LOL.... I can't resist stirring the pot some more....

The 'optimum' length for a quarter-wave antenna is actually about 6 percent shorter than a true quarter wave. This shortened length compensates for fringing fields at the end of the antenna and produces the desired resonant condition.

If I take the average frequency of the RC channels of about 72.5 MHz this gives a length of 38.3 inches. That would be the ball park number to shoot for when replacing your antenna.

But really, it is not all that terribly critical. You will probably be just fine with a 2-inch shorter antenna. Just do a thorough inspection and range check. If your antenna wire was stressed there may be hidden breaks elsewhere within the plastic insulation, or the connection at the receiver circuit board may have been damaged. If in doubt it is always best to have the wire replaced.

By the way, the length of the antenna is not the whole story. The length and dress of the other wiring within the airplane has an effect similar to the length of the antenna. This wiring actually provides the 'other side' of the antenna - there is no such thing as a one-sided antenna. Since the receiver manufacturer has no idea what you will put in your airplane in the way of servos, extension, switch harnesses, etc, his impedance matching at the receiver is just a guess. The effect of lengthing or shortening your antenna by a few inches is probably smaller than the variations in wiring from plane to plane.