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Hi there Steve
Thanks for the plots. Really interesting.
Oil Delta T 33F
Water Delta T 15F
Cores Delta P 2.6in h2o
OAT 70F (21C)
hp 42
rpm 4000
Interesting how this test reveals the symbiotic relationship between oil and water cooling.
A drop in oil T of 52F (212-160) caused a 12F drop in the water T
A drop in h2o T of 59F (212-153) caused a 10F drop in the oil T
So the oil is the bigger player in the system but not massively. (not very scientific language)
I’ll remeasure the duct inlet size accurately.
The diffuser entry was laid up into the cowl entry.
Then the flange you see in the photo was cut off.
The diffuser joins the cowl ~1/2” inside the cowl lips and then the cowl lips were micro’d flush with the diffuser.
So the diffuser entry sits in a joggle on both upper and lower cowl lips.
These are not sealed with anything, just sit together glass to glass.
I’ve wondered how I might get a better seal without using something like silicon.
That cheek also feeds air to cool coils & alternator regulator (you can see this - right against spinner) which I now plan
to feed from the left cheek to increase air to the water rad.
What was the load on the test stand and how did you get the Delta P across the cores?
Thanks again. Helpful.
Cheers
Steve Izett
> On 30 Dec 2017, at 4:56 am, Steven W. Boese SBoese@uwyo.edu <flyrotary@lancaironline.net> wrote:
>
> Steve,
>
> The attached plot shows the interaction between coolant and oil temperatures obtained on my test stand. The oil cooler and the radiator are fed air from separate ducts and their outlet areas are independently variable. RPM was 4000 and HP was 42 during the test. Water T is the temperature of the coolant coming out of the engine and Oil T is oil temperature returning to the engine from the oil cooler. With those temperatures stabilized at about 210 deg, the air delta P was 2.6 inches of water across the radiator and the oil cooler cores.
>
> After the air flow through the oil cooler was increased while leaving the radiator air flow unchanged, the Oil T dropped from 212 to 160 deg while the Water T dropped from 212 to 200 deg. At this time, the oil cooler oil delta T was 33 deg and the radiator water delta T was 15 deg.
>
> My conclusion from this is that it will be difficult to cause a significant change in the coolant operating temperature by making changes to the oil cooling part of the system. In real life, I was a scientist. It may be useful to run this conclusion past an engineer. Scientists just collect data while engineers figure out what the data means and how make use of it.
>
> From the photo of the front of the radiator inlet duct, comparing the inlet to the prop flange, it would appear that the duct inlet has an area of around 27 sq in. Your previous information indicates an inlet area of 16.5 sq in which may be the area of the inlet through the cowl. What sort of interface do you have between the cowl and duct?
>
> Steve Boese
> RV6A, 1986 13B NA, RD1A, EC2
>
> From: Rotary motors in aircraft <flyrotary@lancaironline.net> on behalf of Stephen Izett stephen.izett@gmail.com<flyrotary@lancaironline.net>
> Sent: Friday, December 29, 2017 12:42:29 AM
> To: Rotary motors in aircraft
> Subject: [FlyRotary] Re: Cooling Issues
>
> Hi Lynn
> Current testing is stationary.
>
> I have had it on the apron doing figure 8’s and it seemed to not overheat.
> Still to hot though.
>
> Once its moving it seems to help with airflow.
>
> I’m not going to give up on our setup just yet.
> I’ve got a few ideas and a bunch of testing and then maybe fly it and see what it does with some wind in its face.
>
> What delta T’s should I expect from the oiling water coolers?
> Sounds like 15F on the water and a fair bit more on the oil?
>
> Cheers
>
> Steve Izett
> <oil and coolant temperature interaction.jpg>--
> Homepage: http://www.flyrotary.com/
> Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html
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