#51
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Quest MicroMaxx "booster" motors are designated 1/8A.5-NE and are NAR certified. They are the 1 second delay motors with the ejection charge removed by Quest. The NE means No Ejection and they weren't sold as booster motors although, in the right model, they will work as such.
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Bill Spadafora http://www.billsplumbing.com billspad@comcast.net bill@billsplumbing.com |
#52
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That could be interesting... Stage a rocket with a D-12 first stage into a pair of sequential Micromax NE motors, then into another 24mm sustainer.
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"AND I hope they are from the planet of the "Chunk spunky Mary-Lou Retton clones". - Ironnerd "Those who trade liberty for security have neither" - Benjamin Franklin "Semroc is almost always the answer" - Stefanj www.paulsavia.com www.soundclick.com/paulsavia |
#53
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Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see: http://www.lulu.com/content/paperba...an-form/8075185 http://www.lulu.com/product/cd/what...of-2%29/6122050 http://www.lulu.com/product/cd/what...of-2%29/6126511 All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com. NAR #54895 SR |
#54
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Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see: http://www.lulu.com/content/paperba...an-form/8075185 http://www.lulu.com/product/cd/what...of-2%29/6122050 http://www.lulu.com/product/cd/what...of-2%29/6126511 All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com. NAR #54895 SR |
#55
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The quasi-ballistic (also called semi-ballistic) Boeing AGM-69 SRAM--Short Range Attack Missile (which would make an interesting scale model rocket, see: http://www.google.com/search?ei=x0g...1.0.V3XCEDsLnt4 )--used a dual-pulse solid rocket motor. The B-52-launched and FB-111-launched SRAM could fly off in any direction, even making "over-the-shoulder" launches in order to strike land targets *behind* the launching aircraft, and it could also function as a high-supersonic, relatively low-altitude cruise missile. Its dual-pulse rocket motor, in which the second propellant grain (which was separated from the first one by an insulating, blow-out bulkhead) could be ignited at any desired time, gave the SRAM its versatile and rather uncanny capabilities. (The Soviet--now Russian--Raduga Kh-15 air-launched quasi-ballistic missile [see: http://www.google.com/search?ei=E1M.....0.9WH24vxjzm4 ], which is very similar to the SRAM, also uses a dual-pulse solid rocket motor.) Now: You could achieve a rather similar--although "pre-programmed"--dual-pulse motor profile by placing a black powder model rocket motor above a re-loadable composite propellant motor (using the common "taped butt-joint" staging method), which would be prepared with a delay charge but *without* an ejection charge. (A small amount of ejection charge powder [or perhaps Pyrodex], placed atop the delay charge, would ignite the black powder upper stage motor after the composite motor's delay charge had burned.) Also: Gap-staging such a motor combination would also be possible, although it would probably be prudent to use some kind of retention system to keep the "upper stage ignition powder" atop the delay charge in the composite lower stage motor (so that the powder couldn't "fall upward" and out of the lower stage motor due to its inertia, when the rocket began to coast after the lower stage ceased thrusting); a disc of model airplane tissue might do the job. Retaining the lower stage motor's ignition powder would be especially important in models with "open-air gap-staging" (scale models of the Aerobee vehicles, the Cuckoo-boosted Skylark sounding rockets, the Iris and Hydra-Iris, the INTA-255, the Boosted Arcas I, etc.), plus: Arranging the two motors to produce a two-pulse tandem motor (in which the upper motor would thrust down through the lower motor, but the two motors would *not* separate [this has been done many times with black powder motors, often a 13 mm motor atop an 18 mm booster motor]) would enable a "pre-programmable" dual-pulse flight profile to be used. This would provide scale realism for flying models of the SRAM, Kh-15, and other dual-pulse (not to be confused with *dual-thrust*) solid propellant vehicles.
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Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see: http://www.lulu.com/content/paperba...an-form/8075185 http://www.lulu.com/product/cd/what...of-2%29/6122050 http://www.lulu.com/product/cd/what...of-2%29/6126511 All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com. NAR #54895 SR |
#56
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I played with this in open rocket some time back, some things to consider; the high impulse short duration thrust usually has a lower average speed than the long burn lower thrust rocket. for the delayed ignition staging events(simulated) I got the best results if the 2nd ignition took place at 1/2 the staging speed(stages separate at 1st stage burnout). it was/is my belief that the delay allowed the sustainer to gain a small advantage from decreased air density.
Rex |
#57
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another item for consideration; the thrust duration of a booster motor is shorter than a non-booster motor by about a tenth of a second.
Rex |
#58
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Thank you for posting this information and your findings! The comparison between the flight profiles of dual-pulse quasi-ballistic missiles and dual-pulse model rockets is interesting:
The only dual-pulse vehicles I've read about in detail (the SRAM and its Kh-15 counterpart [some other missiles, such as anti-tank missiles, utilize multi-pulse propulsion]) flew/fly (the Kh-15 is still deployed by the Russian military) in either parabola-like quasi-ballistic trajectories or in high-velocity horizontal flight. The lofted, parabola-like trajectory utilizes the first thrust pulse to propel the missile into the flight path, and the second pulse to generate a very high speed (about Mach 5 in the case of the Kh-15) descent to its target, which makes defending against such missiles very difficult, and causes even more destruction in the case of the non-nuclear-armed version of the Kh-15 (which also has a nuclear-armed version). The second pulse can also be used to "stretch out" the trajectory horizontally, to achieve greater range to reach a more distant target. However: The F-15-launched ASM-135 ASAT (the air-launched anti-satellite missile, see: http://www.google.com/search?source...1.0.4jwYYgMW0dg ), which used a SRAM two-pulse solid rocket motor as its first stage, flew a trajectory that was more like that of a model rocket, and: For model rocket use, the relatively low velocity produced by the first thrust pulse would create less drag, and the greater mass of such a model (having a tandem, two-pulse motor) should result in it being slowed down less by drag (since it would have a greater mass per unit of frontal area). Also: Your simulation's results (that for a two-stage [with separating stages], delayed-ignition model, having the second stage fire at 1/2 the staging velocity [when the first stage separates and drops away] gives the best results) sound intuitively correct to me, although of course I haven't tested such a staging arrangement in actual flight. The lower average speed should result in lower drag and less altitude loss due to drag (the slightly lower booster-imparted velocity, due to its slightly shorter thrust duration, should also serve to lessen the drag). At some point, though, reducing the initial impulse further (by using a lower-impulse booster motor; say, an A8-0 instead of a C6-0), while it will definitely cut down the drag, just won't hurl the model up high enough for the drag reduction to be worthwhile. In addition: This is an area where a two-pulse tandem motor, having more mass, would give a model more momentum (because of the model's greater mass/frontal area ratio) than a two-stage delayed ignition model whose upper stage had the same drag coefficient as the two-pulse tandem motor-equipped model, because the upper stage--containing one motor instead of two in tandem--would be lighter and more easily slowed by drag. These are interesting considerations to sift, weigh, and compare...
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Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see: http://www.lulu.com/content/paperba...an-form/8075185 http://www.lulu.com/product/cd/what...of-2%29/6122050 http://www.lulu.com/product/cd/what...of-2%29/6126511 All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com. NAR #54895 SR |
#59
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I LIKE full-force core-sample style POWR-PRANGS when I'm not the rocket owner. Hilarity at it's finest.
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When in doubt, WHACK the GAS and DITCH the brake !!! Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't ! Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY. ALL systems are GO for MAYHEM, CHAOS, and HAVOC ! |
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