<div dir="ltr"><div>I got a $20 handheld anemometer from Amazon I use for measuring airflow now. Takes the guesswork out of it. I got it when my son built a wind tunnel project for school and now I use it when working on cooling calculations for my RF generators. Well, that and my pawn-shop FLIR camera. Now you can get a FLIR add on for a cell phone too. I got the FLIR when I was working on a 200kW RF system and for some reason I didn't want to put my hand in it to see where the hotspots were. Handy tools. :)</div><div><br></div><div>Now I'm trying to figure out how to upgrade my old R-12 based R4 compressor to a more modern and efficient Sanden compressor on my 86 Blazer. Of course it worked when it was cooler but now that we're in the mid teens it's not keeping up. Around 118 and I had 90 degree air coming out. bleh. Already upgraded the fan clutch to the big-block version and that helped but that was before the heat got here.<br></div><div><br></div><div>Ken in AZ<br></div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Jun 18, 2021 at 5:46 AM Cecil Bearden <<a href="mailto:crbearden@copper.net">crbearden@copper.net</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div bgcolor="#FFFFFF">
<p>Steve:</p>
<p>I remember all that and had to work with it in hydrology and flow
calculations for the last 40 years. However for the last 10 I
have had a computer program available that does all that stuff and
all I have to do is plug in some numbers. Back when I was
approving plans for new construction, I could look at an
applications, the spillway size and the location and ddo it in my
head....<br>
Cecil<br>
</p>
<div>On 6/18/2021 4:55 AM, Stephen Offiler
wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">I haven't done flow calculations in a long, long
time, and Fluids was not among my favorite subjects back in
school... so with that said, my gut feeling is that Mark's 56%
blockage is probably somewhere in the right ballpark but
dependent on factors like whether the airflow is laminar or
turbulent, maybe Reynold's numbers.... now I'm just spewing
stuff I learned 40 years ago. Mostly to say, there might not
*be* a good way to calculate this outside of a lab with a flow
bench; really, the thing to do is try it, and take
measurements. No idea if you can see high-side pressure while
on the road but I doubt it. Any readouts for coolant or trans
temperatures?
<div><br>
</div>
<div>SO</div>
<div><br>
</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Fri, Jun 18, 2021 at 1:03
AM magreer67 <<a href="mailto:magreer67@gmail.com" target="_blank">magreer67@gmail.com</a>> wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div dir="auto">
<div dir="auto">Wouldn't that be 56% blockage and 44% open
to flow through?</div>
<div dir="auto">Mark Greer</div>
<div dir="auto"><br>
</div>
<div dir="auto"><br>
</div>
<div dir="auto"><br>
</div>
<div id="gmail-m_3390274285365035188gmail-m_-202123088828031218composer_signature" dir="auto">
<div style="font-size:85%;color:rgb(87,87,87)" dir="auto">Sent
from my Verizon, Samsung Galaxy smartphone</div>
</div>
<div dir="auto"><br>
</div>
<div><br>
</div>
<div dir="auto" style="font-size:100%;color:rgb(0,0,0)" align="left">
<div>-------- Original message --------</div>
<div>From: Cecil Bearden <<a href="mailto:crbearden@copper.net" target="_blank">crbearden@copper.net</a>> </div>
<div>Date: 6/17/21 11:34 PM (GMT-05:00) </div>
<div>To: <a href="mailto:at@lists.antique-tractor.com" target="_blank">at@lists.antique-tractor.com</a>
</div>
<div>Subject: Re: [AT] Airflow calculations of perforated
metal for radiator screens </div>
<div><br>
</div>
</div>
<p>The .188 diameter staggered pattern gives .444 sqin hole
area over a 1 sq in area. So I guess it would result in a
44% blockage. However it would be tabout 5 inches from
the grille and then the A/C condensor sets about 6 inches
back from that. I think there would be sufficient room to
pull air from above and below. It just may cause some
additional drag at high speeds. I think I will try it and
make it easy to remove in case it blocks too much
airflow. I have to do something. Time and ability to
work on this stuff gets more valuable daily...<br>
Cecil<br>
</p>
<div>On 6/17/2021 7:48 PM, Brad Loomis wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">The 455 diesel lawn tractor I use at work
has a pull out screen ahead of the radiator. I'm not
there so I can't measure it. But I will try tomorrow and
report back. It does keep the foxtails, thistle,
mustard, and whatever else I kick up out of the
radiator.
<div>Brad</div>
</div>
<br>
<div class="gmail_quote">
<div class="gmail_attr" dir="ltr">On Thu, Jun 17, 2021
at 5:23 PM Cecil Bearden <<a href="mailto:crbearden@copper.net" target="_blank">crbearden@copper.net</a>>
wrote:<br>
</div>
<blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex" class="gmail_quote">I
had to wash the A/C condensor and radiator out on my
2011 Chevy truck <br>
yesterday before I could make a trip to pick up some
auction items. I <br>
put the gauges on my a/c system and it showed 35 low
and 350 high. <br>
before I did anything I went to the water hose and got
it down to 150 <br>
pretty quickly on the high side. The amount of bugs
was crazy. I will <br>
have to remove the radiator and condensor to get them
clean as there is <br>
no room to get anything in the front or behind the
fan. I have one of <br>
those heavy cowcatcher style grill guards in the
front. This truck has <br>
about 170K miles and has made 3 trips to Alaska, so it
may have more <br>
bugs than usual, but the bugs and thi8stle seeds are
terrible here and <br>
getting worse. I want to put a piece of perforated
metal behind the <br>
grill guard to catch the bugs. If it cuts the air
down, it can still <br>
come in between the screening and the grill. I don't
think it will make <br>
a lot of difference in the amount of air entering the
radiator, but <br>
maybe catch the bugs and fluffy crap in the air...
When we figure <br>
airflow into a home, we cut the flow through a window
in half when a <br>
screen is used. I am looking at a peforated metal
with holes .188in <br>
in diameter and offset centers so it gets the most
holes per square <br>
inch. Does anyone have any experience with this type
of screening or <br>
have a formula to determine if it will cut the airflow
too much. I think <br>
the area behind the grill guard and the grill is wide
enough to keep <br>
from cutting down the air flow. Traveling down the
road at 60mph it may <br>
deflect some air around the grill instead of through..<br>
<br>
I just don't want to have to remove this radiator
again. I have to use <br>
a stepladder to work on the d&%$^d thing it is so
tall. It is stock for <br>
that year, but the manufacturers want to see how far
the drivers can <br>
jump to get into a pickup nowdays. I remember a 63
and 66 chevy 1/2 ton <br>
pickup we worked out of on the farm every day. Hauled
20 head of cows <br>
in a bumper trailer with no brakes into OKC
Stockyards. Loaded 60 <br>
bushels of wheat to haul to the elevator when the
lines were long and <br>
the grain truck had not returned. Now, I have a 3/4
ton that I have to <br>
jump into or pull myself in with the steering wheel
and 30 bushels of <br>
rye in the bed causes it to squat, with twice as much
tire under it than <br>
the old ones had.. It doesn't ride all that much
better, just cooler <br>
when the A/C works. OK rant off.....<br>
<br>
Cecil<br>
<br>
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