The last several days have been spent chasing the draw bar force issue. The following results:
1 Happily, the pulley method and the gauge method agree within a couple of grams. The gauge only reads 5 gram increments.
2 the equivalent between the gauge and the pulley weight is the weight on the pulley that can not be lifted by the engine.
By first measuring the pull with the gauge and then setting a weight slightly less than that value. On ten tries on different engines, it was found that the two samples agree within 2 grams.
3 Agreement has been demonstrated between that two measurements going up in weight on the engine and going back down.
4 There is some variation in the measured value at the same weight, but the two techniques measured it within 2 grams. This implies that the motor and or track conditions are changing with testing time or load.
Because of this last result, it points out the critical role of the test process. When the data is taken, the motor operation stress and track condition need to be as close as can be accomplished. The general technique that has been used to date has been in place with this in mind. So the best thing to do is to follow the current testing procedure.
The observed variation was different for each engine. The question is “does motor quality and condition impact this variation?” This variation will be examined during the activity. The older units will have one tune up step and then the Mashima motor. The more recent engines have little time on the motor. It was intended to only look at this variation in the “as received” condition. Depending on the results, these later engines will be tuned to describe the impact on this variation as well as the weight variation. It will be interesting to see if and what impact age and quality has on this variation.