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edwardw

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I'm doing my L1 flight on a 2 grain Pro38 case. I am getting the case from the club the day of flight. There are a few things I was wondering if you all could enlighten me on. I am using my altimeter, so I have no use for a motor ejection charge. how do I disable this or do i have to vent the gasses to the outside. Also, I am retaining the motor with three screws into a plastic donut at the bottom of the motor. The nozzle will stick through the donut. Is this feasible?

Edward
 
A

Austin

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Edward,

As far as the ejection charge goes, you can take an Exacto knife and pierce the center of the top paper cap from the side, then pry the cap off. Dump out the ejection charge and push the cap back in the top. There are usually two ridges of glue along the sides that held the cap on; you can press the paper cap down under these ridges to hold it back on the top of the assembly.

On your retainer...plastic will not due. Use an aluminum or steel one but not plastic as it will melt. It gets very hot around the bottom of the rocket, so plastic should not be used.

Carl
 

Ryan S.

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Originally posted by CTulanko


On your retainer...plastic will not due. Use an aluminum or steel one but not plastic as it will melt. It gets very hot around the bottom of the rocket, so plastic should not be used.

This is definantly true for Pro 38 motors. I have flown rockets multiple times with AT motors with no problems, but after a Pro motor the tape holding the motor in is schorched, and sometimes the back of the rocket is too.
 

lalligood

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Especially if this is your first time with the altimeter, you also might want to consider keeping the ejection powder/charge in the motor to act as a backup in case of any malfunction with the altimeter. Just set it for a longer delay than what you expect for the altimeter to use. (e.g., If 8 seconds from motor burnout to apogee, then set the delay to 10 or the [default] 13 seconds for the Pro38 H153.)
 
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