[Geezer (OP)]

Well, it always had that effect on me!

Recently I found a calculator in the Internet. It's by Prof "Subi" at San Diego State U. You'll find it at:

www.thermofluids.net

I found it extremely helpful. You can test ideas quite quickly with it.

If you know of any similar calculators, please tack them on to this thread.
(BTW, I have no association with Prof Subi or SDSU)
 

[JimBob]

It isn't a thermo calculator or converter but I have a really nice unit cinverter from

http://joshmadison.com/software/convert-for-windows/

It has many, many functions - more than most I've seen. Te best part - it's free!

[Nizzle]

Why not use google...

Just type something like "287 miles in kilometers" and the first search result will be your conversion.
And google can convert a surprising amount of units..

[Geezer (OP)]

It's not just a simple calculator. It lets you model complete systems like IC engines, power plants, jet engines with heat exchange processes, etc etc. All kinds of stuff.

Check it out, you'll see what I mean. BTW, it's free (for a year if I remember correctly.)