I've read that pilots called it the "Gutless" because it was so terribly underpowered.
Can't really blame the designers though -- they were promised twice as much thrust as was eventually delivered.
Guess that's the risk on the cutting edge. I suppose jet powerplant engineers have much refined their ability to estimate thrust from design parameters, cause I dont recall hearing of this happening with other airframes. Or, did Vought engineers gamble that knowingly optomistic predictions from GE would pan out? I wonder