As far as I know ethylene glycol as automotive anti-freeze dates from the
mid-20's
when the "Prestolite" anti-freeze mixture was first marketed.
It is believed that the high-enthalpy and high-boiling point properties were
known before, and glycol used as a
liquid coolant for aircraft engines in the same time period.
If very high speed from a piston-engine powered aircraft was needed, a last
resort could be
to use almost pure ethylene glycol as a coolant, and flying the aircraft with
the cooling flaps
closed to reduce aerodynamic drag. A well known example was the 1939 world
speed record
of 755,11 km/h set by Cpt. Fritz Wendel in a Messerschmitt Bf-109R special
aircraft.
It was reported that the engine was red-hot and almost ruined after the record
flight.
My own experience from liquid-cooled "amps" come from the HF 1 kW SSA1000 and
VHF/UHF 1 kW PA204
solid-state units, both built in the 80's by ITT-Standard Radio in Sweden.
They are intended to use Fluorinert as coolant, but as it is very expensive and
has an enerving tendency to escape
through even very minute leaks, the amateur users I know of use a 50-50 mixture
of distilled water and glycol.
As a water-glycol mixture has about twice the enthalpy as Fluorinert, the
amplifier
runs cooler for a given coolant flow as a side effect.
The reason for using Fluorinert, according to the manufacturer, is that it can
be stored in the cooling
system almost indefinitely without the risk of leaving any residues that can
block the cooling channels or the pump.
73/
Karl-Arne
SM0AOM
----- Original Message -----
From: "Will Matney" <craxd1@ezwv.com>
To: <amps@contesting.com>
Sent: Saturday, March 05, 2005 2:53 PM
Subject: Re: [Amps] Water cooled amp question
> Didn't think it went back that far. However, that Dupont plant has been there
> ever since dirt too. The 1940's was a guess but the more I remember, seems
> like that actually fired up back during WWI maybe or before as the town of
> Dupont is an old one. Along the Kanawaha river which goes through Charleston,
> WV. and dumps into the Ohio river, is where "chemical valley" sprang up.
> During the Civil War, places like Nitro, WV. sprang up making explosives and
> there all along that river. South Charleston was the home of Union Carbide,
> and we all remember Baupal India. Forgive the spelling on Baupal. Every 1-2
> miles up there are large chemical plants and where a lot of the ordinance
> plants once were. The Kanawaha dumps out in the Ohio river about 40 miles
> above my house. Then, the Ohio is a stones throw away (be fishing in it in 10
> minutes). That's the very reason nobody can eat any fish out of the rivers
> here. This has me curious now, I'll have to do some history work.
>
> Will
>
> *********** REPLY SEPARATOR ***********
>
> On 3/5/05 at 8:34 AM G3rzp@aol.com wrote:
> Glycol/water mixtures were in use as antifreeze in aircraft cooling systems
> well prior to WW2. Examples were (are?) Spitfires and Hurricanes, among
> others.
>
> 73
>
> Peter G3RZP
>
>
> __________ NOD32 1.999 (20050215) Information __________
>
> This message was checked by NOD32 antivirus system.
> http://www.nod32.com
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Anti-Virus.
> Version: 7.0.308 / Virus Database: 266.6.2 - Release Date: 2005-03-04
>
>
--
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.308 / Virus Database: 266.6.2 - Release Date: 2005-03-04
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|