Quote:
Originally Posted by pstrbrc
Oops! Apples and oranges. The dryer example is only true because the medium is of variable density. Water can be considered (at least for this discussion) a medium of constant density. Here's the example- nudge your power boat bow-first up against the dock, then go full throttle. Note the max rpms. Then go out into the fishing channel where all the idiots in their row boats are, and go full throttle. Note max rpms. See?  |
Interesting point...
but does a prop have comparable properties (pun!!!) to an enclosed impeller pump?
So I just went and got my spare sump pump- axial impeller like a car water pump- put it in the kitchen sink with water and turned it on with my hand over the outlet.
mmmmm... pump motor so powerful it didn't vary much, unlike the hair dryer. I thought it slowed under load ie. pumping water...