Full VTOL F-35 Foamy

[NickRehm]

You will probably need to retune your control gains because your motors/escs are slightly different than what the original PIDs were tuned for. In the control mixer, for hover and transition flight modes, try using these gains for the rate controller:

Kp_roll_rate = 0.2; //Roll P-gain - rate mode
Ki_roll_rate = 0.3; //Roll I-gain - rate mode
Kd_roll_rate = 0.00013; //Roll D-gain - rate mode (be careful when increasing too high, motors will begin to overheat!)
Kp_pitch_rate = 0.15; //Pitch P-gain - rate mode
Ki_pitch_rate = 0.2; //Pitch I-gain - rate mode
Kd_pitch_rate = 0.00013; //Pitch D-gain - rate mode (be careful when increasing too high, motors will begin to overheat!)

These are reduced P, and increased D from the default, to hopefully prevent the oscillations you are seeing. You may need to tweak them further. If it still oscillates, reduce Kp for whichever axis is oscillating by about 0.03

 

[AdityaPratap]

You will probably need to retune your control gains because your motors/escs are slightly different than what the original PIDs were tuned for. In the control mixer, for hover and transition flight modes, try using these gains for the rate controller:

Kp_roll_rate = 0.2; //Roll P-gain - rate mode
Ki_roll_rate = 0.3; //Roll I-gain - rate mode
Kd_roll_rate = 0.00013; //Roll D-gain - rate mode (be careful when increasing too high, motors will begin to overheat!)
Kp_pitch_rate = 0.15; //Pitch P-gain - rate mode
Ki_pitch_rate = 0.2; //Pitch I-gain - rate mode
Kd_pitch_rate = 0.00013; //Pitch D-gain - rate mode (be careful when increasing too high, motors will begin to overheat!)

These are reduced P, and increased D from the default, to hopefully prevent the oscillations you are seeing. You may need to tweak them further. If it still oscillates, reduce Kp for whichever axis is oscillating by about 0.03

i am thinking of buying new esc , so can you tell me whether this esc will work with the original code? https://emaxmodel.com/collections/l...g-drone-qav210-qav250-multicopters-quadcopter

 

[NickRehm]

Yep should work fine, but you'll need a separate BEC for 5v source to power the FC and servos

 

[AdityaPratap]

Yep should work fine, but you'll need a separate BEC for 5v source to power the FC and servos

hey nick , everything is working fine now , but idk why the motors are not able to lift the plane , i have tried powerful motors too , right now i am using rs2205 2300kv(clone) and 3s battery with 5 inch prop , i have also tried 6 inch propeller and it is able to lift it up but at 80 or 90% throttle

 

[tamuct01]

hey nick , everything is working fine now , but idk why the motors are not able to lift the plane , i have tried powerful motors too , right now i am using rs2205 2300kv(clone) and 3s battery with 5 inch prop , i have also tried 6 inch propeller and it is able to lift it up but at 80 or 90% throttle

I am using Emax ECO 2306-2400KV motors and 5x5x3 props and have thrust for days. I don't think the 1mm size and 100KV difference should have such a large effect on your build. Double-check that your props are on the correct direction and that your ESCs are calibrated. With the props off, connect the Teensy to the computer and make sure that the flight controller is outputting 1000-2000 us signals with your controls. Uncomment the printMotorCommands() function and use the Serial Monitor tool in the Arduino IDE.

 

[NickRehm]

What's your weight with battery? And yea, double check your prop direction

 

[Bo123]

IS there a spreadsheet or something with links to all the parts? A really want to build one of these. I wonder how well it would work with other aircraft, like Harrier, Yak-38, or that VTOL mirage ?

 

[NickRehm]

IS there a spreadsheet or something with links to all the parts? A really want to build one of these. I wonder how well it would work with other aircraft, like Harrier, Yak-38, or that VTOL mirage ?

Yup, everything you need is here: RC VTOL F-35 Parkjet | Hackaday.io

This guy took the setup and threw it on an su-37 body: (4) SU-37 VTOL : Hop1 - YouTube

 

[tamuct01]

IS there a spreadsheet or something with links to all the parts? A really want to build one of these. I wonder how well it would work with other aircraft, like Harrier, Yak-38, or that VTOL mirage ?

I want to say I saw a similar prop setup used to make a Harrier, but with 4 props instead of 3. It used two booms in the (approximate) locations of the Harrier exhaust ports that rotated to move to forward flight. Nick's dRehmFlight VTOL project can certainly be used for any of these projects. Good luck!

 

[AdityaPratap]

What's your weight with battery? And yea, double check your prop direction

approx 650 gram

 

[NickRehm]

With these miniquad motors, they should be putting out at least 350-400g each with a 5" prop on 3s. So not sure why you're low on thrust. Maybe ESC calibration issue where endpoints aren't properly set? Might be worth plugging ESC directly into your rx and going through the standard ESC calibration procedure of throttle high, power on, wait for beeps, power low, armed and calibrated.

 

[stevennh]

hey nick , everything is working fine now , but idk why the motors are not able to lift the plane , i have tried powerful motors too , right now i am using rs2205 2300kv(clone) and 3s battery with 5 inch prop , i have also tried 6 inch propeller and it is able to lift it up but at 80 or 90% throttle

I had the same problem on my first attempt. The props were pitched in the correct direction, but were upside down. The props are not symmetric. Try flipping them over, it worked for me.

 

[stevennh]

In case anyone is interested, I created 3d models from Nick's designs to integrate the flaperons and motor mounts, and to create fairly light ailerons both with integrated hinges. I had a hard time getting the tape and glue hinges to hold, these are very secure but weigh a little more. Decent trade off I think. https://www.thingiverse.com/thing:5545326

 

[stevennh]

@NickRehm quick question. I am struggling a bit flying my latest build. I think perhaps I am just not flying fast enough, but when in full forward flight, I seem to have a hard time keeping the nose flat (keeps going into what you called "high alpha" mode, standing on the tail). I think this is probably a combination of flying too slow, and extra weight with my 3d printed parts. I probably need to move my CG further forward (and fly faster). I had to lower my roll and pitch p Gain to about 70% of your original values for a stable hover, and also lowered the roll and pitch pGain in forward flight by the same amount, perhaps that was a mistake? Thanks in advance for any pointers. I'm still having fun!

 

[NickRehm]

Maybe just a touch of down trim and a bit more speed. Sometimes when mine falls into the high alpha, I need to give it a little power and nose down to get it out, then it'll cruise along like normal. But be very conservative using up elevator in forward flight--because its so maneuverable and tail heavy, it's looking for every excuse to flare up. Maybe a little bit of nose weight would help.