By Pierre 'Piet' MICHIELS with particular thanks to Phil BALL for the translation
After the Battle of Britain and the Blitz, doubt is no longer allowed. The future of the air strategy relies on force projection. The future is in Bomber Command. In addition to questions about tactics and the gradual scrapping of obsolete equipment, the focus should now be put on the intensive use of Heavy Bombers.
However, the move to the mass production of four-engine bombers needs to be done gradually. Obviously nobody can expect that factories will, overnight, stop the production of twin engines bombers to produce four-engine bombers in the quantity and quality required. Tactically, Bomber Command must continue to send aircraft to bomb Europe to counter the German offensive. Thus, cynically, crews of Whitleys and Wellingtons are sacrificed during 1941 and 1942 to fill the gap, awaiting the availability of the Stirling, the arrival of the Halifax and especially of the Lancaster.
Undeniably a technological achievement and also a good looking aircraft, the A. V. Roe Lancaster is paradoxically the result of a crushing technical defeat.
First, we have to look back to 1935, the year the Ministry of Defence produces two specifications one for the construction of a four-engine bomber and the other for a twin-engine bomber. The first, numbered 12/36, for which the Short and Handley-Page factories compete, led to the creation of the Stirling and the Halifax. The second specification, numbered 13/36, has Handley-Page and A. V. Roe competing. But in that particular case, the prerequisites imposed on the two manufacturers, include using the Rolls-Royce Vulture, X24, which is based on the combination of two Peregrine V12s. As Air Headquarters seems to be focusing on larger aircraft, Handley-Page gradually loses interest in the design of a medium bomber and instead devotes its energies on the design of a heavy bomber.
At A. V. Roe chief engineer Roy Chadwick remains alone in trying to meet the absurd specifications drawn up in the corridors of power: to design a twin-engine aircraft capable of carrying a load of 4,000kgs and powered by two engines of 1,500hp with the weight and structure demanded. His first choice, against all technical aeronautical orthodoxy, is to place the fuel tanks in the wings to give the largest bomb bay possible. This choice is crucial to the success of his next design.
Specifications from the British Government are continually changing, and the brilliant engineer decides to go out on a limb again and design a wing and a fuselage made up of several sections, five for the fuselage and five for each wing. During development work, this has the advantage of allowing changes to a particular section of the aircraft, without delaying the development of the other parts. At the production stage, this will allow the manufacture of the various sections in geographically separated plants, which is a strategic advantage. At Woodford it is said with humour that it is about not putting all our eggs in one basket ... especially if it should be bombed. Another benefit is that once in service with operational squadrons, mechanics can easily replace any part damaged, without returning the entire unit to the factory which would surely reduce its operational availability.
Following an obstacle course, a type 679 Avro Manchester bomber is produced by the factory. A problem of lateral stability appears during the first flight in July 1939. Subsequently, the test pilots noticed a strong tendency to drift to port during landing, when the engines are in low power. Then there are worries with the hydraulic controls, unusual engine overheating of the Vulture engines, and finally there is the inadequacy of the propellers. The flights are suspended until October 1940 following the failure of an engine. Engineers finally fit a modified three tail fin which is supposed to counter the drift tendency. There is no significant improvement.
Meanwhile, while the four production sites chosen are awaiting the final plans from Chadwick, the Stirling is already flying and the pre-production Halifax successfully passes Bomber Command tests at Boscombe Down. At A.V. Roe, there is only discouragement.
At the same time, Churchill becomes Prime Minister and ending the procrastination of his predecessor and of the Government, it is decided to limit the number of aircraft types to be built by British industry. The type 679 is not retained. Moreover, after a quick study, the Government decreed that the development of the Rolls-Royce Vulture should be abandoned, thus signing the death warrant of the Manchester which had started limited production. Just over 200 aircraft are built to use up the existing stock of Vulture engines. Delivered to the squadrons, they turn out to be mediocre and unreliable.
Roy Chadwick does not give up. He has in his files plans for a four engine Manchester, the type 683 or Mk. III, but with the abandonment of the Vulture X24 engine, he is now reliant on the delivery of the Rolls-Royce Merlin V12s which are reserved at this time for the Spitfires, Hurricanes and the Halifax Mk. I. Worse, the Air Ministry urges A. V. Roe to forget the plans for a Manchester Mk. III and to consider outsourcing the production of the Halifax. The affront is terrible. At Woodford, the answer is no and there begins an intensive lobbying campaign in the Government. The goal: Give us Merlin engines! For its part, the Handley-Page clan is not happy to see the diminution of its quota of precious engines in favour of a competitor’s aircraft that only exists on paper. The battle is fierce in the corridors of the Air Ministry. Yet, through his personal contacts within the engine’s manufacturer, the engineer managed to steal four Rolls-Royce Merlin Xs ... history often owes much too small events like this.
