Spar Spacer Blocks

[RV7Factory]

Today, I set out to make my 1.438" (1-7/16") spacer blocks but when I put my caliper on the spar ends and I get a measurement of around 1.445- 1.450", not 1.438". I know we are only talking .007-.012, but? Should I make the spacers according to the instructions (1.438") or should I make them to correspond with the ends of the spars? I haven't really seen anybody having issues here, so I am inclined to think I am over-thinking this, but I guess it doesn't hurt to ask. Has anybody who has made the spacers to to the 1.438" spec ever had an issue with the fit being too tight?

 

[Steve]

My blocks are about 1.4375 +/- .003. I had my wings in & out twice without problems.

Steve

 

[Sparky]

Are They Even Needed?

With the matched-hole kits, are they even needed? It's not like you can do much in the way of adjustments. I wasn't planning to use them.

Has anyone else built without using spacer blocks?

 

[briand]

I used bolts with 3 nuts each, covered the threads with electrical tape were they could contact the spar. I had set the distance to 1.440 and when I got the fuse all riveted, flipped and the bolts removed, the gap closed a bit. What I'm trying to say is there is some flex in the parts. Part of the reason I went .002 wider and decided not to install the 12 rivets in the foward flange on the center section until the wings are bolted in place.

 

[RV7ator]

The spacer blocks are utterly pointless with the prepunched kits, just like the empennage jig. The parts will align where the prepunched holes tell them to go. My second -7 spar gap was actually .010-.015 narrower than the spar. Van's said taper the end (good idea in any case), lube 'em up, and shove 'em in. There's acually considerable give in the center section. Slid in just fine.

I think the blocks are an unedited artifact from the -6 instructions.

John Siebold
Boise, ID

 

[cjensen]

Brad,

If you want some good one's, I have a set of PERFECT 1.438" aluminum shims. You can have 'em! I'll send 'em to ya Monday.

 

[Kevin Horton]

Is it possible that the waffle plate is not squeezed tight against the spar bars? My spars where like that. I used a C-clamp on some pieces of wood to squeeze things tight together before making that measurement.

 

[Sparky]

Not Needed

I currently have the forward, center and rear fuselage drilled and clecoed together (tomorrow or the next day I will tear it all apart to to debur and prime) and just went out and measured the center spar spaces (without spacer blocks) . I measured (using a digital caliper) both the top and the bottom of the center spar openings of each side:

Right Top: 1.444"
Right Bottom: 1.431"
Left Top: 1.444"
Left Bottom: 1.430"

My Spars measure anywhere from 1.451" to 1.468" (so it will still be a tight squeeze regardless of whether or not I used spacers).

So I contend that that the spacer blocks are pointless with the new kits as John stated - just extra work.

I'll let you know if I have any problems when it comes time to mate the wings, but I doubt I will.