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5 Motor VTOL controlled via PixHawk

(Asim) #1


I have seen documentation on PixHawk Supporting VTOL config.

How would Pixhawk handles the 5 motor config?

I am familiar with the H frame 4 motor config.

Channel 5: Front right motor, counter-clockwise
Channel 6: Rear left motor, counter-clockwise
Channel 7: Front left motor, clockwise
Channel 8: Rear right motor, clockwise

What about the pusher motor?

  1. How do you control that via Tx?
  2. What port on Pixhawk do you plug the pusher motor?
  3. How do you turn off the 4 x H frame motors once the plane is in transition mode?
  4. What special parameters are required to be set?

Is there a step by step guide available?

Any help will be highly appreciated.

(rollys) #2

Start here.

Good luck.

(Asim) #3

@rollys - You didn’t read my post. That is an H-Frame config link you have posted.

(rollys) #4

Sorry, I’m no expert with ArduPlane but have been following several forums on the quadplane development. I actually use PX4 and have successfully built and flown a few conversions. Having said that, I’m hoping to point you to the right direction. @GregCovey has done a few and you could look at his Ranger setup.

This is done by assigning a switch with Q Flight Modes to FBWA.

If you want to give PX4 a try, you can look at the preconfigured VTOL airframes and probably the QuadRanger would be compatible with your project. Samples of my builds:

QuadRanger FPV view or Ground View

Good luck.

(Greg Covey) #5

Hi Asim and rollys,

Here are some answers to your questions.

  1. How do you control that via Tx?
    The Pixhawk motors are controlled by the QuadPlane Flight Modes.

  2. What port on Pixhawk do you plug the pusher motor?
    Plug the pusher motor into the normal throttle port. The default outputs are shown below but they can be defined to whatever you want using the SERVOx_FUNCTION setting.: More information is here.


  • servo output 1 is aileron*
  • servo output 2 is elevator*
  • servo output 3 is throttle*
  • servo output 4 is rudder*
  1. How do you turn off the 4 x H frame motors once the plane is in transition mode?
    The H-frame motors are turned of automatically once the appropriate speed is achieved. This is set by the ARSPD_FBW_MIN parameter.

  2. What special parameters are required to be set?
    Follow the QuadPlane Frame setup guide in the APM Wiki. Use the Q_FRAME_TYPE parameter to set X-frame or H-frame.

  3. Is there a step by step guide available?
    Yes, see the guide above.

1 Like
(Asim) #6

@GregCovey @rollys Thanks guys…highly appreciated. This gives me a good start.

@GregCovey - watched your Ranger EX videos and mods…Impressive and nice save by the way :slight_smile:
I have one ranger EX as well and really don’t like this plane. Mine won’t even get off the ground as it has become nose heavy after I put on all the gadgets. Are you using the 4S or 3S battery and what amp?. I just finished replacing the stock motor.

for VTOL I will be using a completely different plane.

(Greg Covey) #7

Hi Asim,

Thanks! My Ranger EX was one of my VTOL experiments that failed. I did not like the size and awkwardness of the final VTOL design and did not get it to perform properly a few years ago using the initial APM VTOL firmware implementations. Since then, I have configured my Ranger EX back to an APM plane and it works perfectly as a long range flyer but it does require a runway. You can read about my initial setup here and here.

The stock Ranger EX power system was adequate but required a relatively long take-off when loaded with a big LiPo pack and camera.

Stock Ranger Setup on 4s
Stock Motor: 3715 outrunner 1000kv
Stock ESC: 40-amp with BEC
Stock Prop: 10x6
Battery: 4s 8AH Nano-Tech

I upgraded to the Turnigy SK3 3542-1250kv motor with the same prop and 4s 8AH battery but using a heavy duty 80-100 amp ESC. This combination provides 746 watts at 51 amps using the same 10x6 prop. It gives you just enough extra power for take-offs and still sips the current during normal flight. The larger ESC stays cool inside the fuselage.

So where did my quad power system for the Ranger EX go? Into my FX-79 QuadPlane. It also uses the same forward flight power system as the Ranger EX. The FX-79 initially gave me problems with tucking but they seemed to disappear after stiffening the wings and flying in reasonable winds up to 15mph. The FX-79 breaks down quickly and is easy to transport in its box frame.

The APM firmware has matured nicely for VTOLs. It is feature-rich which also comes with its share of parameters.


(Asim) #8

@GregCovey Thanks for the tips.

Yes, Ranger Ex is a pain in the butt to get it off the ground. I will give it shot next week and see what happens with the new Turnigy Aerodrive SK3 - 3536-1200kv Brushless Outrunner Motor and a new ESC using 4S @5200 mah.

I am planning to modify this plane for VTOL

I have found a precision landing solution for drones from IR-Lock so I will it use it inside the VTOL and lets see if I can land it pinpoint to the target. That’s my goal. VTOL for delivery and precision landing.

Its for a commercial application I am working on. So the above plane is just going to be a Ginny pig for initial testing and lessons learned. We are designing our own V-TOL, a very unique design :slight_smile: I will share details once the product is ready.

Are you attending Inerdrone Sept. 4 to 6?

p.s. is there a reason you used a washer for the motor to give it few degree up?

(Greg Covey) #9

I don’t attend any conferences. I am recently retired as of a month ago and just play with VTOLs for fun.

The stock motor mount on the Ranger EX has insufficient upthrust. If you read the rather long RC Groups threads on the Ranger in the FPV Planes forum you’ll see the recommendations. As for the washer, it was a simple solution without paying for a 3D printed mount. You’ll find many 3D printed motor mounts are available for the Ranger.