Mailing List flyrotary@lancaironline.net Message #19677
From: DaveLeonard <daveleonard@cox.net>
Subject: RE: [FlyRotary] Re: Davies-Craig EWP Test Results
Date: Fri, 1 Apr 2005 10:30:48 -0800
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
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

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