Tiltrotor support for plane #2

Hey Greg,
I updated my picture in the last post with the correct motor/servo mapping as well as the newest param file. I was also wondering if you might tell be able to tell me whether or not I chose the right FRAME_TYPE as 0. I did this because the motor placement for the quad + seems more similar to my build than the quad x. The only caveat here is that the quad + motors 1 and 2 are spinning the same direction. This wouldn’t seem to work, however when I tested out the motors they actually spun opposite of what it shows in the diagram I have posted. By the way, I figured out the reason they would beep at me was because I had accidentally bought a series connector instead of a parallel connector. Thank goodness I didn’t blow the ESC. Thanks Greg!

Hi Casey,

I’m pretty sure that you want Q_FRAME_TYPE set to 1. This keeps your motor output functions to:

  • 33: motor1
  • 34: motor2
  • 36: motor4

The front motor rotation directions don’t matter as long as they are opposite. Also, the rear motor direction doesn’t matter either.

You then want to set Q_TILT_MASK to 11 for motors 4, 2, and 1. I think that SERVO7_FUNCTION should then be set to 41, but I have never had the rear motor tilt.

Hello everyone,

First of all, I would like to say that this is a great community, seeing so many people that is willing to help others.
Now with my issues: Me and my friends are trying to build a QuadPlane Tilt-Rotor with all rotors tilting.We were able to tilt the rotors when the plane is switched from MANUAL or FBWA to QSTABILIZE. We have everyting set but we have one major issue:

When in MANUAL mode everything is looking good. I can see from the “Servo Output” tab, the throttle I’m giving and Pixhawk responds accordingly. BUT when we switch to “QSTABILIZE” mode we can’t see any output to throttle or any output for that matter whatsoever. And from what I understand in QSTABILIZE mode the VTOL should act like a Quadcopter, which means the control surfaces should not move , BUT they do for some reason; only the rudder remains stationary.

I have set the ARMING_REQUIRE to 0 in order to arm the vehicle since not all the calibration is done. I’ve checked the wiring again and again which seems fine. Radio calibration is alson working fine. Since I can not give any output to the motors I can’t do the ESC calibration with Q_ESC_CAL =1.

I really hope you guys can help out. I am including some attachments below with a picture of the VTOL.

Have a great day, thanks!

paramsT.param (16.5 KB)


I am working on a tilt rotor quadplane driven by a petrol engine. The angle of the blades are adjustable by servos. I want to use the quad motor outputs to control the servos. The layout is “PLUS”, the 2 side rotors are tiltable.
I set the parameters below and I would have some questions about it.
I checked the outputs in the status window of the Mission planner. What I recognised, the PWM limits for the servos were not used for SERVO5-8. Only the Q_M_PWM_MAX/MIN limits the output. Is it correct?
The SERVO9-10 stay 0. No output at all. However the SERVO5-8 started to change a lot, when I rotated the PH around the vertical axle. So it looks, it uses the normal quad method to do the yaw control. What can be wrong?
Can I use Chibios for tiltrotor?





Hi Tugrul,

I am not certain that APM Plane supports a setup with all 4 rotors tilting. It was under consideration but I have not kept up with the changes to verify that it was implemented. If not, you will need to fix the two rear rotors and use the MotorTilt=41 for the SERVOn_FUNCTION that controls it. Also, the front rotors use the following SERVOn_FUNCTIONs:

  • TiltMotorLeft=75
  • TiltMotorRight=76

For the front tilt rotors, you need to set the Q_TILT_TYPE parameter to 2 for vectored yaw control. Otherwise, your plane will spin when hovering. The frame looks very nice!

According to your .param file, the motor ESCs should be plugged into Servo Outputs 6, 7, 8, and 9.

You can read more about Tilt rotor setup here.

Good luck!

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Hi Greg,

Thanks a lot for your answer!

I think APM Plane supports the quad-rotor setup with all 4 rotors tilting since it is mentioned in the tilt-rotor web-page under the quadplane support. I solved my problem. As it turns out the “ARMING REQUIRE=0” parameter is bugged for some reason and I had to use “RUDDER_ARMING” instead to arm the vehicle. More on that here : Arming Require.

The problem we are facing now is that the VTOL only lifts off about 1.5 to 2 meters before starting to lose altitued slowly. Now this is our first ever plane. I will list our setup and talk about possible reasons why it won’t lift off.

  • Motors : SunnySky X2814 900 kV motors ( 1500 grams lift at 24.2 Amps with 13x6.5 props)

  • Propellers : 13X5.5 props

  • ESC’s : 40A Hobbywing Skywalker ESC’s (3s)

  • Battery : 6250 mAh 3S Li-Po

  • Total Weight : 4.5 kg

  • Wing Span : 1.5 meters

Possible reasons for the problem :
-Maybe the weight is too much for the battery. In QSTABILIZE mode while hovering at 1m battery only lasts about 1:30 minutes. We are currently trying to decrease weight and find a more powerful battery or even connecting severeal batteries in parallel.

  • Maybe there is some parameter I missed that limits the max throttle, though I highly doubt it.
  • Using 4S ESC’s with 4s batteries might increase efficiency.

You guys here are a lot more experienced than us maybe you guys could guide us to the root of the problem.

I am including our first hover test below.

Have a nice day everyone !

