Romulo Augusto wrote:

Paul,
greetings.

I am preparing myself to build the bottom of our Cozy MK IV, and since we
planned to use a mazda engine in it, what would be the best measures
 diameter) for the cooler intake, using a P51 style duct cooler? The engine I
think will be between 200 or 235Hp ( two rotors), using, at first, the
original cooler in horizontal position like you suggested here.

There's any troubles in use the original NACA scoops inside the duct? I ask
this for now, caused by  I believe the type of cooler system ( air/liquid)
must be defined to perform the required modifications in the bottom of
fuselage, including the landing gear bulkheads, since the NACA scoop is carved
on these strutures. Am I correct?

Thanks!

Romulo Augusto da Cruz, Jr, Ten.Méd. , Cozy #0730
Rua da Bahia 1345/sala1103 Lourdes Belo Horizonte, MG
Fones: 55-31-274-5667, 55-31-9948-2075, 55-31-497-2080
http://www.homeshopping.com.br/~romulojr

Yes. The NACA duct requires major modification to the bottom of 
the fuselage.

I believe this chart supplied by Neil A. Kruiswyk is for a
180 HP engine so you will have to scale it up for a 235 HP 
engine. I am not sure if it has been tested as it is just
a theoretical calculation. To get the area needed
use this formula:

Area needed for 235 HP is equal to 235/180 X area 
shown on chart.

I would ignor the area for hot slow climb and install a couple
of high powered electric radiator fans to enhance
the low speed airflow through the radiator. Why penalize 
the cruise performance when you only do hot slow climbs 
once in a while? Start with the cruise climb required area.

in-out-area-v-temp.jpg

Paul Lamar
 
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