The HG Hawker Audax was a tropicalised variant of the Hawker Hart, a two-seat light bomber which was an early design attributed to Sydney Camm.
The Hawker Hart represented a significant step forward in performance compared with aircraft types that were serving with the Royal Air Force in the inter-war years. It was immediately apparent that the type had considerable potential for adaptation for a number of other roles, including that of Army co-operation duties. As a result, Specification 7/31 was issued seeking an aircraft to replace the Armstrong Whitworth Atlas.
A Hawker Hart (K1438) underwent evaluation for this role, leading to a decision to order the type into RAF service as the Audax I. The first production Audax (K1995) was first flown on 29th December 1931.
The type was very similar in appearance to the Hawker Hart but featured longer exhausts and a message pick-up hook, attached to the undercarriage spreader bar that could be lowered as required. Gun armament remained unchanged from that fitted to the Hawker Hart (a fixed forward-firing Vickers gun on the port side and a defensive Lewis gun fired from the rear cockpit). Four practice bombs or two 112 lb supply containers could also be carried on underwing racks.
The Hawker Audax was powered initially by the Rolls-Royce F.X1 water-cooled engine which later became better known as the Rolls-Royce Kestrel IB. Later, Rolls-Royce Kestrel VIS and Kestrel X were also fitted. Some tropicalised variants included in the range were the Hawker Audax (India) and the Hawker Audax (Singapore), the latter being fitted with the Kestrel V engine.
The Hawker Audax entered RAF service with 4 Sqn at Farnborough in 1932. The Hawker Audax was also exported to Canada (one aircraft for trials and five ex-RAF aircraft supplied after 1939, as instructional airframes). Additionally, exports also went to Egypt (24 aircraft built by Avro as the Avro 674), Persia (30 aircraft with P & W Hornet S2B plus 26 aircraft with Pegasus II or IIM2) and Iraq (34 aircraft with Pegasus IIM2 or Pegasus VIP8). After 1939, ex-RAF aircraft were also supplied to India, South Africa and Southern Rhodesia (now Zimbabwe).
About 400 Audax’s remained in service with the RAF at the start of the Second World War, many utilised in flying operational sorties in East Africa, along the Kenya-Abyssinia border, as well as from RAF Habbaniyah during military operations in Iraq in May 1941. In the UK, the Hawker Audax was mainly relegated to glider towing, training and ‘hack’ duties during the war, and was eventually retired from service in 1945.
Production comprised a total of 265 aircraft by H.G. Hawker (including prototypes and export aircraft), 25 by Gloster Aircraft Company, 141 by Bristol Aeroplane Company, 287 by AV Roe (Avro) and 43 by Westland making a total of 761 aircraft. A further 24 were built as the Avro 674 with the 750 hp Armstrong Siddeley Panther VIA or Panther X for Egypt, making the grand total of 785 aircraft in all.