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  #31  
Old 08-22-2008, 01:26 PM
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ghrocketman ghrocketman is offline
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I stand by my original statements and re-state that this is NOT motor manufacturing and I could care less if it ALTERS the motor performance.
Even the agents at BATFE are SMART enough to surmise that gluing motors together no more constitutes motor manufacturing than taping them does.

Pure horse-pucky to punish the innovative all in the mamby-pamby name of safety.
Typical over-regulation....I would always rather have ZERO regulation than over-regulation, which is why I rarely join any sort of club or governing body...most have WAAAAAYYYYY too many rules/regs.

There is a certain amount of risk involved in the hobby of rocketry....I'd just as soon accept that (part of the fun....no risk/danger=NO FUN) instead of constantly try to weed it out/reduce it.
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  #32  
Old 08-22-2008, 01:55 PM
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Doug Sams Doug Sams is offline
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Quote:
Originally Posted by ghrocketman
Typical over-regulation....
GH,

You're free to do this on your own. The restriction is at club launches. Nobody's gonna bust you for doing it at unsanctioned launches. (Although your NAR/TRA insurance will likely not cover this.)

After reading about this the past 2 days, I'm inclined to glue a couple together just for a cheap thrill I'm thinking a C5-0S to a C6-5 in a Big Bertha. How's that sound?

Doug

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  #33  
Old 08-22-2008, 01:59 PM
shockwaveriderz shockwaveriderz is offline
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Quote:
Originally Posted by Doug Sams
GH,

You're free to do this on your own. The restriction is at club launches. Nobody's gonna bust you for doing it at unsanctioned launches. (Although your NAR/TRA insurance will likely not cover this.)

After reading about this the past 2 days, I'm inclined to glue a couple together just for a cheap thrill I'm thinking a C5-0S to a C6-5 in a Big Bertha. How's that sound?

Doug

.



I've done it with some B6-0/B6-6 and its definately a cheap thrill. with that combination Doug, you would probably get a burnthrough die to the combination of the two engines thrust durations being in excess of 2 seconds.

terry dean
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  #34  
Old 08-22-2008, 02:46 PM
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Shreadvector Shreadvector is offline
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Quote:
Originally Posted by shockwaveriderz
I've done it with some B6-0/B6-6 and its definately a cheap thrill. with that combination Doug, you would probably get a burnthrough die to the combination of the two engines thrust durations being in excess of 2 seconds.

terry dean


The nozzles should be identical. If the lower nozzle is larger it will have losses. if the lower nozzle is smaller it will overpressurize and fail.

And, as stated, if your glue joint and/or sleeve (i.e your homemade casing into which you install 2 normal model rocket motors to create an uncertified device) is bad, it will fail at the joint. And then there is the burn through issue at the bottom....
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  #35  
Old 08-22-2008, 07:54 PM
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Bob Kaplow Bob Kaplow is offline
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I tandemed a few motors back in the day, and don't remember ever using a sleeve over the joint. Most were just butt joined end to end; an A3-0T and A3-6T for B Payload at NARAM-20 IIRC.

The neat ones were sticking a A3-4T into a C6-0 to get into the D class for D BG and similar events. Or a D12-0 C6-3 for E class events.

Around the same time as tandem motors, we had AVI "Gold" series motors that used delay ejection modules epoxied into the end of their motors. I made a neat F2412 tandem probably for a Dual Egglofter that I never fired, and is still in my collection somewhere.
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  #36  
Old 08-22-2008, 11:05 PM
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LeeR LeeR is offline
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Quote:
Originally Posted by bringrose
Hey,

I'm currently designing a model rocket and would like to make it 3 stages and have a few questions and concerns. First is it even possible to do 3 stages and if so is it anything like 2 stages? Second when using this much power should I be considering the weight of the rocket? And lastly do the first 2 stages need to break away or can they just fall out of the tube?

Any help is much appreciated!

Ben


There have been lots of suggestions on getting started in staging with something less ambitious than a 3 stage rocket. Check out this Estes Plan from 1965 (the Augie II). I built this as a kid, and it was a blast to fly. I've toyed with upscaling this to a 24mm 2 stager.

http://www.dars.org/jimz/eirp_28.htm
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  #37  
Old 08-23-2008, 12:39 PM
Green Dragon Green Dragon is offline
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Quote:
Originally Posted by Bob Kaplow

The neat ones were sticking a A3-4T into a C6-0 to get into the D class for D BG and similar events. Or a D12-0 C6-3 for E class events.


That's the tandem motors I remember.

Like a F100-0 / C6-7 tandem to make a baby F, or D20-0/ A3-6T .

doubt I have any fired examples in the dead engine box, will have to dig and see. lol .

~ AL
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