NOTES AND REFERENCES
- C. H. Gibbs-Smith, The Aeroplane: An Historical Survey. (HMSO for The Science Museum, London, 1960), p. 154.
- American bombers operated by the RAF during and after the Second World War are not considered.
- i.e., aeroplanes designed primarily at the manufacturer's expense, although prototype manufacture might be supported by official contract.
- The protagonists were Cdr Murray F. Sueter RN, Director of the Admiralty Air Department andFrederick Handley Page and his chief designer, George R. Volkert, See Chaz Bowyer, Handley Page Bombers of the First World War. (Aston Publications Limited, Bourne End, 1992), p. 9.
- There are at least two stories of the origin of the phrase. Ibid., p. 9.
- Francis K. Mason, The British Bomber since 1914. (Putnam Aeronautical Books, London, 1994), pp. 43–47. Also Bowyer, op. cit., pp. 9–10.
- The aeroplane was to fit inside a 70 foot square shed when the wings were folded. Ibid., p. 44 andBowyer, op. cit., p. 9.
- The Russian pioneer Igor Sikorsky had experimented before the War with very large aeroplanes. Twovery large British flying boats, the Wight Twin and the HB 1000, had been built as prototypes but the 0/100 was the first large aeroplane produced in quantity in Britain. Mason, op. cit., pp. 25–26 and 27–28.
- Bowyer, op. cit., p. 10.
- Regarding the performance indicators discussed in this paper: a. Maximum Speed is measured in level flight with engines at full throttle and with unsupercharged piston engines is achieved at sea level. With supercharged engines, maximum speed is achieved at the greatest altitude at which the supercharger can maintain sea level engine power (lull throttle height'). In this paper, maximum speeds are compared without reference to the heights at which they were achieved. b. Service Ceiling. Service ceiling is the altitude at which the rate of climb falls to 100 feet per min-ute. c. Range. Range figures are either as published or as calculated by assuming a speed of 80 of the maximum throughout the flight. All range figures should be regarded with caution since, as a general rule, range can be extended by reducing the bomb load; published figures are assumed to be with maximum bomb load unless indicated otherwise.
- Aeroplanes at this period were commonly fitted with alternative engines of either higher or lower power than those nominally specified; thus, for example, the 0/400 might be fitted with 275 hp Sunbeam Maori or 350 hp Liberty 12-N engines instead of Rolls Royce Eagle VIHs. Mason, op. cit., P. 94.
- Two guns in the nose, two at the dorsal position amidships and one firing downwards and rearwards through a hatch. Mason, op. cit., p. 94.
- Mason, op. cit., p. 94. Other writers give figures for 0/400 production ranging from 549 to 702; since numbers serve only to indicate the relative success of a design, these discrepancies are not considered significant to the conclusions of this paper.
- E.g., Specification A3B, for a twin-engined aeroplane carrying 3000 lb of bombs, with 300 miles range at 80 mph maximum; three Lewis guns were to be fitted and a crew of three was to be carried (Specification A3B, 1 October 1917, Public Record Office (PRO) AIR 2/948, File AB 275/5447, Pt I, 8th enclosure).
- Mason, op. cit., p. 108.
- The Blackburn Aeroplane and Motor Co Ltd, of Leeds and Brough, Yorkshire.
- Short Brothers Ltd, Rochester; later Short Brothers and Harland Ltd, Belfast.
- This bomb was carried externally beneath the fuselage; the normal (internal) bomb load was 7500 lb (30 x 250 lb bombs).
- The V/1500 weighed 30,000 lb compared with 14,000 lb for the 0/100.
- The first use of a rear gunner in a British heavy bomber.
- Vickers Limited (Aviation Department), of Bexley, Crayford and Weybridge, later Vickers (Aviation) Ltd and then Vickers-Armstrongs Ltd, of Weybridge and Wisley, Surrey.
- Vimy performance with two 375 hp Rolls Royce Eagle VIII engines. PRO AIR 2/948, File AB 275/ 5447, Pt I, 1st enclosure.
- Memo from 'CTD' to 'CGE', 7 May 1918. PRO AIR 2/948, File AB 275/5447, Pt I, 18th enclosure.
- W. G. Tarrant Ltd, of Byfleet, Surrey; the Tabor was their only attempt at a complete aeroplane. Mason, op. cit., p. 127.
- Designed by Kennedy Aeroplanes Limited, South Kensington, but built by the Fairey Aviation Co Ltd, Hayes, Middlesex. Mason, op. cit., p. 92.
