An engine produced at Armstrong Siddeley Motors Ltd in Coventry. This type of engine powered the RWD-6 aircraft, on which the crew of Franciszek Zwirko and Stanislaw Wigura won the Challenge 1932 competition.
| Configuration | 7-cylinder radial |
| Cooling | air |
| Compression ratio | 5.0 |
| Displacement | 7.3 l |
| Weight | 165 kg |
| Maximum power | 180 hp at 2400 rpm |
| Nominal power | 260 hp |
