Zipper (oz12658)

About this Plan

Zipper. Free flight power model.

The original Zipper (oz387) was a 1939 Comet kit. This here is a later redrawn plan from MB in 1973.

Quote: "Old Timer of the Month: Carl Goldberg's Zipper.

The 'handwriting on the wall' appeared in the July 1939 issue of Air Trails. Carl Goldberg began an article entitled 'The 1939 Gas Model' with these words: 'When the thirty-second motor run rule was adopted early in 1938, the boom of large gas models for competitive work was sounded'.

Carl went on to explain the theories behind the design he had created, a model which could handle the power of a big engine that would be required in order to get as much altitude as possible with the new 'short' engine run. (Can you imagine what would have happened if someone had proposed 7 seconds in those days?)

The design Carl described was, of course, his famous Zipper. Advertising for the Comet kit had already appeared, and for years to come, this pylon ship, with its high center of lateral area (a total departure from the then popular existing theory), was to completely dominate the contest scene.

Other important design changes have come along in later years but Carl Goldberg and his Zipper represented the single most significant to point in the history of gas powered free flight. From that time onward, the competition endurance gas model became a functional design in itself that no longer bore any but the most elementary resemblance to its man-carrying counterpart. It could also be said that the evolution was at least inevitable, if not regretable! The modeler who might focus his dissatisfaction on Carl for this should remember - the rule came first, Carl was only finding a way to make the most of it."

Direct submission to Outerzone.

Supplementary file notes

Article.

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