Whoops, sorry for leading everyone 'up the garden path'. I am by no means an expert in matters Vultee, my experience with the Camden aircraft being limited to a couple of hours of general dusting and cleaning on a couple of occasions five or six years ago. My memory is hazy on the details but I definitely remember a sagging aerial that I had to duck under occasionally, and that great big padlock that stopped me getting the canopy open (purely for the purposes of dusting inside, of course
).
So I went a-Googling.
Here is a contemporary photo for sale on that auction website that I reckon shows three wires attached to the vertical fin: one to the mast on the cockpit canopy and one to each wingtip.
Here is another angle on the Camden VV. You can clearly see the (single!) gun and the tensioning spring on the radio mast that I mentioned in my earlier post - looks like the wire from the tail went to the spring and then into the cockpit, with the spring itself the only thing attached to the mast.
And
here is a very clear photo of that gun - but it doesn't show enough of the radio mast to answer the question. Looking at the date on this photo I reckon there's a good chance that this was taken on one of the days that I was there, though I don't recognise the photographer's name.
Finally, I mentioned earlier that this aircraft used to be taken out and ground run. I found
some photos of that too. Note the outer wings were not in situ at the time - I can't for the life of me remember if they are back on or not. I used to have some contacts who knew those in charge of the family trust who now look after the museum but unfortunately I no longer live nearby so I can't go back to see for sure...
That probably raises more questions than it answers!!
Adam