jimc@ucla-cs.UUCP (01/31/86)
This note pertains to a means to detect burnthru in solid rocket
motors. Should the grain crack, or separate from the endplugs, the
reaction will propagate down the crack by radiation and convection and
will rapidly reach the casing, which will be heated for most of the burn
time and will rupture. A large-area heat sensor is needed that covers
the inside of the casing.
One design is a plastic film covered by a zigzag metallized path,
as in a strain gauge or burglar alarm, which would open when overheated.
A perhaps more reliable design is a film or paint that becomes
electrically conducting when it chars, overlaid by a conductive layer
that retains its continuity at that temperature. Activation of the
sensor would indicate that the solid rocket was about to lose its
usefulness, one way or the other, and should be jettisoned forthwith.
[Also posted to Aviation Week.]
James F. Carter (213) 206-1306
UCLA-SEASnet; 2567 Boelter Hall; 405 Hilgard Ave.; Los Angeles, CA 90024
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