First wing attachment

I'm trying to attach the wings to the fuse for the first time. I'm having a problem with the alignment of the stub spars. This is the right wing. Haven't tried the left wing yet.

To begin at the beginning in case it's relevant, the opening in the fuselage was not tall enough to accommodate the main spar so I trimmed that (~1/8") to fit the spar. The spar slides in smoothly and the fore/aft alignment of the stub spars is right on but stub spars and the corresponding fuselage slots are misaligned vertically. The picture below shows the front stub spar with the rear stub spar fully engaged just to show the total misalignment.



I can partially disengage the rear spar and split the difference.

The plans indicate that "If the stub spar interferes with the installation of the wing the stub spar may require local dressing with a file". It seems like the amount of misalignment might be more than I'd think of as "local dressing". I'm just guessing, but I'd estimate that both the front and rear stub spars would have to be filed down a good 1/8" to achieve the proper fit.

So, possibilities I can think of are:
1) Remember the 1/8" I had to enlarge the fuse skin to accommodate? I don't know how it could happen, but perhaps the wheel the main spar slides in on is too high.
2) Maybe dressing the stub spars that much is OK.
3) Other possibilities I don't really want to think about.

Any thoughts?
Thanks.

Something is off somewhere. The trimming of the spar stubs (fwd and aft) should be very minor at most. If the parts don't fit, something is amiss. Triple-check your main spar location - perhaps your spar rollers are misinstalled as you suggested.

I suspect that we all have had to trim a wee bit of the main spar slot to have the main spar tangs slide into the slots without binding.

tomkk said:

To begin at the beginning in case it's relevant, the opening in the fuselage was not tall enough to accommodate the main spar so I trimmed that (~1/8") to fit the spar.

Click to expand...

My guess would be that you have the insertion roller installed backwards.
The bottom surface of the spar stub is supposed to be rolling on the smaller diameter portion of the roller.

rvbuilder2002 said:

My guess would be that you have the insertion roller installed backwards.
The bottom surface of the spar stub is supposed to be rolling on the smaller diameter portion of the roller.

Click to expand...

I was just going through the plans and was looking at that. I think that might be the problem ...

And ... that was the problem ...

TOM LOOK AT YOUR PHOTO DATED 9-25-14. THE RIGHT SIDE ROLLER HAS THE SMALL DIA. FORWARD, IT SHOULD BE REARWARD.

PMLviator said:

TOM LOOK AT YOUR PHOTO DATED 9-25-14. THE RIGHT SIDE ROLLER HAS THE SMALL DIA. FORWARD, IT SHOULD BE REARWARD.

Click to expand...

Yup, that was it for sure. Reversed the roller and it slid in like a champ. Thanks for taking the time to check the photos ...