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Yes, 360 deg of turning does not help the air
flow, mainly because the boundary layer in the duct is being put to
the test to stay attached during that 180 deg turn. If you get separation
of the boundary layer and macro air flow in that turn creating eddies in
the flow, then pressure recovery and smooth flow suffers. However,
at the low duct velocities likely in your testing, I'm not certain that flow
separation would be the problem that it may be at higher duct velocities like
when flying.
The basic challenge is to find the
reason(s) that with 740 ci of core you are not cooling even at 2200 rpm.
Probably the quickest one to confirm or eliminate is air in the system.
Touching or otherwise measuring the temperature profile of the radiator side
tanks should be sufficient to let you know whether entrapped air is significant
or not.
It is my opinion that the area from your inlet
to the face of your radiator is not the major problem area - despite the 180 deg
turn. I think its more likely that the air exiting the radiator that
could be a part of the problem. After exiting the core, the air now has no
duct to gentle guide it toward an exit. It must first face the under the
cowl pressure which can oppose the flow and then after it exits the radiator
under the cowl, it must find its way around various obstructions, mainly the
engine, before it makes the final 180 deg turn and exits the cowl area. If
you try operating with the cowl off the prop blast might interfere with air
exiting the core.
Was your test run with the cowl off or
on?
I presume your cowl exits are on the bottom of your
cowl??
By the way, Bill, good to see you not getting discouraged-
this is a solvable problem. My challenge was oil temps, I try 5 different
modifications (each with an incremental improvement) until finally arriving at
the solution - which drop oil temps 30F and coolant temps followed them
down. Needless to say, finding the actual root case of each problem is
essential, before formulating corrective action.
Hang in there
Ed
----- Original Message -----
Sent: Saturday, October 06, 2007 10:03
PM
Subject: [FlyRotary] Re: Duct?[FlyRotary]
Re: Coolant Water Pressure
Yes, the air will
come in from the nostril, make a 180 degree turn, go through the radiator,
make a 180 degree turn, and exit the cowl…after that I don’t know what it will
do….but I am sure it will be dizzy!!!
Bill
B
From:
Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Ed Anderson
Sent: Saturday, October 06, 2007 7:30
PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Duct?[FlyRotary] Re:
Coolant Water Pressure
Bill, do I interpret your
explanation of your duct below correctly. You pull your air in from up
front of the cowl and then route it via the duct to the firewall side of the
radiator (the side not shown in the photo) and then have it flow through the
core and exit up into the cowl?
----- Original Message -----
Sent:
Saturday, October 06, 2007 7:10 PM
Subject:
[FlyRotary] Re: Coolant Water Pressure
Yes,
Kelly.
There is a duct
that brings air from the left nostril back to the rear of the
radiator. You can just see it as it comes around the corner at the
lower right side of the picture. There is a plenum that diffuses this
air to cover the radiator core and forces all the air that comes into the
nostril to go through the radiator. When I did a tuft test on the face
of the radiator, I got a pretty good flow over the entire face of the
radiator. However, I had a stronger flow at the bottom. That is
part of what caused me to try the fan. That and I felt that I would
need more air flow than was provided through the nostril by prop blast when
ground running. I do not think the fan will be needed at speed in
flight and in fact, may be an impediment at that
time.
Bill
B
From:
Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Kelly Troyer
Sent: Saturday, October 06, 2007 1:01
PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Coolant Water
Pressure
I do not see any sign of ducting to force air
through the radiator instead of around
it........Do you have ducting that is not in the
photo ??
--
Kelly Troyer
"Dyke Delta"_13B
ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil Manifold
--------------
Original message from "Bill Bradburry" <bbradburry@bellsouth.net>:
--------------
Ok, I recently
upgraded my computer to Vista and had to download some software
to get my camera to talk to it…So here are some pictures of my cooling
install
Notice the bypass
hole that you guys are talking about needing to plug. This hole is
in the housing which has been removed, so it is not a
player.
The little rag
you see on the oil line is a high tech way of checking for a leak. (I have
one!)
The red wire is
the air temp sensor for the air after the radiator. It is on top of
the fan.
Hoses are 1
¼” The temperature sensor was moved from the left side of the inlet
to the top
But is reading
temperature as it enters the engine after the radiator. (coolest
place)
My overflow catch
can. I will be replacing this with a pressurized on as per Lynn’s suggestions
in a previous post in order to introduce
An air cushion
above the liquid under pressure so it will not be
“locked”.
I am planning to
try and put suction on the cowling at the exit with a leaf blower in
addition to the prop blast and the small fan to see if an increase in
Air flowing will
help. I haven’t checked the sides of the radiator yet as I have been
alone when running the engine….
All inputs
appreciated. I already know some things should be changed, so don’t
hold back with the suggestions.
Thanks,
Bill
B
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