Following hard work, and five months ahead of schedule, the engineers of A. V. Roe manage to present their four engine bomber on 31 December 1940. Demonstrating a sense of humour, its designer explains to the authorities that we had only to take the fuselage from a Manchester, extend the wings a little, and add two more engines...
9 January 1941, resting on its huge wheels, the plane makes a strong impression on the aviators. A slight wedge shape in the wings, three vertical stabilizers, and a sense of contained power.
It is beautiful, so it's probably good, says a pilot.
Then the first take-off. Sam Browns is at the controls. Chadwick moves away from the group of technicians in order to hide a mixture of apprehension and glee.
BT308 runs down the snow-covered runway, becomes airborne, slowly rises into the sky and begins its first turn. Majestic.
First a whisper, then a shout: Oh boy, oh boy, what an aeroplane ...
February 1941, A. V. Roe finally receives four examples of the new Merlin XX which are then installed on the second prototype, DG595. Engineers take this opportunity to remove the central vertical stabilizer. The test results speak for themselves: almost 500kph (310 mph), ceiling 7,000m (nearly 23,000 feet), payload over 7.000kgs (nearly 7 tons). It is 15% in excess of the requirements of Bomber Command. The competition is held. The plane is born.
In November of that year, at the request of the Air Ministry, which is responsible for the allocation of the Rolls-Royce engines that are in short supply, and wanting to stay in the good graces of the authorities, Chadwick presents DT810 on an experimental basis, the first example with the Bristol Hercules VI radial engines.
With the arrival of Arthur Harris as the head of the staff at High Wycombe in early 1942, things will develop into something more personal. A man of character, if not temperamental, with a phenomenal capacity for work, he will embody all by himself the effort of the projecting the British air force. He has a definite opinion on everything and everyone, and his judgment is rarely at fault. Above all, he hates any form of contradiction from whatever source. In short, he is irreplaceable and he knows it.
Harris considers the year 1942 as the start of the establishment of a new Bomber Command. His Bomber Command. On this basis, 1943 will enable it to develop a real strategy for bombing the Nazi machine. But to do so, he needs a really efficient bomber. His bomber.
However, the Stirling built in the factories of Short Brothers is already obsolete when it is made available to squadrons. Crews who fly on this aircraft confirm its bad reputation. With a limited payload, it is paradoxically a huge plane with very fragile landing gear, a landing in a crosswind is regularly finishing on the belly, says a pilot. Still with some operational units in the summer of 1943, it is as quickly as possible assigned to training units. The unfavourable personal opinion of the boss of Bomber Command of the capabilities of the heavy bomber also crystallizes around the excessive drinking of its designers, an excess that Harris likes to discuss in public. In summary, a first-class funeral.
On the other hand there is the Halifax. In addition to highlighting the less obvious weaknesses in its specifications in comparison with the Lancaster, Harris develops a growing personal animosity toward F. Handley-Page, head of the firm of the same name. He stated that no meaningful result will be achieved as long as Handley-Page and his gang are not held under lock and key. We will achieve nothing in the context of civilized negotiations with these incompetent crooks. In Russia, we would have solved the problem with a revolver. From this point of view, I consider myself a devout communist ... The head of Bomber Command has consistently criticized granting the Halibag priority for Merlin engines and subsequently maintaining the Halifax in production, the Lancaster quickly appears to him as the only bomber capable of ensuring the success of the strategy of area bombing he wants to develop.
Some accusations of favouritism are made against Harris, but it is clear that the new aircraft is technically superior in terms of speed both in level flight and climb, as well as in terms of payload and range. The opinion of the pilots is very clear: the Lanc seems much lighter and does not need nearly as much power. It's a treat to fly it. It has no defects and has a good reputation, regardless of the use made of it. That good opinion is shared by the mechanics. They are unanimous, it is perfection. All controls are within reach and in addition, they are perfect. It's really something else. The Lanc is not like normal flying, it flies into the air. And most of all, it gives us confidence.
