Aerotech engine codes

Jacktango22

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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.
 

tsmith1315

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Those numbers are average thrust only. You can't make any assumptions about the thrust curve beyond that.

Go to Thrustcurve.org and you can find the plots along with total impulse to make better decisions.

You can also enter rocket specs for a quick flight sim.
 

BEC

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…in other words, the ”Estes” engine code and the “Aerotech” engine code is the same code. A general explanation here: https://www.nar.org/standards-and-testing-committee/

As noted by the two posts above, Thrustcurve.org is a resource to see what the time-thrust curves look like for just about any engine out there. The data is also available from the web sites of the certifying organizations (NAR and Tripoli in the US) and from some manufacturers’ web sites. Also everything I’ve ever gotten from Aerotech/Quest has that information in the documentation in the package.


Oh, and let me warn you that the rocketry bug bites much harder the second time around…. :D
 

bjphoenix

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The letter gives an idea of the total impulse, but it implies a range so an Estes E and an Aerotech E might not be totally equivalent in power.
There is kind of an average or maybe a common average thrust that is associated with each letter, if you hear someone about to launch a rocket with a bigger number than you typically recognize for that letter, it's going to be a fast flight. A motor with a relatively high number for its letter class will have high thrust but not burn for very long.
For instance I did level 1 years ago with I think an H123. It has max. thrust of 224N and burn time of 1.8 sec. I'm not familiar with all of the motors available today but I see that Aerotech lists an H999 with max. thrust of 1710 but burn time of only 0.3 sec. That's like hitting the rocket with a really big hammer. If you get to where you recognize what and H123 is and you hear the announcement that they are about to launch an H999, you stop and watch it.
You mentioned F motors- I see that Cesaroni has an F120 listed. That would hit a rocket pretty hard at launch.
 

cls

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Oh, and let me warn you that the rocketry bug bites much harder the second time around…. :D

Oh yeah! Combination of free time a some extra $$$...


The letter gives an idea of the total impulse, but it implies a range so an Estes E and an Aerotech E might not be totally equivalent in power.

To the OP: More than the brand, it's the Isp, efficiency of propellant. The lower weight and larger Isp of APCP propellant combine to give you amazing performance on the same rocket model.

Enjoy!!
 

smstachwick

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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.
 
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