- The Giant was very large, with a tare weight of 19,000 lb. With four 200 hp engines, it failed to take off even when taxied downhill at full throttle. Mason, op. cit., p. 92.
- The British and Colonial Aeroplane Co Ltd, Filton; later the Bristol Aeroplane Co Ltd.
- The Grahame-White Aviation Co Ltd, Hendon.
- Nieuport (England) Limited, Cricklewood.
- The Siddeley Deasy Motor Car Co Ltd, Coventry; later Armstrong-Siddeley Motors Ltd.
- Over 55,000 aeroplanes of all types were built in Britain during the First World War.
- The Tabor had six engines, the uppermost pair being some 28 feet above the ground; after taxying round the Farnborough airfield, the Tabor was turned into wind and a take-off run commenced using the lower four engines. At about 60 mph, tail up, the upper engine throttles were opened, creating an uncontrollable nose-down pitching moment and the aeroplane was destroyed, both pilots being killed. Minute, Brig-Gen R. Brooke-Popham, Director of Research, to Gen Sir Edward Ellington, Director General of Supply and Research, 30 May 1919. PRO AIR 2/1037, Minute 2.
- However, experiments in 1918 with metal construction were inspired by fears of a timber shortage. Questions Relating to Metal Construction, 1918–20. PRO MR 2/58/52536/18.
- Loads in flight act in the opposite direction to loads on the ground; two sets of bracing wires were thus required, known respectively as 'flying' and 'landing' wires.
- Reduced to its simplest structural terms, an aeroplane is an assembly of beams carrying complex com-binations of bending and torsion loads, which change continuously as the aeroplane manoeuvres or encounters atmospheric turbulence.
- Calculations were supported by strength testing of components during the design of the 0/100 (Bowyer, op. cit., p. 10); so far as is known, this practice was followed in the design of all subsequent heavy bombers.
- By the Admiralty Air Department. K. J. Meekcoms, "The origins and evolution of design requirements for British military aircraft", Proceedings of the Institution of Mechanical Engineers, 1990 vol 204 no G2, p. 147.
- President of The Newcomen Society, 1947–49.
- A. P. Thurston, "Reminiscences of Early Aviation (Presidential Address)", Transactions of The Newcomen Society, Volume 27 (1949–51), p. 5.
- i.e., engines with cylinders arranged in line along the engine in one or more 'banks'.
- i.e., engines with their cylinders arranged radially on a cylindrical crank-case in one or more 'rows'.
- Inevitably, the pitch was selected for best performance in cruising flight, which reduced the acceler-ation during take-off (rather like trying to drive away a car in top gear) and increased the ground run required.
- Bowyer, op. cit., p. 9.
- C. Ellam, "Developments in Aircraft Landing Gear, 1900-1939", Transactions of the Newcomen Society, Vol 55 (1983–84), pp. 48–51.
- Before the Second World War, the Air Ministry issued contractual specifications. During the war, responsibility for specifications passed first to the Ministry of Aircraft Production and then to the Ministry of Supply. For simplicity, the paper disregards these transfers of responsibility and uses the term 'Air Ministry' throughout.
- The Virginia continued to be issued to newly-formed bomber squadrons until 1935 and was not finally withdrawn from bombing duties until February 1938.
- Report by Armament Experimental Station, Notes on Multi-Engine Bombers, 31 March 1918, PRO AIR 2/732, E26.
- Letter, Siddeley-Deasy Motor Car Co Ltd to Air Ministry, 18 April 1918, PRO AIR 2/732.
- Replacing Ministry of Munitions publication, HB 806 (1918). Meekcoms, op. cit., p. 147.
- Howard (Ed) Theory and Practice of War; Essays presented to Captain B. H. Liddell Hart, p. 94.
- The Virginia engines produced 1160 hp compared with 720 hp for the Vimy.
- The Virginia could carry 3000 lb of bombs over a range of 985 miles and the maximum speed was 108 mph.
- The Hyderabad bomb load was 1100 lb, the range 500 miles and the maximum speed 109 mph while, at 14,750 lb, the Hinaidi was 750 lb heavier, with a bomb load of 1568 lb, a range of 840 miles and a maximum speed of 115 mph.
- This number was surpassed only during re-armament for the Second World War.
- The Fairey Aviation Co Ltd, Hayes and Stockport.
- The extent of that prejudice may be judged from the fact that AP 970 did not address the design of monoplanes until the 1930 edition. Meekcoms, op. cit., p. 148.
- The Chief of the Air Staff decided on 6 June 1934 to equip one squadron with Hendons. Note summar-ising the decision, PRO AIR 2/850, Enclosure 20A.
