Tag Archives: Avro Lancaster

16–17 May 1943

Wing Commander Guy Penrose Gibson, VC, DSO and Bar, DFC and Bar. (Imperial War Museum)
Wing Commander Guy Penrose Gibson, V.C., D.S.O. and Bar, D.F.C. and Bar. © IWM (CH 11047)

16–17 May 1943: Nineteen modified Avro Lancaster B.III Special long-range heavy bombers of No. 617 Squadron, Royal Air Force, carried out Operation Chastise, a low-level night attack against four hydroelectric dams in the Ruhr Valley.

The purpose of the attack was to disrupt German steel production. It was estimated that 8 tons of water were required to produce 1 ton of steel. Breaching the dams would reduce the available water and hydroelectric power, disrupt transportation of materials on the rivers, and flood iron ore and coal mines and power plants. If the dams were destroyed, it was believed that the effects would be the same as attacks against 26 categories of industrial targets further down the Ruhr Valley.

Led by 24-year-old Wing Commander Guy Penrose Gibson, D.S.O. and Bar, D.F.C. and Bar, a veteran of 172 combat missions, the aircrews of No. 617 Squadron dropped a spinning cylindrical bomb, code-named “Upkeep”, from a height of just 60 feet (18.3 meters) over the reservoirs behind the dams, while flying at precisely 240 miles per hour (386.2 kilometers per hour).

The 9,250-pound (4,195.8 kilogram) Vickers Type 464 bomb was designed to skip along the surface and to strike the dam, and then sink to the bottom. There, a pressure detonator exploded the 6,600 pound (2,994 kilogram) Torpex charge directly against the wall with the water pressure directing the energy through the wall.

Guy Gibson's Avro Lancaster B.III Special, ED932/G, AJ-G, "bombed up" with an Upkeep bomb. © IWM (HU 69915)
Guy Gibson’s Avro Lancaster B.III Special, ED932/G, AJ-G, “bombed up” with a Vickers Type 464 bomb. © IWM (HU 69915)

Nineteen Lancasters took off from RAF Scampton beginning at 9:28 p.m. on the 16th, and flew across the North Sea at only 100 feet (30.5 meters) to avoid being detected by enemy radar. The bombers succeeded in destroying the Möhne and Eder dams and damaging the Sorpe. A fourth dam was attacked but not damaged. The last surviving bomber returned to base at 6:15 a.m. on the 17th.

Of the nineteen Lancasters launched, two were damaged and turned back before reaching the targets. Six were shot down and two more collided with power lines during the low-level night flight. Of 133 airmen participating in the attack, 53 were killed.

GIBSON, Guy, with PO Frederick M. Spafford, FL Robert E.G. Hutchinson, PO Andrew Deering and FO Torger H. Taerum
Wing Commander Guy Penrose Gibson, V.C., D.S.O. and Bar, D.F.C. and Bar, Commander No. 617 Squadron, with the crew of “G George”: Pilot Officer Frederick Mchael Spafford, D.F.C., bomb aimer; Flight Lieutenant Robert Edward George Hutchinson, D.F.C. and Bar, wireless operator; Pilot Officer Andrew Deering, D.F.C., gunner; Flying Officer Torger Harlo Taerum, D.F.C., navigator. Flight engineer Sergeant John Pulford and tail gunner Flight Lieutenant Richard A.D. Trevor-Roper are not present.  © IWM (TR 1127) 

Guy Gibson was awarded the Victoria Cross by King George VI. An additional 33 survivors were also decorated. 617 Squadron became known as “The Dambusters.” A book, The Dam Busters, was written about the raid by Paul Brickhill, who also wrote The Great Escape. A 1955 movie starred Richard Todd, O.B.E., as Wing Commander Gibson. There have been reports that a new movie is planned.

