During World War I, the car makers Siddeley-Deasy had been one of several manufacturers of the Royal Aircraft Factory R.E.8.
Though this aircraft was produced in large numbers, it was rumoured that the upper wing could fail in dives and that its spinning characteristics were dangerous.
There were only small changes to the R.E.8 fuselage: the decking aft of the gunner, together with his gun-ring were raised, and the fin and rudder were larger and more rounded.
[1] Direct comparisons of the RAF 4A powered R.T.1 and the R.E.8 showed the former had much the same top speed but better climb and ceiling because of its lower wing loading.
[1] The R.T.1 flew well and one went for service trials on the Front, the other two going to training units, but with the war at its end there was no chance of further orders.