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From: "DaveLeonard" <daveleonard@cox.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: RE: [FlyRotary] Re: Davies-Craig EWP Test Results
Date: Fri, 1 Apr 2005 10:30:48 -0800
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Bob, Jim is right.  The best way is a flow vs. pressure.  The work to get
the fluid through the entire system is likely going to be more than what you
tested.  I will bet dollars for doughnuts that the more expensive/larger
pump will perform better at the higher pressures.

Think of the difference between a cheap handheld electric drill, and a drill
press.  Under no load, the hand-held drill spins much faster than the drill
press.  But put on a load and the small drill quickly slows down and stops,
the drill press is unaffected.

Dave Leonard


>
>
> It would be interesting to put a valve downstream from the pump and
> close it just a tad (perhaps measure pressure drop across the valve or
> perhaps across the pump) and see how a restriction affects flow.
> Inquiring minds need to know :o) ... Jim S.
>
> Bob White wrote:
>
> >Hi Dave,
> >
> >The only restriction was the hoses I used for the test and the
> flow meter.  Flow
> >was out of the bucket about an inch from the bottom thru the
> test setup and back
> >into the top of the bucket with the hose submerged. The hose
> sizes are similar
> >to what I'm planning on using in the plane.
> >
> >Bob W.
> >
> >
> >On Thu, 31 Mar 2005 05:38:42 -0800
> >"DaveLeonard" <daveleonard@cox.net> wrote:
> >
> >
> >
> >>MessageBob was there any resistance to flow?  The could perform quite
> >>differently if they are pumping against resistance.
> >>
> >>Dave Leonard
> >>
> >>   Th e tiny D-C pump outperforms the WP136.
> >>
> >>  Great report Bob!  Sounds like the little plastic Davies
> Craig pump is the
> >>hands down winner over the WP136 Meziere.  I'm not too
> concerned about the
> >>motor temp, because it's obviously made to run that hot, and
> still give good
> >>service life.  The best part about the test is that you did it,
> and my WP136
> >>is still new in the box.  Now I can send it back to Summit for
> a refund :-)
> >>
> >>  Cheers,
> >>  Rusty (hoping for two successful posts in a row)
> >>
> >>
> >>
> >
> >
> >
> >
>
> >>  Homepage:  http://www.flyrotary.com/
> >>  Archive:   http://lancaironline.net/lists/flyrotary/List.html