clustered & staged mini engines: plugged, 0-delay

[michaer27]

Hi all,
This is my 1st post, and I'm relatively new to rocketry, so please forgive me if it's not eloquent or it's foolish:



My son and I are beginning to design a smaller rocket. We want to make it a little more complex than just a staged rocket - which we just completed. We will probably cluster engines in the booster stage. We are thinking of using some mini A’s or even 1/2 A’s in the booster.

The general plan:

Use a skinny body tube (just big enough in diameter to accomodate a mini engine) and some mini engines as the central motors. There would be a booster stage and a 2nd stage.

The booster would have an AX–0T (or maybe 1/2AX-0T) in the center with three AX–PT or 1/2AX-PT around the outside (the X just means an as-yet unidentified average impulse).

Then the 2nd stage would have just one 1/2A–3T or A-3T or something.

I'd prefer to use engines bigger than micromaxx.

My questions are:

1. Does this make any sense?

2. Are there any mini A’s or 1/2 A’s that are plugged or with 0 time delay? If so, where can I get them?

3. If I cannot get any plugged ones for the outside rockets, what would happen if an engine is enclosed and the ejection charge goes off? Will it blow the chamber it's in apart?

Thank you all very much!

Mike

 

[Luv2launch]

Hello,
First off welcome to the forum.Estes I believe still makes plugged mini engines but at this point they make no zero delay boosters in the mini engines at all they have been OOP for quite some time now.

 

[gpoehlein]

Grab 'em if you find 'em (A10-PT motors are now discontinued).

 

[gpoehlein]

Grab 'em if you find 'em (A10-PT motors are now discontinued).

 

[ScrapDaddy]

The mini engines with 0 delay are oop but I do suggest going with the staging standArd engines because the only other alturnitive would be a tandum mini engine on top of a standard and I have heard the minis don't stage well

 

[ScrapDaddy]

Don't do #3 ahhh I remember it my first kit, the taser twin it was built as par instructions but was not finished, so my first launch in my large backyard I was really new to rocketry so I put 2 c6-5 in (oh boy) there was a nice liftoff but ahh time for the bad news the delay of five seconds caused the rocket to be pointed 90 down And while the ejection charge blew it DID ignite but it lawndarted into the ground.......... It hit my neighbors house:blush: now that was the stupidest thing I ever did....... Don't make the same mistake!!!

 

[chanstevens]

Hi all,
This is my 1st post, and I'm relatively new to rocketry, so please forgive me if it's not eloquent or it's foolish:



My son and I are beginning to design a smaller rocket. We want to make it a little more complex than just a staged rocket - which we just completed. We will probably cluster engines in the booster stage. We are thinking of using some mini A’s or even 1/2 A’s in the booster.

The general plan:

Use a skinny body tube (just big enough in diameter to accomodate a mini engine) and some mini engines as the central motors. There would be a booster stage and a 2nd stage.

The booster would have an AX–0T (or maybe 1/2AX-0T) in the center with three AX–PT or 1/2AX-PT around the outside (the X just means an as-yet unidentified average impulse).

Then the 2nd stage would have just one 1/2A–3T or A-3T or something.

I'd prefer to use engines bigger than micromaxx.

My questions are:

1. Does this make any sense?

2. Are there any mini A’s or 1/2 A’s that are plugged or with 0 time delay? If so, where can I get them?

3. If I cannot get any plugged ones for the outside rockets, what would happen if an engine is enclosed and the ejection charge goes off? Will it blow the chamber it's in apart?

Thank you all very much!

Mike

#3--the ejection charge expands the pressure inside the tube, so one of three things has to happen. 1--the nose cone pops off (or you simply leave the motor tube open/exposed), 2--the motor ejects itself out the rear, 3--the tube expands/blows open.

One big difference, by the way, between a -0 and a -p or plugged motor. A -0 does have a minor ejection charge, just no delay. The charge is intended to ignite an upper stage motor. A -p or plugged has nothing happening out the front end of the motor at all.

 

[ScrapDaddy]

That's not compleatly correct in the booster there is nothing on top of the propelent PERIOD! The lack of anything above will cause the propelent to become unstable and rupture out the top, igniting the upper stage

 

[Micromeister]

#3--the ejection charge expands the pressure inside the tube, so one of three things has to happen. 1--the nose cone pops off (or you simply leave the motor tube open/exposed), 2--the motor ejects itself out the rear, 3--the tube expands/blows open.

One big difference, by the way, between a -0 and a -p or plugged motor. A -0 does have a minor ejection charge, just no delay. The charge is intended to ignite an upper stage motor. A -p or plugged has nothing happening out the front end of the motor at all.

Chan That is completely NOT ture! -0 motor have NOTHING added NO ejection charge period. DO not perpetuate this lie.

At the burn through point of a booster motor the propellant in -O motor can produce some presurization forward but it isn't exactly predictable and not really enough for general use to deploy recovery systems.
While it is true lots of us competition flyers have used this burn through pressure to deploy recovery systems in some specialty light weight models it should NEVER be banked on for general sport flying use.