Re: sport rocket staging timer

On Tue, 29 Apr 2008 08:20:12 +0000, Smaug Ichorfang wrote:

Some friends would like to build a down-sized model of a two-stage sounding
rocket. I'm trying to come up with a design for a timer to ignite the
second stage. The timer should be triggered by a "g" switch which marks
first stage ignition, and time out after (an adjustable) 1.5-2 seconds,
just after the first stage burns out. Commercial designs are available for
around $90. I only need to build ONE of these andd don't have the
programmer so a pic or BASIC STAMP are out. Any ideas or schematics for an
analog or simple digital timer for this application?

When I was a kid, Estes rocket motors were available with an "after-charge",
which is basically a hole at the top of the motor that shoots hot gas
into the nozzle of the second stage right at burn-out. So, no electronics,
batteries, squibs, none of that schtuff was needed.

The idea of a 1.5-2 second timer with batteries and squib and all of that
just seems ludicrous on a rocket where the first stage only lasts 1.5-2
seconds.

Good Luck!
Rich


.

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