The Type 504 was produced in more variants than
any other Avro Type, and almost more than any other British aircraft. This page just summarises the production totals for each variant and production totals
for the various manufacturers. With so many ex-miliary machines being acquied by the civil market
post war, along with unused airframes bought back by Avro, it may be imposible to accurately determine
the number of original Type 504 airframes produced, but hopefully the figures given here come somewhat near the mark.
For full production details of each variant, follow the links below.
Strengthened version of Type 504 for the RNAS, with recessed
top longerons, lower wing root trailing edge cutouts, heavier wing spars and addition of a large fin. One 80 h.p. Gnome
or Le Rhône powerplant.
Higher powered version of Type 504B for the RNAS, with
repositioned rear cockpit and main fuel tank, and a reduction in wing stagger to compensate for relocated C.G. The top
longerons reverted to the straight type of the Type 504A. One 100 h.p. Gnome Monosoupape powerplant.
Two-seat training aircraft. As the 504J with a universal
mount to take different powerplants, most notably the 100 h.p. Gnome Monosoupape, 80 h.p. and 110 h.p. Le Rhône or
130 h.p. Clerget. Postwar aircraft reconditioning was undertaken to Specification 17/23 and the final production
batch was to Specification 15/26.
Two-seat training aircraft to meet Specifications 32/24
and 3/27 for an ab-initio trainer, based on the Type 504K with radial rather than rotar powerplant and featuring several
modifications: replacement of the skid plus elastic shock absorber undercarriage with a semi-oleo type, cutaway centre sections
and wing roots to improve visibilty, fuel tanks located under the upper wing, adjustable tailplane and additional stringers
to round out the fuselage sides. One 180 h.p. Armstrong Siddeley Lynx II, 200 h.p.Lynx III or 215 h.p. Lynx IVC powerplant. Early versions had a wooden fuselage but later production to Specification 6/30 featured a welded steel tube fuselage
and rectangular Frise-type ailerons replacing the tapered type.
of float equipped Type 504N. Equivalent to Type 504O.
Three-seat cabin seaplane, similar to the Type 504O but
featuring a new, wider, fuselage with open cockpit ahead of a glazed cabin, designed to support the Oxford University
Arctic Expedition. One 215 h.p. Armstrong Siddeley Lynx IVC powerplant.
Initially referred to as the Type 504J Mk.II, this was
a reworked and reduced weight variant of the Type 504J, featuring tapered ailerons and cutaway wing roots to improve visibilty.
100 h.p. Gnome Monosoupape, 140 h.p. Armstrong Siddeley Genet Major or 150 h.p. Armstrong Siddeley Mongoose powerplant.
See note 1.
Side-by-side seating version of the Type 504N.
504R with 100 h.p. Bristol Lucifer. This designation was also used by Japan for their float equiped Type 504Ks.
Foreign Derivatives of the Avro
Japan - Yokosuka Naval
Arsenal, Japan, aka Yokosho, from Yokosuka Kaigun Kōshō (横須賀海軍工廠)
aircraft for the Japanese Navy, similar to the Type 504N but with rounded wingtips and an all new undercarriage and tailplane.
Built by Yokosuka, Kawanishi, Watanabe, Mitsubishi, Nippi and Showa. Designated Type 3 Land-based Trainer Kai-1 (K2Y1) with
a 150 h.p. Mitsubishi-built Armstrong-Siddeley Mongoose powerplant and Type 3-2 Land-based Trainer (K2Y2) with a 160 h.p.
Gasuden Jimpu 2 powerplant.
Avrushka (Little Avro), also known as the Duks U-1 (Дукс У-1), the original Duks factories having
become a State Aircraft Plant in 1918. An unauthorised version of the Type 504K, developed by S.V. Ilyushin, and fitted with
a 120 h.p. M.2 powerplant. The VVS designation U-3 was originally assigned in 1925, but this was changed to U-1 in 1926.
the breakdown between 504A, J and K can no longer be precisely defined as aircraft build type changed on the production line
(see Type 504A/K page), the sum of the three variants built can be considered fairly accurate.
the availablity of a great number airframes that had gone directly to store or simply remained as spares, it is difficult
to determine with accuracy how many of the post war aircraft were entirely new build or which used existing/spare airframes.
Export Type 504Ns and 504Os were either supplied in mixed batches or as 504Ns with optional floats, hence
for this site this author will use the term Type 504N/O.