AT 54-1706 forward closure Q

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Jeff

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I am planning on using electronic ejection on an AT motor for this size case (K550W perhaps) and, as these motors come with a delay I am wondering:

1. Do I need to use a seal disk, and

2. can I use a standard forward closure, and if so would I leave out the delay or just put it in without any BP or

3. can I use a plugged forward closure and if so would I put the delay in?
 

troj

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1. Do I need to use a seal disk, and
If the instructions say you need a seal disc for that reload, then yes. If they don't, then no.

2. can I use a standard forward closure, and if so would I leave out the delay or just put it in without any BP or
Leave the delay in. Put a dab of grease on the top of the delay grain before assembly, fill the charge well with dog barf and tape it in place.

3. can I use a plugged forward closure and if so would I put the delay in?
Yes, a plugged closure will work; it has a cavity for the delay, just like a standard closure does.

-Kevin
 

Pantherjon

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Even on my dual deploy flights where I don't put in the charge for the motor ejection I put the delay element in..It gives good 'tracking' smoke for after the propellent burns out..
 

MarkM

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2. can I use a standard forward closure, and if so would I leave out the delay or just put it in without any BP
You MUST put the delay in whether or not you use BP. The motor is designed to work with the delay. Eliminating the delay creates a void - an empty space - and this may cause the motor to not properly pressurize and hence not work properly. Furthermore, not using the delay creates a motor that is not as designed and is against TRA/NAR sanctioned launch guidelines. There is no provision in the Aerotech instructions that allows the delay to be "optional".
 
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ben_ullman

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You MUST put the delay in whether or not you use BP. The motor is designed to work with the delay. Eliminating the delay creates a void - an empty space - and this may cause the motor to not properly pressurize and hence not work properly. Furthermore, not using the delay creates a motor that is not as designed and is against TRA/NAR sanctioned launch guidelines. There is no provision in the Aerotech instructions that allows the delay to be "optional".
Just to elaborate.........

You can leave the delay out in almost all motors (they may be some I don't know of) as long as its a plugged closure and doesn't have a hole you can leave it out and dab some grease. It won't be certed (doesn't matter where I fly) but if you do like I do and keep the delays for tracking in other motors it comes in handy.

These rocket motors aren't as complicated as some lead them to be. Contain and insulate the hot gases from the metal. That is the ultimate goal.

Ben
 

sylvie369

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The K550W is one of the motors that now requires a forward seal disk. There was a news release exactly a year ago about it - you can find it on the Aerotech website in the archived news releases, 5/20/08.

I have flown K550s several times without an ejection charge, using a standard forward closure with the delay installed and the ejection well filled with recovery wadding and taped over. No problem.

You can of course use a plugged forward closure instead.
 
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