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RV9/7 bolts through fwd center section

alpinelakespilot2000

Well Known Member
For the tailwheel versions...

On the forward F904C center section bulkhead (probably the equivlant of F704C for the 7's) there are 5 holes left open to attach the main gear weldments for the trigear versions. I can't find any callouts in the plans about what bolts to put in these holes if we are building the tailwheel version. I assume we don't leave these holes open (?). Do we just use the same bolts for the trigear (with extra washers) or go down a bolt size or two? Any reference to this in the plans or drawings that I might have missed?

Thanks.
 
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Call Van's and you'll find out that they recommend putting bolts in all of those holes. What's this "lightness per Van" thing? Try not to spread misinformation.

When choosing a bolt length, you can measure the required grip length and go from there. Make sure you don't use too many washers, and you don't want more than 2-3 threads showing outside the nut, otherwise the nut may be bottomed out on the shank of the bolt rather than providing any compression.
 
Steve said:
It's Vans general principle to "build it simple and add lightness" thing.

I don't disagree with that one bit. But telling people to leave bolts out of the center section when it contradicts what Van recommends...well, you get my drift.

It's one thing to cut a lightening hole in the VS spar doubler where Van's says it's "optional" but does call it out in the plans. It's a whole 'nuther scenario when we're talking about spar/center section hardware.
 
Thanks for the suggestions. I guess this is another area where the plans or drawings don't specify what to use and assume that you'll use common sense. I call Van's on Monday and see what "common sense" is. :D These bolts would attach the bulkhead web to the bulkhead doubler bars, so I've been assuming that there probably shouldn't be any holes left unused. If it makes my wing spar carry-through stronger, I'll happily live with the extra weight!
 
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Empty holes

Steve in WA,
Please post Van's answer on this.

Got the canoe rolled today,
Steve in UT
 
Van's response:

MY ORIGINAL QUESTION:
For the tailwheel versions...

On the forward F904C center section bulkhead there are 5 holes left open on both left and right sides (through the bulkhead flange and doubler bars) to attach the main gear weldments for the trigear versions. I can't find any callouts in the plans about what bolts to put in these holes if we are building the tailwheel version. I assume we don't leave these holes open (?). Do we just use the same bolts for the trigear (with extra washers) or go down a bolt size or two? Any reference to this in the plans or drawings that I might have missed?


Thanks.

VAN'S RESPONSE:
Stephen,
I had a hard time finding the bolt call out, but it is on DWG 34. The
note calls for 6 each of an AN4-12A bolt. You might need an extra
washer or two or you might use a -11 bolt. The bolts are the same
as those used on the tri-gear, but without the mount the grip length
can be less.
Bruce Reynolds
 
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