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Old 04-06-2019, 05:32 PM
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LeeR LeeR is offline
Retired with Way Too Many Kits
 
Join Date: Jun 2007
Location: Colorado
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Quote:
Originally Posted by mwtoelle
A piston would help, but only the only people that I know that would use them are competition fliers. If the A10 was actually labelled to reflect the actual average of the motor, it would be an A2 instead. I have actually flown 1974 vintage A10-0Ts, and even those motors had a long burn. I even put a comment in my flight log about to A10-0T burning about as long as an A3 motor. In the Estes catalogs of the time it was claimed that the A10s had a 0.26 sec. thrust duration. Current catalogs show the A10s with a 0.80 sec thrust duration. Personally, I think that the A10 has always had the longer duration listed in the newer catalogs. Even the data from S&T concurs with the longer thrust duration. As I have learned over the years, long burn, low thrust motors and windy flight conditions do not mix very well.


Interesting. I’ve only flown a 13mm stager once, my scratch-built Double Mini Max. It was A10 to A10. It flew pretty well, but not the roaring liftoff I expected. Upper stage flight angle was not perfectly vertical, but it’s a gap-stager, so I suspect it may have had a bit of arc-over before upper stage ignition. Recovery was fine. If I were to build another, I’d go 18mm booster. The extra length of an 18mm booster would be no issues since I used at least an inch of gap in the design.

A similar difference in motor average thrust exists with the 18/20 RMS D reloads. Probably a lot more examples, but I noticed this because I bought the 18/20 specifically for the Mars Lander. I thought the D24 might be too much, so I bought the D13 also.Then I looked closer at the thrust curves. The D13W is rated 12.67 N average thrust, the D24T is 14.77 N. The thrust curves are very similar. I’ll try the D24 next flight. I’ve flown it twice on D13 with excellent results.
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Lee Reep
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Projects: Semroc Saturn 1B, Ken Foss Designs Mini Satellite Interceptor
In the Paint Shop: Nothing! Too cold!
Launch-Ready: Farside-X, Maxi Honest John, Super Scamp
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