Yak 52:
I call “clear prop”, while holding my right arm vertical and rotating my extended forefinger in the air for a couple of seconds as a visual signal for those out of earshot – if a Yak is starting up anywhere near you, you need to know about it before it happens. I hold the stick back in the crook of my right arm (old taildragger habits die hard) with my forefinger on the start button to the left of the panel, having flicked up its cover. My left hand rests on the one-third-open throttle lever. A glance round to check all is clear, and I press the button. There’s a loud ‘pop’ followed by an asthmatic wheezing as compressed air is admitted to the cylinders via a pneumatic distributor to turn the engine. The prop jerks slowly round a revolution and I flick the mags to ‘1 + 2’ (you really need three hands for this) and one cylinder fires. I release the start button and pump the throttle to keep the prop turning. More cylinders join in with a sudden roar, and clouds of smoke stream from the exhausts. The prop dissolves into an invisible disc, blowing the smoke instantly backwards – but it’s not sustained and the engine dies, clattering round slower and slower, the prop becoming visible once more. I pump the throttle again, my right hand going to the primer. But before I can decide whether to prime or not, several cylinders fire up raggedly accompanied by more grey smoke which is blasted under the wing by the propwash. The engine dies again, the prop slowing, but only for a second or so. With a glorious throaty roar all the cylinders report for duty, and this time as though they mean it. The engine clears its throat with a cough or two, becomes self-sustaining, and settles into smooth regular song. The battle is won and I snap the starter button cover down.
A friend described a Yak start up as ‘biblical’ – lots of noise, lots of smoke, the ground shaking, and the smiting of lesser objects. This latter point is one to watch; anything much more than idle power can blow over a light aircraft in the propwash.