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 the 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 in 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.
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.
With a further 24 built as the Avro 674 with the 750 hp Armstrong Siddeley Panther VIA or Panther X for Egypt, the grand total comes to 785 aircraft.
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).
About 400 RAF aircraft remained in service at the start of the Second World War, flying operational sorties in East Africa, along the Kenya-Abyssinia border as well as from RAF Habbaniyah, during the Iraqi uprising of May 1941. After 1939, ex-RAF aircraft were also supplied to India, South Africa and Southern Rhodesia.
In the UK, the Hawker Audax was mainly relegated to glider towing, training and ‘hack’ duties until around 1944.
Variants & Numbers
|Audax I||Standard production army cooperation aircraft for RAF|
|Audax (India)||Tropicalised version for RAF use in India. 25 built by Gloster, 25 by Avro.|
|Audax (Singapore)||Tropicalised. Powered by Kestrel V for use in Singapore and Malaya.|
|Canadian Audax||One aircraft only for trials|
|Egyptian Audax||Avro 674 with 750 hp AS Panther VIA or Panther X. Total of 24 aircraft.|
|Iraqi Audax||Known locally as Nisr. 24 with Bristol Pegasus !!M2 and 10 with Pegasus VIP8, total 34 aircraft.|
|Persian Audax||30 aircraft with P&W Hornet S2B and 26 with Bristol Pegasus II or IIM2; total 56 aircraft.|
|Total production 785 aircraft.||761 Audax: Hawker 265, Gloster 25, Bristol 141, Avro 287 and Westland 43. Plus Avro 674 24 aircraft.|
|Powerplants||One 530 hp Rolls-Royce Kestrel IB or 580 hp Kestrel X|
|Span||37 ft 3 in|
|Maximum Weight||4,386 lb|
|Capacity and armament||Two crew. One fixed 0.303 Vickers Machine gun and one defensive Lewis gun mounted in rear cockpit. Carriage of practice bombs of two 112lb supply containers on under-wing racks.|
|Maximum Speed||170 mph at 2,400 ft|
|Endurance||3 hours 30 minutes|