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Old 05-15-2009, 01:26 AM
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blackshire blackshire is offline
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Join Date: Jan 2009
Location: Fairbanks, Alaska
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Originally Posted by FlyBack
Black Shire

In all three configurations both motors are ignited at the same time (like a cluster). A hold back system is required. The D5-P orbiter motor burns slightly longer than the E9-4 booster motor. I guess that makes it a 1 1/2 stage rocket. Separation occurs when the rear ejection parachute deploys from the booster stage. The orbiter motor remains with the orbiter.

The two motors used have different impulses and average thrusts. However, their thrust/time curves have nearly identical shapes. That characteristic is what allows me to meet the conditions stated above. As a consequence, they have different offsets from the vertical C.G. and also different thrust line angles. Getting that part right is a real B... err, challenge.


DJ Miller

Thank you for clarifying this. Having done a bit of preliminary design work (which convinced me that I needed more mathematical design tools than I had at the time) for a flying model of Max Faget's original "DC-3" TSTO Space Shuttle, the last part of your comment feels very familiar... :-)
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see:
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