wrote in message
ups.com...

...

A cow-orker and his brother used to build and launch model rockets in
Williams Bay, Winsconsin. Two of them, using off-the-shelf solid
propellant motors blew up on the launch pad. Both incidents occurred
in the dead of Winter. He thinks the manufacturer of the solid motors
recommends against use below some critical temperature.

One supposes that the BRS makers have taken such effects into
consideration.


That's a common failure mode for black powder rocket motors (e.g. Estes
motors). IIRC, the grain shrinks away from the case and you have too much
surface exposed which causes it to burn faster and generate more pressure
than the case can withstand.

If I were to guess, I would say that the rockets used in the balistic
'chutes is more likely an Ammonium Percloric (spelling? ain't got a clue)
based propellent with a rubber binder. They seem lest susceptable to this
particular problem.

You could ask over on rec.models.rockets...

--
Geoff
The Sea Hawk at Wow Way d0t Com
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