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Problem with QB wings

SabreFlyr

Well Known Member
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Just started recently on my QB wings. I'm in the process of verifying what construction steps have been completed. So far, I found that not all of the snap bushings had been installed (no problem). Also, the bottom flanges of the wing ribs and rear spars had not been dimpled. No problem overall and working on the couple of places where it is a problem.

However, I've now found what I think is a much bigger issue: the rear spar attach holes were not reamed (page 15-04, step 7 [in revision 2]). That should have been done on a drill press before the rear spars were attached to any ribs. The holes should be reamed to 3/8" but they measure about .348". I can get the shank of an 11/32" bit into the holes but not a 23/64". The only solution that I can see is a drill guide of substantial thickness very securely clamped to the rear spar and very carefully positioned. I have a machinist/pilot friend who is glad to make these things for me. Besides the drill guide, I'd probably have him make a 3/8" pin with a tapered end to do the centering. Hopefully, I can get a drill guide made that would be thick enough to just get the reamer through the guide and rear spars.

I generally use a DeWalt cordless drill for most of my drilling but I'm wondering if it will have the necessary torque to drive a 3/8" reamer through the rear spar.

On top of those concerns are those about my building skills. I'm a first-time builder and I've paid PLENTY in the form of the "stupid" tax. For instance, I was just in the process of performing SB 16-03-28 on my wings. Got the rivets for the inboard aileron hinges removed without issue (those 16 rivet holes are better than any of the 24 practice rivet removals I did beforehand). But, in prepping the new hinge bracket parts, I over-countersunk two holes. It hurt to do it, mostly because of lost time, but I ordered a new SB kit to replace those two parts. However, if I make a mistake reaming these rear spar attach holes, I'd probably hang it up on this project! I can just imagine the drill torquing on me and moving the drill guide although I don't think I've ever had a reamer torque on me.

BTW, I checked the corresponding holes in the QB fuselage and they seem to be properly sized (3/8" bolt just barely fits).

I'd be glad to hear all your thoughts.
 
Hi,

Just curious why your QB wing does not have the mod already installed because the mod is dated May 2016 and all QB wings after that date would be built to latest specification.

John
 
Just curious why your QB wing does not have the mod already installed because the mod is dated May 2016 and all QB wings after that date would be built to latest specification.

I bought this kit from a gentleman in Texas about three years ago and he had had it for a couple of years.
 
Would you ream those holes AFTER the wings were aligned and match drilled to the fuselage? Maybe skip ahead in the manual to confirm before you open up those holes.
 
Hi,

Reading the SD it does not recommend doing the mod on completed wings ie QB.

Method of Compliance:

NOTE: Completion of the modifications in this service bulletin as a preventative measure (prior to cracks being detected) on wings that have been fully assembled is not recommended.

John
 
Would you ream those holes AFTER the wings were aligned and match drilled to the fuselage? Maybe skip ahead in the manual to confirm before you open up those holes.

Not according to the directions. Reaming with a drill press is specified in step 7 on page 15-04 before the rear spar is attached to the ribs.

Reading the SD it does not recommend doing the mod on completed wings ie QB.

Method of Compliance:

NOTE: Completion of the modifications in this service bulletin as a preventative measure (prior to cracks being detected) on wings that have been fully assembled is not recommended.

John, these ARE QB wings but the bottom skins have not been installed yet. Access to the forward side of the rear spar is wide open. Factory recommends installing as part of the construction.
 
I can confirm that installing prior to riveting the bottom skin is child’s play compared with after. I had a wing in each state in the wing stand when the SB came out. It will be much more difficult and disruptive to address cracks on a flying airplane. I felt it best to get it out of the way.
 
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