If I find that I will actually get 20 GPM with the WP136, I will figure
out how to mount them (right now they're just hanging on the hoses) and
redo all the hoses.  The WP336 is the higher capacity pump and is rated
at 55 GPM, so the impeller diameter is 2.75 X.  It should also create
7.5 X the maximum head pressure which would bring it from 6 psi to 45
psi. If I had understood how these pumps work better to start, I would
have picked the 336.  I just figured 20+20=40 vs 55 was only a little
worse and I would get redundancy.

If I were to decide not to use an EWP, I have the Paul Lamar remote
pump casting.  The big downside there is building a solid bracket so
that the belts clear all the protuberances on the front cover.  With
just the alternator on the side and the Racing Beat underdrive pulley
set, the bracket and clearance problem worked out real nice.

BTW, someone asked why are we looking at EWP's.  My answer is I have
almost no room between the top of the engine and the cowling,
especially at the back (front cover).  Even cut down, the stock pump
still sticks up some and I just don't have the room.  Jerry Hey built
my engine mount, and I probably should have had him lower my thrust
line a couple of inches. I didn't want to give up the prop clearance
and didn't forsee this problem.  In addition, the stock pump is at the
top of the engine so quits working if you loose a small amount of
coolant.  That was the reason I got the remote casting.  The EWP will
solve these problems and be easier to mount.

Bob W.


On Fri, 4 Mar 2005 19:00:13 -0600
"Russell Duffy" <13brv3@bellsouth.net> wrote:

So are you still deciding whether to use the WP136 pumps, vs maybe the
bigger one (can't remember the number)?  I received the WP136 that I ordered
today.  It's a beefy pump for sure.  It weighs 5 lb 2oz, where the Davies
Craig (DC from now on) weighs 1 lb 11 oz.  Since I wasted all afternoon
waiting for DHL to decide to reschedule my FJO O2 sensor for Monday
(grrrrrrr), I didn't get to see how it would fit on the RV-3.  I think I
could get two of them on there, easier than two DC pumps, but of course I
don't plan any pump change until after it's flying again.

Rusty (only need to add gas and oil, then turn key)

-- http://www.bob-white.com
N93BD - Rotary Powered BD-4 (real soon)

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