The Hawker Demon was a two-seat fighter biplane developed in the early 1930s as a direct response to the Royal Air Force’s need for a fast, capable interceptor.
It was derived from the highly successful Hawker Hart light bomber and designed by Sydney Camm to meet Specification 15/30.
The Demon served as an interim fighter during a transitional period in British aviation, bridging the gap between slower interwar biplanes and the high-performance monoplanes that would dominate World War II.
Development Origins
During RAF air defence exercises in 1930, it became clear that the new Hawker Hart bombers were faster than existing fighters like the Armstrong Whitworth Siskin and Bristol Bulldog.
In some cases, Hart crews were ordered to restrict their speed and altitude to allow interception.
This tactical imbalance prompted the Air Ministry to commission a fighter variant of the Hart.
The first prototype, converted from Hart serial J9933, was fitted with a supercharged Rolls-Royce Kestrel IIS engine and armed with two forward-firing Vickers machine guns and a rear Lewis gun.
These early conversions were known as “Hart Fighters” and were evaluated by No. 23 Squadron RAF in 1931.
The trials were successful, leading to full-scale production under the name Hawker Demon.
Design Features
Airframe
Based on the Hart’s structure, with modifications for fighter roles
Crew
Two (pilot and rear gunner/observer)
Powerplant
Early models
Rolls-Royce Kestrel IIS (485 hp)
Later models
Kestrel V (560 hp) or Kestrel VI (640 hp)
Armament
Two fixed. 303 in (7.7 mm) Vickers machine guns in the nose
One .303 in Lewis gun in the rear cockpit
Provision for light bombs under the wings
Turret Variant
Some Demons were fitted with a Frazer-Nash hydraulic turret and windshield fairing to protect the rear gunner—these were informally known as “Turret Demons”
Production and Variants
A total of 305 Hawker Demons were built:
RAF Demons
233 aircraft, including turret-equipped versions
RAAF Demons
64 aircraft, including
Australian Demon I
General-purpose and army co-operation variant with 600 hp Kestrel V engine
Australian Demon II
Training version with dual controls and target towing gear (10 built)
Production was shared between Hawker Aircraft and Boulton Paul Aircraft, with the latter completing 106 units at their Wolverhampton facility.
The first production Demon flew on 10 February 1933.
Operational Service
RAF Use
Deployed across multiple squadrons, including Nos. 23, 41, 64, and 74.
Used in Malta, Egypt, Sudan, Palestine, and North Africa.
Participated in the Abyssinian crisis of 1935.
RAAF Use
Operated by Nos. 1 and 3 Squadrons for general-purpose, army co-operation, and training roles.
Delivered between 1935 and 1936.
Second-Line Duties
By 1938, the Demon was largely retired from frontline service and reassigned to bombing and gunnery schools.
It remained in limited use during the early years of World War II, primarily for target towing and training.
Legacy
The Hawker Demon was never intended to be a long-term solution, but it filled a critical gap in RAF and RAAF capabilities during a period of rapid technological change.
Its development marked an important step in British fighter evolution, and its service helped refine tactics for multi-crew aircraft operations.
Though overshadowed by later designs like the Hurricane and Spitfire, the Demon remains a symbol of interwar ingenuity and adaptation.
