(b) whatever might arise from the action of the prop slipstream on the particular aircraft's surfaces.
The more power, the more slipstream -- doesn't matter whether it's piston or turboprop.
From a standing start, accelerate the Legend to flying speed in about 5 seconds. After liftoff, the steady push on your back continues as you retract the gear and flaps. Pitch up for the best rate of climb air speed and note climb rates of five thousand feet per minute, and more.
There are a number of WWII fighters that would roll uncontrollably if full power was applied at low speed.
Likely this a/c has engine and fin offset as it was designed around the powerplant, but the approach speed of 85 kt. is a hint that full power below that speed may be a bootfull.
http://www.legendaircraft.net