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Gear leg stiffener clamps

wirejock

Well Known Member
My Mentor Dave Paule came up with the idea. All I did was change the concept on the clamps. The traditional Adel clamps put the stiffener off center and the leg fairings wouldn't fit. I know Adels can be bent but this was cheaper.
Buy two packs of these. Stainless cushion clamps. 11 for less than $5
Harrier Hardware 1.5-inch... https://www.amazon.com/dp/B08CL55T1J?ref=ppx_pop_mob_ap_share

The dimensions in the photo are NOT diameters. They are the location of the new bend from the unbent end.
Using the measurements makes it easier to duplicate and make pairs. if you can measure and fabricate using diameters, knock yourself out. I'm not that smart.

Remove the rubber pad. Make a mark measured from the flat end according to the photo. Bend a little less than 90 at the mark. Shape the clamp round so the two ends come together. I used sockets to reshape them round. Just hold the clamp on a socket and tap, tap, tap. Center the tabs by placing the clamp in a vise and tapping it sideways. Clamp the ends together with a cleko clamp and drill the bolt hole. Cut off the excess. Clean up and replace the pad. Easy peasy.

Edit 11/12/2022
After removing the rubber pads, the top clamp was too big. It had to be removed and the others moved up. The move required one more clamp at the bottom. It was 3" from end to bend.
I ended up with one hole top and bottom both 1/2" from the end and 1/2" from the leg side edge. That leaves about 1/16" gap between the leg and the stiffener for safety and padding.
The other holes land where ever clamps fit best.

20221110_160247.jpg
 
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Howdy Larry and thanks for the tips. I assume you are using aluminum for the stiffener; do you know how wide? (1-1/2"?)

I fooled around with making 1.5" stiffeners and clamps and I did not like the fit under the fairing. I am curious to see how your set up works when the fairings are in place. (I also hope you don't mind me copying yours when you get it figured out!)
 
Done

I just got done with this. I used 3/16” x 1 1/4” 6061. I tapered the lower 8 inches. If i was doing this again, I think I would try 1/8” thick 6061.

I cant speak to 2024 thickness recommendation.
 

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Howdy John. How long were the stiffeners? I have my stiffeners made: 6061 T-6, 1/8" X 1-1/2" wide, about 24" long.

Any issues with yours fitting inside the fairings?
 
Stiffeners

Howdy Larry and thanks for the tips. I assume you are using aluminum for the stiffener; do you know how wide? (1-1/2"?)

I fooled around with making 1.5" stiffeners and clamps and I did not like the fit under the fairing. I am curious to see how your set up works when the fairings are in place. (I also hope you don't mind me copying yours when you get it figured out!)

I have two pieces of 2024 T3 1-1/2X24X.125
They will have to be tapered a little at the bottom. I determined the taper with tokens made from scrap.
 
Copy. Thanks guys. I am starting wheel pant assembly and fit up, I will revisit stiffeners again soon.

Much obliged.
 
Article

Copy. Thanks guys. I am starting wheel pant assembly and fit up, I will revisit stiffeners again soon.

Much obliged.

Mike
I just finished an article on that very subject. Very cool jig that will save you a fortune in swear donations.
Shoot me an e-mail (below). I'll send the draft.
 
Why does it seem like you guys who are about 2 years ahead of me keep having to “wing it” on parts of the build.

Honestly you’re scaring the **** out of me.
 
Some Notes On Origin, Alloys and Size

The concept wasn't my idea, I got it from someone here on VAF. But since I am a retired structural engineer, I had an idea why these work - they decouple the fore-aft stiffness from the up-down stiffness.

Since different alloys of aluminum all have close to the same stiffness, either 6061 or 2024 should work. It's stiffness, not strength, that's the issue.

As for size, I have no idea what's minimally necessary. I'll be using some 1/8" x 1.5" 2024 for my little RV-3B, mainly because that's what I think was originally recommended, but mostly because I have some on hand.

(Edit) The aluminum and the clamps are not dampeners. To dampen vibration you need to absorb some velocity somehow. That would generate a lot of heat. These add stiffness, not damping.

Dave
 
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Impotent

The concept wasn't my idea, I got it from someone here on VAF. But since I am a retired structural engineer, I had an idea why these work - they decouple the fore-aft stiffness from the up-down stiffness.

Since different alloys of aluminum all have close to the same stiffness, either 6061 or 2024 should work. It's stiffness, not strength, that's the issue.

As for size, I have no idea what's minimally necessary. I'll be using some 1/8" x 1.5" 2024 for my little RV-3B, mainly because that's what I think was originally recommended, but mostly because I have some on hand.

Dave

I think it is important to have the metal plate aligned with the center of the round gear leg, and to use the clamps as Larry suggested. I tweaked the Adel clamps, and had to put the aluminum between the clamps halves to get this centered.
 
Winging it

Why does it seem like you guys who are about 2 years ahead of me keep having to “wing it” on parts of the build.

Honestly you’re scaring the **** out of me.

It's that last 90% that kicks your booty. :)
Actually, stiffeners are optional. Vans calls for wooden pieces bonded somewhere. This is easier, more functional and cleaner.

Looks like I'll be removing the clamp rubber. Just a little too much to fit the fairings. Strips of self fusing silicone tape will be used.
 
