Understood.

You do know that engineers are cynics, right? LOL!

Anyhow, I am using ThrustHP which is a relatively useful calculator for thrust and hp based upon the affinity laws. It is not 100% accurate, but I've found it to give very good relative information. It tends to be overly optimistic on HP demand (vs my dyno) and also slightly optimistic on thrust produced, but it has to make some assumptions to work at all.

You can download it for free at my club's website, www.BlueMaxRC.com

Theoretically, a 10" pitch prop would need to be turning nearly 11,000 rpm (static mph) to move through the air at 103 mph, with 100% efficiency. In reality, the props are not that efficient at that rpm, and it would need to turn even faster to move through the air at 103 mph

Would be good to verify the accuracy with another method. Still it was a fun way to use the technology and I personally think it was cool that you used the GPS to see what it could do!!