When it came to just poling the aircraft with everything working, a Whirlwind was fairly benign due to its rather sluggish response and inertia (hence the RAF requirement for basic students to fly a full sortie of solo engine off landings).
The Gnome turbine engine was “fernickerty” but normally controlled by a basic fuel flow computer. “Computer out” was more difficult because manually controlling the engine added another dimension, especially in view of the sluggish engine response. One had to anticipate the effect on the main rotor response, more so than with a piston engine. The effect is similar to “turbo lag” on a car engine.
Coupled with the lack of a cyclic trim system, and no navigation equipment apart from Decca (which was really designed for ships and very complicated to interpret at the best of times) it made the aircraft hard work to operate; the term “one armed paper hangar” was appropriate to aircraft of that generation. I still tend to naturally carry my chart or PLOG under my right arm to this day, rather than put it down in the cockpit…. old habits die hard.
The Whirlwind was being taken out of front line service early in my time. I held at an Whirlwind equipped SAR base for a few weeks in the 1970s, which was the main catalyst for my desire to fly helicopters, having been allowed to attempt to fly one, which I did, after a fashion, under the auspices of Gerry Hermer. He got me to land it, despite the antics of the ground marshaller, who threw away his bats in mock disgust
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I still hold those SAR pilots (and their winch operators and winch men) in very high regard - single pilot, over the sea, day and night, in a totally unstable and unstabilised, underpowered single engined aircraft. I did go on to become an SAR pilot, but thankfully in far more capable helicopters.