[click image to see full-size illustration]

General Description

The oldest and largest of the original motors, the Jetex 350 could hold one, two, or three pellets, giving a duration of 12, 24, or 36 seconds.

The Jetex 350 was later redesignated the "Spacemaster 600A".

Historical Notes

This motor was introduced by Wilmot & Mansour in late 1948. The identical engine is illustrated in their U.S. Patent 2,637,162 (5 May 1953), which was in turn based on their earlier British Application of 19 Jul 1948 (Serial Number 39,434).

When American Telasco Ltd., the sole U.S. distributor began importing them, the motor was redesignated the "Spacemaster 600A".

Remarks

The engine comes with a "springy" tempered aluminum mounting clip, very light in weight, that slips over two of the forward spring heads, and around the nozzle. Originals also came with a "spring compressor." This is a round aluminum rod (hollow at one end) that facilitates compressing the springs when opening and closing the motor.

Suitable Model Aircraft

Performance Specifications

Data posted in green is from original factory packaging and instruction sheets
Numbers in red are, at best, a guess
SI (metric) units provided in brackets

Additional Illustrations

A handsome Jetex 350 kit by Wilmot, Mansour. 
Note the wood-handled spring depression tool.

An old advertising illustration

This is a laboratory thrust curve showing Jetex 350/600A performance.
From Aeromodeller's extensive test report, Nov 1953.
Note that in this 3-pellet configuration the thrust has distinct valleys as combustion moves from one pellet to the next, and thrust peaks after each new pellet gets going. It requires 5-7 seconds for each succeeding pellet to taper down, ignite the next, and resume "average" thrust levels.
Also note that there are significent variances, frequently of 25%, between test runs, due to a variety of reasons.
Click image to see enlargement of graph.
See propellant resources for more details on fuel combustion.