42 THE AVIATION HISTORIAN Issue No 21The 504 had been developed, built and tested
in some secrecy, to the extent that an article on
Aerial Derby entrants in British aviation weekly
Flight used an illustration of the company’s
earlier Type 500. Work on the 504 started in
the basement workshop at Brownsfield Mill
in Manchester’s Great Ancoats Street, but was
completed at the new Clifton Street works at
Miles Platting, a mile or so further out of the
city. The prototype was delivered to Brooklands
in Surrey on September 17, 1913, and made its
maiden flight the next day, arriving at Hendon
on the morning of September 20 to take part in
the Aerial Derby. Thus it was not until December
6 that year that Flight published a feature
praising the new type, as follows:
“With his new 80 h.p. biplane, Mr A.V. Roe
has proved that it is possible today to produce a
machine of the biplane type which is as fast as,
if not faster than, most monoplanes, and which,
moreover, has the advantage that it can be
landed at a speed which is very much below its
normal flying speed.
“In the front portion of the fuselage, and
enclosed by one of the neatest aluminium
shields we have seen, is the engine — an 80 h.p.
Gnome — which is carried in double bearings,
the front one of which is formed by four tubular
extensions of the longerons which converge until
they meet on a channel steel ring which carries
the front ballbearing. A small inspection door
on each side of the engine housing permits of a
general examination of the magneto, carburettor,
oil pump etc, whilst for close inspection the
whole engine housing can be removed by
undoing the butterfly fasteners by means of
which the cowl is attached to the fuselage.“The planes as well as the fuselage are covered
with a fabric, which has squares of stronger
threads woven into it, so that should the fabric
become pierced by a bullet or [other] cause, these
squares will prevent the fabric from tearing.
“The pilot’s and passenger’s seats are arranged
tandem fashion, the pilot occupying the rear
seat, from where he has an excellent view in
all directions, and, owing to the small width of
the fuselage — 2ft 6in [76cm] to be exact — he
is able to survey the country below without
the necessity of leaning out over the side. From
the passenger’s seat an equally excellent view
and the windshield enables him to make his
observations in comfort, protected as he is
against the flow of air.
“During the official tests at Farnborough
recently, we understand, the machine, with pilot,
passenger and four hours’ fuel, climbed 1,000ft
[300m] in 1·75min. Her maximum speed was 80
m.p.h. [128km/h] and her minimum speed 43
m.p.h. [69km/h], thus giving a speed range of
nearly 50 per cent. The weight of the machine
with fuel for three hours and a passenger is
1,550lb [703kg], giving a loading of about
4·5lb/ft² [22kg/m²].”Make-or-break for Avro
It should be noted, however, that Flight was
reporting on the developed prototype which, by
the time it arrived at the Royal Aircraft Factory
for testing, had been fitted with revised ailerons
and a new more streamlined engine cowling.The
504 was described at the time as a larger
development of the successful Avro Type E
which had gone into production as the Type 500
and been sold to the War Office and Admiralty.ABOVE The Avro 504 prototype in its original configuration (in which it raced in October 1913) with a square
cowling bulged to accommodate the 80 h.p. Gnome rotary engine. By the time the aircraft was the subject of a
technical assessment in Flight that December, as seen OPPOSITE, a more streamlined cowling had been fitted.PHILIP JARRETT COLLECTION