Paradoxically, its ingenuity in design and therefore ease of construction will lead the authorities to consider fitting a different engine to cope with the lack of availability of sufficient Rolls-Royce engines for the number of fuselages produced . The uncompromising and narrow-minded head of Bomber Command is furious. The contract value is not high, but it is a matter of principle. Harris does not understand why the all too rare Rolls-Royce Merlin engines cannot be fitted to the Lancaster MK. I and adds that if adaptation is to occur, it must be done on the Halifax, as the Stirling is already fitted with Bristol Hercules engines. In the heated debate that pitted him against the entire hierarchy for months, Harris argues, in vain, three points in opposition to the priority allocation of the precious Merlin to Handley-Page.
First the unquestionable superiority of the Lancaster-Merlin association. Second, the respect due to the brilliant engineer Chadwick and the foresight of the staff of A. V. Roe. Third, doubts as to whether it is possible to fundamentally improve the Halifax which is basically inferior to the Lancaster. At the operational level, the crews support their Chief. In squadrons equipped with the Halifax, it is now usual that an announcement made by a Wing Commander that you will be glad to hear that we are shortly to convert to the Lancaster, is followed by cheers by the crews.
It is clear to all that the Lancaster and Harris will now form a formidable duo. The Chief of Bomber Command did not hesitate to rely on biblical references to declare that by bombing English cities, the Germans have sown the wind. They will now reap the whirlwind
The first contract signed by A. V. Roe with the Air Ministry is for the delivery of 1,070 Lancaster bombers. With the development of the conflict other contracts are being signed and it becomes clear that only the Chadderton and Yeadon factories cannot meet such a request. Other factories should be involved in the production. Armstrong Whitworth in Coventry is one of them, because it has experience in the construction of another bomber the Whitley. Given the operational qualities of the Lancaster, all production means are progressively allocated to the new bomber.
Based on the encouraging results that followed the tests of the prototype DT810, and against the advice of an outraged Harris, the Air Ministry orders Armstrong-Whitworth to produce 300 Lancasters fitted with Bristol engines. DS690 is therefore the object of a particular command to produce the Lancaster Mk. II using a conventional Lancaster Mk. I fuselage, with 4 radial BRISTOL Hercules 14 cylinder engines with sleeve valves and with propellers turning in the wrong direction, opposite to that of the Rolls-Royce Merlin engines.
Serial numbers DS601 to DS852 are built between September 1942 and December 1943 and from DS628 onwards are equipped with Hercules XVI 14-cylinder engines and automated mixture. On this type of engine, air cooled cylinders are set radially around the axis of rotation of the propeller, just like the spokes of a bicycle wheel around its hub. The cylindrical shape of the engine affects the shape of the engine cowling, totally different from the more slender engine cowl of the overwhelming majority of Lancasters which are powered by the liquid-cooled Rolls-Royce Merlin V12.
With an output of 1,615hp, whilst the four engines allow the Mk. II to have a greater rate of climb the flight ceiling is lower and fuel consumption higher. All to allow a bulkier payload but with the same load capacity. Besides the cylindrical cowls, the Mk. II has, from the start, prominent bomb bay doors. That gives it a much more stocky profile, less elegant than the classic Lancaster, and a higher drag coefficient.
At East Wretham, conversion from the twin-engine Wellington to the Lancaster Mk. II took place in March 1943. 115 Squadron shares the infrastructure of the airbase with a Heavy Conversion Unit. Like the vast majority of airfields in Bomber Command, the area is grass dotted with infrastructure such as more or less permanent hangars and Nissen huts, to which is added a control tower, described as unique to East Wretham. The ground is covered with grass and is of a sandy nature which is much appreciated by the crews. The single runway 2-20 is covered with steel mesh. The airfield is surrounded by trees and is located west of the village of East Wretham, Norfolk.
Like many other squadrons, 115 Squadron consists of two flights A and B, each under the command of a Squadron Leader, themselves under the command of a Wing Commander. Crews generally represent 10% of the base personnel. For non-flying personnel the day invariably starts with the DI's daily inspection, first the engines, and then all lines and hoses, every detail being collated in the snag book by the mechanics. At the same time, adjusters and inspectors inspect flight controls and the entire hydraulics and pneumatics systems. A particular group looks after the electricity supply and checks the calibration of the electronics on board the bomber. They are not tied to a particular Lancaster and inspect aircraft after aircraft. In the case of a scheduled mission, the teams test the mechanics, electrics and electronics. The tests are conducted on the ground. In general, it awakens all the crew members who are still asleep says a mechanic.
