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Old 09-24-2017, 06:40 AM
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blackshire blackshire is offline
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Join Date: Jan 2009
Location: Fairbanks, Alaska
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Default Hellfire & its motor

Hello All,

One frequently-encountered problem with scale model rockets involves the rocket nozzles of the full-size scale subjects; the nozzles of model rocket motors are very seldom—virtually never, in fact—the same (or even similar) shapes as those of the full-size vehicles that the models depict. I was pleasantly surprised to discover an exception to this:

I was just looking up information on the AGM-114 Hellfire missile (see: http://www.google.com/search?q=AGM-...1.0.zBHAFkEusuA ) when I came across a curious finding—its rocket motor, which is made by Orbital ATK (see: http://www.orbitalatk.com/defense-s...ed%20032015.pdf [particularly page 2]), looks just like a scaled-up “D” or “E” SU (Single-Use) composite propellant model rocket motor. While its “nozzle tube” (a molded cellulose/phenolic cylinder with the convergent-divergent nozzle “void” in it) is longer, proportionally, than that of a composite “D” or “E” motor, a scale model could use an “extender tube” of the appropriate length and diameter (made of phenolic, or a length of kraft paper tubing flame-proofed with “water glass” [sodium silicate]) to maintain the correct scale proportion, and:

Flying scale models of other missiles that have such rocket motors (the JAGM—Joint Air-to-Ground Missile, the follow-on to the Hellfire, is one [see: http://www.google.com/search?q=jagm...0 .61fXCRf_NZY ]) could also use composite motors and retain scale appearance, with few or no additions or modifications to the models.

I hope this information will be helpful.
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