Proteus Start-up
Moving forward a bit in time, I remember from my youth watching Britanias (102s and 312s) start up at BHX.
Before each engine was started an engineer rotated the prop, a couple of times I think. I can't recall seeing any other turbo-prop being started in this way, and I can't imagine the SRN-4 Hovercraft (which IIRC also had 4 x Proteus engines) having the props swung.
Can any former Britannia crew enlighten me as to what the purpose was of turning the props before fireing the engines up - and I mean fireing, I will never forget those wet starts!