Tag Archives: Operation Chastise

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 in Lincolnshire, England, 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, the Ennepe, 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) 

For his planning, training and execution of the raid, Wing Commander 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 72 feet (22 meters) deep. © IWM (CH 9687)
Möhne Dam after the attack. Note the defensive barrage balloons.

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, 0 inches (31.090 meters) and overall height of 20 feet, 4 inches (6.198 meters), in 3-point position. The Lancaster’s wings had a total area of 1,300.0 square feet (120.8 square meters). Their angle of incidence was 4° and the outer wing panels had 7° dihedral. The span of the horizontal stabilizer was 33 feet, 0 inches (10.058 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 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)

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).

Avro Lancaster three-view illustration (post-war configuration).

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.

Battle of Britain Memorial Flight Vickers-Armstrongs Ltd.-built Lancaster B.I, PA474, escorted by a Hawker Hurricane IIc, LF363. (Royal Air Force)
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

© 2019, Bryan R. Swopes

30 April–1 May 1947

Flight Lieutenant H.B. Martin DSO, DFC, RAFVR, 23 June 1943. (Australian War Memorial UK0235)
Flight Lieutenant Harold Brownlow Morgan Martin DSO, DFC, RAFVR, 23 June 1943. (Australian War Memorial UK0235)

30 April–1 May 1947: Squadron Leader H.B. “Mick” Martin, D.S.O., D.F.C., pilot, and Squadron Leader Edward Barnes “Ted” Sismore, D.S.O., D.F.C., navigator, departed from Heathrow Airport, London, England, at 20:06 D.B.S.T., 30 April, in a Royal Air Force Transport Command de Havilland DH.98 Mosquito PR.34. They flew to Brooklyn Airport, Capetown, South Africa, arriving at 17:35 D.B.S.T., 1 May.

Martin and Sismore with their DH.98 Mosquito at Capetown, South Africa, 1 May 1947.

The total duration of the 6,717 mile (10,810 kilometer) flight was 21 hours, 31 minutes, 30 seconds. This included a 20 minute refueling stop at El Adem, Libya, and a 25 minute stop at Kisumu, Kenya.

Martin and Sismore cut 23 hours, 36 minutes off of the existing record speed for the route set by Flying Officer A.E. Clouston and Mrs. Betty Kirby-Green with a DH.88 Comet, G-ACSS, 14–16 October 1937. ¹

For their record-breaking ² long-distance flight, Martin and Sismore were awarded the Britannia Trophy of the Royal Aero Club of Great Britain.

Flight Lieutenant E.B. Sismore, RAFVR (The Telegraph)
Flight Lieutenant E.B. Sismore, RAFVR, with a DH.98 Mosquito. (The Telegraph)

Their airplane was a de Havilland DH.98 Mosquito PR.34, a very long range, high altitude reconnaissance aircraft. It was the fastest of all Mosquito variants. The identification of their Mosquito is undetermined.

The de Havilland DH.98 Mosquito was designed and built by the de Havilland Aircraft Company, Limited. It was a twin-engine aircraft constructed primarily of wood. The airplane was flown by a pilot and navigator/bombardier. It was produced in bomber, fighter-bomber, night fighter and photo reconnaissance versions.

The PR.34 was 41 feet, 6 inches (13.649 meters) long, with a wingspan of 54 feet, 2 inches (16.510 meters) and overall height of 15 feet, 3 inches (4.648 meters). Its empty weight was 16,630 pounds (7,543 kilograms) and  it had a gross weight of 25,500 pounds (11,567 kilograms)

The Mosquito PR.34 was powered by two liquid-cooled, fuel injected and supercharged, 27.01 liter (1,648.96 cubic inch) Rolls-Royce Merlin 113/114 single overhead camshaft 60° V-12 engines which produced 1,430 horsepower at 27,250 feet (8,306 meters) with 18 inches of boost (1.24 Bar). These engines used S.U. single-point fuel injection. The Merlins drove three-bladed de Havilland Hydromatic constant-speed, quick-feathering, propellers with a diameter of 12 feet, 0 inches (3.658 meters) through a 0.420:1 gear reduction. The Merlin 113 weighed 1,650 pounds (748.4 kilograms) while the 114 was slightly heavier, at 1,654 pounds (750.2 kilograms). The 114 drove a second supercharger for cabin pressurization.

The PR.34 had bulged bomb bay doors to accommodate an 869 gallon auxiliary fuel tank and could carry a 200-gallon (909 liter) “slipper” tank under each wing. The total fuel capacity  of the London–Capetown Mosquito was was 1,267 Imperial gallons (5,760 liters).

The DH.98 Mosquito PR.34 had a maximum speed of 422 miles per hour (679 kilometers per hour) at 30,000 feet (9,144 meters). Its service ceiling was 43,000 feet (13,106 meters) and it had a range of 3,340 miles (5,375 kilometers).

There were 181 PR.34s built, with 50 of those constructed by the Percival Aircraft Company.

Mosquito PR.34 (Imperial War Museum Catalogue number ATP 13464B)
The first Mosquito PR.34, RG176. (Imperial War Museum Catalogue Number ATP 13464B)
AM H.B.M. Martin RAF
AM H.B.M. Martin RAF

(Acting) Squadron Leader Mick Martin (later, Air Marshal Sir Harold Brownlow Morgan Martin, K.C.B., D.S.O. and Bar, D.F.C. and Two Bars, A.F.C., Royal Air Force), was one of the few No. 617 Squadron Avro Lancaster bomber pilots who participated in Operation Chastise, the raid on the Ruhr Valley hydroelectric dams in 1943, to survive the war. (He flew ED909/G, AJ P, “Popsie.” Remarkably, his airplane also survived World War II.) Air Marshal Martin retired from the RAF in 1974. He died 3 November 1988 at the age of 70 years.

