Hughes was not known as a sensible or particularly sane pilot,the crash he had in his recce a/c was because he was not following any sensible testing procedure.
I would imagine the spruce goose would have had lots of development problems,but to see an a/c appear to climb well on what was probably a very restricted fuel load is surely not a surprise - add a useful load and power and control might become problematical.
The guy was a meddling control freak - hardly I would suggest a good psychological profile for a competent engineering test pilot - hey but i am only an engineer...what would i know...
