This is the classic Bud Nosen Trainer. The original design called for a 60 engine, but I’ve heard performance is pretty tame by today’s standards with the recommended engine. By some accounts, a 90 is about right. So it’s up to you.
The short kit includes the full fuselage sides. Each side is made of 7 pieces of 3/16 balsa, to be joined by the builder. The 1/16 ply cabin doubler is extended all the way back to F2. The doubler and the cabin bulkheads have tab-and-slot indexing.
Bulkheads in the original kit were made from strips that were glued together to form rectangles. The bulkheads in my kit are cut full-size from 1/8 plywood, and some of them are doubled to make 1/4 plywood.
The nose of the cowl follows the plan, with a layer of 1/8 ply and two layers of 3/8 balsa, which can be drilled with a center hole for the propeller shaft, or a U-shaped cutout can be made to accommodate an engine inserted from the top.
The wing ribs are cut according to plan, with 1/8 birch ply dihedral joiners to be added to the top spars across the center joint. If this were my building project, I would add some glass cloth at the center joint in addition to the dihedral braces. That’s right, I would go ahead and build this wing in one piece, 102″ long. I’d also build it with three degrees of dihedral per side, as called for on the plan (2.5″ at each tip). But that’s just me. I like loading big giant wings into my 1974 Chevy van.
Maybe you want to make a two piece wing. If so, you’re in luck because the kit also includes a bunch of ribs made of lite ply, with two 1″ holes for wing joiner tubes, so you can build your wing in two pieces if you want. In this case, there would be no dihedral in the center joint, because the airfoil is too thin to allow a slanting wing joiner tube.
But there’s more: if you want dihedral in your two piece wing you can build it with a flat center section and dihedral in the outer panels. In this case, use the lite ply wing ribs with the wing tube holes, and make a dihedral joint on each side. I’m also providing a dihedral gauge for that. This gauge will actually have 1.5 degree, because you want half of the dihedral on each side of the fuselage. It will be marked so you will easily be able to figure it out. If you choose this method, I’m guessing you’re probably one of those guys who would prefer a glassed wing joint over dihedral braces, so I’ll just leave that to you.
However you choose to build the wings, the kit includes some optional plywood pieces intended for bolt-on wings. There is a 1/16 birch ply plate to be placed on top of the wing at the trailing edge. If you split your wing into two pieces, you’ll want to also split this piece to match. There are also several little plywood pieces to be laminated together in two stacks and glued into the fuselage at the rear edge of the cabin, to accept the wing trailing edge bolts. The other thing that’s included are four 1/8 birch ply plates. These are labeled for the leading edge and the spar. They are to be glued to the spars and to the back of the leading edge so they hang down into the cabin. Place a pair of these plates on each side of the root ribs, so you can retain your wing with two dowels, and then drill through F1, the leading edge plate, and the spar plate, for the dowels. I would probably use 5/16 dowels, but that’s just my opinion.