From: "Stephen Izett stephen.izett@gmail.com" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] cooling modes
Date: Tue, 24 Nov 2020 03:57:55 +0800
References: <list-972570@logan.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
In-Reply-To: <list-972570@logan.com>
Message-Id: <9E717483-3E32-4417-AEF2-39DB1A4C0576@gmail.com>

Is that you Roy?
I couldn=E2=80=99t understand your description here. Sorry if I=E2=80=99m =
being being slow.

Steve Izett


> On 23 Nov 2020, at 11:15 pm, Ernest Christley echristley@att.net =
<flyrotary@lancaironline.net> wrote:
>=20
> Just FYI,  I had a HVAC engineer help me with my installation.  One of =
the things I learned is that blowing "into" a heat exchanger will create =
a host of errors, the most obvious being that the blower tends to blow =
stronger in the middle of the stream than at the extremities.  To =
eliminate these errors, put the head of the blower in a box at the rear =
of the heat exchanger.  Cardboard is fine for the box.  Stick the nozzle =
through a hole in the box so that it blows out.  The blower is now =
dropping the pressure in the box.  For good measure, shape the box to =
simulate what the air would encounter leaving the heat exchanger.
>=20
>=20
>=20
> On Friday, November 20, 2020, 5:22:47 PM EST, Stephen Izett =
stephen.izett@gmail.com <flyrotary@lancaironline.net> wrote:
>=20
>=20
> Hi Roy
>=20
> Here is a photo of our Mocal 44 row oil cooler with diffuser. A K&M =
Streamline into a wedge.
> Not sure of the dimensions of hand. The Mocal web site will have specs =
so you could get a rough idea of size.
> I tested this one recently with a leaf blower approximating 100 knot =
air flow and in that test it was very even.
>=20
> Having said that, I tested our water radiator wedge diffuser when I =
built it years ago and had it reasonably even=20
> measuring pressures across the exit face, but now instrumenting it in =
flight its flow is vastly uneven.
>=20
> I have found that the flow is dependant not only on getting the =
diffuser shape right according to the various papers (eg. K&W, London, =
Oblique Flow Diffusers - Streamline )
> But importantly the environment it ends up in. The papers share data =
for ideal conditions with for example unobstructed exit air paths.
> My thoughts now are that this has a significant impact on the =
performance and therefore the advantage of instrumenting in flight and =
reshaping for actual conditions.
>=20
> The data I collected yesterday of our H2O diffuser reveals that the =
air flow in various points across the face are very different.
> Simplified, if I average the pressures at the five points I measured, =
then comparatively the back is up 20%, the centre up 25% and the front =
down 60% from that average figure.
> I=E2=80=99m figuring a 20% difference is probably OK, but my front to =
back/middle difference of ~80% down in the front top of that radiator =
may hold significant room for improvement.
> Further, my data suggests that as IAS rises those differences are =
amplified.=20
> So I am now targeting the modifications for our worst case conditions =
of WOT sea level ~200hp and initial climb numbers of 115KIAS.
>=20
> Cheers.
>=20
> Steve Izett
>=20
> <IMG_1424.jpeg><IMG_1416.jpeg>
>=20
>> On 21 Nov 2020, at 3:37 am, ROY GLENN rglenn14@sbcglobal.net =
<flyrotary@lancaironline.net> wrote:
>>=20
>> Could some ne post a photo of their wedge shape and dimensions.
>> Thanks Roy
>>=20
>> --
>> Homepage:  http://www.flyrotary.com/
>> Archive and UnSub:   =
http://mail.lancaironline.net:81/lists/flyrotary/List.html
>=20
> <IMG_1416.jpeg><IMG_1424.jpeg>--
> Homepage:  http://www.flyrotary.com/
> Archive and UnSub:   =
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