The Aviation Historian — Issue 21 (October 2017)

44 THE AVIATION HISTORIAN Issue No 21

Powered by a 50 h.p. Gnome rotary engine, the

500 was really too small and underpowered for

military use and was used mostly as a trainer.

However, problems in securing a more powerful

engine and A.V. Roe’s diversion in producing the

innovative, but ultimately unsuccessful, Types F

and G enclosed-cockpit monoplane and biplane,

caused Avro to miss the opportunity offered by

the 1912 Military Trials to identify designs

suitable for the newly formed Royal Flying

Corps. So it was not until November that year

that work started on what would become the

504, and April 1913 before the basic layout and

some details of it had been sketched out in an

exercise book by A.V. Roe. Although plainly

influenced by the 500, including the retention of

a narrow-track undercarriage, the 504 differed in

having wings with forward stagger and was

powered by a new 80 h.p. Gnome rotary engine.

Although the earlier Avro designs had been

worked on by volunteers and students in

exchange for flying lessons, the commercial

success of the 500 had allowed Humphrey

Verdon Roe to expand the company. Reg Parrott

became Works Manager in Manchester and Roy

Chadwick took over responsibility for design

work. Chadwick and his assistant, C.R. Taylor,

worked on the fuselage and undercarriage,

while Harry Broadsmith, a former locomotive

and marine engineering apprentice, was given

responsibility for developing the wing design.

Broadsmith had been taken on as a draughtsman

the year before, and now found himself Chief

Draughtsman. Frank Vernon was recruited

from the Locomotive Department of the Great

Central Railway to work on stress calculations as

Broadsmith’s assistant.

The Blackburn Type I

Against this exciting new Avro machine, Robert

Blackburn decided to race a new Type I two-seat

monoplane design. Of similar size to the Avro —

38ft (11·6m) span compared with the 504’s 36ft

(10·9m), and 28ft 6in (8·7m) long compared with

29ft 5in (8·9m) — the Type I was also powered

by one of the new 80 h.p. Gnome engines.

Flight published a description of the Type I in

its December 27, 1913, issue:

“Constructionally, this new machine differs

considerably from the older type, and is a

distinct advance on anything hitherto turned

out by the Blackburn firm. The fuselage is

streamline in shape and triangular in section,

and is built up in the form of a lattice girder.

The front part is of English ash, and is covered

with sheet aluminium, giving it additional

strength and reducing the head resistance. The

engine is covered over for about five-eighths of

its circumference by a beaten-aluminium cowl,

which is continued to form a scuttle dash [the

bodywork between the windscreen and the cowling].

This effectively prevents the exhaust from the

engine reaching either pilot or passenger.

“The mainplanes are rectangular in form,

ABOVE Three examples of the Blackburn Type I were built: the “War of the Roses” two-seater owned by Dr M.G.

Christie (the subject of the Flight report in December 1913, as seen OPPOSITE); a single-seater with a single

kingpost, and the Improved Type I, as seen here in 1914, fitted with a single kingpost and a smaller tailplane.

PHILIP JARRETT COLLECTION