An Avro Lancaster B.III Special drops an "Upkeep" bomb during tests, April 1943. (Imperial War Museum)
An Avro Lancaster B.III Special drops an “Upkeep” bomb during tests at Reculver, April 1943. Imperial War Museum, still from film, IWM (FLM 2340)
After being dropped from an Avro Lancaster, the “special mine” bounces across the water. (Imperial War Museum)
Post-strike reconnaissance photograph shows the breach of the Mohne Dam in the Ruhr Valley, 16 May 1943. (Imperial War Museum)
Post-strike reconnaissance photograph shows the breach of the Möhne Dam in the Ruhr Valley, 17 May 1943. The gap is 250 feet (76 meters) wide and 292 feet (22 meters) deep. © IWM (CH 9687)

The Avro Lancaster B.III Special was a four-engine long range heavy bomber modified to carry the Type 464 bomb. It was operated by a crew of seven: Pilot, flight engineer, navigator, radio operator, bomb aimer, nose gunner and tail gunner. The “Lanc” was 69 feet, 6 inches (21.184 meters) long with a wingspan of 102 feet (31.090 meters) and overall height of 20 feet (6.096 meters). The modified bomber had an empty weight of 35,240 pounds (15,984.6 kilograms and a maximum takeoff weight (MTOW) of 60,000 pounds (27,215.5 kilograms).

The Lancaster B.III Special was powered by the Packard Motor Car Company’s license-built version of the Rolls-Royce Merlin 24, the Packard V-1650-1 Merlin 224. These were liquid-cooled, supercharged, 1,648.96-cubic-inch-displacement (27.022-liter) single overhead cam (SOHC) 60° V-12 engines with four valves per cylinder and a compression ratio of 6.0:1. The Merlin 224 used a two-speed, single-stage supercharger. 100/130-octane aviation gasoline was required. The engine had a Normal Power rating of 1,080 horsepower at 2,650 r.p.m. and 9,500 feet (2,896 meters); Military Power, 1,240 horsepower at 3,000 r.p.m. at 11,000 feet (3,353 meters); and 1,300 horsepower at 3,000 horsepower with 54.3 inches of manifold pressure (1.84 Bar) for Takeoff. The Merlins drove three-bladed de Havilland Hydromatic quick-feathering, constant-speed propellers which had a diameter of 13 feet (3.962 meters). The propeller gear reduction ratio was 0.477:1. The V-1650-1 was 6 feet, 7.7 inches (2.024 meters) long, 2 feet, 6.0 inches (0.762 meters) wide and 3 feet, 6.6 inches (1.082 meters) high. It weighed 1,512 pounds (685.8 kilograms).

These engines gave the Lancaster a cruising speed of 200 miles per hour (321.9 kilometers per hour) and maximum speed of 272 miles per hour (437.7 kilometers per hour). The service ceiling was 24,700 feet (7,528.6 meters) and maximum range was 2,530 miles (4,071.6 kilometers).

Defensive armament for a standard Lancaster consisted of eight air-cooled Browning .303-caliber Mark II machine guns in three power turrets, nose, dorsal and tail. The Lancasters assigned to Operation Chastise had the dorsal turret deleted to reduce weight and aerodynamic drag. The gunner normally operating that turret was moved to the front turret, relieving the bomb aimer to deal with the operation of the specialized mission equipment.

7,377 Avro Lancasters were built. Only two remain in airworthy condition.

The first two modified Avro Lancaster B.III Specials assigned to No. 617 Squadron, RAF Scampton, April 1943. (Royal Air force)
The first two modified Avro Lancaster B.III Specials assigned to No. 617 Squadron, RAF Scampton, April 1943. In the foreground is ED825/G, AJ T. (Royal Air Force)
One of the two flyable Lancasters remaining, “City of London,” the Battle of Britain Memorial Flight Vickers-Armstrongs Ltd.-built Lancaster B.I, PA474. The airplane is marked as “Mickey the Moocher,” EE176, QR M. (Crown Copyright)
Victory Aircraft Ltd.-built Avro Lancaster B Mk.X FM213, marked as KB726, VR A.

Highly Recommended: The Dam Busters, by Paul Brickhill. Evans Brothers, London, 1951

© 2018, Bryan R. Swopes

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29 April 1945

Royal Air Force Avro Lancaster Princess Patricia of No. 514 Squadron at RAF Waterbeach, Cambridgeshire, UK, being loaded with food for Operation Manna, 29 April 1945, (Pilot Officer Penfold, Royal Air Force official photographer)
Royal Air Force Avro Lancaster “Princess Patricia” of No. 514 Squadron at RAF Waterbeach, Cambridgeshire, England, being loaded with food for Operation Manna, 29 April 1945. (Pilot Officer Penfold, Royal Air Force Official Photographer/Imperial War Museum)
A Royal Air Force Avro Lancaster heavy bomber drops food packages over The Netherlands.
A Royal Air Force Avro Lancaster heavy bomber drops food packages over The Netherlands.

