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  #1  
Old 11-16-2011, 09:32 AM
trib trib is offline
 
Join Date: Aug 2005
Location: Virginia Beach, VA
Posts: 474
Default Gear leg stiffener install

After operating for almost 2 years, I've come up with a gear leg shimmy, which occurs on both main and nose gear legs. I've been experimenting with all of the usual fixes and have pretty much stopped it, but am unhappy with the close margin from using proper landing technique to which a shimmy can occur. I've decided to go ahead and install the stiffeners on all 3 legs to increase the margin. I've been documenting how each fix affected the shimmy as I've been troubleshooting, including some videos of the legs with each correction and will post a summary later, after installing the stiffeners.

From the vague directions to install, I understand that the stiffeners are epoxied to the leg, then glass wraps used to install. I had pictured this as sort of wrapping the entire wood stiffener in a sort of "ace bandage" style, covering the wood and leg with an overlapping wrap. From an earlier post, Pierre mentioned 4 single bands of wrap for the stiffener to leg. I was hoping that some who installed the stiffeners could give more detail on how they actually applied the cloth wrap, such as cloth weight, number of wraps (bands), how many layers and width of each wrap. If wrapping in bands, I was thinking carbon fiber might be better. I appreciate any input. Pictures would be even better!
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  #2  
Old 11-16-2011, 09:38 AM
Bob'sRV6A Bob'sRV6A is offline
 
Join Date: Jun 2009
Location: Arroyo Grande, CA
Posts: 227
Default

I bought the stiffeners from woodmanrog@comcast.net and in his instructions for the RV6A, he said Van's no longer recommended the nose gear stiffener. I have not done research into this, but would not install nose gear stiffener anyway, as it would interfer (?) with the Anti-Splat.
I'd like to see some install photos too.
Bob
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  #3  
Old 11-16-2011, 09:43 AM
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woodmanrog woodmanrog is offline
 
Join Date: May 2005
Location: Florida
Posts: 775
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Attach the stiffeners with either bondo or flox to the metal gearleg, preferably to the aft side. after this sets up, then spiral wrap 2" fiberglas tape from top to bottm and whet it out with epoxy resin. Apply a second spiral wrap over the first and make sure they are snug and totally whetted out. I then advise using peelply over the entire assembly to soak up any extraneous resin. Make sure you do this with the airplane lifted off of the gear so as to simulate an in flight condition. Align the stiffeners just as you will be doing for the gearleg fairings Let this set up overnight and you are good to go.
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  #4  
Old 11-16-2011, 01:57 PM
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F1Boss F1Boss is offline
 
Join Date: Aug 2006
Location: Taylor Texas
Posts: 835
Default additional info

Hey Fellas:

Woodman is right, but be sure to wrap the 2" tape at 30 deg min, and wrap the 2nd layer opposite the 1st, using the same 30 deg min.

You can draw some lines on the damper @ 30 deg so you have something to follow.

It's a sloppy job, so plenty of paper on the floor is called for.

Carry on!
Mark
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  #5  
Old 11-16-2011, 04:51 PM
glenn654 glenn654 is offline
 
Join Date: Feb 2005
Posts: 592
Default fairings

Will Van's leg fairings fit after the stiffeners are installed?


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  #6  
Old 11-17-2011, 01:01 AM
nucleus nucleus is offline
 
Join Date: Sep 2006
Location: Bozeman, Montana
Posts: 858
Lightbulb Tires

Tim, did you check your tires for flat spotting?



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  #7  
Old 11-17-2011, 08:27 AM
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woodmanrog woodmanrog is offline
 
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Location: Florida
Posts: 775
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If the stiffeners are built according to Van's plan, the fairings fit with no adjustment needed. For those who do not know-the stiffeners also make a great place to mount flat com antennas to. There is a sacrifice to reception but I rountinely could communicate from 60 Nautical miles out side to side and 40 front to back. Gained 3 knots in cruise just by hiding the antennas.
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  #8  
Old 11-17-2011, 09:03 AM
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olyolson olyolson is offline
 
Join Date: Dec 2009
Location: St Louis, MO
Posts: 1,008
Default Gear stiffners

I had a pretty good shimmy and ordered the stifffners from Roger. Fortunately a buddy (the one that's on the cover of the Vans 2012 calender) had a spare set of 5.00 X 5 tires so I swapped my tires out with the new ones. After removal I discovered some definate flat spotting on the tires. Landings have had no shimmy since then. I had tried messing with the tire pressure for weeks based on some earlier threads. Sometimes I guess the obvious things aren't so obvious at first.

Ps: Roger was kind enough to send my check back.
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  #9  
Old 11-17-2011, 09:25 AM
redhawk redhawk is offline
 
Join Date: May 2008
Location: Boulder, CO
Posts: 198
Default Stiffiners

Hi Tim ,
I did the exact thing on my RV4 as I had a bad shimmy. Just used a hardwood, and shaped it to the leg according to the builders manual, and had fiberglass buddy do the work - he wrapped it like a bandage.
This, in combination with having both my wheels professionally balanced got rid of 99% of the shimmy!
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  #10  
Old 11-17-2011, 09:50 AM
trib trib is offline
 
Join Date: Aug 2005
Location: Virginia Beach, VA
Posts: 474
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Thanks for the replies. As far as checking for flat spots on the tires, I jacked up the wing and rotated the tires and was excited when I found flat spots right away. Later, I realized that of course there are flat spots due to the tire deforming from the weight of the plane. If I check just after landing and taxiing in, no flat spots! After going through all of the tricks, including making spacers for the nose wheel to get the proper bearing pre-load (and actually be able to put the standard torque on the axle nut) and varying tire pressures, etc. I have gotten the shimmy to essentially go away, although sometimes during rollout I get a minor vibration as I transition through an obviously critical speed. This is only for a couple of seconds and is non-existant if I transition quickly through approximately 30 MPH. Always using the proper takeoff and landing technique to keep the nozewheel unloaded as much as possible.

I'm pretty sure the culprit is in the tires, as this is the only real wear in the system and it didn't do this initially. It's about time to change these out and I plan on replacing the worn air-hawks (came with the kit) with Desser Elite retreads. Although everything works OK now, I'm not really satisfied with the small margin to shimmy, so my plan is to put in the stiffeners to increase the margin, not actually to fix a current problem. It's the only sqwalk on the airplane so I want to get rid of it
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