Scale BUSA Super Cub

[BalsaDust]

2 stroke engines on scale airplanes should be illegal.

4 strokes do sound really nice.

 

[TonyHallo]

Took a page out of Spoopy's build and decided to laminate the firewall. No carbon, Kevlar. One 6 ounce layer per side. It's all DIY stuff, plastic drop cloth for the bag sealed with caulking, home made perforated release film, blue shop towels as breather cloth, and fuel tube for the vacuum line. I got the vacuum pump about 30 years ago at a flea market, it will pull about 23" hg. It has a bleeder valve that I use when doing foam parts set to 5" hg, runs steady

 

[dhal22]

Ooh, a tool i can buy. Off to ebay i go.

 

[BalsaDust]

Homemade perforated release film, assuming you meen what some call Peel-Ply? Could you explain what material you used and how you made it?

 

[TonyHallo]

Plastic drop cloth folded over several times then drill holes on approximately 1/2" centers. Release films are used when you don't plan to add any additional top layers. This was my first attempt and the I used 1/4" hollow core drill bit that ended up being too large. I did the firewall in two stages. The first side was done in the basement and it is less than 70F due to the air conditioner. The pump was left on overnight and the epoxy was about 90% cured when the release film and breather were removed, came on great. The second side was done outside in the sunlight. When I came yesterday after about 7 hours the the epoxy was cured and some of the breather had stuck to the lay up, not a big deal, hit it with sanding block and it is mostly gone.

 

[Snoopy1]

Looks good to me. First explain the release film bid not understand that.
Also if I may suggest your vacuum hose going into the bag wrap it with a cloth and make ball around it, some times the plastic will suck into the tube, that makes for a bad day.

 

[TonyHallo]

The hose was captured between two shop towel sheets.

 

[TonyHallo]

Had to move the engine back another 5/8" so that the cowl will fit. This thing is shoehorned in to be sure. This resulted in the need of a 5/8" extension on the prop hub. Decided to make the extension bolt on to the existing tapped holes and drill and tap the extension for the prop bolts. The bolt circle function on the mill DRO make short work of this.
I have throttle and choke servo issues to solve as well along with the fuel tank. One step at a time.

 

[TonyHallo]

I have the throttle and choke servos mounted, have a location for the ignition module and fuel tanks while keeping the scale interior that was made some time ago. The control sticks are automated with two small servos mounted under the floor. As you know I'm too cheap to go for the $15 Miracle servo mounts so I made my own out of 1/16" aluminum angle. These servo can be accessed by removing the windshield and boot cowl.

 

[TonyHallo]

The goal was to remain the scale control sticks and rudder petals. I think it will happen. The fuels tanks will be two 10 ounce Sullivan slant oval tanks hooked up in hopper arrangement. I plan to finish the interior as shown in the full scale photo below, painted Daytona white of course!