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Old 09-15-2006, 11:59 AM
CaninoBD CaninoBD is offline
Craftsman
 
Join Date: Sep 2006
Posts: 131
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Quote:
Originally Posted by Bazookadale
I have a little story to tell here. A long time ago I was a salesman for Sears (thank god that's over) One of the duties a salesman has is changing the tape on the cash register when it runs out - there were two types, 2.75" and 3.75" The first time I changed one I looked at the paper core I had removed and was convinced it was a FSI motor casing! I took it home dug out an old FSI motor - and the tubes were identical, convolutely wound same length, ID and OD, same color kraft paper. I always wondered why they stayed with the oddball size, I guess it was because the could buy an off the shelf tube cheaper than getting an 18mm made special order.

Dale Greene
SPAAR 503



There is a article in the July 1971 Model Rocketry from G. Harry about the motor sizes. The original Carlisle “Rock-A-Chute” was 12.7 mm by 57 mm. When they had the motors made by Brown Manufacturing, he total them he could make them quicker if they didn’t use their special-size paper and use a tube they already had handy for their Zenith Buzz Bomb firework. That tube was 18mm by 70 mm. Later when Vern made them he stay with that size to be compatible. He mention some Europe manufactures using 21mm tubes too, but later switched to18mm. FSI was the one hold out. I guess 21mm tubes were a stander for something and easier to get.

While talking to Doug Pratt at the last ECRM, he pulled a old box of motors from his Van. In the box was some FSI 18mm motors. He said FSI did try to make 18mm motor, but when they pressed them, they all got bulges in the middle of the motor. They never figured out how to press them with the budge, so they never sold tem.

Bruce Canino
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