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Old 04-27-2006 | 06:33 AM
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B.L.E.
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Default RE: 2 cycle vs 4 cycle


ORIGINAL: loughbd

Here's a little item for you. A four cycle engine does not have more torque than a two cycle. It has a higher BEMP, brake effective mean pressure. A two cycle firing every stroke has more torque.
I agree and have been saying this all along. The torque needed to turn a prop is exponential to rpm, to turn a prop twice as fast you need to quadruple the torque delivered to it. Turning a prop twice as fast also quadruples the thrust BTW.
Because of the exponential relationship between RPM and torque, it actually takes more torque to turn a 10x6 at 14,000 rpm than it takes to turn a 12x6 at a somwhat lower rpm.
Not understanding the exponential nature of prop load leads to the popular misconception that 4-strokes make more torque than 2-strokes.