this plane has is thrust vectoring mixed with the rudder and a variable pitch propeller that can be reversed. The mechanism is very different than a helicopter’s rotors and this idea has been around for a while. Shame on you Hackaday writer for not doing ANY research.

  15. Jeramy says:

    As some one who has cracked up many rc airplanes and choppers, I applaud your skill! I like the added benefit of the reverse thrust. Good job sir!

  16. strider_mt2k says:

    Absolutely astounding to watch.

    -and some of us called our home-built RC vehicles with cameras on them “wheeled ROVs” as opposed to “Robots”, because we understood the differences.

  17. vonskippy says:

    Nose down hover from a plane – so very wrong – yet so so so so so very cool.

    //gotta love the new computer radios//

  18. Pietro Lemes says:

    I just couldn’t find the “hack” part, you can buy these variable pitch motors on hobbyking for like cheap.

  19. Andrew says:

    A comment on the people commenting this is doable because it’s a foamie with no inertia — do a youtube search for F3m (a competition category) for much bigger, heavier, completely rigid, outdoor models even 1/2 scale of the real plane. Kind of like what the indoor pilots do but slow motion, and no reverse thrust. Here’s an example: http://www.youtube.com/watch?v=bQlFOAoPN2k

    Note that using variable pitch on electric aircraft is a little pointless since you can just reverse the spin direction in a fraction of a second, quadcopter pilots do this for 3d flying.

    • Arron Bates says:

      wildly incorrect on the pointlessness of VPP… electric motors cannot and do not stop and go in the other direction very well at all. spooling times are horrible. in no way, at all, could that ever do what is in this video. aerobatic quadcopters don’t stop their props at all. The latest aerobatic quad in fact uses collective pitch for the exact same reason it’s used on this plane… a servo adjusting pitch actually is instantaneous, stopping props and reversing is actually a fail, and totally impractical for all practical uses.

      • Andrew says:

        That’s exactly my thoughts too. There would be tremendous stress from stopping and reversing but changing pitch would be almost smooth in comparison.

        • Andrew says:

          Yes, there is stress, so you can’t use it with thin wooden arms for example. But it’s still fast as hell and you should be able to do much of what is seen in this video. It also doesn’t cost much energy because brushless motor braking is “regenerative”.

          I’ve got it implemented in my ESCs but lack the skills to show it off, but check out for example warthox’ videos on youtube or a few other 3d pilots:

          etc.

          Here’s his video about modifying standard fixed-pitch props to be suitable for both pushing and pulling, https://vimeo.com/62015977 (today you can just order them)

          • Andrew says:

            Yes, but eventually you’re going to rip the motor from the frame by stopping it and reversing it because although you can brake the motor electrically, the prop still wants to move in that direction due to the air pressure flowing over it and by reversing it you put pressure on the blade, motor, mounts, etc… Eventually it’s like bending a piece of metal back and forth, it will break.

            If you flip the blades the force is directed to the blades and you won’t get than back and forth action on the motor mounts and surrounding structure. It’ll still put a lot of force on the motor, mounts and prop but I think it will be less destructive.

            * I’m sure there are mechanical engineers on the site who can do the math to prove it one way or another.

          • Andrew says:

            So yes, flipping the blades puts less stress on the mechanics. But calling something “less destructive” (but still destructive) implies that the stress is greater than what the elements can sustain. The builder obviously needs to make sure this is not the case, whichever mechanism he builds.

            If your frame will fail in 6 months with motor reversing, then it probably is fragile and would fail in a little longer time anyway. Either way you’re likely crash the thing in a fraction of that time ;)

      • Andrew says:

        And yes, I’ve seen two or three variable-pitch quadcopter projects on the web, all of them claiming to be the first 3d quads ever, which immediately discredits them.

        Also while your argument is basically “you’re wrong, motor reversing wouldn’t work” so kinda hard to respond a specific argument, note that RC cars have done that forever, their emitters are made for that and the brushless ESCs all support it. The SimonK ESC firmware has had support for this forever, too.

        • Rc cars also tear their transmission out often when you go from full power forward to full reverse, and when that happens they don’t fall out of the air. The only Rc car I have owned out of the 50 or so that would instantly reverse was my Losi Nite crawler, and then I still had to reprogram the esc to do that. Every other RC car I have owned would brake, stop then reverse, alot of time wasted and energy too. The motor would have to kill all of it’s forward momentum then exhilarate in the opposite direction and this would put alot of torque on the frame of the airplane, twisting it in flight.

  20. loopingz says:

    Nice Flyingcraft mixed with amazing skills!

  21. Queeg says:

    Great showmanship skills, too. Just when you think you’ve seen the most amazing thing, he cranks it up another notch. Vertical rolls… In reverse!

  22. David says:

    Why is the title “Collective Pitch” when it’s about cyclic pitch?

  23. Jake says:

    Nothing new, it has been around in the R/C world for years now. I am an avid R/C flyer.

  24. Joe oden says:

    I really want to believe its real. Are there no other videos of someone doing this kind of thing? It doesnt have to be this great or slick. If its real surely a few other flyers are doing something semilar.

  25. Tom Prochazka says:

    Does anybody knows what plane is it? Looks awsome :)

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