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Thanks Charlie.
I’m not looking forward to playing with the cowl flaps.
I wish I could just install 2 of Antisplat Aero’s units.
We will see!
Steve
> On 20 Nov 2020, at 10:58 pm, Charlie England ceengland7@gmail.com <flyrotary@lancaironline.net> wrote:
>
> 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.
>
> 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...
>
> Charlie
>
> Virus-free. www.avast.com
>
> On Fri, Nov 20, 2020 at 8:04 AM Stephen Izett stephen.izett@gmail.com <flyrotary@lancaironline.net> wrote:
> Hi Matt
>
> I’m 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.
>
> I’m wondering what people have found as far as the delta T across their Water Coolers?
> I’m seeing between 8-10F between in to out coolant temps with OAT temps of around 79F.
>
> Cheers
>
> Steve
>
>
>
>
> > On 20 Nov 2020, at 9:46 pm, Matt Boiteau mattboiteau@gmail.com <flyrotary@lancaironline.net> wrote:
> >
> > 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 ?
> >
> > - Matt Boiteau
> >
> >
> > On Fri, Nov 20, 2020 at 5:28 AM Stephen Izett stephen.izett@gmail.com <flyrotary@lancaironline.net> wrote:
> > Hi Guys
> >
> > I thought I should provide an update.
> >
> > Having installed 5 differential pressure transducers and interfaced them via spare Dynon EGT inputs, Ive been collecting some H2O diffuser pressure data.
> >
> > 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.
> >
> > This has revealed the importance of measuring the pressure across the radiator as the pressures behind the radiator is not at all equal.
> >
> > 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.
> >
> > So we will reshape the diffuser wall, making it harder for the air to get to the back and retest.
> >
> > 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.
> >
> > I’m 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.
> >
> > Cheers
> >
> > 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
>
>
> --
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