[luke_nicholls]

So I've tuned my quad to a point where it flies really nicely and does everything i want it do to. The only thing is it that when i start upping the speed (camera angle at 40 degrees) it seems to be unstable. does anyone have any ideas?

[TheOtherCliff]

What do you mean by unstable?  Oscillation?  Won't hold the pitch angle?  Does it have problems at the same power level when not travelling forward but just climbing?

What flight mode are you using?

Could be vibration or PIDs (needs more 'I' term).  If it is a Revo class FC, you could try auto-tune.

Video would help diagnose.

[luke_nicholls]

The stability issue is not oscillations or anything that is not making me able to fly, it does not do it whilst travelling upwards either. The best way i can explain it is that to fly in faster I'm needing more input than i would've thought to corner and do usual simple manoeuvres. Im going to start increasing the I gradually and see how that affects it as i think it may be the problem, its just that i don't get much time to fly so just asking for any easy shortcuts that anyone might know  (i am using acro+)

And i have soft mounted my pdb and fc on the stack.

[TheOtherCliff]

Thinking like "dual rates on transmitter"... It sounds like it simply needs more "high rate"

If that is so you should increase:
  Stabilization -> Advanced -> Bank# -> RateModeResponse(deg/s)
for roll and pitch at least
and make sure that the
  MaxRateLimit(allmodes)(deg/s)
for (RPY) is at least as big