Hover testing
Transition Test

Hi Tuğrul,

Glad you got it working! Can you post the .BIN file from your hover test? Also, what is the C rating on your 6250mAh pack? I suspect that you may need to increase your cell count and decrease the prop size as you are drawing over 100amps.

It looks like you are testing at a University. Be careful when your helpers are so close to the spinning props. Typically, we test with the plane on the ground and a distance away from it.


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Can you help me to understand the working of the tilt rotor with yaw control? I set parameters, but it does not work according to my expectation.
I have made a small drawing for easy understanding. The grey box shows the parameters, what I have set.
When I move the rudder to side totally, the output does not reach the max. allowed number on both side.
Another strange thing is, when I move back the rudder to the center, the output is different according to the direction from I move back, however the input channel shows the same number.
The Servo_max. 1950 works well in Manual mode.





I am just hoping if somenone can help me with the auto mode tuning of a 4 motor tilt rotor (only front motors tilt).
We have successful tuned the plane in quad modes and also in FBWA mode. But in auto modes the pitch behavior is bad. It oscillates in altitude pitching up and down (sometimes very aggressively). It is not able to keep the altitude.
We have tried adjusting the TECS controller with no luck. In the logs the desired and actual pitch angles are not matching at all.

Here some logs of the last flights:


I finally got to maiden my re-designed FireFLY3 VTOL which was created from a crashed FireFLY6 and parts from other planes. To my amazement and joy, it worked quite well! I used Plane v3.9.8 and a Turnigy Talon Tricopter Servo Mount Set from HK for yaw control. I upgraded it with Boca Bearings as shown above in post #27. Fun stuff!

One beautiful project, from which many of us have learned.

Mil gracias, Greg

Thank you

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Thanks, Atico!

I changed the PTCH2SRV_P value from 1.8 to 1.4 and the elevon pitch flutter disappeared.

It will be interesting to see if I can carry a typical payload of my GoPro H3 camera with Feiyu Tech gimbal or S100 mapping camera. The ascending hover value without payload looks to be around 1670 on the RCOUT PWM C3 and 1450 in FBWA mode for a speed around 16m/s.

I had a chance to grab a guy at the field for a video of my FireFLY3 VTOL so I took it. The conditions were not optimal with a crosswind coming from the camera and pilot’s back. Even though I had a new video guy with a new camera and a crosswind, I was happy with both the hover and flying characteristics of the FF3. A week before, in calmer conditions, it really flew nice. Maybe next time, I can put on my zoom lens.

I finally was able to mount my Feiyu Tech G3 Ultra gimbal to the FireFLY6 DIY15 and add an analog air speed sensor. The AS sensor really helps the transitions into wind and when flying in CRUISE or LOITER modes. The original FF6 series didn’t use AS sensors but now that it is running on APM Plane, the sensor really helps the VTOL performance. As usual, the first flight was for calibration only and then I enabled it. It works great!

Just found this topic. But I’m working for a long time with this:

Log: https://drive.google.com/open?id=1SrzyvTSncMg1pmISFn7eCASiXTMenBEn
Params: https://drive.google.com/open?id=1TM6nxKrnoL4Ei9M-AWqB2T9NKFy7T0h4

Test 46: https://youtu.be/R_R8dkj_Qws

Test 47: https://youtu.be/CGYzC9v1_TY

Test 48: https://youtu.be/HINcB43YoW8

If this topic is still activ, I can post more experiences.

Hi lorbass,

Very interesting! Thanks for posting.

On your Test 40, you have discovered what happens when you try to hover a wing in some wind. It becomes a sail as soon as you stop pointing the nose into the wind. These type of designs are really meant for short term hovering and mostly flying.

Also, next time try using the QSTABILIZE mode instead of QHOVER. The throttle response would have been much greater on the roof and perhaps it would have escaped. It was interesting that the fire truck used the bucket extension to retrieve the plane instead of gaining roof access through the stairs. They probably never saw any aircraft like it before! :slight_smile:


Hi Greg,
Thank for the answer.
Yes, a VTOL Tri Tilt needs also a “runway” to slow down, but in the air.
QStabilize, helps to shorten, but continue as rocket.
Therefore I tried to slow down as possible in FBWB and the experiment shows the Video with Test 50

The fire truck is the newest technology in this region. The basket ist standard, the water in an extendable tube, the jet is controlled by a joy stick in the basket (jet by wire :wink:) the basket can carry up to 5 persons. An so I was on the roof to prevent an accident by the perhaps rotating props.
This fun cost me 500 CHF (~450 $)

With my VTOL Tri Tilt I have still the issue of right yaw during the Transitions.

These are the newest videos:
Test 49, Test Climbrate increased to 4m/s, Transitions FBWB

Test 50, Where is the min.Speed in FBWB, 2 Stalls

Happy flying, Otto

Hi Otto,

great tests and also great video documentation. I think, stall speed is 42 kmh (26 mph ;22,7 kn; 11,7 m/s). Did you ever tried to slow down in FBWA with Q_ASSIST enabled (eg Q_ASSIST_SPEED 1m/s lower then ARSPD_FBW_MIN) ?

Ouch! :cry:

Although expensive, I am glad that you could retrieve your VTOL.

Hi Rolf,

Can you confirm that the Q_ASSIST_SPEED function still works on a tilt-rotor configuration? I have only tested this on a QuadPlane and was uncertain of the result on a tilt-rotor configuration.