Sailplane Crutch (oz16295)

About this Plan

Sailplane Crutch. Plan showing alternate method (ie using a crutch) to construct the fuselage of the Comet Goldberg Sailplane (oz1058) design. Kitted by P&W.

Quote: "The plans provided in the kit are used for the fuselage and tail assembly. The Comet plans are used for the wing."

Direct submission to Outerzone.

Quote: "Sailplane 1058: for builders who prefer the crutch technique, here is a plan for the fuselage and empennage drawn by Gene Wallock for the old P&W band sawn kits of the 70s and 80s. The wing construction is unchanged. Gene was the W in P&W; maybe a reader will remember who the P was."

Update 27/9/2025: Have moved the kit review (of the P&W kit) from Model Builder, March 1988 across to here, thanks to RFJ. Previously was at oz1058.

Quote: "Goldberg's Comet Sailplane Revisited. By George Shacklett. A genuine classic OT model, the Goldberg Comet Sailplane was a great model back then, and in the P&W kit, it is just as memorable. The author takes us through its construction.

Many of us in our younger days built various free flight designs by Carl Goldberg which included rubber-powered, U-control, and gas. Later came WC, and Carl's company wore out several die cutters mak-ing Falcons and some others. Goldberg's designs are almost all good flyers; durable, with innovative features (and parts). Those of us who knew Carl and his lifelong professional interest in modeling understand why he was so successful. Every model was well-tested before marketing, and he was always open to problems which the modeler had with any of his kits. I am sorry that I was unable to finish this Sailplane project before his death, since he had given me several helpful pointers.

This was a revisit of the Sailplane for me, since I had built two Ohlsson .60-powered ones in the forties which thermal led like mad (cost $16.95 plus dope and covering). The Sailplane is a larger, updated Zipper or, perhaps, a Zipper descendant. These were among the early pylon designs which really revolutionized free flight in those days. If you build one, you will enjoy it.

CONSTRUCTION: The Sailplane could be scratchbuilt from original plans, of course. I chose, however, the P&W Kit with stripwood from Hobby Horn. This is an excellent kit. The wood is good quality, and machine-cut parts (ribs, formers, etc.) appear to have been meticulously done. In order to scratchbuild, one would have to find rib patterns for all ribs, since the wing is elliptical. The original 'retractable' landing gear (one wheel), and pivoting prop-saving motor mount are probably passe in today's world, especially if you go R/C assist. The latter is highly recommended unless you live on the Salt Flats and have a motorcycle, good binoculars, plus a foolproof dethermalizer.

FUSELAGE: Construction is easy with the Crutch Method (used in kit). It is stronger than the original and more easily built true. Just build the crutch as per plans, and the well-cut formers complete with stringer notches can be glued to the cross members of the crutch. if building free flight, I would suggest lightening holes in the formers aft of the wing. The precut firewall parts go on the nose without problems and you end up with 0-0 thrust line.

Plans for installation of your radio should be made prior to installing stringers. Get all the weight you can get up forward because of the short nose moment. The forward crutch makes a good platform for a plywood or plastic servo mount with receiver below the crutch. Dowels work well for pushrods through the solid formers. Since I needed more weight in the nose after installing a Saito .45 four-cycle, an onboard battery was added inside the cowl for the glow plug. (This gives a very reliable idle which you will need if you like the leisurely type OT flights.) Be sure to cut some access doors to get your equipment. I just used small hooks and rubber bands to hold these, much like Carl did on the original ignition access.

Cowling is optional, but sure helps the looks. Mine is of balsa block with plywood formers front and back, tailormade for the engine used. It is held on with dowels fitted into the firewall and metal straps externally... "

Supplementary file notes

Review.

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