Arducopter 2.9.1b released

[Jumpy07]

  I';ve put a patched version of 2.9.1 (called 2.9.1b) into the downloads area which hopefully resolves the more serious issues we';ve found with 2.9.1:
1) reduce INS_MPU6K_FILTER to 20hz
2) reduce InertialNav Z-axis time constant to 5 (was 7)
3) increased max InertialNav accel correction to 3 m/s (was 1m/s)
4) bug fix for alt_hold being passed as int16_t to get_throttle_althold_with_slew
5) bug fix for throttle after acro flip (was being kept at min throttle if pilot switched out of ACRO mode while inverted)
6) reduce yaw_rate P default to 0.20 (was 0.25)
  I was wondering if some people could give it a try before we push it to the mission planner? The biggest questions are around #2 and #3.  #2 - reducing the time constant shifts the balance of power towards the barometer (i.e. weakens the accelerometer). This makes it safer for people more vibration but barometer misbehaviour appears. In particular try a fast forward flight and then flatten out. See this video around 1:55 where I';m testing a TC of 5 and you can see the drop after flattening out. Of course, people can always increase their TC back to 6 or 7 if their copters are flying well.  #3 - this is probably the most important fix to reduce the risk of vertical fly-aways in Alt-Hold/Loiter/Auto. This problem could appear if people have a lot of accel noise and it had a bias of over 1m/s (i.e when the motors were running there was aliasing which caused the acceleration to appear to be constantly over 1m/s up or down). That limit is now 3m/s. The downside is that if you have a hard landing an alt correction may build up and take a while (30 seconds?) to recover...so you could have a bad altitude for longer after a hard landing.  Anyway, if a couple of people could give it a fly and report back then I';ll push it into the MissionPlanner. thanks!

http://code.google.com/p/arducopter/downloads/list

[Gaza07]

Think I will wait for the 2.9.2 release 2.9.1 seems to fly very well for me 

[benchmark]

Thanks for the info, I may just try it out. How does one load the beta arducopter firmware without using the mission planner?

[rickp]

I';d strongly consider turning off the auto-calibration of the compass and manually calibrate it before flight.

Seems to be causing a few issuses/fly-aways...