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Avro Lancaster

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Avro-Lancaster-Bomber-Inflight.jpg
Type Heavy bomber
Manufacturer Avro
Introduction 1942
Status Retired 1963 (Canada)
Number built 7,377
Cost £45-50,000 (1940's) £1.3-1.5 million (2007)

OVERVIEW

The RAFs main bomber of WW2. Still flying today with the Battle of Britain Memorial Flight. The design originated with the Avro Manchester twin-engined long-range bomber built around the Rolls Royce Vulture engine. Air Ministry policy at the time was to economise on materials, and - like the Germans with their Heinkel 111 and Dornier 217 bombers - they sought to gain the maximum power and range from two engines.

The Vulture proved troublesome - despite offering a significant power increase over the Merlin powerplants then in service. Eventually, Avro gave up on the design after only some 200 Manchesters had been built. Plan B, as it were, was to modify the existing airframe to take four of the readily-available (and proven) Rolls Royce Merlin engines. The result was the Lancaster.

DEVELOPMENT

Roy Chadwick, chief aircraft designer for A.V. Roe, submitted plans to the Air Ministry for the Avro 683. This was a four-engined heavy bomber using the Manchester fuselage - but powered by four Rolls Royce Merlin engines. The Lancaster Mk I first flew in 1941, and was an immediate success. In trials, the Lanc exhibited the most flexible load-carrying characteristics of any Allied heavy bomber. By the time it entered squadron service with the RAF, its nominal 8000lbs bomb-carrying capacity was found, in practice, to be 14000lbs - more than twice the load of the equivalent B-17 Flying Fortress then in use with the United States Army Air Force (USAAF).

THE LANC IN SQUADRON SERVICE

The psychological effect of this aircraft massively reinforced its operational capabilities. In the words of a former Lancaster crew member: "It just looked like what it was - big, tough and nasty. This was a machine that was bent on destruction." Unlike the almost-dainty Hampden and Blenheim, the Lanc had no elegance whatsoever. Aircrews liked the feeling that they were flying something that meant serious harm to the enemy.

LancasterMkII-1.jpg Lancaster Mk I

Demand soon outstripped supply, as the Lancaster proved itself in combat. The shortage of Merlin engines led to the introduction of the Mk II. This version was fitted with the excellent Bristol Hercules 14 cylinder, twin row radial engine, delivering 1675hp compared to the 1620hp of the 12 cylinder, in-line Merlin. The Hercules-powered Lanc returned superior takeoff and climb rate figures, but its top speed was well below that of the Merlin-powered versions. Also, fuel efficiency was inferior to the Rolls Royce engine's returns. Only 301 Mk IIs were built.

OVERSEAS MANUFACTURE OF LANCASTERS

The Canadians came to the rescue, building US-designed Packard Merlins under licence. Apart from some minor differences (e.g: fuel capacities in US gallons rather than Imperial), the Packard Merlins performed admirably, and were hardly distinguishable from their British-built cousins. These engines equipped the Mk III Lancaster, as well as the Canadian-built Mk X (Packard Merlin-engined Mk I), with different maintenance schedules from other Lanc's.

OPERATIONS

History has tended to darken the Lancaster image by highlighting its part in the terror bombing of German cities, with no obvious military targets in mind. At the time, however, memories of the Blitz - and the 50,000 civilian casualties - were too recent for compassion to enter British thinking. If anything, revenge felt good. Air Marshal Harris was quite deliberate in his policy of striking at enemy morale on the home front.

More absorbing are the stories of the Lancaster's employment in special bombing operations. These were carried out in conditions which should have ruled out the use of such a huge, ungainly plane - but which, in the event, achieved remarkable success. The British inventor Barnes Wallis (when he wasn't designing jet engines for the next generation of RAF fighters) produced a remarkable range of rather destructive toys. The three most famous, were the "Bouncing Bomb"; the "Tallboy"; and the "Grand Slam".

Tall_Boy_Bombe1.jpg

Tallboy

Barnes Wallis' dreams of destruction of German infrastructure, came to naught because all his toys were too big and heavy. Until the Lancaster came along. The Tallboy was the most widely used. Lanc's dropped them on U-Boat pens at Le Havre; on V-1 launching facilities at Peenemunde; and, most famously, on the German battleship Tirpitz.

