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  #1  
Old 02-20-2016, 05:09 PM
armondo armondo is offline
 
Join Date: Mar 2005
Posts: 74
Default Am I the only one?

After flying the same RV6 since 1996 (1500 hours plus), recently between the speeds of 33 miles an hour to 36 miles an hour, there is a vibration that appears. I have checked wheel pants, tires, bearings, have found no explanation. Am I the only one with this problem. If you know the answer, let me know before I end up on my shrink's couch. Armondo
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  #2  
Old 02-20-2016, 05:18 PM
Kyle Boatright Kyle Boatright is offline
 
Join Date: Aug 2005
Location: Atlanta, GA
Posts: 4,218
Default

How did you check the tires for balance and roundness? My guess is that the problems stem from one of those.
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Marietta, GA
2001 RV-6 N46KB
2019(?) RV-10
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  #3  
Old 02-20-2016, 05:23 PM
Steve Barnes Steve Barnes is offline
 
Join Date: Jul 2008
Location: Santa Rosa, CA
Posts: 580
Default Had a cyclic pulling, vibration

It felt like my brake disc was warped. Pulled the pants to investigate and found one of the 3 #4 bolts was missing that holds the wheel halves together. That would have been a bad day if one of the other ones let go. 1200 hours since new and original bolts. All bolts have been replaced and will do again every 500 hours.

Steve
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  #4  
Old 02-20-2016, 08:11 PM
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RV3bpilot RV3bpilot is offline
 
Join Date: Oct 2012
Location: New Ulm, Minnesota
Posts: 283
Default Shaking tire

Tires can wear uneven leaving them out of balance. I rotated my tires and got a huge shake and found the left one way out of balance. Had to put 1.5 ounces on it!
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New Ulm, MN 56073
RV3b N219BB
420 hours and counting
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  #5  
Old 02-21-2016, 01:46 PM
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Neal@F14 Neal@F14 is offline
 
Join Date: Aug 2007
Location: Wichita Falls, TX
Posts: 2,182
Default

Mine has developed gear leg / wheel shake in the past couple months. Most noticeable when I slow down after a wheel landing. Speeds about the same mid 30's fast taxi. My tires are half worn out and I flipped them around on the rims at last annual to even out the wear. Methinks it's just time for new ones again.
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Airplaneless once again...
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  #6  
Old 02-21-2016, 05:54 PM
rv7charlie rv7charlie is offline
 
Join Date: May 2006
Location: Pocahontas MS
Posts: 3,884
Default

Did you try flying it without the pants on? (Eliminates the pants as a problem.)

Did you check wheel alignment? Toe in or toe out might cause shimmy at certain speeds. If the gear legs are sagging a bit with age, alignment might be a bit out.

Does braking affect the shimmy?

The 1st -4 I owned never had shimmy at all; the one I currently own will shimmy a bit at roughly those speeds on pavement.

Charlie
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  #7  
Old 02-21-2016, 07:29 PM
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RV6airplanePilot RV6airplanePilot is offline
 
Join Date: May 2010
Location: Ft Laudedale FL
Posts: 180
Default me too

it happens, have seen more in the winter than summer. Just balance or replace tires. You already checked for other issues. Also I use and like the wood leg stiffeners. Can be put under leg fairings. Stops or reduces most common shimmy (front to back). But you can still get some shimmy, even with stiffeners.
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Dale
ATP, dreamer and maintainer; but not a builder
RV6a N18XP 960TT (builder: Jerry Cochran)
RV6a flight experience 2100 hrs
Superior IO-360 2007
Hartzell Blended Airfoil Prop
Dual LS EI, Dual Battery
GRT HX efis & RAIM GPS, 2 axis GRT autopilot
G696, GDL39 WX, Traffic
Dynon D10
Gear Leg Stiffeners from Woodmanrog
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  #8  
Old 02-22-2016, 08:30 AM
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jdeas jdeas is offline
 
Join Date: Mar 2006
Location: SoCal
Posts: 626
Default don't forget the tail wheel

Just replaced the tail wheel bearings to eliminate a buzz/vibration. Has it been more than a couple of years since you changed those bearings?
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----------------------
RV-7 N314SY (KWHP)
IO-360-B1B

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  #9  
Old 02-22-2016, 11:37 AM
ERSANDALL@AOL.COM ERSANDALL@AOL.COM is offline
 
Join Date: Oct 2011
Location: Bonsall,CA
Posts: 24
Default Shimmy

At 31 knots I developed a vibration in the nose wheel. Pretty violent. Went Anti-Spalt bearings and balance, flew with the wheel pant on and off, no change in the vibration.

Had a friend chase me down the taxi way up to 35 knts and take a video with his iPhone. The left main gear started to shimmy so bad that it set up a sympathetic harmonic to the right main gear, which transferred to the nose gear. Quite educational.

Placed the wooden/fiberglass fix on both main gears, and added Sun-Tech Innovations dynamic wheel balancer to the left main gear. Solved the problem.

I do recommend the folks at Anti-Splat and Chris at Sun-Tech.

Hope this helps.
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  #10  
Old 02-22-2016, 11:39 AM
ERSANDALL@AOL.COM ERSANDALL@AOL.COM is offline
 
Join Date: Oct 2011
Location: Bonsall,CA
Posts: 24
Default

At 31 knots I developed a vibration in the nose wheel. Pretty violent. Went Anti-Spalt bearings and balance, flew with the wheel pant on and off, no change in the vibration.

Had a friend chase me down the taxi way up to 35 knts and take a video with his iPhone. The left main gear started to shimmy so bad that it set up a sympathetic harmonic to the right main gear, which transferred to the nose gear. Quite educational.

Placed the wooden/fiberglass fix on both main gears, and added Sun-Tech Innovations dynamic wheel balancer to the left main gear. Solved the problem.

I do recommend the folks at Anti-Splat and Chris at Sun-Tech.

Hope this helps.
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