Mailing List Message #59521
From: <>
Subject: Re: [FlyRotary] Cooling system attempt
Date: Wed, 6 Feb 2013 10:57:01 -0500 (EST)
To: <>
Looks like a clean fabrication job. I guess the big thing is how the air exits the cowl. If you have any difficulties, I'd look at an exit scoop as the solution. 

Brian Trubee

-----Original Message-----
From: Stephen Izett <>
To: Rotary motors in aircraft <>
Sent: Wed, Feb 6, 2013 5:58 am
Subject: [FlyRotary] Cooling system attempt

Hi Guys

Here is our attempt at a cooling duct for water exchanger.

Air enters original duct entry which forms a male plug inside the existing right entry cheek inlet so system is completely sealed.
(Note entry has an area towards spinner that will be shaped to fit some blast tube that will cool coils)
So lower cowl drops away and upper cowl lift up and form a clam shell around the intake duct. 
We will fill the cowl top and bottom around the entry duct and then knife the joint so the finished duct is a perfect fit to the cowl).

Entry to diffuser for the exchanger is approx. 16 sq inch.
The duct then rotates 90 deg anticlockwise while expanding/diffusing in a streamline fashion before entering the wedge diffuser.
The wedge entry is 3"x13" - 39 sq inches. 
The wedge diffuser is sealed to the exchanger. 
Exchanger is 13"x17.5"x 2 3/8" approx 540 sq inches.

We tested the setup with a leaf blower which after an extended tube to diffuse the air into our entry was probably providing only ~25 mph.
Far to much air was passing through the thin end of the wedge diffuser so foam was shaped to 
taper the wedge and provide as even distribution across the face as possible. 
During testing we divided the face of the radiator into a 5 x 4 matrix for making measurements of airflow.
These measurements were taken using a digital Manometer.
After considerable work with the foam insert we achieved our most even distribution across the face.
The results were very stable and reproducible though even distribution was very difficult.

We are yet to develop the diffuser for the oil cooler in the other cheek. 
Total inlet area will be approx. 34 sq inches.
Exit area is approx. 36 sq inches without cowl flaps (We can cut and hinge cowl flaps into the bottom of the cowl).
As she has retractable gear, the nose wheel when extended opens the bottom of the cowl significantly, 
however how this will effect cowl pressures is difficult to determine prior to flight testing.

This setup will hopefully cool a Renesis 4 port which I am hoping will generate 180+hp at 7500rpm.

Steve Izett
Perth Western Australia
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