Composite low power motors?

[New Ocean]

I would buy a bunch of these and a case on the spot if they were offered. I guess that is not enough to warrant starting up a new line of motors

[cavecentral]

If you did research, a company called Green Monkey made 13mm and 18mm research hardware. Not sure if they are still around, or of you'd have to find it used.

Probably your only option besides upping the motor mount size.

[ClayD]

If you did research, a company called Green Monkey made 13mm and 18mm research hardware. Not sure if they are still around, or of you'd have to find it used.

Probably your only option besides upping the motor mount size.

Those sizes are small enough, you could make hardware quite easy with an over the counter tap/die set... Snap ring if you have a lathe...

If you can get green monkey, your issue will be with finding liners...
I am curious if that or SU ex motors from AT are cheaper...

For the work it takes, I personally would want a SU ex motor option in those sizes.

[cavecentral]

Those sizes are small enough, you could make hardware quite easy with an over the counter tap/die set... Snap ring if you have a lathe...

If you can get green monkey, your issue will be with finding liners...
I am curious if that or SU ex motors from AT are cheaper...

For the work it takes, I personally would want a SU ex motor option in those sizes.

Research in 29mm is about as small as I can tolorate. Anything else, I'd use the AT hobblyline or SU.

The smaller ones I'd need to use a different grain geometry than Bates. Too much of a pain making Bates grains that small. Just not frying the casing if you go C-Slot may be a challenge.

[mwtoelle]

The biggest problems with small composite motors are tiny nozzles that require even tinier igniters to light them. I used some of the Aerotech B and C reloads. The biggest problem with them was getting the igniter through the nozzle. Actually, it is difficult to make igniters this small. The B6 propellant grains were about ½" diameter x 7/16" long with a c-slot grain geometry.

[cavecentral]

The biggest problems with small composite motors are tiny nozzles that require even tinier igniters to light them. I used some of the Aerotech B and C reloads. The biggest problem with them was getting the igniter through the nozzle. Actually, it is difficult to make igniters this small. The B6 propellant grains were about ½" diameter x 7/16" long with a c-slot grain geometry.

Some of the smaller AT loads tell you to install the ignitor as you build it. I don't agree with this, but options get fewer on the smaller sizes. I think on 18mm and below, I'd try that.

[rockets4kids]

Green Monkey Aerospace seems to have disappeared without a trace some time back, likely because it is so difficult to produce 13/18/24mm motor casings. The first problem with motors smaller than 29mm is that there is no standard size stock available. You need to purchase oversize stock and turn down the OD and bore out the ID -- a time consuming process. It is also much more difficult to cut threads or snap grooves in these smaller casings.

In my experience, the "sweet spot" for motors -- the size where both casings and grains are easiest to make -- is right around 1" OD. 1" OD tubing is also very available, and a result much less expensive than sizes slightly larger or smaller. As such, I have chosen this as *my* standard sizing for small EX casings.

[Madison Alum]

It would be nice if there was a slightly larger selection of motors for the 18/20 case. The current selection of only two motors (D13/D24) just doesn't justify the cost f the hardware in my mind. For the rare times that I need a D motor in an 18mm bird the D21 works. One thing of note... While Apogee lists both the D10 & 21 single use as in-stock, AT's online store only lists the D21 making me wonder if the D10 is headed OOP (not that I have ever used one or had a need for one).

. Apogee's D10 gave their Diamondback a great ride. I haven't used them on other rockets. They were replaced by Aerotech's D10 this year.

[luke strawwalker]

Vapor wear is terrible. I understand though if it is not profitable.

I dunno... Vaporware has done alright by me... It keeps your celery crunchy and prevents your cooked rice from getting crunchy...

Just don't try to drive your van up onto it for a jackstand... DANG IT!!!!

hehehe... Later! OL JR

[cwbullet]

I think it is time for 18 mm motors. I would love to have an 13 or 18 mm G.

[MarkII]

Some of the smaller AT loads tell you to install the ignitor as you build it. I don't agree with this, but options get fewer on the smaller sizes. I think on 18mm and below, I'd try that.

I do it all the time. It's never been a problem. I have a D13 all assembled, with installed Copperhead igniter, sitting on my shelf right now that I put together at a launch back in May but didn't get a chance to fire. It's all ready to go for the next time I get out to a field.

The largest motor that I built with the igniter installed during assembly per instructions was a G69N in a 38/120 case.

[MarkII]

One of the other problems with the 18/20 motor is finding a kit with an 18mm mount that can handle the reload without becoming a one shot deal. The original Fat Boy was one, I hear. You might very well want to launch such a rocket on an 18mm SU motor in supplication to appease the Rocket Gods, but doing it with an RMS motor gets to be expensive.

[cavecentral]

I do it all the time. It's never been a problem. I have a D13 all assembled, with installed Copperhead igniter, sitting on my shelf right now that I put together at a launch back in May but didn't get a chance to fire. It's all ready to go for the next time I get out to a field.

The largest motor that I built with the igniter installed during assembly per instructions was a G69N in a 38/120 case.

The fact that I build motors at home pre launch and sometimes bring them back unfired is my issue. Small motors and firing in a reasonable amount of time (like at the field) is safe enough. I'm sure copperheads are not likely to go off accidently. A more sensitive ignitor maybe.

[MarkII]

The fact that I build motors at home pre launch and sometimes bring them back unfired is my issue. Small motors and firing in a reasonable amount of time (like at the field) is safe enough. I'm sure copperheads are not likely to go off accidently. A more sensitive ignitor maybe.

Right. I wouldn't do it with say, a ProXX reload with its e-match igniter. That won't get installed until I am at the pad. My point was that AeroTech has users install Copperhead igniters during assembly in quite a few of its D, E, F, G reloads, perhaps even in all of them. In fact, I also did it in an H165 reload.

[cwbullet]

Right. I wouldn't do it with say, a ProXX reload with its e-match igniter. That won't get installed until I am at the pad. My point was that AeroTech has users install Copperhead igniters during assembly in quite a few of its D, E, F, G reloads, perhaps even in all of them. In fact, I also did it in an H165 reload.

I agree with that. Although I have never seen it happen, ematches supposedly have a theoretical chance of going off with static.