Aerotech motor questions

[Joshua F Thomas]

For how popular the AT motors seem to be, it’s quite confusing to try to decipher what their product terms actually mean. Can someone check me on these?

RMS are the reloadables. You buy a case and then you buy engine loads and assemble yourself. I understand that a 24/40-120 is a 24mm engine casing, but what’s the second range of numbers?

These seem to not need engine blocks. How does that work? Do they all have rear-retention mechanisms?

DMS are single-use engines that you assemble yourself, and get around the hazmat issue by being unassembled. Yes?

Thanks in advance.

 

[o1d_dude]

RMS = Reloadable Motor System
DMS = Disposable Motor System

RMS and DMS have an "external" motor block in that the rear rim of the case rides up against the rear of the motor tube. You will need some sort of motor retention to hold the RMS or DMS in place when the depolyment charges lights up. Typically for small MPR birds, the plastic Estes threaded retainer and retainer body system is highly recommended. OOther companies make similar motor retention systems all the way down to 18mm and 24mm. I'm unaware of any system for 13mm which is not to say there is no such thing...I simply don't know.

As you move up to High Power, the Aeropack system of motor retention is most popular but there is greater cost...especially as the motor diameter increases (29mm, 38mm, etc.)

The Hobby Line of AT (29/40-120) is an in-between system. It lives between Low Power and High Power-style motors but doesn't carry the hefty price tag of the big boy toys. It's a good stepping stone for those who want to move up to High Power and smell the flowers along the way. It's also an economical package for those who are content with the HobbyLine of rocket motors and don't want to spend a lot of money for a few seconds of Shock & Awe. Think of this as Mid-Power.

Let your wallet decide how much you want to do rocket-wise.

PS. "Welcome to High Power! Now OPEN YOUR WALLET!"
That's how a successful Level 1 High Power certified rocketeer is usually greeted over the PA system following their cert flight. There's a reason for that.

It's all about converting cash into fire, smoke, and noise.

 

[prfesser]

The "40-120" refers to the total impulse capability. Reloads for this motor case are available from 40 Ns (full E or baby F impulse) to 120 Ns (mid-G impulse).

Be aware that the 29/40-120 case and reloads for it are NOT interchangeable with the AT 29/60, 29/100, 29/120, etc., and their reloads, despite the fact that they're all the same outside diameter.

Best -- Terry

 

[AeroTech]

All DMS are preassembled except for the 75 & 98mm motors. The 75 & 98 mm motors are shipped disassembled in order to reduce the shipping cost from $3,000-$5,000 to something more affordable, by using our DOT special permit that allows them to be shipped via FedEx or UPS as a lower hazard category. Propellant grains or motors are limited to 1,400 grams each when using the permit.

The LMS (Loadable Motor System) 29mm motors are shipped disassembled to take advantage of our USPS approval that allows them to be mailed with no hazmat fee. In that case the propellant grains are limited to 30 grams each.

 

[crossfire]

For how popular the AT motors seem to be, it’s quite confusing to try to decipher what their product terms actually mean. Can someone check me on these?

RMS are the reloadables. You buy a case and then you buy engine loads and assemble yourself. I understand that a 24/40-120 is a 24mm engine casing, but what’s the second range of numbers?

These seem to not need engine blocks. How does that work? Do they all have rear-retention mechanisms?

DMS are single-use engines that you assemble yourself, and get around the hazmat issue by being unassembled. Yes?

Thanks in advance.

DMS motors are single use come fully assembled. All you have to do is adjust the delay and add powder for ejection charge.

 

[Joshua F Thomas]

Thanks, folks.

So say I want to replace my 18mm BP motors with reloadable Aerotechs. What do I need to buy?

 

[DankMemes]

Thanks, folks.

So say I want to replace my 18mm BP motors with reloadable Aerotechs. What do I need to buy?

