Jamie Hellmich
Second Officer
United States
Offline
|
Okay Cory, here is what I have come up with.
I took the cover off the Phantom, and the IMU is way off level port to starboard, and high on the starboard side. I laid a tungsten rod across the IMU, eyeballed for level, and it took 10 business cards under each of the port landing pads to get it the IMU near level.
So I put it back together and started stacking business cards under the rear and left (port) pads, calibrating and a test flight. 14 calibrations and flights to be exact. Balancing between 15 - 25 mph winds, power lines, trees and my house to boot.
It appears to be pretty darn close at this point. With the winds the way they are, I'm going to leave it here for now. I tried GPS and ATTI modes, and it stays put in a nice easy pirouette, which I deem a must for camera pans, and to get away from trouble when low and slow in tight places.
Here is what I wound up with for card counts under the pads:
LR - 19..........LF - 16
RR - 3...........RF - 0
So it only took 3 under the rears to eliminate the minor front drift, but my gosh, 16 business cards to raise the port side and stop the right drift. As well the Phantom is stupid out of level. A level from a port prop spinner to a starboard prop spinner has about a 1/4" to 3/8" gap at the starboard side.
It does fly and hover level though.
I don't know how, why, or what causes this to fix the yaw drift issue, but it has. I can only assume that the IMU should be mounted level in the aircraft, and mine definitely is not. And further, the shimming I did during calibration, definitely was in the direction of leveling the IMU the way it is installed.
It remains to be seen how this affects the other flight controls, hovering, stability, etc... And I'll be checking that out when these winds calm down.
I'm also not sure how DJI can send these out with the IMU that far off level. Unless it doesn't matter, and shimming under the landing pads for IMU calibration is correcting something else.
Please weigh in with any thoughts.... Cory or anyone.
Jamie
|
-
Tungsten rod across IMU
|