Recommended "A Impulse" Engines for a Two Stage Rocket

[Harrison Vance]

I currently plan on building a two stage rocket that will fit two 13mm "A Impulse" Estes rocket engines. The overall goal is to compete in the B Engine Altitude Contest located at NARAM-63 this year. These are strictly my thoughts on what engines I'd like to pick for this event. Let me know what you all think and if you have any suggestions please let me know!

First Stage:
Engine: A10-0T
Burn Time: 1.1 seconds
Total Impulse: 1.9 N-s
Max Thrust: 9.7 N
Propellant Mass (g): 3.6 grams

Second Stage:
Engine: A3-4T
Burn Time: 1.0 seconds
Total Impulse: 2.2 N-s
Max Thrust: 5.8 N
Propellant Mass (g): 3.3 grams

Personal Note: As far as the second stage goes I do see a possibility in using the A10-3T engine as it has the extra kick needed to compete for altitude, but with that extra kick I'm concerned about the rocket's performance as it could throw the rocket off of it's projected course. Listed below is the A10-3T engine specifications for you all to compare. Again any feedback/suggestions are appreciated!

Supplementary Second Stage
Engine: A10-3T
Burn Time: 0.9 seconds
Total Impulse: 2.0 N-s
Max Thrust: 12.6 N
Propellant Mass (g): 3.8 grams

 

[neil_w]

It's hard for me to imagine any scenario where a A10 would be better for second stage than the A3. For altitude you generally want to maximize total impulse, and longer/slower burns are generally better as well. Easiest way to really answer it, though, is to simulate it and see.

 

[waltr]

Exactly what Neil_w said.
Run sims in Open Rocket to determine best combination of motors.
Also adjust weight to find best altitude. Lightest is not the highest.

 

[dhbarr]

The main thing at this size, I would think, is whatever top stage has the longest available total burn+delay time. No matter what, you're probably going to still be coasting incredibly fast when the ejection pops ~4s early.

That, and getting the top stage back from a thousand feet up

 

[neil_w]

The main thing at this size, I would think, is whatever top stage has the longest available total burn+delay time. No matter what, you're probably going to still be coasting incredibly fast when the ejection pops ~4s early.

A3-6T is coming relatively soon... https://www.rocketryforum.com/threads/estes-a3-6t-availability.172745/ ... but not soon enough for NARAM 63.

 

[aerostadt]

There is some good information in this thread. In theory there are lots of possible combinations of A-motors that can be used, but in practice the number of A-motors in the U.S. is the limiting factor.