The 1-11 engines, as perhaps are all large jet engines, were started by air. This can be taken from the APU or a ground source.
You pressed the start switch on a 1-11 and it opened the air valve in the engine cowling to allow the high pressure air to the engine start system.
Only on the 1-11 the said valve was notorious for sticking, and this could be cured by giving it a ‘whack’. Not hard enough to damage it, but hard enough to encourage the valve to open.
I well remember being the captain of a DAN 1-11 when the valve didn’t open in Toulouse one afternoon. I left the F/O in the jet, stationed a member to the handling crew at the front to give the F/O the thumbs up when I was ready, and then hitting the valve with the rubber bit of the fire axe – all watched by some passengers looking out of the terminal window and the rear of the aeroplane.
It was certainly in the stub wing, and it was very noisy closing the the cowling up after the start. I don't remember any rod to twist, but it was over 25 years ago. Lets see 25 multiply by 365 and then by 2 pints a night and the memory may not be that sharp!
Hey ho – interesting times.