The prototypes had used the Rolls-Royce Eagle piston engine, but Pythons were used in production aircraft.

By this point other engine designs were already entering pre-production, and it seemed there was little need for the ASX in its existing form.

Lincoln B.2 RF403 had two Pythons similarly installed and was used for high-altitude bombing trials at Woomera, South Australia.

These trials were principally of the ballistic casings for the Blue Danube atomic weapon: the Lincoln was the only available aircraft that could accommodate the large weapon casing, measuring 62 inches diameter x 24 feet (7.3 m) in length.

Maximum release height and speed for the first eleven tests was 275 mph and 34,783 ft (10,602 m) with a bombing error of 61 ft.[2] An Armstrong Siddeley Python is on display at the East Midlands Aeropark Castle Donington.