A huge, menacing surface raider, Tirpitz had been sitting in a sheltered anchorage in a fjord in occupied Norway, for over two years. All attempts to sink her had been in vain. The most successful to date, had been a daring underwater commando raid. The limpet mines had inflicted enough damage to keep Tirpitz out of action during a critical phase of Allied convoy activity. The Tallboy, however, proved to be the Tirpitz's nemesis.

Repeated raids at great height (defeating the battleship's powerful anti-aircraft armament) by Nos. 9 and 617 Sqns, saw a number of tantalising near-misses with the gigantic 11,000lbs Tallboy. Finally, on 12 November 1944, 30 Lancasters dropped their Tallboy loads, and scored hits with at least two bombs. The Tirpitz was ripped apart internally as her magazines erupted; within 10 minutes, she had turned turtle and settled on the bottom of her Kaa Fjord anchorage.

Another dream-come-true for Barnes Wallis, was his 22,000lbs "Earthquake Bomb". Known in RAF circles as the "Grand Slam", this was designed to smash through steel or concrete armour; burrow deep into the target; then explode deep in the bowels of the earth, with a Doomsday result. Probably inspired by tales of Adolf Hitler's reputedly-impenetrable redoubts in the Austrian Alps, it achieved moderate military success - and left some spectacular craters.

By far the most effective, however, was the Bouncing Bomb. This was specifically designed to breach the dams on the Eder and Mohne systems, inducing large-scale flooding and hampering the German war effort accordingly. The bomb had to be released at about 150ft above the water level of the dam. Working out this height brought about yet another stroke of genius...

The heavy bomber's altimeter didn't work below 200ft, so a system of intersecting searchlight beams was fitted to the plane - calibrated to meet at 150ft. At the designated point of approach to the target, the bomb-aimer would press his switch - releasing the aircraft's curious cargo. Which would then bounce along the water surface, sinking when it struck the dam wall, and exploding when the pressure-switch told it it had reached the bottom of the dam wall.

It did exactly that, and a lot of German farmers were sorely inconvenienced. The Nazi war effort was not seriously hampered in purely military terms - but the propaganda value was huge. The very fact that the British were able to inflict such damage on important infrastructure - without loss to themselves - was a huge boost to British morale, and a corresponding blow to German confidence.

dux002.jpg

Bouncing Bomb


Technical Details - Lancaster I

Crew: 7 (Pilot, Flight Engineer, Observer/Nose Gunner/Bomb Aimer, Navigator, Wireless Operator, Mid-upper Gunner, Tail Gunner.

Powerplants: 4 x Rolls-Royce Merlin XXIV 12 cyl. V block, liquid- cooled engines - 1620 hp each.

Maximum range: 2527 miles

Maximum speed: 286 mph

Service Ceiling: 24,671 ft

Armament: 8 x .303" machine guns (2 in nose turret, 2 in mid- upper turret, 4 in rear turret).

Total ammo carried: 14000rds.

Bomb load: 1941: 8000 lbs. (HE/Incendiary bombs.)

1944: 22000 lbs = 1 x Grand Slam bomb

EPILOGUE

The end of World War II was not, of course, the end of the story for this unique airframe. Civilian versions such as the York transport aircraft, continued in service until the advent of the Comet jet airliner. In the military field, the Lincoln carried on the Avro bomber tradition. A longer-ranged, higher-altitude development of the Lancaster, it carried the same bombload, with defensive armament of twin .50" MGs in nose and tail turrets, and twin 20mm cannon in the mid-upper turret.

Final iteration of the proven Roy Chadwick design line, was the Type 686 - built to Specification R5/46 immediately after the war, for a Maritime Reconnaissance (MR) aircraft. The plane entered Squadron service with RAF Coastal Command in April 1951. Chadwick's wife happened to be a descendant of the famous explorer Sir Ernest Shackleton, so the choice of name for the new aircraft (made to roam the arid wastes of the northern seas) was doubly appropriate.

The ancestry of the "Shack" was obvious - even after the tricycle-undercarriage Mk III was brought into service. Powered by four Rolls Royce Griffons, and once described as "10,000 loose rivets flying in close formation", the Shackleton performed MR, Search And Rescue (SAR) and Airborne Early Warning (AEW) duties until 1991. Even then, examples of the Mk III still flew with the South African Air Force. Six examples of the type fly to this day, although retired from active service.

Gshackleton.jpg


(Above): Avro Shackleton (E-3 Sentry in background)