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Gear Issues...

R

rexbaker

Member
Hey everyone, I have a recently purchased RV-6 that was bought for me by a buddy of mine while I was out of the country for a while. After finally getting to fly it a little bit, Ive notice from time to time the right main wheel seems to be toed out, and appears as though someone has smacked it on the ground too hard once or twice.

I was curious if anyone has any ideas or knowledge of how to fix this problem without removing the gear, or if someone could point me in the right direction to have the gear bent back to the proper angles.

Thanks for the help in advance.

Rex
 
Gear Leg Straightening

If it is the gear leg that is bent consult Langair Machining to see if it is repairable. http://www.langair.com/ Langair is the company that makes the gear legs for Vans and he also straightens them.

If it is the gear mount then it will need to be repaired or replaced. I have seen the bolt hole that locks in the leg to the mount elongated causing the issue you discribed. This was evident by jacking the plane and observing movement of the leg. In that case it was drilled to a larger size and a larger bolt installed.

Good Luck.

Eulice
 
I don't believe Langeair can or will rebend the gear leg.

If you do need to replace the gear leg, depending on when your mount was manufactured, you might need to get an undrilled gear leg.
The 2004 and earlier gear legs were match drilled to the mount. In late 2004/early 2005, they began jig drilling the mount & gear leg holes.
I ran into this problem as I purchased a pre-drilled gear leg and attempted to match it to an early mount. I ended up with a toe-out condition.
I was able to oversize the hole and re-align to correct the toe out.
 
If it is not the actual gear leg that is bent, but mis matched bolts and holes, what should I be looking for if I jack up he airplane? Will the wheels actually be loose in the motor mount?
 
Oh yea...and if oversizing the holes is the correct solution, are there any recommendations besides pulling the motor and taking the mount and and gear legs to a machine shop to have them drilled and matched?
 
Gear Legs

Once you have the plane jacked up, try to move the leg or legs forward and aft. Taking the weight off the gear should allow movement if the holes are elongated. If there is no movement, and the wheels are toed, then you probably have bent legs or mount.

I believe taking the engine and gear mount off the plane are the only way to drill to a larger size. Before I did that I would make sure it is not just a worn bolt. You should be able to remove the bolt and inspect with the plane jacked up. You should also be able to see the elongated hole with the bolt removed, if that is the problem.

Eulice
 
Langaire straightens anything they make!!!

We will most definitely straighten that leg for you as long as it is not bent too bad. And, if you are still able to fly on it, then it is definitely not bent too bad to be fixed.

If you can take the weight off that leg and twist the leg in it's mount, then the hole in the engine mount is likely elongated. The engine mounts usually show wear before the gear leg when things start to go bad. If it is not too terribly out of shape, you can just ream it up to an oversize bolt. You can get piloted reamers that guide themselves through the holes and do a nice job.

There is a member on the forums that sells the oversize bolts. The nominal size bolt is 0.3125 (5/16), my memory says he has bolts that are 1/64 and 1/32 over. That is the best solution in my opinion, but others have found different solutions they liked better.


If it is just a bent gear leg, then you can just contact Langaire for details on how to get it fixed.

Richard Squires
(Langaire Aircraft Parts LLC)
 
Richard@Langair said:
We will most definitely straighten that leg for you as long as it is not bent too bad. And, if you are still able to fly on it, then it is definitely not bent too bad to be fixed.

If you can take the weight off that leg and twist the leg in it's mount, then the hole in the engine mount is likely elongated. The engine mounts usually show wear before the gear leg when things start to go bad. If it is not too terribly out of shape, you can just ream it up to an oversize bolt. You can get piloted reamers that guide themselves through the holes and do a nice job.

There is a member on the forums that sells the oversize bolts. The nominal size bolt is 0.3125 (5/16), my memory says he has bolts that are 1/64 and 1/32 over. That is the best solution in my opinion, but others have found different solutions they liked better.


If it is just a bent gear leg, then you can just contact Langaire for details on how to get it fixed.

Richard Squires
(Langaire Aircraft Parts LLC)
Click to expand...

I am very interested in hearing about the ablility to straighten out a bent gear leg. In out conversations, this could not be done. This is why I ended up oversizing the gear leg/mount holes.
 
jacking the aircraft

You can jack it from the tiedown hardpoint about halfway out on the bottom of the wing. Just put a suitable bolt in there and put your jack on the bolt. Make sure your jack can not slip off the bolthead though!!! That would be catastrophic!!!!!
 
jacking tip

....just as you would block up your car when jacking, I built a sawhorse the height of the firewall, and after jacking, supported the fuselage with this so there was little weight on the jacks, and the ship was rock solid.
You may be tugging and torqung to remove the gear leg, so you need it secure!
Some guys have a lift point in the hangar, and can strap and support the fuselage that way.
 
One more piece of amplifying information. The gear, at low speed only, has a shimy while on the ground. I thought it was rough pavement based on how random it was, but it seems to me that could be indicivtive of a worn bolt or elongated mounting holes.

Does any one know who sells the enlarged bolts on the forum to fix this? And does anyone have any further suggestions that would not require to pull the motor mount off the airplane if this is the issue?

Thanks for all the help so far!

Rex
 
Rex - perfectly aligned gear can shimmy. Don't worry about it until after you fix the gear. It may or may not go away and if it doesn't you can start investigating the thousand theories of why this occurs and the remedies that sometimes work and sometimes don't.
The worst shimmy I ever felt was on Vans 7. But it has a gazillion hours on it too.
 
jacking

I have found that it is much safer to remove the cowling and use the engine mount with adequate strength webbing to lift the airplane with an engine hoist. As others have said, build a sawhorse the correct height and place it under the firewall with a towel draped across it once you have it high enough.

I used to use the "bolt in the tiedown hole" method and nearly had a catostrophic accident. I decided that buying a used engine hoist from someone was much cheaper than repairing a wing. Good luck.
 
gear

If it is just the socket holes that are oversize, properly drilled and reamed doublers can be welded to the sockets. Doubler should be at least the thickness of the socket. If you can find someone who is really good with a TIG or MIG, the doublers can be LIGHTLY tack welded with the gear leg in place without compromising the heat treat of the gear. One small tack weld, let it cool completely, than another tack, etc. You will then have to remove the mount to finish weld.

The bolts should be a tight fit in the gear and the socket. The common mistake is drilling and/or reaming with a 5/16 drill or reamer. The AN bolts are typically .001 to .0025 under 5/16. This translates to quite a bit of movement at the end of the axles. I have reamers that start around
.309 and I enlarge the hole .001 at a time until the bolt is a drive fit. I don't like to go to 3/8" because if you make a mistake there is no easy fix.
The slightly oversize AN5 bolts are hard to find.
 
Make sure you inspect the engine mount tubes near the fitting carefully,,,I have seen 2 RV6's with cracked and broken tubes.
 
Does anyone know what size the bolts on the gear leg are and where I can get them? I am trying to put together all the parts before I start tearing apart the plane...

Rex
 
I jacked the airplane up yesterday afternoon to check if the gear leg had any play in it, and it was rock solid in the mount. I guess that takes out the possibility of an elongated hole. I also flipped the tire around so it wears a little bit better. Tire has been wearing on the inside, and I understand the normal wear pattern on an rv's tires are on the outside.

Anyone have any other thoughts about what it could be or other ways to fix the alignment on the aircraft? Right wheel has a pretty good toe out and both gear look like it was dropped from a stall from about 10 feet.

Thanks!

Rex
 
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