Jerry Hey wrote:
Paul, I have been trying to come to some finality on the
radiator
plenum. I reversed your process and started out with
physical
model
of poster paper and plywood and then as I encountered
problems,
tried
to work it out with cad. Anyway, here is what I have come up
with.
Please take it into consideration with the cowl designs.
The cowl should slope back from under the spinner to a
point
5/8"
below the rear lower corner of the radiator header tank. From
there
the louvers take over and it will flat and horizontal back to
the
firewall. The flat bottom needs to be 14.5 inches wide to
allow
room
for the louvers.
The photo was taken before I put the extension on the plenum
to
get
it
out the front of the cowl. In the photo, the plywood
represents
the
radiator and the duct tape is the header tanks. The plenum
opening
is
48 sq in which expands to 71.5 sq. in. before it enters the
wedge
portion. Jerry
Don't need to do that. Keep a constant AREA duct up to the
start
of the core.
Paul Lamar
Jerry,
Have you bought a spinner yet? I'm planning on a 16" spinner
also,
maybe from a mustang II, and was wondering about the price.
Your
radiator has the same dimensions and looks like your inlet duct
is
similar to what I'm planning.
Brian Trubee
No, I have not bought the spinner yet. I think the Mustang 2
spinner
will be quite expensive. If we could get a few guys together, we
might
be able to get Brian Alley to build us some CF spinners. His
work
is
beautiful. I have not talked to him about this and have no
idea
if
he would do it or the price. Jerry
I got some bad news for you Jerry. No way is that stock cowl and 12
inch spinner
going to work.
Paul Lamar
Interesting. According to my mock up of which I have sent a number
of pictures, including one today showing clearance with the 12 inch
spinner, I have plenty of clearance on top for the runners. The
cowl
should be about 34 inches wide at the S beam which is 31 inches
overall. What is the height at the firewall of the cowl you have
drawn? What is its width 35 inches in front of the firewall? Jerry
You are fooling yourself Jerry as that line does not go all the way
across
the top of the cowl. You got to do this stuff in 3D. I'll send a
drawing
with dimensions.
Paul Lamar
Here are the real numbers on my cowl width at the end of the S Beam.
As you can see, I have plenty of room. Measured by Brian Alley
today. Jerry
"Jerry, I measured the mold and it is 34" so I'd say
the cowl with coremat is 33 1/2" at 24" forward of the
firewall and 6" below the prop centerline. Call me in
the shop tommorrow. I'll be here all day!!!
Send me a sketch of what he is talking about. Is this the width
of the cowl 24 inches in front of the firewall six inches below
the thrust line? Is so what does that have to do with the top
surface of the cowl? It is the top surface of the stock Tailwind
cowl being as low as it is that causes problems with the wrap over
intake manifold. Get a quote from him on a new cowl design.
Paul Lamar
Your drawing showed the S beam ends sticking through the sides of the
cowl so I had to deal with that first. Until we get the cowl
drawn as it really is we cannot have faith in the drawings
predictions. The physical model looks a less alarming regarding room
over the top. Then there is the possibility of increasing the spinner
diameter a TINY AMOUNT and, at the same time, raising the top of the
firewall JUST ENOUGH to get what we are looking for while retaining
the look of the Tailwind and the ability to see over the nose. I don't
feel I have exhausted my options yet. Jerry
I fixed the cowl even though that had no bearing on the real problem.
More bad news. Even my mail box intake manifold won't fit the
stock cowl. This one is made with the 3 inch center line radius 2 inch tube.
Would be slightly smaller with the R$B Wagner pipe.
You will never see over the nose :) I can make a blocky cowl that fits
if that is what you want :)
Paul Lamar
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