Not recommended

It's that last 90% that kicks your booty. :)
Actually, stiffeners are optional. Vans calls for wooden pieces bonded somewhere. This is easier, more functional and cleaner.

Looks like I'll be removing the clamp rubber. Just a little too much to fit the fairings. Strips of self fusing silicone tape will be used.

I would not recommend silicone tape.
I figured as the legs flex, the taper of the legs would work the dampener clamps down the leg. So I wanted a tape that had some good adhesive. I followed Paul Dye's recommendation and used a single layer of gorilla tape. The adhesive is strong, and I am hoping the adhesive will "bleed through" over time and keep the clamp from working its way down the leg.
 
I disagree with the effectiveness of the pic in post #3

From looking at the pic from post #3 I really don’t see how the flat piece of aluminum adds much stiffness to the gear leg in the vertical axis. I can see how it adds stiffness to the horizontal axis (keeping the gear from flexing back but not in the vertical direction resisting hundreds of lbs. If you take the flat piece by itself and hold it 4”-6” (the spacing of the clamp) it wouldn’t take much to bend it. You would do much better using 3/4” plywood by 1” to 1.5” wide by a little less than the length of the leg and wrap fiberglass around the full length of the plywood
 
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From looking at the pic from post #3 I really don’t see how the flat piece of aluminum adds much stiffness to the gear leg in the vertical axis. I can see how it adds stiffness to the horizontal axis (keeping the gear from flexing back but not in the vertical direction resisting hundreds of lbs. If you take the flat piece by itself and hold it 4”-6” (the spacing of the clamp) it wouldn’t take much to bend it. You would do much better using 3/4” plywood by 1” to 1.5” wide by a little less than the length of the leg and wrap fiberglass around the full length of the plywood

The whole point is to stop shimmy fore and aft, without affecting the up and down motion of the leg…..and experience is showing that the aluminum bar does a pretty job at this.
 
Silicone tape

I would not recommend silicone tape.
I figured as the legs flex, the taper of the legs would work the dampener clamps down the leg. So I wanted a tape that had some good adhesive. I followed Paul Dye's recommendation and used a single layer of gorilla tape. The adhesive is strong, and I am hoping the adhesive will "bleed through" over time and keep the clamp from working its way down the leg.

Silicone tape really hangs on under the pressure. If it moves during my Phase 1 before the pants and fairings get installed, I will replace with Gorilla tape. I just hate trying to get that stuff off. The gooey residue it leaves behind is a major pain. I'm not opposed to using it. I just prefer to try this first.
 
Thanks for the clarification. I saw gear leg stiffener on the subject line. Should have said something like anti-shimmy bracket
 
Dampener hardware

After some persuasion, the DAMPENERS are installed. I had to switch hardware to...
AN525-10R7
MS21042-3
AN960-1032L
There was not enough room for traditional hardware.
20221114_113135.jpg
 
Just me

I spaced the clamps evenly, you did not. It appeared to me that the gear leg taper is constant, which would imply a even spacing. Your varied spacing suggest the gear legs are not a straight taper.

Just curious what determined your clamp spacing?
 
Spacing

I spaced the clamps evenly, you did not. It appeared to me that the gear leg taper is constant, which would imply a even spacing. Your varied spacing suggest the gear legs are not a straight taper.

Just curious what determined your clamp spacing?

I'm not that smart. I just slipped them in place to find a happy place. Then adjusted position to allow for the tape.
I doubt my custom clamps are dimensionallly perfect either.
 
Article

I sent you an email about your mod. I’d like to put it on my RV-7 during its CI

Thanks
 
Thanks David & Larry for sharing this. Great thing about experimental is the constant improvements that are discovered.
 
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Officially, Vans plans show Wood Damping Strips.
View attachment 33714

This is what it looks like (or can look like) if done the old fashioned way as Larry shows above:

IMG_1931.jpg

IMG_2040.jpg

This is my “new” RV6 - started by someone else in 1992, finished by me last fall. Nobody had tried the flat metal dampener yet. On my original RV6 from 20 years ago, I also did it this way. Probably more time consuming than the flat metal, but the results have been good. No shimmy or shake at any speed.
A plus - with the gear leg fairing properly aligned, I put a flush screw through the fairing and into the wood dampener, which is the hidden under the upper intersection fairing. Holds the leg fairing in the proper place while fitting the upper fairing, and after.

Might need to zoom in………. and flip…..
 
I am eagerly getting ready to do this “axis modulus decoupling” modification because my RV-4 shakes like a dog trying to pass a peach pit on rollout. Question:anyone have issues with the metal clamps (with rubber removed) wearing through the tape and scoring the gear legs?

Easy enough to inspect for every year—just curious.
 
Inspection

I am eagerly getting ready to do this “axis modulus decoupling” modification because my RV-4 shakes like a dog trying to pass a peach pit on rollout. Question:anyone have issues with the metal clamps (with rubber removed) wearing through the tape and scoring the gear legs?

Easy enough to inspect for every year—just curious.

I inspected at 50 hours and found no indication of problems.
I am about to do my conditional inspection at 110 hours and will let you know what i find, but I dont expect much.
 
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