Sunday, November 1, 2009

24mm Aerotech G Possible

According to this thread on TRF, Aerotech may eventually bring out 24mm RMS G motors.

One poster speculated that one, probably the first, might be simply two F35W grains together, which would make roughly a G70W with about 110Ns total impulse and 1.4s burn time. That would work well with delays on perhaps 5,8, and 11 seconds.

If they really do, it'd be interesting to see what the hardware looks like. 120Ns hardware would be about 6 to 7 inches long - too long for 24mm mounts with an engine block, but just fine for something like the Mozzie or 24mm saucer. I'm hoping the hardware would at least be compatible with one of the two current 24mm RMS sets, likely the 24/60 which has thicker walls designed for higher pressure, and is designed more like HPR hardware than the 24/40 set.

If they really do come out, then they'd prolly come out several loads as well with more loads for the 24/60 case, which I'm really hoping will eventually include Black Jack, White Lightning (F35W), Blue Thunder, and maybe even Redlines.

All is still speculation based on 9 words from Gary Rosenfield, but fun speculation indeed!


DTH Rocket said...

Ooooo! Perfect for mach rockets! If they come out with it the first thing I'm going to do is make a 24mm fiberglass airframe.

The EGE said...

I've got one planned for the F32, using cardboard tubing and basswood fins protected with wood glue. Should break Mach on E30s, F32s, and any Gs.

KenKzak said...

Unless Gary pulls off a Warp 9 miracle for the 24/60, a 24mm G WILL require a longer case. Any other formulation certainly will.
Start planning ahead and do away with those forward motor stops.
As a rocketeer who has always tried to be ever ready for "More Power", it's a very rare rocket of mine that has a motor stop at all, even at 18mm. That's what masking tape is for, if the motor doesn't have a thrust ring of it's own these days.

Aerotech and Vulcan had a variety of 24mm F & G SU motors in the old days. I still have a fistfull of them to use up. It'll be nice to see some of those motor options return, one way or another...

The EGE said...

Ken: I figured that it'd definitely require new hardware. To get even an 80Ns baby G with 30g of propellant (about the limit for the 24/60 case) would require an Isp of about 281, way higher than the 230s achieved with Warp Nine or the 250 with NT Blue Thunder mix, which is effectively optimized anyway.

I don't have motor stops in most of my larger rockets. My Mozzie can handle up to a 29/180 case, the biggest that physically fits in the body tube, and the Nike-Apache could probably fit a 29/360 case if I really packed it well. Most of my 18mm rocket do, though, because D motors would lose 90% of my 18mm fleet, and I don't see the E25 coming back anytime soon.

Besides, with new molded cases for the G80, F32, and E20 and the built-in ring on RMS and ProX cases, there's not a lot of motors that even need a motor block anyway.

~~~~ The EGE

R2K said...

I am a bit worried about making cases for one or two reloads. It feels like a waste, I certainly wont buy a case just to fly one motor. What is the problem with just bringing back the G55 and F101?

The EGE said...

R2K: I agree, hence why I chose the 29/40-120 case, which is more expensive and can't fit in my 24mm rockets, for flying Fs, because the 29mm case has way more motor options. I would want at least 3 or 4 motors for the 24/60 case or a 24/G case before I'd buy it.

The G55 and F101 back would be nice, but they're so high-thrust that they'd strip the fins off msost 24mm rockets - they were intended mostly for heavy payload rockets (before HPR became readily available) and Machbusters. A 24mm G50 or G70 would be somewhat more practical, and also under the 80N limit.

Plus, reloads can have multiple grains and come in under 30g per grain. Unless you have an LMS motor (which I want to see more of, like perhaps an F32 LMS), then RMS loads will be way cheaper to ship than SU motors.

KenKzak said...

Aerotech is getting away from SU motors using labor intensive components. If they were to consider bringing those motors back, or others like them, they would need be reconfigured to fit either the new molded cases or a reload case. As EGE mentioned a 24mm G will need a longer case no matter what.

What 80nt limit?
That merely separates an F from a G.
If it's a G, it's more than 80nt.

What is the signifigance of 30g propellant slugs?

The EGE said...

Ken: It's a lot cheaper to ship under DoT rules if you keep all pieces of propellant (slugs in RMS and LMS, all propellant in a SU motor) under 30g.

The 80N average thrust limit is one limit on model rocket motor versus high power motor.

KenKzak said...

I was assuming total impulse. I forgot there was a modroc limit on average impulse.

I didn't know about the DoT 30g threshold.
Baah, it just means that some small motors are cheaper to ship, not the other way around. It all depends on your outlook.