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Old 01-06-2007, 12:34 AM
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CPMcGraw CPMcGraw is offline
Join Date: Mar 2005
Location: Mobile, Alabama
Posts: 5,357

Originally Posted by Carl@Semroc
Good input! This is very well received. As I said, the first step is to get a large enough list to get started, get the list approved, then be able to ship samples for testing.

How about any other different sizes? The 15mm will probably be removed. It just does not have too many good uses.

I wouldn't discount this size just yet, Carl. This is an intermediate diameter between the standard 18 and the mini 13; I can see possibilities here for "B" class motors that can't be done in 13. If I had some power numbers that I could feed into RockSim's Motor Editor, I could run some tests on various designs. Since we don't have those numbers yet, I really don't know what the potential is.

Maybe that is something you could work up for us -- a RockSim motor chart with all of the data you've worked out to this point. With a starting point like that, we can start playing with the motors before you get them in production, and we can give you additional feedback as to what works and what doesn't.

I'm also interested in the 10 as a class; if I can get 500' from a 13mm A3, and even 200' on a 1/2 A3, then there is potential in this size. What have you been able to realistically predict as far as power in this size package?

Side thought here -- are you considering the 18mm "S" series for anything, or is this a dead size?

About the port burning C engines, we did have a 3/4C19 that was reliable in testing, but the full C was too much to drill. Maybe if it was done in two operations... In any case, it would be closer to a C32 with the same .3 second burn. Peak thrust of 60 N - 13 pounds. That looks like too much warranty work! >400G's in a Sky Hook!

My Triton 3-stage design needs a reliable 18mm booster for the first stage. Right now, it will take a D12 to get it off the pad with enough kick for a 48" rod; I'd like something in the 18mm size for lifting heavier stacks like this, and like the old Centuri T-Bird.
Craig McGraw

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