RT.1 B6625 with a Hispano-Suiza. This was the first aircraft to carry the S-D name.

RT.I B6626 with an RAF 4A for comparative trials.

B6627 showing the more streamlined and revised Hispano-Suiza installation in the second RT.1.

Mystery photograph! RT.I B6630 with the serial marked in a style not normally seen on S-D aircraft. It carries the legend ‘No.6’ on the fin. Five RE.8s were allocated for modification to RT.I standard. All records denote that only three were so modified. Even if there were five, how does B6630 merit No.6?

An RT.I, believed to be B6627, having come to grief on the Isle of Grain, May 9, 1918.