Volaré SafeTorque for the Web

by George Bredehoft, Volaré Products, 2017

Use this JavaScript calculator to determine the SAFE TORQUE (in inch/ounces) for your rubber motor.
Main Rubber WidthInput your motor's rubber width (in decimal inches) and how many strands (1 loop = 2 strands). If your motor is made of loops of two different widths, input the supplementary loop(s) in the SECONDARY input areas. Use the TAB key or the mouse to move to the next blank. Press CALCULATE and observe the results in the other blanks. To calculate another motor torque, just overlay new values over the old (or press CLEAR) and re-CALCULATE.
Main Rubber Strands
Secondary Rubber Width
Secondary Rubber Strands
Note: this program is based on Don DeLoach's published table of torque values, using his T-75 (75% of max torque) as the baseline. Please read additional notes below.
Equivalent 1/8s
Safe Torque

DECIMAL EQUIVALENTS
1/16"0.0625
3/32"0.09375
1/8"0.125
3/16"0.1875
1/4"0.25

There are some general notes and points to consider when using this tool in conjunction with winding motors for your model airplane.

1. this does NOT calculate maximum torque of a motor. It calculates a value that is close to 75% of the maximum torque of the motor.

2. while 75% of maximum torque "should" be a safe number to wind to, it may NOT be safe for your exact model airplane. Your plane may not handle the torque energy that your motor can produce.

3. this calculation assumes that the thickness of rubber strands is a constant thickness. This is NOT true. Don has observed that the thickness of rubber varies from batch to batch - and even within a single batch. A variance of about 15% has been observed in Super Sport rubber; thicknesses from 0.040" to 0.045". This WILL affect the total energy available and the maximum torque that any motor can acheive, however it should not affect you and your motor if you stop winding at 75% - or what I am calling the Safe Torque.

4. Every motor will break sometime. Especially if and when you are winding to higher torques. The higher torque values you use, the sooner your motor will break.

REFERENCE: click HERE to read Don's original article
Questions and/or comments are always welcome.