Tag Archives: Rolls-Royce Merlin

12 November 1944

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Tirpitz
KMS Tirpitz anchored in Bogen Bay, Ofotfjord, near Narvik, Norway, circa 1943–1944. (U.S. Navy Historical Center)

12 November 1944: No. 9 Squadron and No. 617 Squadron (Dambusters), Royal Air Force, sent a force of 32 Avro Lancaster long range heavy bombers to attack the 49,948 metric-ton-displacement Kriegsmarine battleship KMS Tirpitz at Tromsø Fjord, Norway. The attack was filmed by a photo aircraft of No. 463 Squadron, Royal Australian Air Force.

The Lancasters were armed with 12,030 pound (5,457 kilogram) Tallboy bombs. They bombed from altitudes from 12,000 to 16,000 feet (3,658–4,877 meters). Two of the bombs hit the battleship, one was a very near miss and another three also were close enough that they probably contributed to the overall damage. Many other Tallboys landed within the torpedo nets that surrounded the ship and cratered the seabed, removing the sandy bottom which had been built up under Tirpitz‘ hull to prevent her from sinking. Tirpitz immediately began to list and was then rocked by an internal explosion. It capsized and sank to the sea bed. As many as 1,204 sailors were killed.

KMS Tirpitz under attack, 12 November 1944. The battleship is visible to the left of the bomb splashes and is firing its main guns at the bombers. (Unattributed)
KMS Tirpitz under attack, 12 November 1944. The battleship is visible to the right of the bomb splashes and is firing its main guns at the bombers. (Unattributed)

Tirpitz was a Bismarck-class battleship armed with a main battery of eight 38-centimeter (15-inch/52-caliber) guns in four turrets. These guns had a maximum range of 22.7 miles (36.5 kilometers) when firing a 1,800 pound (816 kilogram) projectile. The German Navy did not use its heavy warships to directly engage the British fleet, but instead to raid the Atlantic convoys.  The merchant ships with their destroyer escorts were defenseless against a battleship or battle cruiser. Allied forces expended tremendous effort and resources to contain or destroy Tirpitz throughout the war.

A Royal Air Force Avro Lancaster being "bombed up" with a 12,000 pound Tallboy earth-penetrating bomb.
A Royal Air Force Avro Lancaster being “bombed up” with a 12,030 pound (5,456.7 kilogram) Tallboy earth-penetrating bomb. (Royal Air Force)

The Avro Lancaster was a four-engine long range heavy bomber. It wasn’t as fast as the American B-17 Flying Fortress, but was capable of flying longer distances with a heavier bomb load. It was operated by a crew of seven: Pilot, flight engineer, navigator, radio operator, bomb aimer/nose gunner, top gunner and tail gunner. The “Lanc” was 69 feet, 4 inches (21.133 meters) long, with a wingspan of 102 feet (31.090 meters) and had an overall height of 20 feet, 6 inches (6.248 meters). It had a maximum takeoff weight (MTOW) of 72,000 pounds (32,657 kilograms) when carrying a 22,000 pound (9,979 kilogram) Grand Slam bomb.

The Lancaster was powered by four liquid-cooled, supercharged, 1,648.96-cubic-inch-displacement (27.01 liter), Rolls Royce Merlin XX or Packard V-1650 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). They turned three-bladed de Havilland Hydromatic constant-speed propellers which had a diameter of 13 feet (3.962 meters) through a 0.420:1 gear reduction.

These Merlin engines, the same as those powering Supermarine Spitfire, Hawker Hurricane and North American P-51 Mustang fighters, gave the Lancaster a maximum speed of 282 miles per hour (456 kilometers per hour) at 13,000 feet (3,962 meters) at a weight of 63,000 pounds (28,576 kilometers per hour). The service ceiling was 21,400 feet (6,523 meters) and maximum range was 2,530 miles (4,073 kilometers).

Defensive armament for a standard Lancaster consisted of eight Browning Mark II .303-caliber machine guns in three power turrets, nose, dorsal and tail. Modified bombers deleted various combinations of guns to reduce weight.

The Tallboy (Bomb, Medium Capacity, 12,000 lb) was a special demolition bomb designed to be dropped from high altitude, reach supersonic speeds, then penetrate as far as 90 feet (27 meters) into the ground before detonating. It was built of a specially hardened steel casing filled with 5,200 pounds (2,358 kilograms) of Torpex explosive. The bomb was designed by Barnes Wallis, who had also designed the special bomb used by the Dambusters in their famous 1943 attack on the Ruhr Valley hydroelectric dams, as well as the Grand Slam, a 22,000-pound (10,000 kilogram) scaled-up version of the Tallboy. The Tallboy and Grand Slam bombs were very successfully used against U-boat pens and heavily fortified underground rocket facilities.

