That sounds a lot like the original Aerotech hybrid... (Actually, there's a piece that screws into the front of the casing in place of the solid motor's closure, and a fitting on the tank screws into that...)
-dave w
Ya, I know.
My upgrade would to install a long motor case diameter tank that is considerably lighter than a conventional tank. Heck use a different regulation system so it can be "pad loaded" like AeroTech (by Kline).
Jerry
On 10 Oct 2003 08:08:39 -0700, snipped-for-privacy@propulsionpolymers.com (Marcus Leech) is alleged to have written:
That is a potential problem. Hybrids do, in general, suffer from lower thrust than solid motors of the same overall size, since the oxidizer is stored in a seperate compartment from the fuel, so your "combustion chamber" volume is necessarily reduced in volume if you keep the overall motor size the same. However, two things are working in my favor, here:
1) I don't necessarily care to get the highest possible thrust from the motors. Rather, I'm looking at this as an inexpensive way to reuse existing casings to allow people to fly a variety of hybrids without a huge investment in new hardware. Any time there's a new motor design, people resist trying it because they have sunk costs in their existing hardware. It makes sense to me that giving people a way to apply that same investment to a new motor line would be welcomed. 2) Instantaneous thrust is dependent on burning surface area, not volume of the combustion chamber. If people are willing to pay a little more per flight for higher thrust, there's no reason that the fuel grain geometry couldn't be tweaked to increase the burning surface area. Professional hybrid motors use multiple cores to acheive greatly increased surface area in the same volume -- as an example, think of a grain with 7 cores arranged like the holes in a "medusa" nozzle....I'll definitely look Robert up, and see what he has to say. If nothing else, this has given me something to experiment with in my CFT.
- Rick "Gas passer" Dickinson
Rick, your work sounds fantastic! I hope you're documenting it. If you have pictures and information, I could create an "experimental" section on flyhybrids.org for it.
Gary Rosenfield once showed me a prototype AT G hybrid. I had a very hard time handing it back to him!
Doug Pratt
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