Re: New file uploaded to Indoor_Construction

From: <j.bartek_at_sbcglobal.net>
Date: 06 Oct 2014 07:50:35 -0700

Fred
 Great bit of math there! I appreciate the work you did to get that calculating the energy from the torque curve. One thing I'd like to know. Is there a convention that you're putting "loop length" for the motor length in the inputs? It seems less obvious to me. I know that motor weight is the critical part for total energy.
 

 When I'm issued Tan rubber (.080 inches wide) for the Double Whammy contest at Racine, I get 28 inches of rubber that I make into a 14 inch loop, roughly, of 1.7 grams. I put in 100 turns on my 15:1 winder and get a good flight to the ceiling (40 feet) despite the Delta Dart prop and an overweight plane. The experts get 2 minutes with the same rubber and probably a few more turns.
 

 I found experience charts for Tan II in the July-August FAC Newsletter that seem to answer my question. When I put 14 inches for length in the charts and 0.186 for total width, I get 1.8 grams for weight and 1600 for max turns, fitting my experience with a motor of 0.160 inches total width. Working backwards from the 2 gram motor, 20 inches long, in your Excel input, I get about 0.14 inches for total width and 2600 for max turns. I see the turns at launch in your inputs was 2520 which hits the chart pretty close.
 

 I think this answers my question, but I'd appreciate you putting a bit more definition in your "how to" paper defining the motor. Please say if the calculation works best for single loop motors, and if "loop length" is the required input. Out door folk might be able to extend it to a 3 loop, 10 gram motor 20 inches long for P-30, if they remember that weight is the critical point.
 

 I know it's hard to put yourself in a neophyte's shoes if you haven't been there for a while. Thanks again for the informative class on Tan Sport 2010.

Received on Mon Oct 06 2014 - 07:50:35 CEST