RE: Mystery Solved! How to select the proper gearing for your electric RC!
The first part of that is about a scientific as I've seen! [X(]
The second part is a good basic speed calculator that will put you a bit on the high side up to 30 or 40mph, then it starts getting way off due to drag and wind resistance. Consider a speed record car capable of 110mph to 130mph. That equation would predict that car to reach closer to 200mph.
Agreed, for most of us running in the 20 - 40mph range, it's a great way to guess-timate top speed!