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Removing main gear leg fairing

Sam I Am

Member
I'm in the process of upgrading all the hoses on my RV9A that I purchased 3 years ago. Yesterday I attempted to remove the main gear leg fairings to replace the aluminum tubing brake lines with TS Flightlines brake lines. What I found appears to be fairings that are formed around the legs with no seam to remove them now. They are rock solid on the leg and appear to be filled with foam. The pic is from the floor skyward. I cannot find a wire attaching to a piano hinge. Anyone have advice for removing these without destroying the fairings and having to make new ones? If I do have to make new ones, is this a big job for a novice? Would the intersecting fairings have to be made over as well? Thanks in advance for any help.
 

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I'm in the process of upgrading all the hoses on my RV9A that I purchased 3 years ago. Yesterday I attempted to remove the main gear leg fairings to replace the aluminum tubing brake lines with TS Flightlines brake lines. What I found appears to be fairings that are formed around the legs with no seam to remove them now. They are rock solid on the leg and appear to be filled with foam. The pic is from the floor skyward. I cannot find a wire attaching to a piano hinge. Anyone have advice for removing these without destroying the fairings and having to make new ones? If I do have to make new ones, is this a big job for a novice? Would the intersecting fairings have to be made over as well? Thanks in advance for any help.

Someone may have other ideas but I believe there is no way to remove what I see in the photo other than to destroy them. Van's sells a leg fairing kit for the round rod landing gear and it comes with instructions.

The upper and lower fairing will need to be remade. The odds they match the shape of the new fairing are not good
 
Here's what I found

I went to the hangar yesterday with an attitude of adventure having no idea what was below the pretty fairings. After 4 hours, I successfully destroyed the left fairing to remove. The builder had no expectation of inspection of the main gear without great effort. He had fiberglassed the wood shims, brake line tube, and fairing into a great mass all the way down the gear. I used John Croke's recommendation for using the oscillating saw and that worked excellent. The other leg will not take as much time to remove as I won't be in salvage mode like yesterday.

Questions for the brain trust:

Many areas of paint were removed over time from rubbing where there was no glue between the wood and leg. I plan to sand down the gear leg to remove all old glue then prime and paint with rattle cans to prepare for the next 18 years. Any other suggestions?

How important are the wood dampening strips for shimmy control? If I place them on the gear legs, shouldn't they be glassed onto the leg without incorporating the new brake lines and fairing? How do I incorporate the shims to prevent chaffing of the leg like I found this time?

Any other suggestions?

Thanks to Gary and Stu for your excellent advice yesterday. Stu, you have excellent content on your YouTube channel!
 

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Late to the game, but you can use a hacksaw blade or maybe a reciprocating saw to split the trailing edge. BTDT. Drill a couple of holes in the TE for clekos before you do that, so you get good alignment when you glue 'em back together at the TE.
 
That's if they are not epoxied to the rest of the stuff

Hi Kyle, As I wrote, the builder fiberglassed and epoxied everything into one. There was not way to separate the fairing from the gear, underlying wood and brake tube for the nice expoxy/fiberglass encasement. I suppose great for shimmy, not so good for maintenance and inspection. Thanks for your reply!
 
You're clearly in for a new fairing build here. And all I could suppose is that leaving the strut dampers off or changing their characteristics would change the way you craft behaves on the ground.

Were you satisfied with the damping before the tear down?
 
What was wrong with the original aluminum tubing?

The reason I'm asking, is that my 65 year old Cessna has that and they are leak-free; I'm planning on using that tube for my RV-3B.

Thanks,
Dave
 
What you have is standard for a lot of early RVs. Some people did the wood stiffener wrapped with glass as a shimmy preventer during construction, others on an as needed basis. I don’t know how many actually needed it. The foam encapsulation was excess then and now. Usually the solid brake line was taped to the front of the leg, no foam.

The upper fairing, built in place, kept the fairing in alignment with help from the one on the wheel pant.

Be sure to remove all scratches on the gear leg before priming it.
 
You're clearly in for a new fairing build here. And all I could suppose is that leaving the strut dampers off or changing their characteristics would change the way you craft behaves on the ground.