29 April 1945: With the defeat of Nazi Germany imminent, millions of Dutch citizens were still under the control of the occupying German army. Food was very scarce. The Allies tried to negotiate a cease fire so that American and British airplanes could fly into The Netherlands and drop food to the people.

The truce had not yet been agreed to by Germany, but on 29 April, Operations Manna and Chowhound began.

The first night, to test the feasibility of the project, two Royal Air Force Avro Lancaster four-engine long range heavy bombers of No. 101 Squadron—Bad Penny, crewed by Canadians, and a second ship flown by an Australian crew—were loaded with food at RAF Ludford Magna and flew into The Netherlands at barely 50 feet (15 meters) above the ground.

To drop the food they simply opened the bomb bay doors and the bags and packages fell to the starving people below.

A Royal Air Force Avro Lancaster drops bundles of food in The Netherlands during Operation Manna, 1945. (International Bomber Command Center)

With Flight Sergeant Robert Fairful Upcott, D.F.M., Royal Canadian Air Force, [service number R187858] leading with Bad Penny, the two Lancasters ¹ dropped their food on the Racetrack Duindigt at Wassernaar, near The Hague, then returned along the same corridor they had flown on the way in. At 2:00 p.m. that afternoon, another 200 Lancasters followed.

Flight crew of Avro Lancaster, “Bad Penny.” Standing, left to right: Wireless Operator Stan Jones; Flight Engineer John Corner; Aircraft Commander, Flight Sergeant Robert F. Upcott,D.F.M.; and Navigator Bill Walton. Kneeling, Aerial Gunner Bill Demo; Mid-Upper Gunner Ossie Blower; and Bomb Aimer Bill Gray. (Canadian Historical Aircraft Association)

Over the next ten days, approximately 11,000 tons (9,979 Metric tons) of food were dropped by Royal Air Force Lancasters and U.S. Army Air Force B-17 Flying Fortress bombers.

A Royal Air Force Avro Lancaster drops food packages from its bomb bay while flying at very low level over The Netherlands during Operation Manna.
A Royal Air Force Avro Lancaster drops food packages from its bomb bay while flying at very low level over The Netherlands during Operation Manna.

¹ The second Lancaster was commanded by Flight Officer P.G.L. Collett, Royal Australian Air Force (A424149).

© 2018, Bryan R. Swopes

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19 March 1945

Pilot Officer P. Martin's Avro Lancaster B Mk.I Special, PB996, YZ-C, releases the 22,000-pound Grand Slam earth-penetrating bomb over teh railway viaduct at Arnsberg, Germany, 19 March 1945. (Imperial War Museum)
Pilot Officer P. Martin’s Avro Lancaster B Mk.I Special, PB996, YZ-C, releases the 22,000-pound Grand Slam earth-penetrating bomb over the railway viaduct at Arnsberg, Germany, 19 March 1945. © IWM (CH 15735)
The Grand Slam bomb drops away from the No. 617 Squadron Lancaster B Mk.I Special, YZ-C, 19 March 1945. (Imperial War Museum)
The Grand Slam bomb drops away from the No. 617 Squadron Lancaster B Mk.I Special, YZ-C, 19 March 1945. © IWM (CH 15374)

19 March 1945: Modified Avro Lancaster B Mk.I Special heavy bombers of No. 617 Squadron, Royal Air Force, attacked the railway viaduct at Arnsberg, Germany, using the 22,000 pound (9,979 kilogram) Grand Slam earth-penetrating bomb. The bomb had been first used just days before, 14 March, against another railway viaduct.

The Grand Slam bomb dropped by Flying Officer Martin's Avro Lancaster exploeds underneath the railway viaduct at Arnsberg, Germany. (Imperial War Museum)
The Grand Slam bomb dropped by Flying Officer Martin’s Avro Lancaster explodes underneath the railway viaduct at Arnsberg, Germany. Bomb craters from previous unsuccessful attacks are visible in this RAF photograph. © IWM (CH 15378)

The Grand Slam was the largest and heaviest aerial bomb used during World War II. It was designed by aircraft engineer Barnes Neville Wallis, and was scaled up from his earlier, smaller “Tallboy.” (Wallis also designed the “Upkeep” Special Mine used to attack hydroelectric dams in the Ruhr Valley in 1943.)

