Avro 504

the most widely used British trainer of World War One

an airplane featured on the Hall of Fame of the Air

Roe began building planes in 1906, he became the first Englishman to fly, at Brooklands in July 1908.

After considerable experimentation with biplanes and triplanes, Roe produced the E500 biplane in 1912 that met with War Department approval; 12 were ordered within a year. The Avro 504 developed directly from the E500 machine. It moved rapidly into production, first flying in July, 1913. A graceful, two-seater biplane, it's equal-span wings balanced the fuselage, whose box-girder body blended into to the circular housing for the 80 HP Gnome rotary engine. The 504 took fourth place in the Second Aerial Derby on September 20, flying at 66.5 MPH.

As war loomed in 1914, the War Department ordered twelve Avro 504s and even more after hostilities started. A 504 achieved the unenviable distinction of being the first English aircraft shot down in combat, when Lt. V. Waterfall of No. 5 Squadron, flying an Avro 504 over Belgium went down under infantry fire.

The Friedrichshafen Raid

Avro 504 biplanes participated in a more successful event on Nov. 21, 1914 when Sqn. Cdr. E.F. Briggs, Flt Lt. S.V. Sippe, and Flt. Cdr J.T. Babbington led some RNAS machines on a bombing raid on the Zeppelin sheds at Lake Constance.  At 09:30 AM, three brand-new, untested Manchester-built machines, flown by Briggs (in a/c number 874), Babington (873) and Sippé (875), took off from Belfort, France.  Avro 504 piloted by Flt Sub-Lt R P Cannon broke its tailskid and was forced to abort. Flying around neutral Switzerland, the three machines flew over Lake Constance to Friedrichshafen, a distance of 125 miles, and caught the Germans completely unawares, dropping 20-lb pounds. I imagine the "guy in back" tossing them over the side like deadly grapefruits. It was a sensational raid, although the Germans were secretive about the damage they suffered. Briggs was shot down when flying low over the sheds; he was taken prisoner and managed to escape two year later. His companions completed the round trip in about four hours. All three pilots were awarded the Distinguished Service Order, Gazetted on 1 January 1915.

Like the story of any aircraft, the story of the Avro 504 is the story of its development through many letter-denoted variants: 504A through 504R. (The plain "504" signified the 1914 protoype and first production version.)  The 504K was the main production version, with thousands built.

Avro 504A

Like the 504, retaining the 80-hp Gnome, but with shorter ailerons for better downward visibility. Several hundred were produced. Records are incomplete, but the total number of 504As and 504Js totalled 1,455. The 504A was the main production version of 1915-16.

Avro 504B

A naval version produced for the Admiralty, 240 built. Also used the 80-hp Gnome, but reverted to the larger ailerons. The 504B introduced the tailskid, a large piece of ash wood, sprung with a rubber cord, and hinged to a pylon underneath the tail. All later 504s retained this tailskid.

Avro 504C

A single-seat version, also produced for the RNAS, eighty of these were built. A big fuel tank in place of the front seat permitted a increase (over 2X)  in endurance to 8 and 1/2 hours. The upper wing was notched to permit an upward-firing Lewis gun. (The 504D designated a similar model for the RFC.)

Avro 504E

Another naval model, the 504E mounted the more powerful 100-hp Gnome Monosoupape engine. With this extra power, the Navy could squeeze in the extra fuel tank between the two seats. (The 504F, 504G, and 504H were not produced in large numbers.)

Avro 504J

This was the first of the large-scale production versions (along with the 504K). Several hundred were built. The 504J externally resembled the 504A; the difference lay under the hood, where a 100-hp Gnome drove the Avro. Another significant innovation of the 504J was the Gosport speaking tube, which enabled the flying instructor to communicate (shout) to the student.  "No, no, no, you ninny. I said pull up on the stick."

