Dumb Question

[azgreg]

I'm considering building a few mid-power rockets and I have a question about reloadable motors. Do you use the shoulder of the motor casing instead of a motor block?

 

[kjohnson]

Normally, yes. You can still use a motor block if you want with 24mm and 29mm hobby line cases, you just have to make sure the forward closure with the ejection cap will fit through it.


kj

 

[Aksrockets]

Definitely. Using a motor block limits motor size. A big no-no with MPRs and HPRs.

Alex

 

[gpoehlein]

Plus, if you decide to use Estes 24mm motors in your rocket, you can put a couple wraps of 1/4" masking tape around the back end of the motor to make a "shoulder". Also, motor retention can be an issue - if you want to use Estes E motor clips, you should remove (file or dremel) about an eighth of an inch from the inside end. They are a little too long to allow an Aerotech motor ejection cap past them. I've also heard of people bending them back on themselves so they wrap back over the band that holds them in place - the clip then doesn't even go through the motor tube (it isn't needed since the shoulder or flange at the back of the motor serves the same purpose).

 

[T-Rex]

No such thing as a dumb question here..

 

[Eat, sleep, and Fly]

I'm considering building a few mid-power rockets and I have a question about reloadable motors. Do you use the shoulder of the motor casing instead of a motor block?

There is no such thing as a dumb question, to answer your question... yes

 

[bjphoenix]

I'm considering building a few mid-power rockets and I have a question about reloadable motors. Do you use the shoulder of the motor casing instead of a motor block?

There is no need for an engine block, the shoulder on the end closure works very well for that. Plus as mentioned different motors are different lengths. I have several rockets with 38mm mounts, and I bought the 38/240 and 38/480 cases for my use. Built with the 480 tube a motor is almost twice as long as if I had built with the 240 tube, and if I wanted to get L2 certification I could buy another tube and build J motors. Without an engine block I can use any length engine that I want.

 

[cbrarick]

Instead of blocks (which limit the length of the motor, which is bad) or clips (not so secure when you are shelling out $$ for cases that you want to reuse) you should consider aeropack retainers....there's cheaper ways but nothing as easy to use and certain to work. Just glue them on with some JB weld, which you can find at home depot or lowes....

Link to their website: https://aeropack.net/

I'm sure this will start the retainer debate....

 

[Tom W]

If installing a 24mm mount and if the rocket can handle it I set the thrust block up for an Estes E9 BP motor but remove some/most of the inside wraps so the red cap and/or the ejection charge canister on the reloadable casings can easily pass through. I glue this thin thrust block in with epoxy.

This way I can use any of the Estes 24mm BP motors from C-E with the one inch E to D/C adaptor or the 24mm AT single use motors that do not come with a thust block or the 24/40 reloadable case which uses the rear enclosure as a thurst block. I do NOT have the 24/60 case so my system may NOT work with that particular case.

The extra length of the E clip doesn't get in the way of the shorter motors but I file the top part of the clip a little anyway to make sure the red ejection caps can pass thru easily.

I always use tape in addition to the clip to secure my motors. If you cover the outside of the motor tube with a coat of thin epoxy the tape doesn't tear the motor tube up when you remove it.

I also use the friction fit method to help take some load off the thust block when using the AT single use E-15's and E-30's.

On 29mm mounts I do not use any thrust blocks and use the one on the motor.

If possible try out whatever method you decide to use with all possible motors before you glue the motor tube into the rocket so you can easily make any adjustments.

 

[Handeman]

For most mid-powered rockets, I never put motor blocks or retention clips in the rockets. The shoulder on the aft enclosure will act as the thrust block against the bottom of the MMT. As was mentioned earlier, you can put 4 or 5 wraps of masking tape on the lower end of Estes, or SU motors to make a shoulder and install these the same way the RMS motors go in.

With that said, most Estes 24mm rockets I build, I build stock, with the only mod being to grind down the forward end of the motor retainer clip so the upper part of the 24/40 cases will fit into the rocket. This can be done after assembly, but it's much easier to do before.

The motor clip actually works quite well for motor retention. Just twist a piece of wire around the clip and the nozzle to prevent the clip from lifting away from the motor and letting it push out. I attached a pic of a 24/40 case in an Estes Stormcaster that is done that way.

 

[Zeus-cat]

There is no such thing as a dumb question...

If you really believe that I would like to introduce you to several of my former bosses...

 

[Eat, sleep, and Fly]

If you really believe that I would like to introduce you to several of my former bosses...

:gavel:
My grade school teachers would tell us "there is no such thing as a stupid question"... and the next thing I know, someone asks a dumb question, and they let em' know it too:kill:

 

[Barracuda]

I just use a thrust block(forgot the size) that fits over the motor tube(24mm) to retain the hook,it's a little bent.Slide it down flush w/the bottom,tight enough to stay where you put it.Works great on my bumblebee