Hit and miss engines.

[Frank DolmanParticipant @frankdolman72357]

[Frank DolmanParticipant @frankdolman72357]

     Why, please, are Hit and miss engines so called?

[John OlsenParticipant @johnolsen79199]

Because the usual form of governor for these engines works by holding the exhaust valve open when the engine reaches the desired maximum speed.  This causes the engine to stop firing, then as it slows down the exhaust valve is released again and the engine starts firing again. This gives a characteristic sort of chuff..chuff..chuff..clickey clickety chuff chuff chuff beat to the engine. When you put a load on, they fire more often and at maximum load will never quite reach the maximum speed so they don’t miss any beats.

 

regards

John

[Frank DolmanParticipant @frankdolman72357]

   Thank you John.  Very clear.

[John Wood1Participant @johnwood1]

Hi.  When if fires it ‘hits’ and when the open exhaust valve prevents this it ‘misses’ Have a look on YouTube and you will find several videos. Fascinating engines to watch!

 

Cheers

John

[Author]

Posts