There’s a lot of vendors you can choose from, my go to is Chris Short, csrocketry.com the same applies for reloads all the way through 29mm

There are three things you’ll need:

1:

But you’ll need the complete case (I recommend buying the complete set and saving a few dollars) it include the case ( sleeve the propellant goes into) and the forward and rear closures (caps that hold the propellent in)

https://www.csrocketry.com/rocket-m...h-18/20-complete-complete-motor-hardware.html
2:

Then you’ll need the reloads, aerotech composite reloads are sold I’m D impulse, and carry significantly more power than comparable size black powder motors. These are sold in 3 packs, with all the necessary components and aerotech first fire initiators, Which are way different than the starters that estes use. As composite motors light from the top of the motor rather than the nozzle end. There’s several Loads you can pick for that you can choose for your rocket:


https://www.csrocketry.com/rocket-motors/aerotech-rocketry/motors/18mm/18-20-reloads.html

3:

One last piece you’ll need is the tool to adjust the delay. Aerotech sells there motors with the longest delay for which they are certified, which means you’ll need to adjust it for the rocket your flying, as the out of the box delay may deploy the chute after the rocket is on the ground... this is accomplished by drilling the delay grain with a special tool that shortens the delay... The tool below is issuable from 18-38mm motors


https://www.csrocketry.com/rocket-m...aerotech-rocket-delay-drilling-tool-rddt.html

Beyond that you’ll need some grease for the O-rings (this is applied during assembly to ensure a good deal and prevent binding as you tighten the closures), and baby wipes for cleaning the soot out of the case after launch.


If you want to experiment with composite motors before you get into reloads, try the Qjet line, it’s an aerotech motor sold in a-d impulse in a disposable platform..

https://www.csrocketry.com/rocket-motors/aerotech-rocketry/motors/q-jet-motors.html

 

[BEC]

3:

One last piece you’ll need is the tool to adjust the delay. Aerotech sells there motors with the longest delay for which they are certified, which means you’ll need to adjust it for the rocket your flying, as the out of the box delay may deploy the chute after the rocket is on the ground... this is accomplished by drilling the delay grain with a special tool that shortens the delay... The tool below is issuable from 18-38mm motors


https://www.csrocketry.com/rocket-m...aerotech-rocket-delay-drilling-tool-rddt.html

This is not (at least yet) true of the 18/20 reloads. Check the csrocketry link you posted for the reloads. One has to order the kit with the delay you want to use (or get the appropriate hobby delay kits to change one to another).

It doesn't look like Chris stocks the hobby delay kits. Wildman does. Delay kits include the delay element itself and the necessary spacer that you substitute for the ones supplied in the reload kits to provide a different delay. Here is an excerpt from the current Aerotech price list about these.

 

[Joshua F Thomas]

This is not (at least yet) true of the 18/20 reloads. Check the csrocketry link you posted for the reloads. One has to order the kit with the delay you want to use (or get the appropriate hobby delay kits to change one to another).

It doesn't look like Chris stocks the hobby delay kits. Wildman does. Delay kits include the delay element itself and the necessary spacer that you substitute for the ones supplied in the reload kits to provide a different delay. Here is an excerpt from the current Aerotech price list about these.View attachment 427097

The T and W here are the propellant type?

 

[BEC]

Yes. Blue Thunder and White Lightning respectively.

 

[DankMemes]

Blue thunder definitely look cool

 

[DankMemes]

This is not (at least yet) true of the 18/20 reloads. Check the csrocketry link you posted for the reloads. One has to order the kit with the delay you want to use (or get the appropriate hobby delay kits to change one to another).

Good callout used to the loads for my hobby line case, use the 18/20 and the d24 only when flying my 1/200 Saturn V or the exo skell with my son at the park

It doesn't look like Chris stocks the hobby delay kits. Wildman does. Delay kits include the delay element itself and the necessary spacer that you substitute for the ones supplied in the reload kits to provide a different delay. Here is an excerpt from the current Aerotech price list about these.View attachment 427097

This is not (at least yet) true of the 18/20 reloads. Check the csrocketry link you posted for the reloads. One has to order the kit with the delay you want to use (or get the appropriate hobby delay kits to change one to another).


Good callout, used to my hobbyline loads, most fly the 18/20 in my 1/200 th Saturn V
It doesn't look like Chris stocks the hobby delay kits. Wildman does. Delay kits include the delay element itself and the necessary spacer that you substitute for the ones supplied in the reload kits to provide a different delay. Here is an excerpt from the current Aerotech price list about these.View attachment 427097

 

[AeroTech]

BTW Terry...congrats on winning the TRA President’s Award this year!

- Gary

The "40-120" refers to the total impulse capability. Reloads for this motor case are available from 40 Ns (full E or baby F impulse) to 120 Ns (mid-G impulse).

Be aware that the 29/40-120 case and reloads for it are NOT interchangeable with the AT 29/60, 29/100, 29/120, etc., and their reloads, despite the fact that they're all the same outside diameter.

Best -- Terry