ETLB Squawk Forums — Archive

Anyone have their wing root end brackets not line up with the holes in the fuse? My Rear spar fittings go right in the holes. Great Fit. However one of my front spar fittings is about 1/8" to far forward...The one on the leading edge (front) of the front spar is good, but the other one (backside of front spar) is too far forward. It runs into the vertical member (is that station 2?) where the spar carry-through channel is monuted. Seeing as how these fittings are held in place inside the fuse with pins, not bolted tight, could I just put in a 1/8" spacer on the spar (another piece of the same aluminum), to line it up?
I tried to build everything to spec... I think I just misaligned the piece at station 2. I dont see any other way to fix it. I can "unglue" the whole fuse and station 2, to change its position.

If I can see your problem through words correctly I'd say you are better off simply epoxying an extra 1/8" ply gusset to the aft side of the forward spar to bring it back in alignment, drill the fitting holes through so all holes are concentric, put in 1/8" longer bolts, and be done with it.  The problem with using an aluminum spacer instead of the epoxied ply gusset is that the two aluminum plates would parallelagram causing the bolt to load in bending too in extreme loads rather than just in shear as designed.  Now I am not saying that the bolt would ever come close to being the weak link even in bending loadings but it is always better to keep the loading of fasteners as designed.

Isn't the aft face of the forward spar already covered by a ply gusset where the aluminum fittings bolt on?  If so, just copy its size and properly bond in the correct offset thickness of ply.

R

Remember the wing fittings go over the aluminum channel that is bolted to the vertical wood member from below.
The wing root fittings are below the vertical member so it shouldn�t interfere with it even if it is a little off. The position and drilling of the holes for the aluminum carry trough is the last thing you do in the rigging process. The rear carry through is fixed in fore/aft position  so the front channel carry through position is adjusted as needed.

George

Sorry for bouncing such an old tread, but I believe that a clarification could help future builders.  Theosus did not make a mistake, if you build exactly as per plan the distance from the front and rear spar root fittings is about 1/8 greater than the distance between centrelines of station 2 and 4, as illustrated by the longitudinal section through the fuselage of my CAD model, constructed exactly as per the 1600R model plans.  It appear to me that the simpler adjustment to make is to attach the RS-300 alum channel almost flash at the back of the RS-11 cross member, instead than centered as it is shown in the Mini Max plans (detail on pag. 14 for the 1600R-Sport plans).

If you build per plans, the rear spar bracket of front spar may come
1/16 inch too close to the U channel, but no more. This is a fairly minor
mis-alignment that I didn't even notice it when I fitted my wings to the fuselage.
Actually I didn’t realize this 1/16 mismatch till I re-did the calculations
just now from my plans.