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Drilling rear spars to set incidence

G

gabbiesrv7a

Member
BUMMER, I did the unthinkable even after measuring and futzing and what i thought was aligning the rear spar forks with the rear spar of the wing. Drilled way off the mark and now dont have 5/8 inch clearance (left wing). Called Vans, and they suggested sending a couple of pics, but worst case I will need to replace the 705B (center section bar) and the Left 605C (bar doubler). Anyone put themselves in this predicament and any "easy" way or miracle fixes to get out of this, or is this one of those, bite the bullet, and redo the whole rear spar assembly things. Oh my aching head and back! thanx.

Keep on keepin' on, gary
 
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Gary - so sorry to hear of your incident. Vans will help you (as they did when I damaged my rear wing spar). Don't worry. Also don't feel bad - I've replaced a bunch of parts so far.

To help us that follow you, can you describe in detail what went wrong and what you wish you had done better? For example, were you using a drill guide? Long or short bit? It may be painful, but it might help someone else (me!) from having the same experience!
 
Yeah, I think RivetHead's suggestion was actually intended to be humorous. No way I'd ever weld a hole shut in aluminum and re-drill. Besides, 2024 won't weld at all.
 
Do it right

I did the same thing on my -7a after following the blue prints and not seeing the updated plans in the rvator magazine. I replaced the parts and can now sleep at night knowing that it is sound, secure and safe. Dont take a short cut because you will always wonder...

My 2 cents
 
Sorry for not responding right away, but I was still in a stupor...lol. Yep, I called Vans as soon as I posted and will send a pic to them, but sounds like I will need to replace the entire 705B center section bar or cut it in half and replace the defective Left half and 605C bar doubler at a minimum.
Essentially what I did was fit the left wing, marked everything, center punched the 705B, then revoved the wing. Made a jig from 1.5 thick solid wood stock and cut to fit snuggly between the rear wing spar and the fuse. I pilot drilled the jig and aligned with center punch on 705B and drilled 1/8, 1/4and 5/16"....perfect with min 5/8 clearance all around. I figured the full size hole in the 705B would center the standard sized bit to finish drilling the 707 wing spar and 605C bar doubler. Used the jig with 5/16 hole, drilled the 707/605. removed the jig and whalah...two holes in the 705B, one perfectly centered from drilling with the wing off, the other too high and way too close to edge. It became glaringly apparent, my drill bit wasnt in the original hole, as I decided at the last moment to secure with a clamp (which I didnt do on my dry fit procedure) that apparently moved the jig. I will try to upload a pic but not sure how to do, but wanted at least to post this description. A hard lesson to learn, but one hopefully not to be repeated. gary
 
Marc DeGirolamo said:
What alloy is it ?....unfortunately if it is 2024 T4 (as in my -4) it is not a weldable alloy.....6061 is weldable but I am not sure I would recommend doing it in such a critical area.....
my .02
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Yep, its 2024 and i discussed it with a welder who said the flame would be too hot and turn it to mush.
 
Yes, you are way off base with why I used the forum, but thanx for the lecture. I cant control what others think or perceive. Sorry I offended you.
 
Gary - thanks for describing how you drilled the holes. I am planning on (hopefully) getting the wings in their final position and then drilling all 3 pieces of metal (2 fuse, 1 wing) simultaneously with long bits and a set of homemade drill guides (hardwood blocks that hold the bit straight). I hadn't thought of drilling 1 of the 3 metal pieces and then using that as a guide.

Posting your method will help someone - and that is what these forums are really for.

Sure wish Vans could put 1/4" extra metal all around on this joint!
 
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Wayne said:
I did the same thing on my -7a after following the blue prints and not seeing the updated plans in the rvator magazine.
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I must have missed the RVator update you're mentioning...can you tell me which issue had that plans revision?

Thanks,

Dave
 
good task for getting help

I had an expert set of eyes help me with this step. It is great to be able to talk things out and make things make sense, as well as an extra set of eyes when you are drilling, just to make sure your not drilling crooked.

Randy 8A
flying
 
I think there's about three or four different pages in the long journey I took on this. Yeah, it's a pain in the neck, but it's not as bad as a lot of folk thinks. It's easy to open the skin back up and it's easy to drill the rivets off the doubler plate on the rear spar because you're not going to use it again so you can destroy it. Same thing for the half doubler in the fuse (by the way, this was a point when I was glad I used screws and nutplates on the baggage compartment).

In the end, for me, it came down to this. Do you really want to be sitting in a runup area wondering how that rear spar attach point is doing every time you go fly.

I put the wings back on and i can't say I'm completely happy with how it came out -- I'm probably going to try to find a close tolerance bolt to go here. But I'm confident in it.

If you need any help or morale building during the process, just holler. There aren't many of us who've done this, from what I understand. But me and Ken Scott are two of them.
 
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