RE: Realistic Propeller Thrust Calculator?
Francis,
Please read what Pé Reivers wrote... That should give you a good reply.
Although you had used the ThrustHP (which I cannot trust); the Reivers PropPower is much better and employs such a factor that the user must dial-in to get the results. You can use it, or download it from [link=http://mvvs.nl/prop-power-calculator.xls]right here[/link].
It requires MS Office, or Google OpenOffice to use independently on your PC.