The Avro504 was built in a number of variants and it should be noted that this web page concentrates on Avro504 to Avro504H - Other variants are dealt with on alternative web pages on this website.
Ultimately manufactured by at least 18 sub-contractors, the total number built during the First World War remains unclear, although there is general agreement that it was more than 8,000. Furthermore, if the total were to include aircraft built overseas then it exceeds 10,000. It should be noted that the numbers quoted in this entry follow those presented at www.britishaviation-ptp.com/avro504.html which we believe to be the most comprehensive list available.
The Avro 504 was a lightly-built, conventional tractor biplane with staggered, two bay wings. As originally flown on 18th September 1913, the prototype featured inverse-tapered ailerons, which relied on warping of their tips to provide roll control.
The distinctive undercarriage comprised a pair of undercarriage legs incorporating bungee-sprung suspension, with an extended central curved ash skid. The nominally 80hp Gnome Monosoupape 7-cylinder engine was mounted in a square cowling with bulged sides.
Early changes to the design involved the adoption of a more streamlined cowling and conventional ailerons.
Among a number of notable flights, the prototype climbed over Brooklands to a height of 15,000 ft on 4th February 1914. This was followed by an officially observed climb, with a passenger, to 14,420 ft on 10th February.
The Avro 504
The Avro 504 was ordered into production in mid-1913 and a total of 67 production Avro 504s were built for the RFC and RNAS.
Perhaps the most notable Avro 504 operational sortie was made by the RNAS with a successful long-range flight to bomb the Zeppelin Airship Sheds at Friederichshafen on 21st November 1914.
The Avro 504A
The Avro 504A was a revised model for the Royal Flying Corps. with wider chord wing struts and ailerons of a reduced span. 1,485 Avro 504As were built.
The Avro 504B
Built for the Royal Naval Air Service, the Avro 504B featured more significant modifications such as a larger dorsal fin ahead of an unbalanced rudder.
Less obvious externally however, was the use of larger cross-section wing spars. Additional changes included on some aircraft with curved cut-outs to the rear cockpit sides, to improve crew access whilst it also reverted to longer span ailerons.
A total of 200 Avro 504B were built.
Avro 504C and Avro 504D
The threat of night-bombing by Zeppelin airships led to the development of the next two Avro 504 versions. These were the single seat, long endurance, coastal patrol Avro 504C for the RNAS and the Avro 504D, built specifically for the Royal Flying Corps (RFC).
The Avro 504C offered eight hours endurance and was intended to intercept airships before they made landfall. An upward firing machine gun was fitted, using incendiary ammunition.
The 504D was designed for Zeppelin interception by the RFC and it retained the original ‘comma-shaped’ rudder unlike the Royal Naval Air Service (RNAS) aircraft, with their fixed fin and unbalanced rudder.
80 Avro 504Cs and just six Avro 504Ds were built.
Avro 504E and Avro 504F
The last of the early models were, in effect, experimental versions and comprised of 10 Royal Naval Air Service (RNAS) Avro 504E's, fitted with a 100 hp Gnome Monosoupape engine and reduced wing stagger.
A single Avro 504F was built, converted from an Avro 504C and featured a 75 hp Rolls-Royce Hawk in-line engine.
Avro504G and Avro 504H
The 30 RNAS Avro 504Gs were conversions of the Avro 504B, fitted with bomb racks, twin synchronised forward-firing Vickers guns and a Scarff-mounted Lewis gun in the rear cockpit.
Finally, 12 Avro 504Hs were strengthened and converted versions of the Avro 504C, used for catapult trials.
|Powerplant||One 80hp Gnome||One 80hp Gnome, 80hp Le Rhone, or 80hp Clerget rotary engine|
|Span||36 ft 0 in|
|Maximum Weight||1,550 lb||1,700 lb|
|Capacity and armament||Two seats, unarmed||Two seat, four 20lb bombs. Anti-Zeppelin aircraft (504C, D) fitted with one Lewis gun and increased fuel capacity|
|Maximum Speed||81 mph||86 mph|
|Range||3 hours||4.5 hr (504C, D 8 hr)|
Variants & Numbers Built
|Avro 504 prototype||One only|
|Avro 504||Original model. 80hp Gnome, Le Rhône or Clerget engines. 67 built|
|Avro 504A||Modified with smaller ailerons and broader struts. 80hp Gnome, Le Rhône or Clerget engines. 1,485 built|
|Avro 504B||Version for RNAS with stronger wing spars and a larger fin. 80hp Gnome or Le Rhône engines. 200 built|
|Avro 504C||Single-seat anti-Zeppelin aircraft for the RNAS. The 504C was fitted with an extra fuel tank, in place of the observer.80hp Gnome engine. 80 built|
|Avro 504D||Single-seat anti-Zeppelin aircraft for the Royal Flying Corps. 80hp Gnome engine. 6 built|
|Avro 504E||100hp Gnome Monosoupape engine. 10 built|
|Avro 504F||One aircraft fitted with the 75hp Rolls Royce Hawk engine. An order for 30 was cancelled and replaced by 504Bs. One aircraft (converted Avro 504C)|
|Avro 504G||Two-seat training variant of the 504B for the RNAS. 80hp Gnome engine. 30 built|
|Avro 504H||Used for catapult trials. 80hp Gnome engine. 12 (converted Avro 504C)|
No examples of early Avro 504 (prototype to Avro 504H) survive.