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Thunder Power RC . Real Raptors . Mikado Modellhubschrauber

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e-Ark X-400 - MX400 > Stock MX400 Pro-Motor burned up...smoking
 
 
GyroMedia
Heliman
Location: Florida

Like many other newbie's I'm having one problem after another getting my heli to be normal. After assembling my MX400 and getting it trimmed, it was hovering great. After my 3rd flight hovering, I starting moving to fast forward and entered tranlational lift until the heli was flying forward about 25 feet. This was unintentional forward flight. I cringed a bit, then managed to turn around and fly back. After dropping power the heli started descending too fast and then put the power back in. Off course it gained too much altitude and I was in forward flight again in the opposite direction and now over my neighbor's house, but still under control. I managed to turn it around and come back, but in the process I put it into the grass a bit too hard. The feathering shaft was bent, along with the flybar. Both were replaced and I have been having lots of other problems since. After hovering for 5 minutes, the motor made a strange sound and lost power. Upon inspection the ESC and motor were scalding hot and the motor was smoking. The motor has been sent back to Hobby Center Warranty. I have read many other stories about the motor and esc getting hot. I use the Futaba 6exh TX with the settings suggested in other posts. Why would the motor burn up without any other settings being adjusted from the first 3 flights? Is there a FAQ list somewhere that includes a setup of electric heli's from start to finish? Long boring post...sorry, but thanks for any advice. One other question. How much movement should there be sliding the main blade grips in and out along the feathering shaft?

B
12-14-2007 05:18 AM
 
 
hueyman
Senior Heliman
Location: Joliet, Il.

there should be no side to side movement of the blade grips. The spindle assembly should be snug up against the rubber o-rings (dampers). on each side of the spindle there is usually an o-ring that fits into the head block, then a spacer, then the bladegrip/bearing assembly then a nut or screw at the end of the spindle. When it is all tight the spacers should be compressing the o-rings. The overheating after the crash can be caused by lots of things. Main gear or mesh could have jammed making it too tight. Check the main gear mesh, tail drive gear and belt for binding. Check your servos to ensure they are not jammng or binding. Check all the linkages and the swashplate movement with servos disconnected to ensure they are not binding. Recheck your pitch through the whole pitch curve. Also, have you checked the mainshaft to be sure it did not get bent. If bent it can stress the motor/esc/battery but I wouldn't think it would get them that hot unless the shaft was extremely bent. I'm sure you would notice a shaft that bent as soon as you spooled up.

Huh?
12-14-2007 03:18 PM
 
 
GyroMedia
Heliman
Location: Florida

Stock MX400 Pro-Motor burned up...smoking

Thanks,

I will have plenty of time to recheck any binding while the motor is being subject to warranty. The controls all seemed to run smoothly but I never rechecked the gear mesh after the crash. The main shaft seemed to be straight. I held the heli up sideways and ran the blades up several times to check that and didn't see any wobble that might be associated with a bent shaft. I do remember the pinion gear had slipped up a bit and the allen head pin was hitting the main gear, so I repositioned the pinion but never rechecked the gear mesh. The tail servo is a JR digital, and I have a Futaba 401 gyro. The tail servo constantly makes a humming sound when powered up. I assumed that was due to the constant monitoring by the gyro, could that be associated with binding or improper installation?

B
12-14-2007 06:08 PM
 
 
AirmanBob
Senior Heliman
Location: U.S.A.

I have the MX400 Pro also with the stock
motor. Probably about a 250 or 300 watt motor.

Over-heating of the motor and ESC has been
an on-going problem with this heli.

I tried a smaller pinion to un-load the motor
a little but it did not help.

I now limit my flights to about 5 minutes then
sit and let it cool down.

I use 2200mah 20c lipos by the way.

I may try a motor my son uses in his MX450XS.
It's an AMMO 27-45-2700 and no matter how long
he fly's the motor stays cool. Gotta wait till
after x-mas to do that. That motor is rated for
518 watts.

More watts = more power....

AB
12-14-2007 10:52 PM
 
 
hueyman
Senior Heliman
Location: Joliet, Il.

I've never used digital servos but have read that they sometimes normally hum. If the servo was not humming before the crash it is possible you damaged it and could be contributing to the overheating. I am assuming you had checked the motor/esc temps before the crash and they were not a problem. I use a 450hdx motor and dynam 30a esc and 11t pinion in a stock mx400 and have not had any overheating problems. if you didn't have overheating before, then I wouldn't expect a motor/esc replacement will help unless the throttle was left on a bit after the crash. If the mainshaft could not turn after the crash and the throttle was on it could have overheated and damaged esc/motor/battery. I've had things overheat afew times after a rebuild and it usually turned out to be the pitch curve was screwed up. Had to go through the setup again then all was good.

Huh?
12-15-2007 01:40 AM
 
 
hueyman
Senior Heliman
Location: Joliet, Il.

ignore duplicate post.

Huh?
12-15-2007 01:40 AM
 
 
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GrandRC . CanoMod . Futaba-RC

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e-Ark X-400 - MX400 > Stock MX400 Pro-Motor burned up...smoking
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