Saturday, May 26, 2012

Vans Aircraft RV-12 Build, Section 22: FWD Lower Fuselage (part 3)

Reference: page 22-03, 5 hours

This post deals with more work on the RV-12 lower firewall and with the "fun" of fuel tank sealant. It isn't that bad just messy and be glad we don't have to drive solid rivet coated with fuel tank sealant for the RV-12. So here are the tips I use when using fuel sealant:

1. Wear old cloths.
2. Wear gloves and safety glasses.
3. Have a set of "proSeal" clecos.
4. Pre-plan each job.
5. I use an old electronic scale to measure both components.
6. Use a zip-lock bag or syringe (depending on job size) to squirt the mixed fuel tank sealant where I need it.
7. New Popsicle sticks and tongue depressors come in handy.
8. Clean up as needed with Acetone or MEK.
9. Remember the sealant get everywhere no matter how careful you are, so learn to roll with it.
10. It will remain soft and "flow" for a lot long than you think it should.
11. Store in a cool to cold place (not the freezer) as this helps extend the shelf life of the unmixed components.

Step 1: Cut apart and deburr the F-1257 Rudder Pedla Supports Channels.

Step 2: Dimple the aft two holes and nutplate attach holes in the F-1257 Rudder Support Channels. Dimple the corresponding holes in the F-1201B Firewall Shelf.

Builder's note: I modified an old die so as not to damage the flange of the Rudder Support Channel.

Step 3: Dimple then rivet nutplates to the F-1201B Firewall Shelf and F-1257 Rudder Channels as shown in Figure 2 of the RV-12 aircraft planes on page 22-03.

Step 4: Smear a thin layer of fuel sealant on the top surface of the top flange of the F-1201C Firewall Bottom. Cleco then rivet the Firewall Shelf and Rudder Pedal Support Channels to the Fwd Lwr Fuse Assembly per the call outs in Figure 2 on the RV-12 plans page 22-03.

See, that wasn't so bad!

Step 5: Fill the tooling holes on the Firewall bottom with blind rivets.

Step 6: Make the F-1201L Bracket from AA6-063X3/4X3/4 aluminum angle per the dimensions given in figure 3 on page 22-03 of the RV-12 plans.

Step 7: Draw a centerline on the forward face of the F-1201L Bracket.

Step 8: Place the Bracket flush against the Tunnel Rib and Firewall Bottom dimples as shown in figure 4 of Van's Aircraft plans on page 22-03. Align the centerline on the forward face of the bracket with the gascolator attach hole. then match-drill #40 the nutplate attach holes in the firewall bottom into the bracket(use a small wood block to protect your fingers.) Remove the bracket and machine countersink the nutplate attach holes in the forward face of the bracket for the dimples in the firewall bottom.

Step 9: Cleco the F-1201L Bracket to the Firewall Bottom. Match-drill #30 and cleco the two holes in the inboard flange of the bracket into the F-1217-A-R Tunnel Rib (a #30 12 inch extension bit is useful for these holes. Match-Drill #12 the gascolator attach hole in the firewall bottom into the bracket.

Builder's note: I found a 90 degree drill worked better for drilling these two holes.

Step 10: Deburr the Tunnel Rib and F-1201L Bracket. Prime the bracket.

Step 11: Rivet the Bracket to the Tunnel Rib and with a nutplate to the F-1201C Firewall bottom inside the tunnel.

This completes page 22-03. I am really falling behind on getting things posted for the RV-12 airplane. Today is July 5th 2012, but this post is for May 26th. So much time so little to do!!! Strike that and reverse it. The Arlington FunFly is just around the corner, the weather looks good and the camping site is reserved. If Van's Aircraft has any new developments I'll be sure to post it here.