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giboman
11-01-2007, 12:30 PM
I've just put a Hurricane 550 together for a friend. Stock motor and ESC.
On it's third flight the motor lost power at the top of a loop, on it's way down he wasn't able to control it and it went in hard. WOW! These birds are tough...just a broken tail fin, bent flybar and broken skids.

The next day he called and said he was trying it out in his yard, it barely had enough power to get into the hover. He tried 2 different fully charged packs of 2250 20c batteries with the same result. Later that afternoon i went and had a look myself. took off staright into the hover with no problem at all, everything seemed fine. Checked for any loose connections or anything else that looked suspect, all looked fine.

We took the heli out this afternoon to test it. Flew great for around 2-3 minutes then the motor cut then slowly picked up again with barely any power at all. He got the bird back down safely (his first auto). Tried the motor again and it just about got into the hover. The ESC was cool, barely warm and the motor was hot but you could hold your finger on it without screaming! 5 minutes later we hovered the heli for the remainding 2 minutes of the battery, everything was fine!

Electrics are not my thing, does anyone have a clue as to what is happening here?

Finless
11-01-2007, 05:32 PM
Check the gear on the auto clutch bearing as it may be slipping. The gear can get a hairline crack between 2 teeth and allow it to slip.

Bob

giboman
11-01-2007, 05:34 PM
will do Bob.

Thanks for your help

AussieJester
11-02-2007, 01:33 AM
Had this IDENTICAL issue when i first started flying my heli (actually just mentioned it in another thread in this forum co-coincidently LoL) (http://www.helifreak.com/showthread.php?t=49938) I still have no idea why it happened but changing to governor mode on the ESC eliminated the problem entirely 40 flights later hasn't skipped a beat....maybe try this if you cant find any other reason behind it IF you do find something though please let us know :-) FYI was and still am running same throttle curve DX6 95-65-95 (idle up) if that is any help...

Best of luck

giboman
11-02-2007, 07:54 AM
Check the gear on the auto clutch bearing as it may be slipping. The gear can get a hairline crack between 2 teeth and allow it to slip.

Bob

FINLESS DOES IT AGAIN!

Great one Bob, the gear was slipping on the one way bearing. I seperated them but couldn't see any cracks, just lots of oil. You could see the marks where it had been slipping.