Hello,
I just came across a 1943 Handbook Maintenance Instructions manual for the SCR-274-N radio set (used in p-47, among many others), that may be of use to some folks, if it hasn't been posted before!
http://www.scr-274-n.info/to12r23scr2742.pdf
I found it off of
SCR-274-N Links to other sites.
I was wondering if some folks knowledgeable in such things could answer a few radio-related questions for me about early model P-47's.
First off, I am trying to figure out the actual wire-paths for this radio set for an early P-47 D (-15-RE). The only illustration I have been able to find, with this actual radio in it, is the blurry illustration of the right-cockpit from the pilot's manual (p.20 in my copy). The MBI P-47 book has a painted version of this illustration, and I believe I have also found the source photograph that the illustration was based from, (I think it was in the Detail and Scale book), but all three illustrations are blurred and the wiring obscured by the t-30 microphone set looped over the command transmitter control box several times. I am also trying to figure out what the two seemingly-featureless boxes to the bottom-left of the crystal-selector switch are. It appears that the further-left box might have wiring running to the command receiver control box, but this doesn't make much sense according to the manual, and also appears to be the wrong direction from where the wires are twisting off of the command receiver control box itself. Not to mention the command receiver and transmitter, where the wires would logically connect, is located in the storage compartment aft of the cockpit. The only thing I've been able to find out for certain, is where to plug in the mic and where to plug in the headphones!
Secondly, in the manual I posted above, there seems to be no reference to a crystal selector switch, but I know the p-47 C\early D had one located left of the BC-450-A command control box. What did it link into? I notice two-jacks coming off of it in the illustration, one of which seems to go up into the sill, near the fluorescent panel light, the other seems to go into the unidentified box, bellow left of the crystal filter selector box. On the MBI painted-illustration, (which I don't really trust 100%), you can make out "voice and both" on the switch box, which makes sense with instructions in the pilot manual. Also in the MBI illustration, you can see what appears to be "switchbox BC-348" written. There is a radio-command control box called a BC-348 -- but it looks nothing like the example here. That one looks more like something on a B-17. I was wondering if anyone had a good, clear photograph of this crystal-selector box so i can verify what the text reads.
As far as I can tell, a similar radio setup was used in p-39D's, and P-40 series aircraft, as well as possibly the A-36\early mustangs, but without the crystal-select box. I also can't seem to find any sort of antenna relay control, so that is confusing as well.
Lastly, does anyone know what the DF loop on the back of some CBI p-47's was hooked into, and what sort of control box it had in the cockpit?
I'm afraid I'm one of those obsessive types when it comes to model airplanes...
Cheers!