From: "Stephen Izett stephen.izett@gmail.com" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] Cooling Mods to Glasair
Date: Sat, 21 Nov 2020 06:29:21 +0800
References: <list-966086@logan.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
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Message-Id: <DDCAB667-7C2A-4D51-9680-A197CBADA663@gmail.com>

Thanks Charlie.

I=E2=80=99m not looking forward to playing with the cowl flaps.
I wish I could just install 2 of Antisplat Aero=E2=80=99s units.
We will see!

Steve

> On 20 Nov 2020, at 10:58 pm, Charlie England ceengland7@gmail.com =
<flyrotary@lancaironline.net> wrote:
>=20
> When I was preparing to build my wedge diffuser, Tracy looked at my =
mold & thought it looked a little too thick at the back (IIRC, it varied =
from about 4.5" at the front to a bit under 1/2" at the back). When I =
tested it using a leaf blower & a piece of thread on a stick to =
visualize exit flow, virtually all the air was coming out the back 1/4 =
of the radiator's area. I ended up with the back edge of the diffuser =
almost touching the core, to get even flow across the full face of the =
core. It's not a straight wedge; it's almost the inverse of the curve =
you see in a K&W Streamline Diffuser. I'm nowhere near flying, so I =
can't tell how effective it will be for actual cooling, but at least =
exit air flow is fairly even across the face of the core.
>=20
> Cowl flaps: I remember Bill Eslick having issues with being able to =
close his cowl flap due to air pressure holding it open, and I think he =
ended up using the flap actuator linear actuator used for RV's wing =
flaps. I later saw an idea from another friend's Lyc powered RV8. He put =
the pivot point for his cowl flap near the middle of the flap, so it =
acts more like a throttle butterfly. The leading edge of the flap is =
rounded like a teardrop, and the mating point on the cowl matches it, to =
smooth flow. Just a thought...
>=20
> Charlie
>=20
> 	Virus-free. www.avast.com
>=20
> On Fri, Nov 20, 2020 at 8:04 AM Stephen Izett stephen.izett@gmail.com =
<flyrotary@lancaironline.net> wrote:
> Hi Matt
>=20
> I=E2=80=99m finding the wedge wall needs to be more curved inwards =
towards the back to reduce the area and air flow in that region.
> Pretty much as London describes in his investigation back in 1968.
> My copy is too big to send over this channel.
>=20
> I=E2=80=99m wondering what people have found as far as the delta T =
across their Water Coolers?
> I=E2=80=99m seeing between 8-10F between in to out coolant temps with =
OAT temps of around 79F.
>=20
> Cheers
>=20
> Steve
>=20
>=20
>=20
>=20
> > On 20 Nov 2020, at 9:46 pm, Matt Boiteau mattboiteau@gmail.com =
<flyrotary@lancaironline.net> wrote:
> >=20
> > Ah that's so great to hear that you are at that testing phase.
> > I too believe the wedge shape isn't all it's supposed to be.
> > What reshape did you end up with ?
> >=20
> > - Matt Boiteau
> >=20
> >=20
> > On Fri, Nov 20, 2020 at 5:28 AM Stephen Izett =
stephen.izett@gmail.com <flyrotary@lancaironline.net> wrote:
> > Hi Guys
> >=20
> > I thought I should provide  an update.
> >=20
> > Having installed 5 differential pressure transducers and interfaced =
them via spare Dynon EGT inputs, Ive been collecting some H2O diffuser =
pressure data.
> >=20
> > First tests took pressure readings at 5 points (4 taps, 4 inches in =
from the four corners and one in the middle) referenced to the ships =
Static system.
> > Today I changed those taps to reference the pressure directly across =
the core at these same locations.
> >=20
> > This has revealed the importance of measuring the pressure across =
the radiator as the pressures behind the radiator is not at all equal.
> >=20
> > The data has revealed that our wedge diffuser was not equally =
distributing the air pressure across the radiator face very well at all.
> > Far more air was going through the back area as others have reported =
in the past.
> >=20
> > So we will reshape the diffuser wall, making it harder for the air =
to get to the back and retest.
> >=20
> > We have also increased the Oil inlet area from ~9in2 to ~ 14in2 and =
this has improved the oil temps.
> > On a flight today OAT of 79F on climb out Oil and H2O temps peaked =
at 210F.
> >=20
> > I=E2=80=99m very happy with the changes and expect to get further =
improvements, and will shortly turn our attension to mechanising the =
cowl flaps to get temps up and cooling drag down in the cooler air.
> >=20
> > Cheers
> >=20
> > Steve Izett
> > Glasair Super IIRG Renesis 4 port RD1C, EC2, EM3
> > --
> > Homepage:  http://www.flyrotary.com/
> > Archive and UnSub:   =
http://mail.lancaironline.net:81/lists/flyrotary/List.html
>=20
>=20
> --
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