Just empirical evidence mind you, but everything I've ever read about the C-47 Skytrain indicates it was surprisingly tough, not only to the rigors associated with operating out of barely improved forward airstrips, but also under combat. I've read a few accounts of C-47's flying the "Hump" in Burma surviving pretty vicious attacks by the Japanese. Quite a few came back from the Normandy troop drops with major damage, yet come back they did.
In one book (might have been "Fire in the Sky" by Bergurud) there are comments on the ruggedness built into the Skytrain/Dakota. The author makes the assertion that one of the reasons was because there was still alot about aeronautics and aircraft design that was done by guess work (no computer simulations to test things out on). This caused aircraft designers of the day (and the Douglas designers in particular) to over-engineer their designs. The antithisis of this philosphy was followed by the design team that build the Zero fighter, where everything possible was done to save weight. This was done both to compensate for the lower output engines of the Japanese as well as to give great fuel economy and maneuverability.
In short, the Gooney Bird should be fairly rugged, and may ("may" I said) need another look at by HTC.
