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Old 08-03-2017, 08:35 PM
goatflieg's Avatar
goatflieg goatflieg is offline
Join Date: Jul 2013
Location: Clarkston, MI
Posts: 385
Default RV-8 plans gotcha: DWG 73 View A-A

This is old news to some, but I didn't see anything when I searched, so I'll share my experience.
I was working on mounting my vertical stabilizer onto my QB fuselage. I had questions about squaring up my VS for Van's builder support, and got good advice. While I had them on the phone I asked them if the pilot hole near the bottom of the tail bulkhead could be used as a pilot hole for the lowest of the three bottom bolts that attach the rear spar to the fuselage; it looked about right on the plans. They said that should work fine; that hole isn't as critical as the two holes above that need to be drilled through the hinge bracket, spar, bulkhead and tail spring mount. So I drilled a #40 hole through the tail spring mount in the center of the existing pilot hole in the aft bulkhead, which was about #12 in size. Got my vertical stabilizer mounted, clamped square and centered and used the #40 hole to mark the location on the back of the rear spar with the drill punch. I drilled the #40 hole through the back of the rear spar, remounted it with a cleco, and everything was lining up and centering well... but when I began calculating where the upper two bolts were supposed to go, the vertical distance didn't match the plans at all. The plans called for the vertical spacing between centers of the upper holes to be 7/8"... but the actual distance I needed from my existing bottom hole was almost 1-3/4"! I called Van's back, and they said yeah, that's something that they've known about awhile; the actual vertical spacing is 1-23/32". I breathed a big sigh of relief; that would work very well with my existing hole. After a careful layout, the upper holes were drilled accurately, all three holes were sized out to 1/4" per plans, and placed just where I wanted them. But I thought I'd put this out for other builders.
To recap: DWG 73, View A-A gives an incorrect vertical spacing of 7/8" between the centers of the one lower and two upper mounting bolts on the bottom of the vertical stabilizer rear spar. The correct vertical spacing is 1-23/32".
Martin J Filiatrault
Clarkston, MI
RV-8 #83507 - empennage complete (except fiberglass)
QB wings & fuselage work continues
N657AR reserved
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Old 08-04-2017, 10:26 AM
GatorJim's Avatar
GatorJim GatorJim is offline
Join Date: Sep 2012
Location: Orlando, FL
Posts: 43

This has been corrected to the 1-23/32" dimension on later versions of the plans.
Jim Heekin
Orlando, FL
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Old 08-04-2017, 11:43 AM
xblueh2o xblueh2o is offline
Join Date: Apr 2011
Location: SF East Bay
Posts: 753

My Dwg 73 dated 11-15-05 shows the 1 23/32" in View A-A and the R1 detail notes that the dimension was changed from 7/8 to the 1 23/32 in zone F8.
I am curious of the date for your Dwg 73.
RV-8 with the Showplanes Fastback conversion
Emp completed except for glass work
Wings completed except for bottom skin and glass work
Fuselage underway
N18451 reserved
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