[ARC5] 274N's in 1942

[Michael Tauson]

On Sat, Jul 4, 2009 at 7:11 AM, Bob Macklin<macklinbob at msn.com> wrote:

This is a repost from before:

On Fri, Jul 3, 2009 at 12:56 PM, Robert  Eleazer<releazer at earthlink.net> wrote:
> A book on the 347th Fighter Group in WWII that covers its action on Guadalcanal says
> that "Cheap radios in the P-39's and P-400's had to be set on frequency daily with a
> frequency meter." There is even a picture of a USAAF technician with a BC-221 performing
> that task; unfortunately you can't see the radios.

Actally they were SCR-274-Ns.  The early ones at least could only
achieve .03% dial accuracy which was outside the original spec and
they were tagged in bright yellow on the dial that a frequency meter
was required to set the frequency.

I can't speak for Army practices for certainty but the Navy generally
set their ATA transmitters using an LM frequency meter anyway and they
were in spec.   When WE started building the SCR-274-N, they couldn't
achieve the specified precision due to problems building the tuning
caps so had to get a variance to continue construction.  THis was
fixed in later versions but I *believe* the practice of using the
BC-221 was maintained anyway.

> This could not have been with SCR-274N radios. They did not drift that much, did they?

IT wasn't a matter of drift; it was a matter of the tuned frequency's accuracy.

> I can only conclude that they were SCR-283's, those TRF sets with the changeable coil
> sets. Now, I had thought that the 283 was limited to the home front, and have seen
> installations of training and test aircraft that had them, even rather late in the war, both in
> person and in books. My pilot's manual on the P-40 says the D model had the 283 and
> the E model the 274N.  And finally there is a rather poor photo in the book of troops
> listening to air combat over a radio they salvaged out of a wrecked P-39, and it looks more
> or less like a 283 as much as anything.

The SCR-A*-183/-283 and the GF/RU saw action in the earlier aircraft
though were phased out as later models went into service.  Even so,
some survived the entire war in combat aircraft while others found
homes in the relative safety of training aircraft.

And then, added:

> When we did enter the war we started in Australia with the P-40s and P-39s
> we had sold them.
> The P40s that went to the AVG (Flying Tigers) did not have normal military
> radios. What I understand was that what they did have was PISS POOR!

The AVG's P-40s had SCR-A*-183s (the 12v equivalent to the SCR-A*-283)
which is the same as all the early model (12v) P-40s as well as other
aircraft had.

BEst rgeards,

Michael WH7HG
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