Barry Hobson wrote a very useful tool for R/C aircraft enthusiasts called ThrustHP. This is a Windows based tool for calculating speed and thrust given certain parameters. Unfortunately if you are using Linux or MacOS then you would need to install Wine or MS-Windows. To address this issue the tool has now been ported to the web.
You are free to download and host elsewhere, though you are asked to retain attribution. If you do make any changes I would be interested in receiving them, and adding credit.
To use it follow this link.
To use it offline, get the zip file.
Last updated: 2008-06-24