This is a version of the Type R made by Ediswan and is part of the collection of The National Museum of Computing and the images were kindly supplied by them.
The electrodes are mounted horizontally whereas R and R have the electrodes mounted vertically.
The brass base cap has the letter G on one side and A on the other to help ensure the correct orientation when presented to the base. The grid support is twisted for extra rigidity in the same way as the Marconi R.
The Maker identification on the glass is Royal Ediswan.
The valve was supplied in a cylindrical box of thick cardboard.
The backstamp.
Here the RAF stamp (arrow) is clearly seen.
The balloon envelope is mm in diameter, and excluding the B4 base pins, is mm tall.
References: 1003 Type R Type was first introduced in 1916. See also1916 adverts.
