I would assume if you were going to tach a 9x6 prop you were planning on flying it Otherwise why bother

If I were going to fly a different prop, I would tach the prop I was planning on using

Your right, all planes will not fly the same speed on a given prop, BUT the speed POTENTIAL OF A GIVEN PROP AT A GIVEN rpm IS static with one of the variables in actual speed attained being the shape and cleanliness of the airframe. And if the speed potential is XX MPH, some would be flying planes at that speed.

But, I applaud your efforts at whatever your trying to do, in whatever way your trying to do it, and I wish you luck. I am absolutely convinced something will come of it.

cajun