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 09:44:26 +0800
References: <list-10492771@logan.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
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Message-Id: <9F2CAA32-52B1-43C8-8A4D-8AE9562B74F6@gmail.com>

Hi Steve

I took a moment and estimated the total duct scaled from the drawing as =
being about 18.5 in^2 (Prop Flange is I think 6 in)
Then I have taken away 2 in^2 for feeding the coils/alternator.
It=E2=80=99s that 2 in^2 I=E2=80=99ll redeem for water cooling and move =
the coiling air for the coils/alternator.
I just realised to that I should probably be feeding the coils and =
alternator from diffused (slowed) air and not from free stream air.

I=E2=80=99ve always measured from the inside minimum neck of the entry =
and not included the lips. What is the convention?
You appear to have measured from the outside of the flange which I =
measure to be about 27 inch^2.

I=E2=80=99ve wondered how effective the inlet area right against the =
prop spinner will be at cruise.=20

Steve
> 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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