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-   -   RV-4 Spar Splice Plates (https://vansairforce.net/community/showthread.php?t=96428)

rocketbob 02-14-2013 05:42 PM

Quote:

Originally Posted by az_gila (Post 744321)
It appears that extra 1/16 is caused by the dihedral. The bolt spacing differs (1.25 vs 1.125) for the first 4 bolts or so of the spar and the 1/16 extra is a "left over" dimension.

I'm betting the RV-4 is closer to the -6 than the F-1 on the bolt spacing.

Anyone got any -4 plans to check?

It does make a difference if you need to fabricate two extra splice plates - hopefully the OP has one upper and one lower...:)

According to the RV-4 plans all four splice plates are exactly the same and symmetrical. The different spacing applies to the top and bottom of the spar web holes but not the splice plates. Bottom left of pg 13 of the RV-4 plans.

Pg. 15 of the RV-6 plans show the same thing. In fact they look identical to the RV-4 parts.

So my earlier statement stands, you could use your existing plates to drill the others.

az_gila 02-14-2013 05:53 PM

Quote:

Originally Posted by rocketbob (Post 744385)
According to the RV-4 plans all four splice plates are exactly the same and symmetrical. The different spacing applies to the top and bottom of the spar web holes but not the splice plates. Bottom left of pg 13 of the RV-4 plans.

Pg. 15 of the RV-6 plans show the same thing. In fact they look identical to the RV-4 parts.

You are correct... the extra 1/16 is there because the plans don't reference the spar hole dimensions to the centerline of the spar holes...:rolleyes:

I could claim hard reading on the 11x17 preview plans, but I'll just send myself back to plans reading school....:)

More importantly, it does make it easier to duplicate the missing plates.

F1Boss 02-15-2013 08:29 AM

Old school talents required here
 
RocketBob sez: "According to the RV-4 plans all four splice plates are exactly the same and symmetrical."

Well, that would be nice. In the real world, it's not really probable that such would happen using any sort of hand drilling procedure. Some machining techniques can't get it right either! That's why oversize bolts are available.

BTW the F1 plates are NOT completely interchangeable; the lower plates are chamfered along their lower edges. Your plates may end up the same way for bulkhead flange clearance. After drilling, carefully mark the plates' positioning (top, lower, front, this side fwd, etc). All this in in the F1 manual, even tho the hole positioning on those parts is as close as possible using modern machining techniques. Once reamed to fit the spars per the manual, the parts are locked into that orientation; they do not interchange.

As usual, be careful what you read on the internet.

If you drill the plates to exactly match the current plates, which probably don't match each other to start with, you will re-order the parts and start over again, or go with the very expensive oversize bolts. Ugh.

So, you will likely drill the parts up using the early RV type setup where you set the spars up on sawhorses, with the drilled plates on top (pinned), and proceed to drill the clamped lower plates one hole at a time, using the drilled plates and the spars themselves as the drill template. Drill bushings will help greatly, but since the holes are not likely to be perfect 90 deg holes, simply setting things up and going after it with .374 & .249 drill bits would not be my recommendation.

If you need further info, send me a PM. Hole exact placement is less important than getting the holes round, and the correct size. Think 'tractor', not 'space shuttle'.

Carry on!
Mark


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