(Acting) Squadron Leader Ted Sismore (later, Air Commodore Edward Barnes Sismore, D.S.O., D.F.C. and Two Bars, A.F.C., A.E., O.D. (K.), ³ M.B.I.M.), was known as the best long-range low-level navigator in the Royal Air Force. He was the lead navigator for the attack of Amiens Prison, 18 February 1944, and the raid on the Gestapo headquarters at Copenhagen, Denmark in 1945. Air Commodore Sismore retired from the Royal Air Force, 23 June 1976. He died 22 March 2012 at the age of 90 years.

The Britannia Trophy of the Royal Aero Club of Great Britain.
The Britannia Trophy of the Royal Aero Club of Great Britain.

¹ FAI Record File Number 13242

² This flight does not appear to be an official Fédération Aéronautique Internationale record.

³ Order of Dannebrog, Degree of Knight, conferred by His Majesty the King of Denmark, 18 March 1949.

© 2018, Bryan R. Swopes

Victoria Cross, Wing Commander Guy Penrose Gibson, D.S.O. and Bar, D.F.C. and Bar.

Wing Commander Guy Penrose Gibson, VC, DSO and Bar, DFC and Bar, Royal Air Force, at RAF Scampton, 27 May 1943. (Imperial War Museum TR 1002)
Wing Commander Guy Penrose Gibson, V.C., D.S.O. and Bar, D.F.C. and Bar, Royal Air Force, at RAF Scampton, 27 May 1943. (Imperial War Museum TR 1002)
Victoria Cross
Victoria Cross

Wing Commander Guy Penrose Gibson, D.S.O. and Bar, D.F.C. and Bar, was awarded the Victoria Cross by His Majesty King George VI in a ceremony at RAF Scampton, Lincolnshire, England. Wing Commander Gibson received the medal for his leadership of No. 617 Squadron, The Dambusters, during Operation Chastise, an attack on Germany’s Ruhr Valley hydroelectric dams, 16–17 May 1943.

The Victoria Cross ranks with the George Cross as the United Kingdom’s highest award for gallantry.

The first British medal to be created for bravery, the Victoria Cross was instituted in 1856, with the first recipients being personnel honored for their gallantry during the Crimean War.

The bronze cross pattée, which bears the inscription “FOR VALOUR,” is cast from the metal of Russian guns captured at Sevastopol during the Crimean campaign. The Victoria Cross is awarded for most conspicuous bravery, or some daring or pre-eminent act of valour or self-sacrifice, or extreme devotion to duty in the presence of the enemy.

The King has a word with Flight Lieutenant Les Munro from New Zealand. Wing Commander Guy Gibson is on the right and Air Vice Marshal Ralph Cochrane, Commander of No 5 Group is behind Flight Lieutenant Munro and to the right. (Imperial War Museum TR 999)
His Majesty The King has a word with Flight Lieutenant John Leslie Munro, Royal New Zealand Air Force, at RAF Scampton, 27 May 1943. Wing Commander Gibson is on the right, facing Munro. (Imperial War Museum TR 999)

Screen Shot 2016-05-26 at 09.40.32Air Ministry, 28th May, 1943.


     The KING has been graciously pleased to confer the VICTORIA CROSS on the undermentioned officer in recognition of most conspicuous bravery: —

Acting Wing Commander Guy Penrose GIBSON, D.S.O., D.F.C. (39438), Reserve of Air Force Officers, No. 617 Squadron: —

     This officer served as a night bomber pilot at the beginning of the war and quickly established a reputation as an outstanding operational pilot. In addition to taking the fullest possible share in all normal operations, he made single-handed attacks during his “rest” nights on such highly defended objectives as the German battleship Tirpitz, then completing in Wilhelmshaven.

     When his tour of operational duty was concluded, he asked for a further operational posting and went to a night-fighter unit instead of being posted for instructional duties. In the course of his second operational tour, he destroyed at least three enemy bombers and contributed much to the raising and development of new night-fighter formations.

     After a short period in a training unit, he again volunteered for operational duties and returned to night bombers. Both as an operational pilot and as leader of his squadron, he achieved outstandingly successful results and his personal courage knew no bounds. Berlin, Cologne, Danzig, Gdynia, Genoa, Le Creusot, Milan, Nuremberg and Stuttgart were among the targets he attacked by day and by night.

     On the conclusion of his third operational tour, Wing Commander Gibson pressed strongly to be allowed to remain on operations and he was selected to command a squadron then forming for special tasks. Under his inspiring leadership, this squadron has now executed one of the most devastating attacks of the war—the breaching of the Moehne and Eder dams.

     The task was fraught with danger and difficulty. Wing Commander Gibson personally made the initial attack on the Moehne dam. Descending to within a few feet of the water and taking the full brunt of the antiaircraft defences, he delivered his attack with great accuracy. Afterwards he circled very low for 30 minutes, drawing the enemy fire on himself in order to leave as free a run as possible to the following aircraft which were attacking the dam in turn.

     Wing Commander Gibson then led the remainder of his force to the Eder dam where, with complete disregard for his own safety, he repeated his tactics and once more drew on himself the enemy fire so that the attack could be successfully developed.

     Wing Commander Gibson has completed over 170 sorties, involving more than 600 hours operational flying. Throughout his operational career, prolonged exceptionally at his own request, he has shown leadership, determination and valour of the highest order.

The London Gazette, Tuesday, 25 May 1943, No. 3630 at Page 2361

Wing Commander Guy P. Gibson VC, 1944. © IWM (CH 13618)
Wing Commander Guy P. Gibson V.C., D.S.O. and Bar, D.F.C. and Bar, Royal Air Force, 1944. © IWM (CH 13618)

© 2019, Bryan R. Swopes