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Re: [PSUBS-MAILIST] motor thought



Hi Steve.
 
Thanks for the explaination. It did help me to understand better and I appreciate you taking the time to help.
Bill Akins.
 
 
 
----- Original Message -----
Sent: Saturday, April 08, 2006 8:06 PM
Subject: RE: [PSUBS-MAILIST] motor thought

 Bill

 

I?m sure there is someone in the group who could explain this more eloquently or correctly but I will have a go.

 

It is hard to throw out the rules you are familiar with but, it is not like a plane prop where there is an area of low pressure in front of the prop causing the air to be sucked in or pushed in and through so to speak.  With the atmosphere as your altitude increases you loose efficiency because the air is less ?thick?. This doesn?t happen in the big blue because you are immersed in a non compressible fluid. If you move water it is replaced by more water without causing a low pressure point or vacuum.

 

There is no change in density so the force causing movement is applied mechanical pressure not suction so to speak. If you were to stop the flow of air the prop would still spin just like when you block the vacuum cleaner, (in fact by blocking the hose the motor spins more freely in the cleaner) if you block the nozzle it should stop the pump (depending on the type). The area of low pressure is the rest of the ocean.

 

Steve P