Nice work Charlie.
Steve
> On 21 Nov 2020, at 6:50 am, Charlie England
ceengland7@gmail.com <flyrotary@lancaironline.net>
wrote:
>
> My (untested in combat) version for my radiator looks
similar, but because the inlet is offset, I had to use a
turning vane to get flow into the lower front of the core.
The outside doesn't give a good idea on how 'tight' the
inner surface is. I had to use expanding foam to fill the
inside, then re-shape, then glass over the foam. As I
said, the back 1/4-1/3 of the diffuser tapers tightly to
almost touch the core at the back.
>
> After observing both rotary and piston installations
that work, I'm beginning to think that turning vanes may
be the 'good enough' vs fighting for perfection in
diffuser shape. My oil cooler core has a much more
elaborate vane setup, driven by the very short duct length
and even greater offset to the bottom edge of the core.
>
> Charlie
>
>
> On 11/20/2020 4:22 PM, Stephen Izett
stephen.izett@gmail.com wrote:
>> Hi Roy
>>
>> 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.
>>
>> Having said that, I tested our water radiator
wedge diffuser when I built it years ago and had it
reasonably even
>> measuring pressures across the exit face, but now
instrumenting it in flight its flow is vastly uneven.
>>
>> 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.
>>
>> 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’m 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.
>> So I am now targeting the modifications for our
worst case conditions of WOT sea level ~200hp and initial
climb numbers of 115KIAS.
>>
>> Cheers.
>>
>> Steve Izett
>>
>>
>>
>>> On 21 Nov 2020, at 3:37 am, ROY GLENN
rglenn14@sbcglobal.net <flyrotary@lancaironline.net>
wrote:
>>>
>>> Could some ne post a photo of their wedge
shape and dimensions.
>>> Thanks Roy
>>>
>>> --
>>> Homepage:
http://www.flyrotary.com/
>>> Archive and UnSub:
http://mail.lancaironline.net:81/lists/flyrotary/List.html
>>
>
>
>
>
> This email has been checked for viruses by Avast
antivirus software.
>
www.avast.com
>
>
> <rad duct1.JPG>--
> Homepage:
http://www.flyrotary.com/
> Archive and UnSub:
http://mail.lancaironline.net:81/lists/flyrotary/List.html
--
Homepage:
http://www.flyrotary.com/
Archive and UnSub:
http://mail.lancaironline.net:81/lists/flyrotary/List.html