Avro 504K

The definitive version of the Avro 504, with 6,350 produced. The key feature of the 504K was its universal engine mount, designed by H. E. Broadsmith, permitting a wide variety of rotary engines to be installed:

• 90-hp RAF 1A and Thulin
• 100-hp Gnome Monosoupape, Curtiss K6, and Sunbeam
• 110-hp Le Rhone
• 130-hp Clerget
• 150-hp Bentley BR1
• 170-hp ABC Wasp
• 220-hp Hispano-Suiza

At the peak of wartime production, Avro planned on building 100 per week, as well as 20 sets of parts for assembly in Egypt. 52 were sold to the American Expeditionary Forces as trainers.

The advantages that the 504 had over previous trainers were numerous. It carried a rotary engine, vital to familiarize flying students. The 504K, introduced in 1917, sported a new type of universal engine mount which consisted of two bearer plates that could accommodate any sort of engine. Another advantage was the ease with which students and instructors could communicate in the cockpit, thanks to the "Gosport Speaking Tube". It was more robust than the delicate Farman trainer, and more manoueverable than the heavy BE2c.  The 504's relatively light weight in comparison to its wing size prevented the plane from dropping dramatically when power was reduced, and the "forgiving" quality of its controls were ideal for training. So too was the skid that could be outfitted under the nose, designed to prevent tipping during landing.

Specifications of the Avro 504K:

• Engine: 110hp Le Rhone rotary engine
• Absolute Ceiling: 16,000 feet
• Wingspan: 36 feet
• Length: 29 ft 5 in
• Height: 10 ft 5 in
• Wing area: 330 sq ft
• Weight: 1,230 lb. empty; 1,829 lb. maximum take-off

Avro 504N

Production of the Avro 504 was spread out among many different firms:

• A. V. Roe and Co Ltd, Park Works, Newton Heath, Manchester; and at Hamble Aerodrome, near Southampton, Hants.
• Australian Aircraft and Engineering Co Ltd, Sydney, NSW, Australia
• Brush Electrical Engineering Co Ltd, Loughborough
• Canadian Aeroplanes Ltd, Toronto, Canada
• Eastbourne Aviation Co Ltd, Eastbourne
• Grahame-White Aviation Co Ltd, Hendon Aerodrome, London
• Harland and Wolff Ltd, Belfast
• The Henderson Scottish Aviation Factory, Aberdeen
• Hewlett and Blondeau Ltd, Oak Road, Leagrave, Luton, Beds.
• Humber Motor Co Ltd, Coventry Morgan and Co, Leighton Buzzard, Beds.
• Nakalima Hikoki Seisaku Sho, Ohta-Machi, Tokyo, Japan
• Parnall and Sons, Mivart Street, Eastville, Bristol
• Frederick Sage and Co Ltd, Peterborough and London
• S. E. Saunders Ltd, East Cowes, Isle of Wight Savages Ltd, King's Lynn,
• Societe Anonyme Belge de Constructions Aeronautiques Haren, Brussels, Belgium
• Sunbeam Motor Car Co Ltd, Wolverhampton
• Yokosuka Naval Arsenal, Japan

Postwar Service

Sources:

• Avro504.org
  
• The Aerodrome
• Canadian Aviation Museum
  
• Pilots and Planes of the First Air War

British and Empire Aces of World War I, by Christopher Shores No. 45 of the Osprey Aircraft of the Aces series. Thirty-six colorful profile plates of many types of aircraft, including Airco D.H.2, Bristol Scout, Spad S.VII, Sopwith Pup, S.E.5a, Nieuport 17, Sopwith Triplane, Bristol F.2B, Airco D.H.5, Nieuport 23, Nieuport 27, Sopwith Camel, Sopwith Dolphin, and Sopwith Snipe. Many original period photos, including a unique one of King George V inspecting RAF pilots (Ira 'Taffy' Jones among them) in August, 1918. After a chronological summary of British aerial combat in World War One, the book offers short biographies of over 50 Empire pilots: from England, Scotland, Wales, Ireland, Canada, South Africa, New Zealand, and Australia. Buy 'British and Empire Aces of World War I' at Amazon.com