History Preserved: Carl Goldberg's Prototype Zipper

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As seen in the December 2016 issue of Model Aviation.


Carl Goldberg’s Prototype Zipper

Carl Goldberg’s Zipper is one of the most famous Free Flight models of all time. It is hard to believe that at its debut contest, the 1938 Nats, it wasn’t successful.

Here’s the story in Carl’s own words (as quoted from the July 1939 issue of Air Trails).

“[The Zipper] was finished at exactly 5 p.m. and the meet was due to close at 5:30. Two or three hasty test glides seemed to be O.K., and so I made the first flight an official one. With the motor throttled down, the ship climbed nicely; the glide seemed rather fast, but because of the very short time remaining and the high wind I didn’t pay any attention to it. Running to the waiting line, I just managed to become the last one signed up for an official flight. There wasn’t any choice but to open the motor wide, which I did. The model sped across the cement runway, lifting much too slowly, and was just starting a mild bank when it crashed into a car standing about two hundred feet from the point of release.”

That flight and crash gave Carl the opportunity to improve the design, as well as some frustrations with the timer, which cost Carl the win at the Midwestern States meet.

A Zipper did win the 1938 Midwestern States meet. Carl’s friend, Dick Obarski, built a winning Zipper that was based on Carl’s design.

It wasn’t until the Mississippi Valley Contest, held in St. Louis, that Carl placed first flying his Zipper. For the rest of the contest season, Carl, Dick, and Carl’s friend, Andy Anderson, dominated with their Zipper models.

When the Zipper was kitted by Comet, Carl enlarged the design to a wingspan of 4 1/2 feet (the prototype Zipper’s wingspan is 4 feet) and changed the fuselage from a diamond shape to an oval to make it easier for an average modeler to build and fly. More than 700 Zippers reportedly flew at the 1939 Nats.

Do you want to see the prototype Zipper up close? The museum is proud to present a 360° view of the Zipper, as well as a short Fly By video discussing its history.

Check them out on the museum’s blog, http://amablog.modelaircraft.org/amamuseum.  —National Model Aviation Museum staff


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