Failure of Nose Gear (now with bolt pics)

[rhill]

Photos of the gear and socket,please. Has the wheel strut been lose of wobbly of late?

[AlexPeterson]

On my 6A, the edges of the hole in the gear leg were quite sharp. I took the gear leg off for inspection after a couple years' use, and I could not get the bolt out without significant effort, like a couple hours' worth. It appeared that the sharp edge on the gear leg hole had caused quite a bit of disruption to the bolt. Additionally, the stock AN bolt seems to leave too much clearance, allowing some wobble (even if not perceived). There is discussion elsewhere on these forums about using a close tolerance bolt in this location. I also chamfered the hole in the leg.

It could be causal in this case - very glad nothing worse happened!

[flytoday]

I'll try to get and post some photos of the sheared bolt, strut, socket, etc. I didn't notice any wobble at all. Generally I'm able to land on the mains and briefly hold the nosewheel off. Less than 10% grass field ops.

[mikehoover]

Originally Posted by flytoday

I recovered the sheared bolt and a washer from under the plane. Bolt end had the nut still on it. I might be able to informally get a lab to examine the failure plane. No prior shopping cart wobble.

So the "headless" bolt with nut still on was found out of the hole - it fell out?

[curtis]

With concern for the wear on both the NLG bolt and the hole thru the fitting I removed mine a couple of months ago during the conditional inspection. With over 325 hours my bolt and fitting still looked like new. This was accomplished in less than an hour and I'll probably inspect this more often since it is easier to replace a worn bolt instead of a damaged mount due to a worn bolt.

[Bill_H]

Contact Vans. They might be interested in doing metallurgical tests. Maybe a bad bolt?

[flytoday]

Originally Posted by mikehoover

So the "headless" bolt with nut still on was found out of the hole - it fell out?

I found what looked like part of a bolt, with a nut on it, and a washer on the taxiway right under my engine. I'll assume it fell from my plane.

I'm not a builder, pretty ignorant to the internal structures, so since then I'm learning that it isn't just a simple bolt through a hole.

Carl

[flytoday]

Zoomed in on the right edge of the picture, here's the bolt on the taxiway...



Carl

[RV6_OKLA]

May be a good application for a titanium bolt from Doug's new advertiser!

[ty1295]

If you get a good closeup picture of the break we can fairly easily see if a crack existed prior.

1 Common way bolts break is they get loose, slop, etc followed by sudden load.

We can calculate shear load force fairly easy with diameter and material type. Not a hard calculation at all.