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Wayne.B Wayne.B is offline
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First recorded activity by BoatBanter: Jan 2007
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Default Paradise Found, aka, The Marina at Marigot Bay, Passarelles, etc.

On Mon, 29 Mar 2010 09:47:44 -0700 (PDT), Tim
wrote:

Reply:
I read somewhere that the QE2 gets 6" per gallon.- Hide quoted text -

- Show quoted text -


Which probably translates out to be about a gallon per piston stroke.
Maybe more!


Fairly easy to figure out: At 20 knots they are doing approximately
6000 x 12 = 72,000 inches/hour. If they are burning 1,000 gallons per
hour which I believe is in the ballpark, that would be 7.2 inch/gal
which jibes pretty closely with the 6 in/gal stated previously.

What we don't know is what RPM the engines are turning at, the number
of pistons, and whether they are 2 cycle or 4 cycle - all of which
would impact fuel per power stroke. Just for grins, let's estimate
720 RPM, 10 pistons and a 2 stroke engine. That's 12 RPS x 10
powerstrokes per rev = 120 PowerStrokes/sec. Fuel burn at 1,000 gph
is less that 1/3 gal/sec so the amount of fuel per power stroke is
actually not all that high, maybe about 1/4 ounce per stroke.