Tag Archives: A.V. Roe & Co. Limited

12 November 1944

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

20 September 1958

Avro Vulcan VX770.
The first of two prototypes, Avro Type 698 VX770. (BAE Systems)

20 September 1958: The first prototype Avro Vulcan strategic bomber, VX770, piloted by Rolls-Royce test pilot Keith Roland Sturt, was on a test flight from the Rolls-Royce Flight Test Establishment, RAF Hucknall, when it diverted to make a scheduled fly-past for an air show being held at RAF Syerston in Nottinghamshire. Also aboard were Co-Pilot Ronald W. Ward of Fairey Aviation; Rolls-Royce Flight Engineer William E. Howkins; and Navigator, Flight Lieutenant Raymond M. (“Polly”) Parrott, Royal Air Force.

VX770 approched RAF Syerstone at 12:57 p.m. (GMT) and flew east along Runway 07–25 at about 250 feet (76 meters). As the Vulcan passed the control tower at an estimated speed of 350 knots, it began a right turn.

Seen from below, VX770 shows the full delta wing of the prototype. Production aircraft used a modified wing with curved leading edges in order to delay compressibility effects at high speeds. (Unattributed)
Seen from below, VX770 shows the full delta wing of the prototypes. Production aircraft used a modified wing with curved leading edges in order to delay compressibility effects at high speeds. (Unattributed)

Witnesses saw a “kink” form in the leading edge of the Vulcan’s right wing, which then began to disintegrate from the leading edge aft. Wing surface panels could be seen being stripped off before the wing spar failed completely. Clouds of fuel from ruptured tanks trailed as the bomber rolled to the left. The top of the vertical fin came off, the nose pitched upward toward vertical, then straight down, and with both wings on fire, the airplane crashed near the east end of the runway.

All four crew members were killed, as were three RAF fire/rescue personnel on the ground. Several others were injured.

The right wing of Avro Vulcan VX770 disintegrates.
The right wing of Avro Vulcan VX770 disintegrates. (© Mary Evans/The National Archives, London, England)
Clouds of vaporized fuel trail the doomed bomber.
Clouds of vaporized fuel trail the doomed bomber. (Unattributed)
Vulcan VX770 crashed at the east end of Runway 07-25.
Vulcan VX770 crashed at the east end of Runway 07-25. Debris spread over 1,400 feet (427 meters). (MEV-10473694 © Mary Evans/The National Archives, London, England)

A short video clip of the fly-by and crash can be seen on You Tube:

The cause of the Vulcan’s wing failure was not determined. Metal fatigue was suspected. The airplane had been used in flight testing for six years and it is possible that it’s design limits may have been exceeded during that period. There was also speculation that vibrations from the new Rolls-Royce Conway “bypass turbojet” engine, which is now called a turbofan, may have weakened the wing.

According to the investigative report, Keith Sturt was considered to be an “above average” and “capable and careful” pilot. He had accumulated 1,644 hours of flight time over six years. He had flown VX770 for 91 hours, 40 minutes. Sturt was a former Flight Lieutenant of the Royal Air Force, having been inducted into the service in 1945.

VX770 was the first of two Type 698 prototypes built by A.V. Roe & Co., Ltd., at Woodford, Cheshire. It made its first flight 30 August 1951 with Chief Test Pilot R.J. “Roly” Falk. Originally equipped with Rolls-Royce Avon R.A.3 turbojet engines, these were soon replaced with more powerful Armstrong Siddely Sapphire A.S.Sa.6 engines. During modification in 1953, fuel cells were added to the wings. As production airplanes were built with Bristol Olympus Mk.102 engines, VX770 was modified accordingly. During its final flight, it was powered by Rolls-Royce Conway RCo.10 turbofans.

Keith Roland Sturt was born in Guildford, Surrey, England, 20 April 1929, the son of George Sturt and Daisy May Raveney Sturt. On 20 June 1957, Sturt married Mrs. Colin Weal Coulthard (née Norah Ellen Creighton) in Surrey.

© 2018, Bryan R. Swopes