A1134 amplifier mounting

I think it may simply be the era that the kit was first designed – the A1134 is very much a prewar design, along with the TR9 and T1083/R1082 transmitter/receivers, using 2v filament valves, when dedicated batteries were the norm.

Andy

Hi Andy

I have read that batteries were charged every mission – probably in the notes of a W/O operator. If I were a W/O I would do it every mission too! BUt you would imagine that there would have been banks of them on charge waiting to be used.

Actually I’ve remembered now that the glass accumulator batteries on the Stirling are behind the radio ‘stack’ in a nice deep shelf, not so sure about the HT ones. Will have to have a look at the pics.

Seems odd that the SBA had a motor-generator HT and LT output for itself – you have imagined that a common one would be used. But then again I think (without proof) that the design of the SBA deliberately avoided reliance on any other kit.

Cheers
James

James, there is indeed a battery inside the amplifier, but this is the Grid Bias battery only. The current drain is minute, so it has a long life, almost as long as its shelf-life.
In addition the amplifier needs a 120v HT battery, and a 2v accumulator for the valve filaments, mounted externally. (There was also a ‘Power Unit Type 173’ which generates the HT from the aircraft 24v supply, but I think this may be a post-war addition). So there has to be a secure mounting for a brick-sized HT battery and glass-jar 2v accumulator, and maybe spares? I know that freshly-charged accumulators were installed for each mission, but I’m not sure how long the HT battery lasted, I assume there must have been a scheduled maintenance period to replace it, maybe every mission?

Hi Andy

I believe that there is battery inside the anplifier, but I guess you would know that. On the Stirling other ‘electronic’ function batteries are on the floor opposite the W/O. I have a nice pic of a W/O in the doorway clutching some batteries, presumably for recharging.

Cheers
James

As well as the amplifier mounting, there is also the installation of the amplifier batteries to consider, I don’t think I’ve seen any information for any aircraft.

I’ve been looking at amplifier installations in any pictures of the Lancaster I can find, with the usual problem – they all look to be different!

Andy

If anyone has any details of the mounting for the A1134 in the Mosquito I’d be interested to see them. We have the amp, and I know it goes somewhere behind the pilot’s seat, but beyond that….

Hi Cees

I’ve seen various pics on the net from repro installations with bungees but I always assumed they were a pragmatic means of mounting them without any other info. Was it a Stirling site that had the bungees?

Hi James

think we’ve got a bathtube Morse, but if not I’ll be in touch 🙂

John

From a dig I once found an A1134 amplifier with strands of bungee cord attached to the brackets on the side. Was the mounting flexible?
Cees

Hi

Any chance that you might put up a drawing of the mounting method or just a text desciption please?

John – I assume that you have a bath-tub morse key? If not I have one that you can have.

Cheers
James

And you are in even more luck as I have found that Stirling brake pressure valve mounting, will send some pics to you soon.
Cees

PM sent 🙂

John

John, you are in luck! I’ve just had a mounting CNC cut as per the AVRO drawings for a Lancaster Wireless operators compartment. If you can PM a contact number I’ll give you the details.