Message-ID: <002401c3dd6f$c30a3400$0202a8c0@eric>
From: "Eric Ruttan" <ericruttan@chartermi.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-2936724@logan.com>
Subject: Re: [FlyRotary] Re: Cooling Article - SportAviation Mag
Date: Sat, 17 Jan 2004 22:04:17 -0500

It would seem that one could put a divider on the rad to split it into
"smaller" rads and shorten the duct.


----- Original Message ----- 
From: "Ed Anderson" <eanderson@carolina.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Saturday, January 17, 2004 6:21 PM
Subject: [FlyRotary] Re: Cooling Article - SportAviation Mag


Keep in mind, Kelvin, that the are referring to optimum type ducts.
Naturally, If you can accommondate an optimum duct then you have the best
solution.  However, I have read research papers on short ducts as well.  It
seems that a short duct can provided adequate cooling, in fact better
cooling than a long duct that has separation of air flow and distruption due
to eddies.  You do not however, get as much pressure recovery with a short
duct.  This means that you will probably have higher air flow velocity
throught your radiator.  While this will probably cool adequately your
cooling drag will increase considerably.  Depending on what proportion of
your total drag your cooling drag factor is will determine how much impact
it has on performance.

As long as you have sufficient mass flow throught your radiator you will
cool.  However, you will likely be incurring more drag than when using an
optimum duct.

Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
  ----- Original Message ----- 
  From: kevin lane
  To: Rotary motors in aircraft
  Sent: Saturday, January 17, 2004 1:52 PM
  Subject: [FlyRotary] Re: Cooling Article - SportAviation Mag


  in that article they mentioned that optimal entry duct length is 2 to 3
times the height or width of the radiator, whatever is greater.  with my
belly-mounted radiator, 8 x 22", that means I need something between 4 and 6
feet?  since I am eyeball engineering this thing and mimicking the p-51 I
have an entry duct closer to 22" in length.  does this seem reasonable?
with a 6' scoop perhaps I could make water landings :-)
  Kevin Lane  Portland, OR
  e-mail-> n3773@comcast.net
  web-> http://home.comcast.net/~n3773
  (browse w/ internet explorer)
    ----- Original Message ----- 
    From: Ed Anderson
    To: Rotary motors in aircraft
    Sent: Friday, January 16, 2004 5:18 PM
    Subject: [FlyRotary] Cooling Article - SportAviation Mag


    Excellent article in EAA Sport Aviation Mag I received today,  on liquid
cooling. In reading it, much seemed familar and sure enough one of the two
references is Kuchemann and Weber.  They also point out that the Streamline
Duct is a more practical alternative to the 7 Deg optimum duct for aviation
use as well as other useful information.  Well worth reading.


    Ed Anderson
    RV-6A N494BW Rotary Powered
    Matthews, NC