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Freemasm 11-22-2021 02:46 PM

Flap/ Fuse interface
Surely someone will chime in telling me I did something wrong. All is good.

Background = Fabbed a second set of flaps. First set was per drawing and not such a good fit. Second set was basically a custom set length(s) wise to get a tight fit; everything was match marked and cut to fit.

Mounting the flaps to the wing, I don't get a good fit where the bottom flap skin overlaps the fuse bottom. There is progressive interference towards the leading flap edge. What did others do in a similar situation?

- Try to form the overlapping skin to relieve the interference
- Shim between the IB flap rib/skin to make the fuse and flap surfaces planar?
- Something else?

If this were a second build, I'd probably know enough that getting the last fraction of a degree wing incidence would cause more work than it was worth.

Your help here is appreciated.

DavidAhrens 11-22-2021 08:01 PM

Better flap fit
Hi; I had to look through your posts to see what aircraft you are building. Appears to be a rocket?
Anyway, the RV4, 6 and rocket can be more difficult than the prepunched aircraft to get a nice fit at the lower flap to fuselage area. I usually use a piece of aluminum riveted to the bottom of the flap bent to match fuselage. This helps to hide the fact that one flap may be lower than the other by a small amount. I have also seen people build out or box the fuselage to better match the flap bottom.
Build on!

andoman 11-23-2021 08:45 AM

I acquired my rocket project with the flaps already built and fitted. Their “stops” are set up opposite of the plans:
There is no overlap of flap / fuselage on the bottom.
Rather, there are angles on the fuselage that the tops of the flaps contact when the bottoms are even with the fuselage.

Edit: since I acquired the project with wings removed for transport, I’m curious to learn if there was a specific cosmetic reason that the flap stops were installed on the fuselage by the original builder.
I hope I don’t find something odd or I’ll fitting…

Little Al 11-26-2021 10:39 AM

I have the same problem with flaps being to long and will be rebuild new shorter ones.
The fit on the bottom skin is very common not only on Rockets but Rv4 and 6s. Simp bent aluminum to match the off set riveted to the end of the flap is the fit at this point. Mine will need this as well

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