P2V flips over on takeoff?

[jiminyfixit]

What would cause my salvaged/repaired P2V to instantly flip over as soon as I throttle up on takeoff? Could it be a defective MC? or one slower motor? I have a non-contact digital tachometer coming so I can test motor RPM balance. This was the first test flight since finishing repairs and updating firmware. I did all the pre-flight procedures; waited for GPS lock and calibrated the compass.

I DID get some interesting video.

Looking forward to more great "Pilots" input.

Cheers,

Jim

 

[4wd]

I recall one similar where the shell was accidentally rotated 90 degrees when re-assembled after repairs.

 

[enseth]

There has been a previous post with someone having exactly the same problem. It might be relevant to your problem.

viewtopic.php?f=5&t=20191&p=184280&hilit=flip#p184280

 

[jiminyfixit]

The shell halves are OK, (thanks 4wd), but I DO detect a slight difference in front to back RPMs when tilting. Enough to make me pull the halves apart and check my M1 plug. Thanks enseth for the link. It's funny how you miss posts when you don't have that particular problem 6 days ago. Thanks guys!!!

 

[jimdenburg]

If that doesn't take care of the problem, you might want to check the prop balance. I had the same thing happen once after putting on "new" props. They weren't the original DJIs but the aftermarket XOXOs, and it turned out they were so horribly balanced that I couldn't get off the ground without tipping.

 

[jiminyfixit]

Unfortunately I was using my brand new dji props that I had balanced perfectly. Nicked 1/4" off two of them, even WITH prop guards. Tall grass CAN bite. Will test fly with balanced XOXOs next time. Waiting for digital tach to check RPMs before test flying again. Loved the "flipper" vidoes.

 

[gunslinger]

Unfortunately I was using my brand new dji props that I had balanced perfectly. Nicked 1/4" off two of them, even WITH prop guards. Tall grass CAN bite. Will test fly with balanced XOXOs next time. Waiting for digital tach to check RPMs before test flying again. Loved the "flipper" vidoes.

You're going to balance XOXOXO props? Quick... what brand of tape are you going to use... I'll buy stock !!!! :lol: :lol: :lol:

 

[jiminyfixit]

Gunslinger;

I actually sanded material off the thick/heavy side instead of using tape. The ........props are actually several grams lighter than the dji originals, but, as you know, are NOT precision molded. Inferior tooling. (I used to be a plastics mold maker, years ago).

BTW, NICE website!!!