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Modefo's RC Helicopters . XHELI.COM . Autography FlightPower

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Aerial Photography and Video > Askman mount Vibration?
 
 
starjoe
Heliman
Location: PA

I picked up an Askman mount for my e620 and am having difficulty sorting out a vibration issue. Before I attached the mount, I made sure the heli was as vibration free as possible and never had an problems with vibration before the mount was attached.

The weird thing is that it comes and goes. Sometimes it is worse than others without changing anything. I have tried different head speeds with varying success, using double-sided tape between the quickmount plates, placed foam between the plates, and tried moving the cg slightly. Sometimes it will start shaking so badly, that I have to land for fear of damaging something. Any ideas?

If anyone has a 30size askman mount, can you let me know how you are mounting it to the heli?

Thanks
10-01-2008 03:39 AM
 
 
HiroboEric
Veteran
Location: Los Angeles, CA.

Try using soft head damper with silicon based axel grease. Also make sure you blade have snug and equal tension on both side. The blades should give together.

Eric Pacheco, AirWorksRC.com
10-01-2008 03:45 AM
HOMEPAGE  
 
 
ErBr
Heliman
Location: Montreal, Canada

After putting some foam coming from a camping mat, all the vibrations were gone. Before that, 90% of the photos were blurred. Now, 90% perfectly clear at 1/500 sec with a G9 camera.

10-01-2008 04:07 AM
 
 
starjoe
Heliman
Location: PA

Thanks for the replies.

I have tried changing out the red dampeners for the blue w/ silicone grease and it actually got worse. I will give the blade tightness a check.

I have some 3/8" foam between the skids now, I will have to try some thicker foam and see if that helps.
10-02-2008 03:06 AM
 
 
monterey_tip
Veteran
Location: Monterey, Ca - USA

Hey Starjoe,
I have the same problem with mine on the Logo 20 with 720 blades. I did the same thing, pulled the head apart, cleaned and greased everything and it still does it. I don't seem to remember it happening when I had the pan mount hard bolted to the top frame. I'm starting to suspect it is due to this wobble: http://aircam.smugmug.com/gallery/3...0041_TDXpT-A-LB

Does yours have this much movement? Mine bounces like a bobblehead.

Tip
10-05-2008 06:53 AM
HOMEPAGE  
 
 
cameraman
Heliman
Location: Yorkshire, England

Tip...
[Mine bounces like a bobblehead]

I'm not surprised, I've just seen your polar bear encounter

Cheers, David
10-05-2008 10:57 AM
 
 
starjoe
Heliman
Location: PA

Yes Tip, mine wobbles about the same as yours.

If use a small bungee cord in the front and rear of the mount to lock it from rotating, the vibration is pretty much gone. Unfortunately, you lose the 360 rotation of the mount.

I have cut some neoprene and rolled it up, then zip tied it between the quick mount but have not had a chance to test it yet without the bungee cords locking the mount. I am also thinking of reinforcing the top piece of carbon to stiffen it up a bit.
10-06-2008 01:37 AM
 
 
monterey_tip
Veteran
Location: Monterey, Ca - USA

Nothing like playing peek a boo with a polar bear


I took everything apart today to test fly the heli with just skids and it flys smooth as silk. I really tightened up the nuts on the plate and the bolt to give it a little more resistance. It's more stable, but hopefully won't tear up my pan servo.

Before, I had some nylon spacers and bolts holding the two together and it was fine...no vibes, but as you mentioned, no 360 pan either. To make it easier to switch, I strapped some zip ties front and back and had the bad vibes. I like your neoprene rolled between the plates idea, it seems like that should work. I might try that next.

Tip
10-06-2008 02:19 AM
HOMEPAGE  
 
 
starjoe
Heliman
Location: PA

Tip,

The neoprene seems to have helped slightly, as I am able to run a slightly higher head speed, but it hasn't cured it.

Like you, I have tightened every bolt I could, especially the top metal piece with the four screws around the self lock nut. I haven't had a chance to try it yet, but when I placed the heli on the mount it still seemed to wobble quite a bit. The legs seems to be too flex able allowing a slight oscillation/vibration in flight that gradually get worse. I think my next step is going to be stiffening the legs a bit.
10-07-2008 02:19 AM
 
 
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Aerial Photography and Video > Askman mount Vibration?
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