# 3x F23 motors = ?

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#### rocketsonly

##### Well-Known Member
First, lets start out with some specs for the Aerotech F23:

Propellant mass: 32g
Total Impulse: 56 N-sec

If I'm using three of these motors in one launch, will the combined power equal a G66 with 96g of propellant, and 168 N-sec?

EDIT: I mean G69

169Ns is no longer a G , it is an H69

Originally posted by rocketsonly
First, lets start out with some specs for the Aerotech F23:

Propellant mass: 32g
Total Impulse: 56 N-sec

If I'm using three of these motors in one launch, will the combined power equal a G66 with 96g of propellant, and 168 N-sec?

You could just use a G64, which has less propellant.

rocketsonly

With a total propellant mass of 96 grams it's still a model rocket if the total weight is below 1 pound, or a Large Model Rocket if the weight exceeds 1 pound but is below 1500 grams.

It is not the same as flying a high power H69 motor, it's just a cluster with an average thrust equivalent to a single H69 motor with 168 NS total impulse equivalent to a single 5% H engine.

The advantage of the cluster is that you do not need certification to fly it as you would if it were an actual H69 motor.

Bob Krech

im going to check on that...i think i recall seeing that anything leaving the ground with more than 120Ns of thrust on board requires certification. im not sure though. i'll check on it.

apparently i was misinformed

Size. My model rocket will not weigh more than 1,500 grams (53 ounces) at liftoff and will not contain more than 125 grams (4.4 ounces) of propellant or 320 N-sec (71.9 pound-seconds) of total impulse. If my model rocket weighs more than one pound (453 grams) at liftoff or has more than four ounces (113 grams) of propellant, I will check and comply with Federal Aviation Administration regulations before flying.

https://nar.org/NARmrsc.html

that should clear it up. as per NAR rules.

The NAR safety code sez a model rocket is <1500g, <125g of propellant, and <320 N-s of total impulse.

Well, I guess I typed too slow...

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