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lr172

Well Known Member
I purchased my 6A kit partially completed and the previous owner didn't leave enough edge distance on the rear spar. I have since replaced that spar and re-drilled the hole. The Fuse Spar was not replaced, so I had to use those holes to guide the drill through the wing spar. I used a drill guide and clamps to keep the fuse spar holes clean.

I came close, but not perfect. The hole in the spar is clean, as is one of the Spar Ears in the fuse. The second spar ear is off just a bit. You can see a sliver of space in the shape of a crescent moon. The sliver is about 1/32 at it's largest and about 1/4 of the circumference .

I was a little worried that in one direction of force, the load my only be carried by the one spar ear. My options are to leave it and move on or drill the hole out to 3/8" I computed the actual distance from the edge of the hole to the edge of material for a 5/8" edge distance. I still have that distance met if I go to a 3/8" hole. However, I would not make the 3/4" edge distance required for a 3/8" bolt. The question is, is this required or is the amount of material specified for the 5/8" bolt good with the 3/8" bolt.

I appreciate your recommendations here.

Larry
 
Aft spar hole issue

Larry, I've seen several RV's that had the same issue as yours. They had been drilled out to 3/8 inch either to clean up the hole or had an adjustment to the angle of incidence in one or both wings requiring going up one bolt size. Providing you have proper edge distance it is perfectly acceptable to go up one size. It's recommended that you use a stepped reamer to achieve the final dimension as a drill bit can leave a poorly finished hole. Good luck

Rex
 
R. Daniels said:
Larry, I've seen several RV's that had the same issue as yours. They had been drilled out to 3/8 inch either to clean up the hole or had an adjustment to the angle of incidence in one or both wings requiring going up one bolt size. Providing you have proper edge distance it is perfectly acceptable to go up one size. It's recommended that you use a stepped reamer to achieve the final dimension as a drill bit can leave a poorly finished hole. Good luck

Rex
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Rex,

Thanks for sharing your experience here. I don't think there is immediate risk with the current holes. More long-term in nature. Your post got me thinkgin that I should leave the 5/16" for my phase I flight testing and be sure that I don't have an incidence issues to deal with. I posted a while back about my wing twist. I think I have it set up with a good compromise, but I am now thinking adjustment could be necessary. Once I confirm that I am rigged correctly without significant issues I can drill it out to 3/8" should be but a few hours of work to do later.

Larry
 
Rockyjs said:
Larry,
You may be able to fit an NAS oversized close tolerance bolt when your ready and not have to drill up to the full 3/8. Check with these people

http://www.gen-aircraft-hardware.com/default.asp
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Rocky,

I looked at that site, but it only shows a 6X oversize. I always thought these oversize bolts were a few thousands oversize. I do not know how to interpret the NAS part numbers. Do you know how much bigger a 6X is over standard?

Thanks,

Larry
 
lr172 said:
Rocky,

I looked at that site, but it only shows a 6X oversize. I always thought these oversize bolts were a few thousands oversize. I do not know how to interpret the NAS part numbers. Do you know how much bigger a 6X is over standard?

Thanks,

Larry
Click to expand...

The X suffix is 0.0156 inch oversize and the Y suffix is 0.0312 oversize.

They both tend to be hard to find though.
 
lr172 said:
I computed the actual distance from the edge of the hole to the edge of material for a 5/8" edge distance. I still have that distance met if I go to a 3/8" hole. However, I would not make the 3/4" edge distance required for a 3/8" bolt. The question is, is this required or is the amount of material specified for the 5/8" bolt good with the 3/8"
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You have more room to work with than you think. Edge distance is measured from the center of the hole, not from the outside edge of the hole.

Erich
 
Given that I will be re-drilling to 3/8, I took the time to double check my incidence and surprisingly I was off some. I must have had a problem with levelling before.

I moved each wing close to the 1/16" that I have to work with by going from 5/16" to 3/8". I intend to drill it out to 13/64" and use a 3/8" reamer to finish it. However, the holes may not be perfectly round, as the reamer will take out the last of the offseting holes. Will the reamer still work well and "find" the center? I will be using a 1/2" steel drill bushing that I made for the drilling? Should I make one of these for the reaming as well? I have never used a reamer before. I am assuming that it will work. Given the cramped space, I am not sure how else to keep the reamer square to the metal.

Thanks for your help with this.

Larry
 
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