Wallis’ idea was that a very heavy, supersonic bomb could penetrate deep into the earth and detonate, causing an “earthquake” which could destroy nearby heavily protected targets.

The Grand Slam bomb was 26 feet, 6 inches (8.077 meters) long and had a maximum diameter of 3 feet, 6 inches (1.067 meters). When fully loaded with the explosive material, Torpex, the bomb weighed 22,000 pounds (9,979 kilograms). The bomb case was cast of steel at the Clyde Alloy and Steel Company, Galsgow, Scotland, then, after several days of cooling, machined to its precise shape. The casing made up approximately 60% of the bomb’s total weight.

A "Bomb, Medium Capacity, 22,000 Pounds, lifted by a crane at a Royal Air Force bomb dump. (Imperial War Museum)
A “Bomb, Medium Capacity, 22,000 Pounds”—the Grand Slam—lifted by a crane at a Royal Air Force bomb dump. © IWM (CH 15369)

The bomb case was filled with molten Torpex. Torpex was an explosive designed for torpedo warheads and depth charges. It was made up of approximately equal quantities of two other explosives, Research Department Formula X (RDX), 42%, and trinitrotoluol (TNT), 40%, mixed with 18% powdered aluminum and wax. The resulting combination was approximately 1.4 times more powerful than TNT alone. About one month was required for the explosive to cool after being poured into the bomb case.

Because of its size and weight, the only Allied bomber capable of carrying the Grand Slam was a specially modified Avro Lancaster B.I Special, flown by No. 617 Squadron, Royal Air Force, “The Dambusters.”

Wallis intended for the Grand Slam to be dropped from very high altitudes so that during its fall, it would go supersonic. The bomb had large fins that caused it to rotate for stability. However, the bombers could not carry it to the planned release altitude, and it was typically dropped from approximately 9,000 feet (2,743 meters). Its very sleek design did allow it to come close to the speed of sound, however, and its stability made it a very accurate weapon. The bomb was capable of penetrating 20-foot-thick (6 meters) reinforced concrete roofs of submarine bases.

A Grand Slam bomb penetrated this reinforced concrete submarine pen. man at the top of the photograph gives scale. (Imperial War Museum)
A Grand Slam bomb penetrated the 7 meter (23 feet) thick roof this reinforced concrete submarine pen. The man at the top of the photograph gives scale. (Imperial War Museum)

Barnes Neville Wallis, Esq., M. Inst. C.E., F.R.Ae.S., Assistant Chief Designer Vickers-Armstrongs Ltd., was appointed Commander of the Most Excellent Order of the British Empire (Civil Division), by His Majesty, King George VI, 2 June 1943.

Sir Barnes Neville Wallis C.B.E., was knighted by Her Majesty, Queen Elizabeth II, 13 December 1968.

© 2017, Bryan R. Swopes

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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 69 feet, 4 inches (21.133 meters) long with a wingspan of 102 feet, 0 inches (31.090) meters and had an overall height of 20 feet, 6 inches (6.248 meters). The Mk.I had an empty weight of 36,457 pounds (16,537 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.

The Mark I had a cruise speed of 200 miles per hour (322 kilometers per hour) and a maximum speed of 282 miles per hour (462 kilometers per hour) at 63,000 pounds (28,576 kilograms). Its service ceiling was 19,000 feet (5,791 meters) and 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.

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.

This Battle of Britain Memorial Flight Lancaster B1, PA474, is one of only two flyable "Lancs" in existence. This one was built by Vickers. It is named Phantom of the Ruhr. ( )
This Royal Air Force Battle of Britain Memorial Flight Avro Lancaster Mk.I, PA474, “City of Lincoln,” is one of only two flyable “Lancs” in existence. This one was built by Vickers in 1945. (Kogo via Wikipedia)
Avro Lancaster Mk.X FM213, of the Canadian Warplane Heritage Museum, marked VR A and nicknamed “Vera.” FM213 was built by Victory Aircraft Ltd., Malton, Ontario, Canada.

© 2018, Bryan R. Swopes

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