Cabbie (oz14379)

About this Plan

Cabbie. Radio control sport biplane model, for electric power. Foam construction.

Direct submission to Outerzone.

Quote: "Cabbie, by Bill Bowne. Cabbie started as a Ken Willard-designed Schoolgirl (oz816), shrunken and modified for foam construction. A little change here, a little change there, another change here - and it wasn’t a Schoolgirl anymore. So, the new name, Cabbie (from CAbin BIplane, plus a few extra letters).

Cabbie does have impeccable manners - she’ll fly slow enough to let you relax and enjoy the view, whilst being very stable and trustworthy. Go to full throttle, and she’ll still be stable - but she’ll loop as long as you hold the stick back.

Cabbie boasts a grand total of 7 pieces of wood, none of them balsa. The rest of her bones are foam, a little carbon fibre, and some music wire.

A word about the mix of green and white foams. Except for the windshield, all the white foam is 6 mm Model Plane Foam (similar, I’m told, to the fabled 6 mm Depron). The green bits are 1/8” foam I hot-wired from house insulation foam, and that white windshield is 1/8” (actually 3 mm) Dollar Store foam. As the 1/8” poplar (lite) ply sold in the US is actually 3 mm, there are no potential metric/inch mismatches (it’s a model airplane, not a Mars probe).

For higher stress areas, I used NON-foaming, Clear Gorilla (Polyurethane) Glue; foam-safe glues such as Foam-Tac and Foam-cure are fine for most remaining gluing, although I did use thin CYA on the main undercarriage and dihedral braces. Finally, I used clear Polycrylic water-soluble ‘polyurethane’ (it really isn’t) to adhere Cabbie’s bond paper markings.

One 'oopsie' I encountered is that Sharpie pens WILL bleed through acrylic paints, so please, either don’t use them where the ink will be exposed, or use something else (i.e., a really soft pencil). Those little bits of blue ink you see here and there? Those were where the Sharpie I used bled through. Only a smear of glue over the marks sealed it enough to cover with paint.

Wing: Aside from the spars and dihedral angles, both wings build up the same way. Gorilla glue (or CYA) the carbon fibre spar halves (lightly sand the spars to give the glue a better grip) to the ply spar brace. Let cure. As the wings have different dihedral angles, I recommend doing one wing at a time.

Cut the spar and dihedral brace slots in the bottom panels. Spread very thin layers of Gorilla glue on the bottoms of the step layers (an old credit card works fine) and laminate the upper layers to the lower ones. I like to do the laminating LE to LE, to make it harder for me to build two left wings (Harder, not impossible!). Wipe away any leakage and let the wings cure under heavy, flat weights.

Sand the root dihedral. Glue the spar assembly into the wing panels and join the panels (two boards, taped together and covered with plastic sandwich wrap, provide a simple jig). Let all cure completely before sanding in the airfoil..."

Supplementary file notes

Build notes.
Decals.
Photo pack (of 12 build pics).
Statistics.

CAD file

This plan is available for download in CAD format.

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