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Side-valved Two strokes for angels.

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Niels

Well-Known Member
Joined
Aug 15, 2019
Messages
436
Two stroke engines without valves are dying fast.
Two strokes with exhaust valves sell very well for ships.
It is great fun for an old man to see if exhaust-valved two strokes can be useful in aircrafts.
I made a PPL forty years ago and cancelled it when money went low 36 years ago.
It was always a feeling of there must be a better way of turning propellers without making so much noise and pollution.
Let me try to argue using two plant sizes:

80 horsepower at 2400 rpm/1,7meter prop.Direct coupled
40 horsepower at 3000 rpm/1,4meter prop.Ditto
The difference in vibrations beween a six- and a four-cylindered C-172 was real.
A friend sold aircrafts with two cylinder ,boxer HKS engines and that was unpleasant.
Mass balance is almost perfect so the difference comes from the unsteady torque between engine and propeller.
A two cylinder boxer two-stroke is a beast as well.
A 90 degree V2 two stroke can be shown to be between a four and a six cylindered fourstroke in torque variation so that is my dream concept.
Pistons are not really suited to control exhaust and normal valves has been formidable for this job.
 
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