"Clocking" Gear Leg Fairings and Wood Dampeners

[tx_jayhawk]

Hi All,

I just spent several hours obsessing over main landing gear fairing alignment, and I want to make sure the great alignment I have now is retained after removing and reinstalling fiarings. It seems to me that the clamp and possibly (Fairings etc.) intersection fairings are not going to do it to sufficient accuracy. In short, I would like to somehow "clock" the location, so that it is always easy to achieve on installation.

My current thought is to slightly enlarge the fairing centerline notches at the end of the fairings. With the fairing in place, I can then lay down a raised bead of jb weld on the gear leg itself in a "t" pattern in the notch and end of the fiaring. This would serve as a good locater for the fairing. Any other thoughts?

Also, regarding the wood dampener...how necessary is that for a 7A? It does not seem that people are really installing that anymore? Is foam used instead?

Thanks,
Scott
7A Getting Close

 

[flion]

Intersection fairings are the answer. Actually, I also got a tip somewhere and extended the hinge pin that holds the back of the fairing together so that it touched the fuselage. Then I drilled a hole there and left the pin long enough so it engages the hole. However, the intersection fairings are the final word; they will secure the fairings in position.

As for stiffeners, I would not put them on the mains again. The one I have on the nose gear keeps splitting (it's not a glue failure; it's that the grain is parallel to the leg), which probably means I'm being too hard on it. I'm thinking I might try a fiberglass wrap. In any case, avoid foam. It will simply trap moisture near your gear leg; there have been reports on the forum of people using foam (primarily the expanding stuff) and getting pitting on the legs.

 

[LifeofReiley]

Just foam... wood stiffeners are not necessary and really don't do anything except come loose and cause problems.

 

[roadrunner20]

I used foam and have no gear pitting after almost 4 years.
The intersection fairing secures my alignment.

 

[tx_jayhawk]

Main Fairing Twist?

THe instructions are clear about being careful to avoid twist in the fairing. On one of mine it is spot on straight, while the other may have up to 3 or 4 32nds of twist from top to bottom. I redid the trailing edge once using a piece of angle to ensure it was straight, and at this point I've concluded that is about as straight as I will get with that particular fairing (it came a bit twisted).

How much will this effect things? Is up to 1/8" going to be noticeable in handling or other impacts?

Thanks,
Scott
7A

 

[Bob Axsom]

Think about the size of the pitch trim tab vs. the LG fairing

You are right about about need to align the landing gear fairings with respect to twist and the centerline of the aircraft. Misalignment does affect performance - you will probably not care that much and will not know the difference if you are not going for maximum speed but it is part of the overall rigging requirement. You are right in assuming that the cuffs are not going to assure proper rigging. My landing gear fairings are all fiberglass and they are not removable without cutting them off. The trailing edges were epoxied together with an aluminum angle and sacrificial clecos to assure straightness. I used no wood stiffeners on my RV-6A. The strut fairings are cemented in place with foaming adhesive at the top and bottom - they are hollow in the middle (all three of them). Six years of testing, traveling and racing with no problems. Right brake wear will probably be a problem because of the tendency to drag it with right rudder application during takeoff. Be sure to keep the nose caster breakout force up - even though you set it correctly during the build it yields quickly at first and needs to be checked and tightened soon in the early operational phase. After a year or so it seems to hold well but it is an annual condition inspection check sheet line item.

Bob Axsom