Were you satisfied with the damping before the tear down?

Hi Bill, Yes I was satisfied, never had a shimmy issue with the previous setup. So...without the dampers, what's the probability of a shimmy issue going forward? I spoke with an RV guy this afternoon from another part of the country and he said it is uncommon to add the dampers in his neck of the woods and not an issue.

What was wrong with the original aluminum tubing?

The reason I'm asking, is that my 65 year old Cessna has that and they are leak-free; I'm planning on using that tube for my RV-3B.

Thanks,
Dave

Hi Dave, There was nothing wrong with the previous setup at this point. Just 17 years old and concerned with cycling fatigue of the aluminum tubing. Your Cessna likely has power steering :eek: instead of using brakes. Many more cycles on an RV. My A&P IA friend who makes his living working on the older stuff pushes for maintenance on outdated parts. He was working on a Cherokee today about the same vintage as your Cessna that the right side main gear went 90 degrees of travel upon landing resulting in a ground loop because of metal fatigue of the main frame of the gear. I don't like these kinds of surprises! I was glad I did decide to replace the brake lines for the chaffing that was going on the gear legs in the uninspectable area of my plane. Going forward, I will be able to inspect! Thanks for the question.

What you have is standard for a lot of early RVs. Some people did the wood stiffener wrapped with glass as a shimmy preventer during construction, others on an as needed basis. I don’t know how many actually needed it. The foam encapsulation was excess then and now. Usually the solid brake line was taped to the front of the leg, no foam.

The upper fairing, built in place, kept the fairing in alignment with help from the one on the wheel pant.

Be sure to remove all scratches on the gear leg before priming it.

Hi Bruce, thanks for that. I spent today polishing the gear legs to remove the marks and they are ready for primer. After reading the construction manual, specifically the portion on the wood dampers, I'm going to try without them this time. I will use the procedures for mounting the fairing based on Van's recommendations so I can adjust, remove, and add underneath as needed.
 
I prefer hard aluminum lines over hoses any day. They last indefinitely (except in the case of mechanical chafing). There are exceptions where hoses are better like on engine fluids and movement areas like rudder pedal master cylinders. There is no meaningful fatigue in a hard lines due to hydraulic pressure cycling. And with a proper flexing coil movement cycling isn't an issue. Hoses are nice when working on brake calipers but those could be short lengths right at the brake itself. If your IA told you that hard lines wear out he needs to talk to a materials expert, structural engineer or metallurgist.
 
I prefer hard aluminum lines over hoses any day. They last indefinitely (except in the case of mechanical chafing). There are exceptions where hoses are better like on engine fluids and movement areas like rudder pedal master cylinders. There is no meaningful fatigue in a hard lines due to hydraulic pressure cycling. And with a proper flexing coil movement cycling isn't an issue. Hoses are nice when working on brake calipers but those could be short lengths right at the brake itself. If your IA told you that hard lines wear out he needs to talk to a materials expert, structural engineer or metallurgist.

I agree - hardlines are used all over aircraft where they are intended not to move, and to last the life of the structure. Hoses are used to bridge moving parts. They both have their places, and replacing hardlines “just to replace them goes against the engineering of the aircraft. Most IA’s are not design engineers....
 
My RV7 had no stiffeners originally. In that configuration I had some small shimmy problems and also found the plane very "skippy" on touch down. Any touch down other than perfect resulted in a rebound or 2...

The stiffeners resolved both problems. The change in landing characteristics was huge enough I frequently recommend them to anyone learning to fly an RV with out them.

Although I glassed mine on; if I were to do it again I would use high quality gaffing tape as others on the forum have had good luck with.

PS: If you need to trim the length of the stiffeners, trim the big/top end. That will let you slide the stiffener up the leg further, giving more clearance inside the fairing.
 
I was going to say, maybe re-asses the need to replace the brake lines.
Too late now. Adventure begun.


What was wrong with the original aluminum tubing?

The reason I'm asking, is that my 65 year old Cessna has that and they are leak-free; I'm planning on using that tube for my RV-3B.

Thanks,
Dave
 
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