Revision of the Hobby Shopper EZB Motor Stick Test, April, 2002
by Larry Coslick
There were several articles in the INAV ISSUE 105 directed toward my testing procedure for EZB motor sticks. After reading the articles, I decided to re-test my M/S's using the same procedure as described in the Hobby Shopper article, ISSUE 90.
The side-bending test in question uses 2 penny sets that are .12" high to support each end of the M/S. A dime is centered under the M/S and a 10.67-gram weight is placed on top of the M/S over the dime. The M/S passes the test if the dime can be pulled out without disturbing the M/S.
After the M/S's were re-tested, it was obvious that there was a flaw in the way that the original test was made. The Hobby Shopper M/S test was designed just for that article and for the M/S's that were cut for the prototype. The problem was that I didn't compare the penny test with my side-bending jig. My jig uses a mechanism that is not available to the public so I had to come up with an easier way to test the M/S's. I happened to select a stiff piece of balsa for the prototype and didn't realize it by using the new test. I would have detected the wood's stiffness by using my jig had a comparison test been made. After the article was complete the penny test was put away and never given a thought until ISSUE 105.
My side-bending jig uses a spring-loaded center post that drives a pointer along a numbered scale from 0 to 30. Readings in the range of 10 to 20 indicate a usable M/S, 10 being the stiffest. These numbers have no numerical value and are only used to compare one stick against another. I was able to measure the deflection and came up with a weight that would compare with my jig's reading. The new weight uses a dime, quarter combination with a balsa handle and weighs 7.9 grams.
I re-tested 10 M/S's using the penny test with the new weight and concluded that any M/S that clears the base will work.
The 10 M/S's that were tested range in length from 8.5" to 9" and weigh .16 to .19 grams.
