10-30-2011, 05:53 PM
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Freeform rocketry advocate.
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Join Date: Jan 2008
Location: Claremont, CA "The intellectual capitol of the world."-WSJ
Posts: 3,780
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Quote:
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Originally Posted by CPMcGraw
Using the new graph, as Jerry indicated, the engine is "soft". It appears great, once the model is airborne, but getting off the ground it doesn't have a lot of "oomph" when used in a design that weighs in over 13 oz loaded.
I also tried it out in the SEMROC SLS Laser-X...
Altitude -- 554'
Deployment V -- 4 FPS
Rod length -- 60" (took 49") 
This is a 12.5 oz design loaded, and shows great flight numbers, but lousy take-off numbers. |
I have strongly suggested Estes upgrade to 1/4" x 48" rods (USR standard) and forsake 3/16" going forward. The AT by E motors need a stiffer rod and the Estes E motors need a longer rod due to low take-off speeds. These E motors should be considered to have a max liftoff weight of a pound or less, and better if between 1/2 and 3/4 pound. I would say the MLOW of a D12 is 30-50% higher than an E12.
Counter-intuitive but true.
Jerry |