Motors Change

[Bad Raven]

So, I had some expensive BBB Racing 2206 2500kV motors on an unsuitable large so heavy quad frame, etc, it flew well but their extreme power was effectively being wasted, with the result of short duration flights.

When I got a lighter stiffer GEPRC Mk4 Frame I transferred them (with pleasing results).

I'd had a set of RacerStar 2205 2300kV "Racing Edition" motors for ages waiting to put on the old frame to keep it going as a knockabout hack. So, finally I did. Only the motors were changed, even the props are the same as they were undersized for the 3B's.

Easy Swap?

It's become the quad from hell.................... 

The power does not seem a lot different, a bit less punch as expected, but they sound OK at all throttle states.

And thats where it ends................. 

The complete PID settings now appear shot to hell, its now showing oscillations/juddering (classic PIDS high symptoms), while simultaneously being considerably looser in stability (classic PIDS low symptoms).

One motor is running on slowly beyond disarm by around five seconds (!) before stopping.  The motors only develop power on OneShot 125. On DShot 300 they throttle well but do not develop enough power to even lift off!! They are 30A ESC and would on the old motors send the quad skywards so fast you could not see it move till it stopped and on our tree lined site I never managed full throttle in level flight...... ffs!!

There was in initially considerable banding interference from throttle on video which a power Cap has reduced, but not enough (it was clean with the old motors without one). As said, the motors sound OK, nice and smooth, easy linear throttling (set as above). They sure don't act it otherwise!

I have made it better with PID tuning (which now seems on a knife edge), improved routing of video wiring, adding a capacitor to the power supply (the ESCs already have huge capacitors). But its still nowhere near good enough or as it was with the old motors. Swapped to another quad, the props are fine.

I'm quite staggered how much the flying ability has deteriorated with only a motor change and now not at all sure what to do! The quad is not worth spending more money on, so if I cannot cure it in settings or at least a very low cost, its going to be retired, which would be a shame.

 

[ched]

Interesting. Who would have thought that such a dramatic change with just a motor change?
It will be interesting to see if you solve it.