[Boatanchors] SCR-274N in B-25

[john fitzsimmons]

LOL my big mistake here was assuming that all the radio equipment was at the radio op's position!  I didn't think to look at the nav position.  That poor radio op probably got quite the workout crawling back and forth thru that tunnel in the event equipment needed adjustment in the forward compartment.

In any event the pages visible in that link are for the C and D model, which had the two turrets aft of the bomb bay and no waist gunner position.  All bets are off for the later versions which had one turret just forward of the bomb bay.

Anyway, to the OP who posed the question, perhaps that B-25 flight manual might be a good purchase to get the definitive skinny on where the equipment was located.

--- On Fri, 10/1/10, Kludge <wh7hg.hi at gmail.com> wrote:

From: Kludge <wh7hg.hi at gmail.com>
Subject: RE: [Boatanchors] SCR-274N in B-25
To: "'john
 fitzsimmons'" <w3jn at yahoo.com>
Date: Friday, October 1, 2010, 8:13 PM




 
 






From: john
fitzsimmons [mailto:w3jn at yahoo.com] 

Obviously these pictures are the factory configuration.  No
doubt the BC-375s were gleefully ripped out and tossed overboard whenever
command sets became available - perhaps later in the war, or postwar?



 

Okay, I see the problem.  The
BC-375/BC-348 combination (referred to as the SCR-287) was a liaison set used
for long range communications.  This was the radio operator’s equipment.  The
SCR-274-N was a command set intended for plane-to-plane and short range
plane-to-ground (tower etc) communications and was used mostly by the pilot
& copilot.  *Both* lived in the same airplanes.  The T-47A/ART-13 replaced
the BC-375, not the SCR-274-N, and that didn’t happen until late in the
war. 

   

By way of reference, the BC-191 –
the 12v version of the BC-375 – came out in 1935 with the 24v BC-375
appearing around 1940-1941.  The BC-191 was paired with the BC-224 (functionally
a 12v BC-348 predecessor) and, in a few very early cases, a BC-A*-179 or -199
which were receivers from early versions of the SCR-A*-183.  The BC-191/BC-224 combination
was called the SCR-187 and was the liaison set used in heavy 12v aircraft like
the early B-17s.  These same airplanes carried SCR-A*-183 command equipment as
well. 

   

The first WE contracts for the SCR-274-N
came out in 1941 and this system was installed in new construction 24v aircraft,
sometimes to replace the 12v SCR-A*-183 command equipment used in earlier 12v aircraft
or as specified equipment in new designs like the B-25.  (There was a 24v
version of the SCR-A*-183 called the SCR-A*-283 which was used in some aircraft
like the 24v Curtis P-40s.)   

   

Now, if you
look at your own reference: http://books.google.com/books?id=jDYNpgTvxh0C&printsec=frontcover&dq=b-25+flight+manual&source=bl&ots=Kto5oQWQz1&sig=ugNV3iimOhfoGO_PjFzcyHu9nGs&hl=en&ei=73SkTN7AHYS0lQeJ9M3JCw&sa=X&oi=book_result&ct=result&resnum=8&ved=0CDQQ6AEwBw#v=onepage&q&f=false
and turn to page 25, you’ll see a photograph of the navigator’s
position looking aft which means looking toward the bomb bay and the tunnel
over it.  On the left side of the picture (hence the right side of the
aircraft), you’ll see the modulator, antenna relay and receivers for the
SCR-274-N command system while on the right is the BC-433 ADF receiver.  Out of
sight behind the receivers are the SCR-274-N transmitters.  While the equipment
except the transmitters may be in front of the tunnel (I can’t tell for certain
if it is entirely.), anyone going into the tunnel still had to squeeze past it
to go there.  Was it a tight fit?  No doubt.  At the same time, it’s a
good bet that anyone who had to go through there watched his diet carefully. 
:-D 

   

Does this help any? 

   



Best regards, 



  



Michael, WH7HG BL01xh

http://www.nationalmssociety.org/chapters/NTH/index.aspx
 

http://wh7hg.blogspot.com/


http://kludges-other-blog.blogspot.com


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