Is this rear spar edge distance typical?

[alpinelakespilot2000]

Finally got my wing sweep to 0 degrees, my incidence (measured with the block) to 0.0 degrees, and am preparing to drill the rear spars. I've measured about the best I can 5/8" around all pieces. What I'm left with is what you see below inside the center box. It's about 1/8" wide by 1/4" tall. If I drill anywhere within this box I should have adequate edge distance all around.



Is this typical of how much leeway others have had in drilling the rear spar? Van's doesn't leave much extra for error, that's for sure! Just looking for confirmation before I do the deed! Thanks.

 

[Stephen Lindberg]

Steve: Looks good. I'm building a 7A but that's about what I had. Are you going to drill using drill blocks? I recommend it. Keeps the hole round and normal to the surface.

 

[alpinelakespilot2000]

Thanks Steve. I remember you noting on an earlier thread that you had about 1/8" extra. It looks like I'll have about an extra 1/16" on both the spar and fuse. fork, so I guess I have a total of 1/8". I'll definitely plan on using a block for the drilling and plan on having a helper to confirm that my long drill bit is indeed square. Time to just do it, I guess.

 

[cytoxin]

5/16 reamer///// looks forward swept to me.

looks forward swept to me unless you really trimmed the spars closer than i did.
i had to trim the spar to clear the AN 470 rivet head that is at the top of the opening..mine is a 7a though
if you dont use a reamer (and i would ) use a drillbit one size under, then final to 5/16. did this this weekend on the canopy hinge and the "up one size" still left me with a press fit for the bushing. while drilling up from 1/4 to 5/16 did not. TESTED 3 times prior to drilling with the same resuslts each time. i would highly reccomend a reamer in a hole one size under 5/16. the longer the bit the easier it is to keep straight. a drill block (easily made on a good drill press) is a big plus.
oh yeah i had 1/16 -1/8 ADDTIONAL OVER MINIMUMS. vans trims everything close
all in all i would use the .311 reamer in a 90 deg drill through a block

 

[sportpilot]

rear spar RV9a

Steve, here is our webpage with pictures on where and how we drilled the rear spar attach. It looks like we had about the same clearence. Our clearence limit is depicted by the red circle. We used a one inch square steel block starting with a 1/8 inch pilot hole, and enlarged the block progressively up to the bolt size. We used drills and used a pair of channel lock pliers to hold the drill block onto the spar. It worked real good except that as you step up to the next drill, it has a tendency to "wander" off center and you must be careful not to let this happen. A drill bit with less than a 90 degree point would help stop this and center itself better. Ours came out perfect, and there is very little to spare. Here are our pictures. Good luck..

Our pictures of how we drilled the rear spar on RV9a

 

[alpinelakespilot2000]

looks forward swept to me unless you really trimmed the spars closer than i did.
i had to trim the spar to clear the AN 470 rivet head that is at the top of the opening..mine is a 7a though

Actually I've been taking all the sweep out of the wings for the past week. I now have four plumb bobs at both roots and both wing tips. All four point right to the same stretched fishline. I didn't trim the rear spar at all. I think the 9/9a wing is significantly different in this regard. Thanks for making sure I checked, though.

 

[alpinelakespilot2000]

Our pictures of how we drilled the rear spar on RV9a[/URL]

Thanks Claude-I don't have a high speed connect at home, so I'll check at work tomorrow. Looks like a very thorough set of slides though, so I'll look forward to it. Thanks.

 

[cytoxin]

well,,,,that sounds good to me

Actually I've been taking all the sweep out of the wings for the past week. I now have four plumb bobs at both roots and both wing tips. All four point right to the same stretched fishline. I didn't trim the rear spar at all. I think the 9/9a wing is significantly different in this regard. Thanks for making sure I checked, though.

good luck drill straight