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Old Aug 12, 2012, 12:33 PM
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This is one possessed heli

10 flights = 10 crashes

capture the last 2 crashes on video.

the most amazing part is that the main blades (fiber glass) have survived all 10 crashes.. I'm starting to think the blades are possessed by evil....

Trex 450 pro FBL crash (0 min 44 sec)
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Old Aug 12, 2012, 07:11 PM
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Wow !

HAve you tested on the floor less blades ?

[ run it on the ground to address vibration ]

I have to ask , whats the cause ? control rod coming off ? That is severe , looks like something is letting go
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Old Aug 12, 2012, 08:11 PM
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Man that would be frustratating! I had a similer issue that turned out to be caused by bad main shaft bearings. I replaced the bearings and that solved the issue This seggestion is a shot in the dark, but you might try grounding the tail bearing to the tail boom, and the tail boom to the moter mount. The heli looked like it was flying ok and then just took a dive, that might be an indication of static build up. Maybe--Maybe not any way good luck.
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Old Aug 12, 2012, 10:22 PM
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I found it....

2 problems

1st -- something causing the initial cyclic shake.. possible vibration.

2nd -- now this is what really causes it to crash: so when the heli start to shake, the servos use more power and this 40amp/5v/3amp esc is crap... when the servos use about 2AMPs it shuts off.. so receiver/gyro/servos lose power and the possessed heli goes bananas...


Replace the ESC and no more crashes... now still have to shase down that shaking... it is not all the time and it does go away by itself... so I'm thinking some odd vibration.


It is not main bearings since they are new and I'm using thrust bearings and main shaft turns smooth as silk.

Tomorrow I'm going to try different blades.... this pair survived 10 crashes... something not right.
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Old Aug 13, 2012, 02:10 AM
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wow that looks weird...
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Old Aug 13, 2012, 03:39 AM
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Change out the blade bearings. If they are notchy, they are bad. You do oil them don't you?



Quote:
Originally Posted by electrojolt View Post
I found it....

2 problems

1st -- something causing the initial cyclic shake.. possible vibration.

2nd -- now this is what really causes it to crash: so when the heli start to shake, the servos use more power and this 40amp/5v/3amp esc is crap... when the servos use about 2AMPs it shuts off.. so receiver/gyro/servos lose power and the possessed heli goes bananas...


Replace the ESC and no more crashes... now still have to shase down that shaking... it is not all the time and it does go away by itself... so I'm thinking some odd vibration.


It is not main bearings since they are new and I'm using thrust bearings and main shaft turns smooth as silk.

Tomorrow I'm going to try different blades.... this pair survived 10 crashes... something not right.
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Old Aug 13, 2012, 01:05 PM
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Originally Posted by iflyhelis View Post
Change out the blade bearings. If they are notchy, they are bad. You do oil them don't you?
Blade grip bearings are nice and smooth.


Swaped servos today just to be sure and Cyclic shake still there... comes and goes.... must be some odd vibrations...


tried the CF blades from my own 450 pro and much better... but still not 100%

going to try to lower the AEL gyro gain...
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Old Aug 15, 2012, 06:16 AM
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Possible bent main shaft, have you ever changed it after your 10 crashes?
To check if it is straight, take it out then roll it on a flat counter top. If it rolls smooth you are golden, if it rolls & you see it go up & down it is time for a new one.

I have even had loose tracking tape cause a vibration by throwing the blade tracking off. But you said you tried a different set of blades & it wasn't 100% fixed.


Quote:
Originally Posted by electrojolt View Post
Blade grip bearings are nice and smooth.


Swaped servos today just to be sure and Cyclic shake still there... comes and goes.... must be some odd vibrations...


tried the CF blades from my own 450 pro and much better... but still not 100%

going to try to lower the AEL gyro gain...
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Old Aug 15, 2012, 08:24 AM
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Quote:
Originally Posted by iflyhelis View Post
Possible bent main shaft, have you ever changed it after your 10 crashes?
To check if it is straight, take it out then roll it on a flat counter top. If it rolls smooth you are golden, if it rolls & you see it go up & down it is time for a new one.

I have even had loose tracking tape cause a vibration by throwing the blade tracking off. But you said you tried a different set of blades & it wasn't 100% fixed.
Oh yeah... 10 crashes.. Replaced 10 shafts.. Grrrrr. I have a feeling that there are some vibes in the front torque tube gears..
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Old Aug 16, 2012, 12:39 PM
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Lowered the roll gain from 40 to 30 and no more shakes...

I notice a small anomaly with blade traking..

flyin tail in, Ii notice that the LT side of the main blades track perfect... one single line very thin.... but the RT side I see the 2 blades with about 2 mm gap between the 2 blades.

my other 2 helis don't do this... when blade traking is off... it is off uniform all arround.

what can it be?
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Old Aug 16, 2012, 02:58 PM
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feathering shaft.
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Last edited by prop bender; Aug 16, 2012 at 02:59 PM. Reason: check spell
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Old Aug 16, 2012, 08:32 PM
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Hey electrojolt

Good to see you flying in a field instead of your backyard!
Sorry to see the flippy over heli go boom boom boom boom boom boom boom boom boom boom.

What kind of heli is this one?
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Old Aug 17, 2012, 12:07 AM
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Hey electrojolt

Good to see you flying in a field instead of your backyard!
Sorry to see the flippy over heli go boom boom boom boom boom boom boom boom boom boom.

What kind of heli is this one?
Hey man... yes indeed this was my 1st time out in a large field, it was great not having to worry about trees.

oh yeah, the crazy heli.. it is my bother's JMT PRO.

It all started when he didn't have the gyro setup correctly and crashed it even before taking off.... the AEL gyro was reversed..

lost 2 tini control arm bearing for the head.

replace head with tarot head.

1st ESC was ran the motor too slow.

then it had a slow tail wable due to tail blade grips too tight.

2nd esc was shuting down the 5v power supply.

It is now finaly flying but with roll/ael gain lowered a bit.
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Old Aug 17, 2012, 09:44 PM
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So...
Did you get a little crazy in the field?

I sooo enjoy high speed dives and leveling out close to the ground and then pulling up again once the heli flies across me.

I don't know that I'll ever be coordinated enough for 3D but I don't care.
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Old Aug 20, 2012, 12:17 PM
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Oh yeah, it was nice to fly in the open space.

So I installed my cf blades on this possessed heli and shakes are completely gone. Even with roll gain raised back to 40.
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