I am recently retired and back into the hobby again. Using open rocket and learning a lot from the threads on this forum.
Quick question: I have always used Estes engines and understand the code system very well. I am looking to try some Aerotech engines at the E and F level for the first time and note the larger number (compared to Estes) …. Such as a F23 (or higher) Aerotech to an Estes F 15.
I am looking for a way to wrap my mind around what this means as I try to determine a suitable engine for the rocket at hand. A more intense and front loaded thrust curve? Any guidance would be much appreciated.
AeroTech motors, as stated before, use the same system as the Estes motors, just with some minor adjustments. Total impulse range, average thrust, delay time. The main difference is that AeroTech will include another letter to denote the propellant type, which will give you an idea what the smoke and flame will look like. B4-4FJ for example, or B4FJ if you're not specifying a delay time. "FJ" is Black Max, which produces black smoke, W is for White Lightning, which produces a brilliant white flame, T is for Blue Thunder, which produces a violet-blue flame, etc. The propellant types also have their own unique thrust and burn characteristics. A Blue Thunder motor will generally produce more thrust than a motor with a comparable amount of White Lightning, for example.
A few propellants used in larger motors have their own idiosyncrasies to watch out for. Warp 9 propellant (suffix N, such as a G339N) doesn't allow for the use of delay grains and ejection charges, for example, meaning that you have to supply your own electronic deployment with a Warp 9 motor.
The F23 motor you saw is a Black Max (FJ) motor. Thick, black smoke and pretty low thrust for the F class.
To answer your question about the higher thrust than Estes, it's because these are composite-propellant motors with ammonium perchlorate oxidizer. In terms of chemistry, these motors are more similar to the Space Shuttle's Solid Rocket Boosters than anything Estes makes. Estes motors use black powder, which is cheap but not suited to motors larger than E or F class for various reasons. Chiefly among them, black powder can crack and produce a catastrophic failure of the motor, and this tendency increases with larger motors. Composites are more reliable.
Most Estes rockets should be OK to fly on AeroTech motors, I just wouldn't recommend going crazy on the thrust. For motors like an F50 or G80, rockets with heavier and sturdier construction are generally more suitable. AeroTech manufactures their own line of these mid-power kits under the Enerjet brand, and you may be able to find some stuff you like from LOC/Precision, North Coast Rocketry, and others.
The thrust curves and lots of other information on available rocket motors can be found on thrustcurve.org. Great site, poke around there to learn about the motors that are available.