Hit and Miss

Any number of small open crank engines, the most commonly seen probably being Amanco.

I have a Fuller and Johnson Hit and Miss engine which has an unusual type of governer. It has a sprung weight in the flywheel that, as the engine fires and spins up, flys out and activates an arm that locks in to the pushrod that then holds the exhaust valve open. As the engine slows down, the lever pops out of engagement with the exhaust valve which shuts, the engine fires and starts all over again. Of course if you load the engine up to keep the revs down to where you have set the governor, it fires every stroke.

I have set the governor for the Rally field driving a Lister pump and it fire once every 4.5 seconds (13.3 times a minute)....needless to say it is very economical.

-- Pete Aldous

My car engine is actually fitted with a hit & miss governor. It is called a rev limiter in modern parlance and cuts the fuel injection when maximum revs are reached. I have no idea how economical it would be if I were to cruise at the governor setting. In 5th, it would probably not make the engine speed, in

John

Just the same as any other governor - except that they do it by entirely suppressing a power stroke, rather than just throttling it..

They can do this by suppressing valve opening, fueling (mainly diesels) or ignition (mainly petrol). Suppressing ignition is still wasteful of fuel, but those were simpler times... The most famous example is perhaps that of Biggles' aircraft, and the practice of "blipping the throttle". As the rotary Gnome engine had no throttle to speak of (what with whirling around and all that), this was actually blipping the magneto.

Hit or miss governing gives uneven firing. So it was mainly used on engines with huge flywheels that only fired once a fortnight anyway. Once they became fast enough for firing to approximate a continuous process, or for any notion of "balance" between cylinders not to be laughable, then it went out of favour. But by then a carburettor looked more like a venturi and less like an oil lamp.