In the event that the aircraft has not flown for more than two days or it has undergone repairs a flight check is conducted by the entire crew later in the afternoon. Then the bombs are transported from their bunker and loaded into the huge bomb bay. The Browning machine guns are cleaned and loaded with ammunition. It is not until the last moment that the ground staff, after checking the oil levels of each engine, refuel the aircraft with 100 octane fuel. Meanwhile, crews attend their respective briefings, pilots, navigators, flight engineer, radio operator, gunners and the bomb aimer. Finally, after the weather briefing, they are all given the usual wakey-wakey Benzedrine tablets by the doctors.
Constant deliveries of new bombers cover the losses. DS690 is thus made available in early July, after Armstrong-Whitworth technicians and staff quickly perform final adjustments after several flight tests. Declared ready for service, the bomber is given a single letter code to be added to the 115 Squadron KO marking allocated at the beginning of hostilities.
For DS690 it is C-for-Charlie. Since the conversion of the Squadron to the Lancaster Mk. II in March 1943, this is the third aircraft to carry this marking, the previous two having been lost on operations together with their entire crews.
The weaknesses of the Lancaster are known.
Foremost is the absence of any active defence under the fuselage of the bomber. No turret is installed below the aircraft and even more dangerous no look out can be maintained at night. Harris’ opinion is that a pair of machine guns and a gunner is more weight and less bomb load.
Secondly, even if numerous, these machine guns, two in the nose, two on the back and four in the tail, are only.303 inches calibre. This is similar to the 7.62mm NATO rifle. The opposing night-fighters are equipped with 20mm and sometimes 30mm guns. The Chief of Bomber Command, however, believes that darkness is the best ally of the bomber, adding that if we increase the calibre, it adds weight. Moreover, the rules of engagement are set by the pilot who allows firing at range in response to a prior attack or when the gunner is sure that the enemy fighter has located the bomber. The presence of the gunners is mainly for psychological benefit, their passive role often being reduced to that of an armed vigil rather than as an active defensive element like on American bombers.
The third weakness is structural. The Lancaster is designed as a flying bomb bay with the fuel tanks housed exclusively in the wings. In fact, there are three inter-connecting tanks in each wing, the first between the fuselage and inboard engine, the second between the two engines and the third beyond the outboard engine. During the flight, the load is centred on the fuselage due to the presence of the bomb load, and fuel is distributed evenly between the tanks. Returning from the target, the contents of the external tanks are distributed in the tanks located near the lighter airframe, so as not to overload the wings. The fuel is permanently stored near the fuselage.
The fourth and final inconvenience is also related to the structure of the aircraft. Due to the presence of a spar that can hinder access to the main entrance door, the escape hatches located in the nose and tail only measure approximately 70cm (27.5in.) by 50cm (19.7in.).
The development of engine mass production under the Packard licence which guarantees constant supply and the necessary operational reliability, signs the death warrant of the production of the Mk. II model after 301 units have been built. The rythm of production of this type of Lancaster being 5 aircraft per week and per plant, at an average cost of 42.000 £ per unit, meaning an actual value of 1.800.000,00 Euros.
The Bristol Hercules engine is entirely reliable and continues its brilliant career equipping other heavy bombers, like the Halifax Mk. III variant, which so fitted has paradoxically better technical characteristics than the original Mk. II. Thus once again, by a curious irony of history, proving Harris correct...
Gradually assigned to training units, the last operationnal flight of a Lancaster Mk. II is made in September 1944. The aircraft was not unworthy, with an average of 150 hours of operational flight recorded per aircraft constructed.
Picture’s credit to : Avrosysdemons.co.uk, avrosysdemons.co.uk, aviation-militaire.kazeo.com, ww2aircraft.com, ww2vehicles.com, lancaster-archive.com, ww2aircraft.net, lancasterheritagecentre, aeromovies.fr, hidehalldemon.co.uk, secondworldwar.org, lancasterdiary.com, iwmorg.co.uk, ww2aircraft.net, jn.passieux.fr, jn.passieux.fr, rayalordinancesurvey, - , - ,network54.com, Mr Pierre Michiels, Mr Pierre Michiels