RV-8 Gear bolt torque

[olyolson]

I am the second owner of an RV-8 and recently read a thread about checking the security of the 3 main gear attaching bolts on each side. Just finishing the second annual with my mechanic and I removed the access panels so now would be a good time to check the bolts. I looked through the plans documents and the construction manual on the USB I got from Vans. I can?t seem to find the right page that discusses the recommended torque values for these bolts. Maybe reviewing the paper plans I have at the hangar would be a better plan.

Anyone know these values and what page I can find this info?

[rv8ch]

Steve Smith created a really useful thread here:

http://www.vansairforce.com/communit...ad.php?t=42630

This is a "must read" for any RV-8 owner.

[NLPete]

Look on page 8-19 for the proper procedure and torque values. My page is dated 5/28/04.

[fl-mike]

page 8-44 in my manual.
>>>> snip >>>> (bold by me)
When tightening the nuts on the NAS bolts that attach the U-803 Outboard Attach Brackets to the fuselage, a
socket can be fitted to the nut with the use of a universal joint, and an assortment of different length extensions
to allow the torque wrench to be located outside of the L.G. Box Assembly. Tighten the nuts on each outboard
attach bracket by first hand-tightening each nut until it just contacts the washer, then alternate between them,
tightening in 5 in./lb. increments until reaching the final torque of 240 in/lbs. This will leave a gap of approximately
0.030-inch between the face of each outboard attach bracket and the U-805-1 Outboard Wear Plates.
CAUTION: DO NOT over tighten these bolts. Doing so will bend the outboard attach bracket and actually
weaken the assembly. Check these bolts and re-torqued after the first ten flying hours, then again
at 50 hours, and annually thereafter. Failure to do so could lead to premature wear. The consequences
of a loose gear leg are easy to imagine. If you put the proper torque on the bolts and there is less than the
required .030 gap, then file or machine the faces of the outboard attach bracket until the correct gap is obtained.

Torque the remaining landing gear attachment bolts to the standard values for each bolt size and nut type.

[Bob Kuykendall]

I would recommend sending a cheap endoscope down the tower and seeing what type of nuts are there. If they're the MS21042-6 or NAS679A6 nuts, I would recommend replacing the bolts with NAS6606-27 and the nuts with NAS1804-6.

We've seen many instances where builders complained about having to re-torque the NAS679 nuts because they've loosened up. But what's happening is not that the nuts are loosening, but rather that they are being stressed beyond their limits and actually leapfrogging over the threads of the bolt. Our tests showed that the NAS1804s are about 30% stronger than the NAS679, and that appears to be enough more that builders aren't finding them loose like the NAS679s. Steve Smith, who started the "Breaking News" thread, installed the 1804s during his initial build, and we've checked them at every condition inspection since and I don't think they've never needed re-torquing.

[Wunderon]

Wondering what others use for prevailing torque when tightening from the (NAS) bolt head? I?m at around 80 in/lb (target 320 in/lb).

[Pilot135pd]

Originally Posted by Wunderon

Wondering what others use for prevailing torque when tightening from the (NAS) bolt head? I?m at around 80 in/lb (target 320 in/lb).

I'm almost sure they address that in that thread.