Wittman Buster (oz15910)

About this Plan

Wittman Buster. Profile scale model for control line. Wingspan 23 in. MVVS 2.5 cc engine shown. Scale is 1/8.

Quote: "Buster is, and probably always will be, the best known of the Goodyear Racers. One of the first to appear, it won the first Goodyear Race at the Cleveland National Air Races in 1947. It went on to post an excellent winning record for many years before being retired to join the Spirit of St, Louis and the Wright Brothers' Flyer in the Smithsonian Museum. Thus it is 'the' symbol of all the Formula I category racers.

Buster wasn't new when it came to Cleveland in 1947 - only the name, pilot and engine were. In fact, it was probably one of the oldest planes, having first competed in 1931 and each year following (until WW II intervened) as Chief Oshgosh, with designer Steve Wittman at the controls. It had gone through many modifications over the years and was powered by at least three different engines. Many of its design features had already been put to use in production airplanes. The new name just signaled a new era with new fields to conquer.

I chose Buster to model partly as a sentimental gesture, for it spanned (as I did) both the pre- and post-WW II eras of pylon racing, but mostly because it had the good proportions and force arrangements for easy conversion to control-line competition. Both the diesel and glow versions of the rear exhaust MVVS 2.5 cc engine had found their way into my hands and a model was needed to evaluate them.

I had used the 'hollow profile' type of construction on two previous Thompson Trophy Racer models and found it sturdy enough, yet not too difficult or complex to construct. It provided a cleaner model and lighter weight in the search for a few more miles per hour. I used, and recommend using, epoxy glue and paint throughout.

Construction: The wing should be built first (it also reaches back into history, for it is a variation of that used on Jim Walker's Fireball, the first kit of a U-Control model). Cut the bottom sheet to shape from 6 x 3/32 sheet balsa. Mark rib and spar locations and glue the ribs in place, pinning from the bottom to follow the rib contour. Install the 1/16 spar sections between the ribs and glue on the 1/16 thick leading edge doubler. Sand the spar tops to match the ribs and taper the trailing edge-to match the upper rib contour.

Glue the plywood bellcrank mount in its cutout in the bottom sheet, then install the bellcrank and leadouts. A piece of 1/8 OD brass tubing can be used as a drill for the leadout passages, after rotating a regular drill in one end until the edges are sharp. Cut the top sheet of 3/32 sheet balsa approximately to shape. Mark and cut out the 1/4 x 3/4 slot over the bellcrank pushrod hole and glue in place. Use plenty of pins, making sure that the top sheet is securely glued to all ribs and spars. Add the leading edge, tips, leadout guide tubes and tip weight, sand to shape and set aside.

Trace the right fuselage side on a sheet of hard 1/16 balsa, including the locations of all structural parts, and cut out. (The fin is a separate piece, so cut it out later.) Trace and cut out the 1/4 plywood core engine mount, wing saddle and other structural members. Pin the sheet side to a flat surface and glue the various parts into their proper locations, including the tail skid support..."

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