Bernard,

Your data matches up with the results we got from my nephew's science fair project over two years from 2016-2017. We launched an Estes Aerobee clone some 60 times on B6-4s with an Altimeter2. All of the engines were purchased at about the same time and were presumably from recent lots. Although we were researching the effect of various nose shapes on peak altitude, we ultimately decided that thrust variation and delay time variation from motor-to-motor was of greater effect than what shape the pointy end had. I'll see if he has that data stashed away somewhere as my copy resides forever lost in a hard drive that spins and whirles but is otherwise inaccessable.

At the time, I remember being disappointed at the inconsistency; sort of still am. I don't know enough about black powder chemistry to know if I'm being unreasonable. My take would be that the motor variation would preclude model rocketry from being the basis of any true science experimentation, unless, of course, you made hundreds of launches.


As to Bernard's data, I suspect we'd need a bunch more launches of both old and new motors to draw any definitive conclusions.

__________________
NAR 79743
NARTrek Silver
I miss being SAM 062

Awaiting First Launch: Too numerous to count
Finishing: Zooch Saturn V; Alway/Nau BioArcas; Estes Expedition; TLP Standard
Repair/Rescue: Cherokee-D (2); Centuri Nike-Smoke; MX-774
On the Bench: 2650;
Dream Stage: 1/39.37 R-7