Modding Skyviper with brushless motors

Hello Guys,

I was thinking if it is possible to mod skyviper in someway to use brushless motors ,

That will mean using different frame motors and batteries probably but :

what will be the way as to get the signal for brushless in terms of electronics hardware and what impact changes will have in firmware or parameters software ?

any hints in this matter very welcome.


There were some talks here

Basically, you have to install ESCs to control the brushless motors. Not 100% sure all about that. One comment was that there really isn’t enough room in the frame to install the ESCs, but maybe there are some really tiny ones out there.

tiny ESCs do exist

Post #74 documents the start of a build. Apparently the GPS module has to be connected or it refuses to arm. FETs don’t have to be removed to connect ESCs. I’m guessing this is doable with a larger frame, quality ESCs, brushless motors, adequate battery and micro transformer to reduce to 3.7v for the flight controller.

Great project to think about but the spring has me back in my garage working on a collection of old motorcycles.

Thanks Dude, I,ll read on.

Hi guys
I place the SkyViper electronics into a 250 racing quad frame
I changed the motor output to PWM, first I use a small servo to be sure that I was getting a good PWM signal
Now I have all the part mounted on this small 250mm frame, with a step down converter to get 4,1v from the Lipo
It all seems to work OK regarding orientacion, motor order, and inputs from the controller. Quad compensates OK so the problem now its just settings.
I am able to Arm the quad, turn on motors, move it up, front left rigth yaw, but I can not go down, motors
But Im not able to calibrate either the settings from APM or the ESCs.
The minimal trottle its too much, and if i change the minimal trottle down, motors wont turn on until I push it Up too much

Its a little bit hard to explain, I made a shot video with what I have until now ( its 3 videos really )

Any advice on how to track down this issue? besides the horrible PID problem, im quite concern about the fact that I cant make it hover without gaining altitude. But If i tie the quad to a rope, it kind of hovers

Hi @Andresc4, looks good!

You need to adjust PID value. Default is too high for small frame. Probably you will need to change value directly at Mission Planner full parameter menu, (or Sky Viper Web Flight Parameter menu if you have not updated Sky Viper firmware to master.), because you may need to set value lower than we can set through Mission Planner extended tuning menu.

1, Try to set minimum value you can set at Mission Planner extended tuning menu. Rate P, I, D, and see you will not see fast oscillation.
2, If #1 is not enough, change ATC_RAT_xx value directly with MP full parameter or SV parameter menu.
Once copter is flyable, you can proceed to auto tuning to refine.

See my post on conversion, I have attached DataFlash log of my similar sized quad. Open it with Dronee Plotter or something, check ATC_RAT_xx values.

Be careful when you do auto tune. SV transmitter range is very short. I lost my first one fly away on windy day…


For the hover problem, you might need to look here

I think you can use MP to calibrate your hover value, but i’m not experienced with it. The problem is you’ve got the SV default values attached to more powerful motors, so your vertical “center” it needs to be re-calibrated.

Nice work so far!

Another thing to consider regarding the throttle and ESC calibration fun… in the V2450GPS transmitter, the sticks bump against the round plastic edges before you can get to a ‘true’ zero throttle. Since they are round, you also can’t do a true ‘down and to the left’ movement with the sticks. While we were able to adjust for that in the parameters and work around it, if you are moving these boards to different frames and hardware you will bump into this issue. Maybe try removing the top half of the TX casing when doing ESC calibration? Check the throttle values via the WebAP or in a ground station program to see what actual value you are seeing from the throttle travel.

And yes… being on these new motors will absolutely mean you will need new PIDs and throttle values.

Hope that helps. Good luck and Fly Safe!

I notice about 3/16" amount of play up and down with both sticks. If the plastic were epoxied to the metal sticks, assuming they were perfectly centered, would this correct the true zero throttle issue?