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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 -----
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 :-)
----- Original Message -----
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
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