Can you trim F-802L-1 to fit U-803 landing gear brackets?

[inktomi]

I may have just destroyed my project. I'm having a lot of trouble aligning the U-803 brackets 3/16" in from the outer edge. I actually didn't do it on one side, and drilled the longeron with it flush - which means that hole is probably impossible to get a washer and nut on due to it being so close to the edge of the inside.

You can see how far off from center it is. What do you think? Is it impossible to get the washer and nut on, or is it possible? If this is a mistake that isn't recoverable, I'm pretty much hosed.




The reason for this is that I'm worried about edge distance on the skin and F-802L-1. If I try to put the bracket 3/16" in like the directions say, I will need to remove quite a bit of the edge of the aft Zee channel (F-802L-1) - see the arrows below.



If I have things flush with the edges, then this would align as I've trimmed it right now. But you end up with the hole not being centered, and I think that might make the whole thing impossible to actually assemble.

Any ideas? I really hope I didn't just turn my fuselage into trash. These parts are extreamly buried, and some of the first that go together. You can see below the aft F-802L-1 sticks out further than the fore one, and it interferes with the gear bracket. I'd have to trim it back probably 2/16" or so - and that would make that skin rivet awfully close.

 

[inktomi]

Maybe I could use something like a HiLok fastener instead of the normal bolt/washer/nut combo?

 

[RV7 To Go]

Looks like you have the Grove gear. In an earlier post Grove recommended the hardware below. Not sure what you have. Many have been able to put the bolt in from the top down which makes easy access to the nut. Hard to tell from the pic if the bolt head would clear but worth a try. I used the bolts and nuts as per Steve Smith's testing and put the bolts in top down on my stock Vans gear. I would't worry too much about the one close rivet.

Breaking News: tests on landing gear nuts and bolts

The data source is..... Dave, The service history of the RV-8 landing gear includes several incidents in which the nuts securing the saddles at the outboard landing gear attachments failed in tension. Thanks, Bob K. Bob, I'd like to run those failures to ground. Where did you find the data...

vansairforce.net

 

[inktomi]

Ok, so would you recommend leaving the brackets flush rather than putting them in by 3/16” to better center the holes? I do have the grove gear.

I’d have to shave about 2/16” off the zee braces under the floor to make it fit with the bracket in 3/16” from the edge. That will almost have the river head flush with the edge most likely.

My landing gear came with the hardware you linked, so luckily I have all that already rather than the normal nuts.

 

[PhatRV]

Before you do anything drastic, call Vans tech support for help. They know the load and can make recommendation to fix it. Aluminum airplane are repairable so don't do anything drastic yet.

 

[scsmith]

If you have to, you could file a flat on a washer to get on there. If you can not get a bolt head or nut on there, you might try a smaller diameter nut. The NAS1804 does have a pretty small "footprint" so that may save you.

I would not worry at all about trimming the Z-braces a little. They need to be full cross section strength in the middle, but at the ends, no big deal to trim them if you have to. Its been long enough ago that I don't remember any problem finding a happy spot for those holes that pretty much maintained good edge clearance on everything.

 

[Jonnyb]

Before doing anything else I would email tech support with all the photos you can and then give them a ring.

 

[inktomi]

Thank you everyone! I sent all the same info, along with these additional photos, in to Vans.

 

[inktomi]

OK, I called Vans this morning and went over the issue with them:

- They didn't want to really say yes or no to anything, because I'm using third party landing gear
- They asked me this leading question: "if you can fit the bolt in the hole, would it be the same strength as the original location?"

The obvious answer to that is yes, the bolt is centered in the pre-drilled parts and just a few 16ths off location in the others.

They agreed we could remove part of the Zee bracket. I ended up removing it almost all the way to that rivet in the skin - so I'm going to put another rivet in 2-diameters away from it since this original rivet will most likely fall out at some point. I want to ensure that will be covered by the fairing before I do this though.

But.. tonight, I'll get under the plane and see if I can get the bolt into the hole and seated or not. That will be the deciding factor.

 

[Jonnyb]

You can file down a standard washer to fit against the wall of the weldment, then I would try a NAS1804 nut as someone mentioned above. They have a very small footprint and is probably your best chance at getting a nut on the end of it.

 

[Webb]

See your pm’s.