RunRyder RC
WATCH
 1 page 1288 views POST REPLY
HomeAircraftHelicopter
e-
Align
T-REX 450 › Unexplained shaking
08-21-2014 08:54 PM  4 years agoPost 1
kenkadish

rrNovice

Dewitt, NY

My Posts: All  Forum  Topic

I need a little help/suggestions regarding my Trex 450 Pro DFC. All stock with the exception of AR7200bx controller. I have about 135 crash free flights.

My heli has developed a shake, not a tail wag, but a shake which is most noticeable watching the skids. It shakes in FF and in turns. Not quite as noticeable in a hover.

This shaking just started, and prior to this, the heli was butter smooth in flight.

I have checked everything over, and all looks good. Replaced the dampeners with Align DFC dampeners, although the old ones looked just fine, and it made no difference. Also switched blades; again, no difference.

Main bearings look and feel good, main gear has all its teeth, swash and DFC links are perhaps slightly loose but nothing extraordinary.

Blades track perfectly, and there is no vibration when I spin up. The wobble seems to start after about 2 minutes of flight, and it doesn't matter if I am in normal or IU mode. Turned down dial 1 of the BX...made no difference. BTW, BX has all dials in default position.

I am a sport/scale flier, absolutely no 3D anything, and not so much as a hard landing.

So what do I check from here?

Doesn't make sense that it would be the main or feathering shaft...do I replace the thrust bearings in the head?

Just looking for suggestions.

TIA,

Ken

Learning every day!

PM  EMAIL  HOMEPAGE  Attn:RR  Quote
08-21-2014 11:57 PM  4 years agoPost 2
wrongler

rrProfessor

Brewerton, New York

My Posts: All  Forum  Topic

What is the difference in head speed between Normal and Idle up.
Most times an increase in head speed will limit the shake.
You say you don't have it until 2 minutes into the flight.
Maybe bad Lipo ???

Bill Whittaker

PM  EMAIL  GALLERY  Attn:RR  Quote
08-22-2014 02:32 AM  4 years agoPost 3
mrgnz

rrNovice

new zealand

My Posts: All  Forum  Topic

have you taken a look down the list at my problem, MRGNZ, wobble trex 550 dfc ? does it sound the same ?

PM  EMAIL  GALLERY  Attn:RR  Quote
08-25-2014 02:25 AM  3 years agoPost 4
mrgnz

rrNovice

new zealand

My Posts: All  Forum  Topic

hi its me again check out my post the people there have helped me find my wobble, doubled up the gyro tape and turned the gain down 10% on the gyro and its good as gold now.

PM  EMAIL  GALLERY  Attn:RR  Quote
08-26-2014 11:45 AM  3 years agoPost 5
Richardmid1

rrProfessor

Leeds, England

My Posts: All  Forum  Topic

Check for feathering shaft bolts coming loose or main blades being too tight. Also balance the main blades statically AND dynamically.

Other than that and assuming the main shaft and spindle is straight and the head block isn't bent it's simply a resonance issue that can be cured by increasing the head speed as already mentioned.

60% of the time, it works every time!

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
08-26-2014 01:32 PM  3 years agoPost 6
dkshema

rrMaster

Cedar Rapids, IA

My Posts: All  Forum  Topic

turned the gain down 10
I think you mean turned the pots from 12 o'clock to the 10 o'clock position.

-----

If this suddenly began, consider that you may have inadvertently ended up bending a shaft slightly. Also, check the torque tube and its support bearing. The support bearing wants to be off-center so you don't set up a standing wave in the tube, causing lots of vibes.

-----
Dave

* Making the World Better -- One Helicopter at a time! *

Team Heliproz

PM  EMAIL  GALLERY  Attn:RR  Quote
08-26-2014 08:31 PM  3 years agoPost 7
mrgnz

rrNovice

new zealand

My Posts: All  Forum  Topic

yes sorry I did mean turn the pots down 10%

PM  EMAIL  GALLERY  Attn:RR  Quote
08-28-2014 12:53 AM  3 years agoPost 8
kenkadish

rrNovice

Dewitt, NY

My Posts: All  Forum  Topic

Sorry to be a little late in the response/update. Disassembled the head, inspected the feathering shaft and thrust bearings, and re-greased just for good measure.

Checked the screws for the landing skids.

No difference.

Re-programmed the Ar7200 just for practice and got to checking servo movement.

I found that the aileron servo (left side) has a jitter/shake when slowly being moved around mid-stick.

I could easily re-create and repeat this condition, and am thinking this is the cause of the shake.

New servo on the way, but of course, now the shake has disappeared???

More to follow, and thanks for the indulgence.

Ken

Learning every day!

PM  EMAIL  HOMEPAGE  Attn:RR  Quote
09-10-2014 09:29 PM  3 years agoPost 9
timmay

rrApprentice

Orange County CA

My Posts: All  Forum  Topic

Its the servo!
Its the servo. I was running Bx at one point on my 450 Pro. Had about the same amount of flights as you. My Align 410M servo developed slop. It would shimmy in a hover. Replaced bad servo and issue was gone.

PM  EMAIL  HOMEPAGE  GALLERY  Attn:RR  Quote
WATCH
 1 page 1288 views POST REPLY
HomeAircraftHelicopter
e-
Align
T-REX 450 › Unexplained shaking
 Print TOPIC  Make Suggestion 

 6  Topic Subscribe

Tuesday, August 21 - 4:45 pm - Copyright © 2000-2018 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online