Tag Archives: Roy Chadwick C.B.E. F.R.S.A. F.R.Ae.S.

9 January 1941

BT308, the Avro Lancaster prototype, at RAF Ringway, 9 January 1941. (Avro Heritage Museum)
Captain Harry Albert (“Sam”) Brown, O.B.E. (Photograph courtesy of Neil Corbett, Test & Research Pilots, Flight Test Engineers)

9 January 1941: Test pilot Captain Harry Albert (“Sam”) Brown, O.B.E., (1896–1953) makes the first flight of the Avro Lancaster prototype, BT308, at RAF Ringway, Cheshire, England, south of Manchester.

Throughout World War II, 7,377 of these long range heavy bombers were produced for the Royal Air Force. The majority were powered by Rolls-Royce or Packard Merlin V-12 engines—the same engines that powered the Supermarine Spitfire and North American P-51 Mustang fighters.

The bomber was designed by Roy Chadwick, F.R.S.A., F.R.Ae.S., the Chief Designer and Engineer of A. V. Roe & Company Limited, based on the earlier twin-engine Avro Manchester Mk.I. Because of this, it was originally designated as the Manchester Mk.III, before being re-named Lancaster. Chadwick was appointed Commander of the Most Excellent Order of the British Empire, 2 June 1943, for his work.

The first prototype, BT308, was unarmed and had three small vertical fins.

Avro 683 Lancaster prototype BT308, shortly after the first flight at Manchester, 9 January 1941. (A.V.Roe via R.A.Scholefield) Photograph used with permission.
Avro 683 Lancaster prototype BT308, shortly after the first flight at RAF Ringway, Manchester, England, 9 January 1941. (A.V.Roe via R.A.Scholefield) Photograph is from The R.A. Scholefield Collection and is used with permission.

With the second prototype, DG595, the small center vertical fin was deleted and two larger fins were used at the outboard ends of a longer horizontal tailplane. DG595 was also equipped with power gun turrets at the nose, dorsal and ventral positions, and at the tail.

Avro Lancaster DG595, the second protoype of the Royal Air Force four-engine heavy bomber. This armed prototype has the twin-tail arrangement of the production aircraft. (Unattributed)
Avro Lancaster DG595, the second protoype of the Royal Air Force four-engine long range heavy bomber. This armed prototype has the twin-tail arrangement of the production aircraft. (Test & Research Pilots, Flight Test Engineers)
Air Ministry clearance form for Avro 638 Lancaster BT308. Shown on page 1 are the aircraft's engine type and serial numbers.
Air Ministry clearance form for Avro 683 Lancaster BT308. Shown on page 1 are the aircraft’s engine type and serial numbers.
Air Ministry test flight clearance form, Page 2.
Air Ministry test flight clearance form, Page 2. This form is signed by the airplane’s designer, Roy Chadwick, 5 January 1941.

The first production model, Lancaster Mk.I, was operated by a crew of seven: pilot, flight engineer, navigator/bombardier, radio operator and three gunners. It was a large, all-metal, mid-wing monoplane with retractable landing gear. It was 68 feet, 11 inches (21.001 meters) long with a wingspan of 102 feet, 0 inches (31.090) meters and an overall height of 19 feet, 6 inches (5.944 meters). The Mk.I had an empty weight of 36,900 pounds (16,738 kilograms) and its maximum takeoff weight was 68,000 pounds (30,909 kilograms).

BT308 and early production Lancasters were equipped with four liquid-cooled, supercharged, 1,648.96-cubic-inch-displacement (27.01 liter), Roll-Royce Merlin XX single overhead camshaft (SOHC) 60° V-12 engines, which were rated at 1,480 horsepower at 3,000 r.p.m. to 6,000 feet (1,829 meters). The Merlins drove three-bladed de Havilland Hydromatic quick-feathering, constant-speed airscrews (propellers), which had a diameter of 13 feet, 0 inches (3.962 meters), through a 0.420:1 gear reduction.

DG595 was used for performance testing at the Aeroplane and Armament Experimental Establishment (A&AEE) at Boscombe Down. The Mark I had a maximum economic cruise speed of 267 miles per hour (430 kilometers per hour) at 20,800 feet (6,340 meters), and a maximum speed of 286 miles per hour (460 kilometers per hour) at 20,000 feet (6,096 meters) at a gross weight of 45,300 pounds (20,548 kilograms).¹ Its service ceiling was 20,000 feet (6,096 meters) at 64,500 pounds (29,257 kilograms). It had a range of  2,530 miles (4,072 kilometers) with a 7,000 pound (3,175 kilogram) bomb load.

The Lancaster was designed to carry a 14,000 pound (6,350 kilogram) bomb load, but modified bombers carried the 22,000 pound (9,979 kilogram) Grand Slam bomb. For defense, the standard Lancaster had eight Browning .303-caliber Mark II machine guns in three power-operated turrets, with a total of 14,000 rounds of ammunition.

According to the Royal Air Force, “Almost half all Lancasters delivered during the war (3,345 of 7,373) were lost on operations with the loss of over 21,000 crew members.”

Only two airworthy Avro Lancasters are in existence.

The Royal Air Force Battle of Britain Memorial Flight Avro Lancaster Mk.I, PA474. This airplane was built in 1945 by Vickers Armstongs Ltd. at Broughton, Wales, United Kingdom. (Battle of Britain Memorial Flight)
The Canadian Warplane Heritage Museum’s Avro Lancaster Mk.X FM213, flies formation with an Royal Canadian Air Force CF-188 Hornet. The bomber is marked VR A and nicknamed “Vera.” FM213 was built by Victory Aircraft Ltd., Malton, Ontario, Canada. (Canadian Warplane Heritage Museum)

¹ Speeds shown are True Air Speed (T.A.S.)

© 2019, Bryan R. Swopes