A very successful Army cooperation aircraft developed from the Hawker Hart.
Hawker Audax RAF K2012 An air to air photograph of RAF Hawker Audax I K2012

The 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 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 Cooperation 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 Hart but featured longer exhausts and a message pick-up hook, attached to the undercarriage spreader bar that could be lowered as required.


Hawker Audax K3055 A standard production Hawker Audax K3055, showing extended exhaust and message hook.


Gun armament remained unchanged from that fitted to the 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 Audax was powered initially by the Rolls-Royce F.X1 water-cooled engine which later became better known as the Kestrel IB. Later, Kestrel VIS and Kestrel X were also fitted. Some tropicalised variants included in the range were the Audax (India) and the Audax (Singapore), the latter being fitted with the Kestrel V engine.


The Audax entered RAF service with 4 Sqn at Farnborough in 1932.


Production comprised a total of 265 aircraft by Hawker (including prototypes and export aircraft), 25 by Gloster, 141 by Bristol, 287 by Avro and 43 by Westland for a total of 761 aircraft. With a further 24 Avro 674 for Egypt, the grand total comes to 785 aircraft.


Hawker Audax (Persian) with Pratt & Whitney Hornet engine A Persian Hawker Audax with Pratt & Whitney Hornet S2B engine.


The Audax was exported to Canada (one aircraft for trials and five ex-RAF aircraft supplied after 1939 as instructional airframes); Egypt (24 aircraft built by Avro as the Avro 674 with Panther VIA or Panther X engines); Persia (30 aircraft with P&W Hornet S2B, 26 aircraft with Pegasus II or IIM2); Iraq (34 aircraft with Pegasus IIM2 or Pegasus VIP8).


About 400 RAF aircraft remained in service at the start of the Second World War, seeing operational service in East Africa along the Kenya – Abyssinia border and also from RAF Habbaniyah during the Iraqi uprising of May 1941. Ex-RAF aircraft were supplied after 1939 to India, South Africa and Southern Rhodesia.


In the UK, the 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. 


  Audax I
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


No Hawker Audax aircraft survive.

Other information