WOT?

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Jegs

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The manufacture's graph for my volvo TMD41B shows that the power output peaks @ approximately 3150 revs & remains flat until the max revs @ 3800. The torque curve peaks @ approx. 2900.

I am giving general consideration to an appropriate propeller & the expert view seems to be that it is necessary for the engine to reach max. revs.

My thought is that, in view of the power curve, it might make sense to 'prop' for max revs of 3200 - any comments?

John G
 
If max revs underload should be 3800 then you need to prop for 3900 or 4000 with a clean bottom so you can still hit 3800 end of season.

If you prop for 3200 they will be under too much load, EGT with rocket, valves burn, the artic will melt and all sorts. A lightly loaded high revving diesel is a happy diesel.
 
burgundyben said:
If max revs underload should be 3800 then you need to prop for 3900 or 4000 with a clean bottom so you can still hit 3800 end of season.

If you prop for 3200 they will be under too much load, EGT with rocket, valves burn, the artic will melt and all sorts......
Click to expand...

.... and you forgot to mention that Big Bill probably would make a visit...
 
Jegs said:
The manufacture's graph for my volvo TMD41B shows that the power output peaks @ approximately 3150 revs & remains flat until the max revs @ 3800. The torque curve peaks @ approx. 2900.

I am giving general consideration to an appropriate propeller & the expert view seems to be that it is necessary for the engine to reach max. revs.

My thought is that, in view of the power curve, it might make sense to 'prop' for max revs of 3200 - any comments?

John G
Click to expand...
Think about it, why would the engine be rated to 3900 max loaded speed rating then prop it to 3200, it would never get up on the plane if you did. Prop science is a balance between engine and the loading you put on it. That's why cars have gears to build the speed up, if they didn't need it you would pull away in 4th gear, it's the same principal to prop the engine to max revs. Remember a marine engine is running up hill all the time.
 
Gentlemen,

Thank you for your replies, my thought was merely that the engine was producing maximum power @ 3150 & that the extra revs were not contributing anything also slow propeller revolutions are better.

John G
 
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