A flight of three Avro Lancaster bombers of No. 617 Squadron, Royal Air Force, photographed 8 May 1945. The airplane closest to the camera, marked KC-B, is a Lancaster B Mk.I. The other two are Lancaster B Mk.I Specials modified to carry the 22,000 pound Grand Slam bomb. They are identified by the "YZ" fuselage codes. Photograph from the collection of Mrs. Cresswell, © IWM MH-30796.
A flight of three Avro Lancaster bombers of No. 617 Squadron, Royal Air Force, photographed 8 May 1945. The airplane closest to the camera, marked KC-B, is a Lancaster B Mk.I. The other two are Lancaster B Mk.I Specials modified to carry the 22,000 pound Grand Slam bomb. They are identified by the “YZ” fuselage codes. Photograph from the collection of Mrs. Cresswell, © IWM MH-30796.

© 2016, Bryan R. Swopes

2 August 1947

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British South American Airways’ Avro Lancastrian Mk.III, G-AGWH, R.M.A. Star Dust. (SDASM)

2 August 1947: At 1:46 p.m., British South American Airways Flight CS59 departed Buenos Aires, Argentina enroute Santiago, Chile. The airliner was an Avro Lancastrian Mk.III, registration G-AGWH, named R.M.A. Star Dust. The flight was under the command of Captain Reginald J. Cook, D.S.O., D.F.C., D.F.M., with First Officer Norman Hilton Cook, Second Officer Donald S. Checklin, Radio Operator Dennis B. Harmer and “Stargirl” Iris Morcen Evans. On this flight, in addition to the five-person airline crew, there were just six passengers.

Captain Reginald J. Cook, D.S.O., D.F.C., D.F.M.

At 5:41 p.m., Santiago airport received a routine Morse code signal from G-AGWH indicating the flight would arrive in four minutes:

ETA SANTIAGO 17.45 HRS STENDEC

The radio operator at Santiago did not understand “STENDEC” and asked the airliner’s radio operator to repeat it, which he did, twice. The airliner never arrived. A five-day search was unsuccessful. The meaning of the last word in the message has never been determined.

The fate of Star Dust remained a mystery until 1998, when two mountain climbers on Mount Tupungato—at 21,555 feet (6,570 meters), one of the highest mountains in South America—50 miles east of Santiago, found a wrecked Rolls-Royce Merlin aircraft engine in the ice of a glacier at the 15,000 foot level (4,572 meters). A search of the glacier in 2000 located additional wreckage and it was confirmed that this was the missing Lancastrian. The crash site is at S. 33°22’15.0″, W. 69°45’40.0″.

Investigators determined that the airliner had flown into the glacier at high speed and the crash caused an avalanche which buried the wreckage.

In 2002 the remains of eight persons were recovered from the glacier, five of which were identified through DNA.

Volcan Tupungato, 21,560 feet ( 6,570 meters). (Diode via Wikipedia)
1948 B.S.A.A. advertisement.

The Avro 691 Lancastrian Mk.III was a four-engine civil transport based on the World War II very long range heavy bomber, the Avro Lancaster. The Mk.III variant was built specifically for the British South American Airways Corporation by A.V. Roe & Co. Ltd, at Woodford, Cheshire, England, and was an improved version of the British Overseas Airways Corporation Lancastrian Mk.I. Eighteen Mk.IIIs were built for BSAAC. G-AGWH, serial number 1280, was the second of this series. It first flew on 11 November 1945 and was registered to BSAAC 16 January 1946.

The airliner was operated by a flight crew of four and carried one flight attendant. It could carry up to thirteen passengers. The Lancastrian Mk.III was 76 feet, 10 inches (23.419 meters) long with a wingspan of 102 feet (31.090 meters) and overall height of 19 feet, 6 inches (5.944 meters). The empty weight was 30,220 pounds (13,707.6 kilograms) and gross weight was 65,000 pounds (29,483.5 kilograms).

Avro Lancastrian Mk.III, G-AGWH, R.M.A. Star Dust

The Lancastrian Mk.III was powered by four 1,648.9-cubic-inch-displacement (27.04 liter) liquid-cooled, supercharged, Rolls-Royce Merlin T24/2 ¹ single overhead camshaft (SOHC) 60° V-12 engines producing 1,650 horsepower and turning three bladed propellers.

These gave the airplane a cruise speed of 245 miles per hour (394.3 kilometers per hour) and a maximum speed of 315 miles per hour (506.9 kilometers per hour). The service ceiling was 25,500 feet (7,772 meters) and the range was 4,150 miles (6,679 kilometers).

Site of the wreck of Avro Lancastrian G-AGWH, S. 33°22’15.0″, W. 69°45’40.0″. (Google Maps)

¹ Two of G-AGWH’s Merlin T24/2 engines had been completely overhauled and converted to the Merlin 500-2 configuration. One engine was converted to a Merlin 502. The fourth engine remained as a T24/2. All engines had less than 1,200 hours total time since new (TTSN) and the converted engines were approximately 500 hours since overhaul (TSOH).

© 2018, Bryan R. Swopes