I just recently bought a Launch Pad AM 39 Exocet missile. I would like to keep it the model with its single motor mount, however, most exocet missiles (in real life) have two motors on them. So i was wondering if I could make a booster like the Exocet MM40 Block 3 that would have have a dual motor booster (24mm) that would ignite the single 24mm motor on the original model. The reason I ask is so I could still launch my rocket in areas that don't allow dual or multistage motors?

It is probably a stupid idea, but i was just wondering with you rocket Experts out there.

The other idea that I was thinking about was to make a three motor system where the rocket could use the 24mm motor, and then have the option to use two 18mm motors. This would make it the rocket have three motor tubes all abreast (would that even fit in a Bt-80 tube?)

Hopefully i made sense and i would appreciate any feedback.

Two motor booster to a single motor sustainer? Sure. You will need to design a guide or funnel to direct the booster gases to the sustainer nozzle. I did one back in the '70s just to see if I could. It worked.

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Clear skies and fair winds,
Mike

NAR 31689

BT-20 OD = 0.736"
BT-50 OD = 0.976"

2 x 0.736 + 0.976 = 2.448"

BT-80 ID = 2.560"

Looks to me like you'd have to get creative with the centering "rings" (really they'd be 2-piece things) but ought to just fit.

In fact you could put 6 18mm tubes around the central 24mm. Just sayin'...

Edit: Oh look, I just invented the Cluster Duck https://www.apogeerockets.com/Rocke...ts/Cluster_Duck

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Rich Holmes
Camillus, NY
Secretary / newsletter editor
Syracuse Rocket Club

http://richsrockets.wordpress.com

One of Oregon Rocketry's veteran members made a Two-to-One two stager, using some kind of ductwork. I never asked him about the details.

It was a BT-60 sized model, as I recall. Kind of like a Super Alpha with a booster. It performed really well.

Note that the ducting shouldn't be airtight, and can't have kinks. You're channeling flame and sparks, not hot gas. A badly designed duct would act as a baffle.

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NAR #27085 - Oregon Rocketry - SAM

Sure. I used to fly a BT70 2 stager, with a 3x18mm booster , and a 2x24mm sustainer. Vented the booster, and didn't use any ducting. It staged OK *most* of the time. With some ducting, I would expect reliability to be improved (but keep some venting).

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Paul
If we weren't all crazy, we would go insane - Jimmy Buffett
NAR #87246 www.wooshrocketry.org

Be sure to read the chapter on Staging in the Handbook. G. Harry describes the mechanism of engine-to-engine staging rather well, and explains what needs to occur in some detail. The simple answer is "yes, it can be done". The more complex answer is "as long as it does this... and this...".

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Craig McGraw

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AMA 352635