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post #15 of Old 07-09-2009
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Originally Posted by Mipcar View Post
For instance if I am motoring my boat and try to go to full power too early then I will get smoke but if I allow the boat speed to increase and I incrementally open the throttle I can achieve full power and no smoke from the engine.
I think this is also because you are dumping more fuel in the cylinders than can be burnt efficiently until the pistons get up to speed.

Originally Posted by Mipcar View Post
Same with a propeller driven aircraft, on the ground your max static rpm will be lower then what you will achieve when you are flying. In an aircraft this effect is more easily seen as if you place the aircraft in a dive to increase air speed you can actually over speed your motor if you do not reduce power.Mychael
Interesting. Good analogy, and it IS easier to visualize with an aircraft. So, with momentum, the force of the air/water pushing the front of the prop aids in increasing the RPM and reduces the load on the motor. Correct? Is this what you mean by angle of attack (as the pitch of the prop isn't changing, (with the boat anyway))? Makes sense, but I never thought about it (obviously, physics isn't my strong suit!).

Last edited by L124C; 07-09-2009 at 12:46 AM.
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