From: "Stephen Izett stephen.izett@gmail.com" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] Re: Cooling Issues
Date: Sat, 30 Dec 2017 08:04:36 +0800
References: <list-10492771@logan.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
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Message-Id: <B544B57F-A2A9-4599-A4DC-B60497BEB88F@gmail.com>

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=E2=80=99ll 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.=20
The diffuser joins the cowl ~1/2=E2=80=9D inside the cowl lips and then =
the cowl lips were micro=E2=80=99d 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.=20
I=E2=80=99ve 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=20
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:
>=20
> Steve,
>=20
> 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.
>=20
> 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.
>=20
> 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.
>=20
> =46rom 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?
>=20
> Steve Boese
> RV6A, 1986 13B NA, RD1A, EC2
>=20
> 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
> =20
> Hi Lynn
> Current testing is stationary.
>=20
> I have had it on the apron doing figure 8=E2=80=99s and it seemed to =
not overheat.=20
> Still to hot though.
>=20
> Once its moving it seems to help with airflow.
>=20
> I=E2=80=99m not going to give up on our setup just yet.
> I=E2=80=99ve 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.
>=20
> What delta T=E2=80=99s should I expect from the oiling water coolers?
> Sounds like 15F on the water and a fair bit more on the oil?
>=20
> Cheers
>=20
> Steve Izett
> <oil and coolant temperature interaction.jpg>--
> Homepage:  http://www.flyrotary.com/
> Archive and UnSub:   =
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