For anyone interested, regulators do give more flying time. Here's how it works:

A regulator is just a resistor, as Bill points out. But, it is a highly efficient variable resistor. The MPI regulator has the equivalent circuit of 8 transistors, 2 Op-Amps, and over 20 resistors. It rapidly adjusts the circuit resistance, and also has overload protection.

When you place a resistor in your battery circuit, it restricts current flow. This applies to any resistance, not just a regulator. Less current flow means less power usage, and that means longer battery life. The amount of increased life depends on how much you are dropping the voltage. For example, if you have a 4 cell nicad pack that charges to 5.76 volts, and you are dropping the voltage to 4.8, you won't see much of a flight time increase (in the order of 5-10%). If you are using 3 cell Lithiums at 12.25 volts and drop it to the same 4.8 volts, then you will see a considerable increase in flight time (like 100%). Both examples assume you are using the same milliamphour ratings. For those of you thinking that the servos can't use 12.25 volts......I am currently using a Seiko that can take 12 volts right off the battery. There is a lot of equipment out there we are just starting to tap into.

Let's keep open minds and keep learning from each other!

CJ

PS - Joe, the electric guys could probably answer your question best. They are really up on how fast a particular battery can be fast charged. Usually the manufacturers are conservative in their instructions.