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11-13-2011, 05:29 AM
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Join Date: May 2005
Location: Florida
Posts: 774
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Stiffeners available
I still have some gearleg stiffeners available for sale. Email me for info at:
woodmanrog@comcast.net
Temporarily you could reduce your tire pressures to about 25lbs and see if this doesn't help. It sounds like you have the typical oscilliting gearleg problem.
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11-13-2011, 07:11 AM
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Join Date: Aug 2006
Location: Twin Falls, ID
Posts: 683
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Put the gear stiffeners on. Not only gets rid of the vibration witch can get very bad sometimes but dampens out the gear for much better landings. Gets rid of the pogo stick action also. Don
__________________
RV 7 N212MD Flying as of 12/22/2007
Backcountry/TCOW Super Cub flying 03/12/2011
Next project?
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11-13-2011, 04:42 PM
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Join Date: Jan 2005
Posts: 369
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First check your tire inflation. If i put too much in mine (+38 psi) i get shimmy. With less pressure, no problem.
Mark
__________________
Mark Strahler
RV-6 (Purchased flying)
KFFC-Peachtree City, GA
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11-13-2011, 04:48 PM
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been here awhile
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Join Date: Dec 2004
Location: North Alabama
Posts: 4,301
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Quote:
Originally Posted by strahler13
First check your tire inflation. If i put too much in mine (+38 psi) i get shimmy. With less pressure, no problem.
Mark
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Tire inflation is a major factor, don't hesitate to drop the pressure. After the tires have worn out of round a bit I find 24 psi will prevent most shimmy on my RV-6 and still perform safely.
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11-13-2011, 07:09 PM
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Join Date: May 2007
Location: Granbury, Tx
Posts: 78
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check the air pressure. ?To much air will increase to landing gear shake. Less pressure means more friction and helps the gear track without the shake.
sam
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11-13-2011, 07:34 PM
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Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
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I agree that tire inflation pressure is also important, but I didn't mention it in my previous post because a pressure adjustment should not be used to compensate for an out of round or out of balance condition that is causing leg shimmy.
First verify everything is working correctly with the tire/wheel, then use pressure adjustments if there is still an issue.
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11-14-2011, 07:53 AM
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Join Date: Jan 2005
Location: Round Rock, TX
Posts: 211
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Shimmy
When I owned my Bingelis RV-3 it would shimmy in the 20-25 kt speed region while taxiing or after landing and lowering the tail wheel . It was happening because the springy gear legs wanted to track out then back in with the tail on the ground. It never happened with the tail off the ground. Solution was to put wooden stiffeners on the back of the gear legs and to balance the wheel pants. Once I did that the shimmy went away.
__________________
Stu McCurdy (Falcon)
RV-8, 78TX, Flying
Formation Flying, Inc (FFI)
Falcon Flight
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11-14-2011, 09:31 AM
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Join Date: Jan 2005
Location: 57AZ - NW Tucson area
Posts: 10,011
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Quote:
Originally Posted by Sam Buchanan
Tire inflation is a major factor, don't hesitate to drop the pressure. After the tires have worn out of round a bit I find 24 psi will prevent most shimmy on my RV-6 and still perform safely.
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Goodyear specifies a service load rating of 800 pounds (per tire) at a 31 psi pressure for their 4 ply 5x5.00 tires.
If you are using the 4 ply tires at 24 psi it is way outside the manufacturer's service load rating.
Page 4 of this PDF file
http://www.goodyearaviation.com/reso.../datatires.pdf
Interesting data here -
http://www.goodyearaviation.com/reso...ngtechinfo.pdf
If you inflate when the plane is on the gear (i.e. loaded) you should add 4% to the inflation pressure...  - just aim 1 or 2 psi higher... 
__________________
Gil Alexander
EAA Technical Counselor, Airframe Mechanic
Half completed RV-10 QB purchased
RV-6A N61GX - finally flying
Grumman Tiger N12GA - flying
La Cholla Airpark (57AZ) Tucson AZ
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11-14-2011, 10:52 AM
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Join Date: Mar 2005
Location: Molalla, Oregon (KOL05)
Posts: 529
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Try this...
Dave,
This sounds like typical gear leg shimmy/vibration. As per the previous suggestions try these out:
- Ensure that the main tires are inflated to 25-28 PSI if using the original issued Aero Classic tires. If using a 'better' grade (Goodyear, Michelin, etc) you may be able to inflate them a smidge higher. Tire inflation pressure is the 1st defense against shimmy/vibration.
- Check for flat spots or other damage. This may be the reason the shimmy gets started in the first place. Balancing the tire may also help. (Are the valve stems aligned with the red dot on the tires?)
- Change runway surfaces... Does it happen on all paved surfaces? What about grass?
- Note what load condition the event starts at? Light or heavy?
- Gear leg stiffeners are typically a 'last resort'. Most of the time shimmy can be solved with proper tire inflation.
- Note what GPS ground speed this occurs at and operate outside of that range if possible. Slower taxi speeds tend to alleviate it.
Most of the time shimmy is a transient event and only occurrs at a specific speed range. This is a well known idiosynchasy of the taper rod gear leg. I have also seen some RV's that when one leg begins to vibrate, it will cause the other to follow. Give me a call at Van's if none of these solutions work...
__________________
Joe Blank
RV-6
IO-320-D1A
Advanced Flight Systems
Van's Aircraft Inc. Technical Support-Retired
EAA Tech Counselor & Flight Advisor
www.westcoastravens.com
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