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Date: Thu, 14 Jun 2007 22:53:29 -0400
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Subject: Re: Boost Pump
From: "bob mackey" <n103md@yahoo.com>
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> I'm looking at a Dukes pump that's rated 11.0 PSI low and 25 PSI
> on high. Flow rate is 35 GPM @ 21.0 PSI. I don't know how this
> compares to the pumps being used in Lancair installations, but
> wouldn't seem that the Dukes could overload the system, especially
> if  the engine-driven pump was inoperative.
> If you were idling and hit the high boost, yes. At full TO power it should
> be less than the engine-driven output. My question is: could the output of
> the two pumps combine and overwhelm the return line causing pressure and
> thus fuel flow to go out of limits?

Bill:
You might want to check those specs... you wrote that the
Dukes pump is rated at 35 GPM (gallons per MINUTE)
while the engine uses 32-36 GPH (gallons per HOUR).

If you can really fill a 5 gallon can from the Dukes pump
in 8.57 seconds, it can probably flood an IO-550.

I use a system that flows 35 GPM liquid propane at about 200 psi.
That generates a flame about 100 feet high. That kind of flow
might be excessive even in an Lancair IV.