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DanG

I'm New Here
Anyone out there able to fill me in on the mod to the vertical fin for the Showplanes fastback mod? I am ready to start on the vertical and would rather incorporate the mod upfront instead of undoing something. Not ready to drop the cash just yet for the kit. Thanks, Dan G
 
DanG said:
Anyone out there able to fill me in on the mod to the vertical fin for the Showplanes fastback mod? I am ready to start on the vertical and would rather incorporate the mod upfront instead of undoing something. Not ready to drop the cash just yet for the kit. Thanks, Dan G
Click to expand...

My manual says to do the following:

Relocate the VS705 nose rib and trim the VS801PP skin referring to figure 1-1. Drill new holes in the VS801PP skin and the VS705 nose rib using the same spacing, (NOTE; if the nose rib has already been installed, backdrill the new holes using the rib as a guide) drill a new hole at the first location fwd of the spar left and right maintaining edge distance.

Figure 1-1 shows VS705 angled up 5 degrees from VS702 main spar.


Hope that helps. I have not done it yet. However I will probably do the same thing on my RV4 due to my rocket conversion.
 
I couldn't get the stock VS705 rib to fit very well in the tipped-up-5-degrees position. Hammerformed a new one that did fit, very easy to do.
 
<<it is really pretty easy to do, at least after someone has shown you how.>>

True enough.



Trim the VS skin 5 degrees. Hold a piece of MDO board up to the skin and trace around it. Bandsaw a blade width inside the line and radius the edge. Lay your new form block on some 3003 or 5052 and trace around it, then offset 1/2" from that line and cut. Make a clamp block (more tracing). Align everything, clamp the blocks firmly, and gently hammer the flanges around the block. Trim, deburr, and prime.
 
I had already built my vertical when I did the showplanes stab mod. I drilled out the existing rivets, reworked the stab skin, machined a little off the nose of the rib and made it fit. Its adequate.

I think the better solution is either make a new rib like Dan H, or obtain a new blank rib from Vans (no pre-punched holes) and 'adjust' it to fit.

Robert Grigson
RV-8 Showplanes Fastback, Currently firewall fwd
 
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