- Probably because the specification tare weight was limited to 6500 lb as proposed by the Geneva Disarmament Conference; this limit was later discarded. Mason, op. cit., p. 292.
- They were the first British heavy bombers to exceed 200 mph.
- A 'geodetic' curve follows the shortest distance between two points on a curved surface. The Wellington structure used two sets of curves, so that members met at right-angles to form a self-sup-porting network which required minimal internal framing and provided alternative load paths if a mem-ber was severed.
- Sir W. G. Armstrong-Whitworth Aircraft Ltd, of Coventry.
- The Treasury levied a heavy, retrospective Excess Profits Tax, while the Air Ministry cancelled 92% of outstanding contracts; the effect on industry was calamitous. Mason, op. cit., p. 116.
- "Mr. Handley Page informed me that he could greatly reduce the weight of the Hinaidi by fitting metal wings. I should like this investigated but as far as I know he has no experience in metal work" Minute, Chief of the Air Staff to Air Member for Supply and Research, 25 March 1927. PRO AIR 2/781, Minute 1.
- ". . it is very doubtful whether that firm could produce a satisfactory metal Hinaidi more than 200 lbs lighter than the present composite one . . .". Memo, Gp Capt H. M. Cave, for Director of Technical Development, to Air Member for Supply and Research, 6 April 1927. PRO AIR 2/781, Enclosure 3A.
- Possibly because RAF experience in the Middle East, and India showed that wooden aeroplanes did not survive well in conditions of high, and variable humidity and temperature; recurrent fears of a timber shortage may also have played a part.
- The short title of A. V. Roe & Co Ltd, Hamble and Manchester.
- Napier, Rolls Royce, Bristol and Armstrong-Siddeley.
- Providing 'fine pitch' for take-off and landing or 'coarse pitch' for climbing and cruising.
- The generators produced at least 1500 watts at 24 volts dc; on some Marks of Wellington the power generated reached 3000 watts.
- AP 1578C, L, M, N & P, Pilot's Notes for Wellington III, X, XL XII, XIII & XIV (Air Ministry, January 1944), pp. 9–11.
- Air Staff Requirement for Night Bomber Heyford Replacement, (undated but thought to be March 1934). PRO AIR 2/279, Enclosure 5A.
- 'In order to increase the flexibility . . . should be suitable not only as a night bomber but also as a bomber-transport in an emergency. Load carrying capacity and range are, therefore, of primary import-ance and all round defence is essential. The minimum requirements . . . are, therefore . . . a range of 1260 miles at normal RPM, with a crew of 5 whilst carrying 1500 lb of bombs. The . . . fuselage should be so designed that 10 troops in addition to the crew can be carried when the aircraft is employed as a transport. . . nose, tail and amidships gun positions will be required.' Ibid., p. 1.
- '. . . In laying out the bodies for my performance estimates . . . a body to accommodate. . 10 troops is necessarily so much larger than that required for the pure bomber that the top speed performance is 10 mph less than that of the pure bomber.' Minute from R. N. Lipptrot, RDA3, to Assistant Director/ RDA and Director of Technical Development, 10 May 1934. PRO AIR 2/729, Enclosure 9A.
- Letter, Air Marshal Sir Hugh Dowding (Air Member for Supply and Research) to Air Chief Marshal Sir Edward Ellington (Chief of the Air Staff), 2 August 1934, PRO AIR 2/729, Enclosure 29A.
- The choice was heavily influenced by quotations for prototypes. Note by Air Member for Supply and Research, 16 August 1934. PRO AIR 2/729, Enclosure 33A.
- The Whitley had a maximum weight of 33,500 lb, a maximum speed of 230 mph and a maximum bomb load of 7000 lb.
- In 1932, it had been thought that 'no bomb heavier than 500 lb would be needed'. David Devine, The Broken Wing. (London, Hutchinson, 1966), p. 190.
- The Vulture had 24 cylinders and a single crankshaft. Bearing areas were severely limited and lubrica-tion was difficult. The Vulture produced 1760 hp (about 300 hp less than two Merlins) as fitted to the Manchester but reliability was never acceptable.
- The Royal Aircraft Establishment, Farnborough, Hampshire.
- The system used an enlarged warship-type catapult mechanism, and was, rather quaintly and certainly inaccurately, known as "Frictionless Take Off".
- The prototype was written-off on its first flight by the complete collapse of the landing gear, which led to the fuselage 'breaking its back'.
- In particular, stressing of the wing seems to have ignored the contribution to bending strength of the wing skins and stringers; this was corrected when the design was adapted for the Lancaster. Letter, H. B. Howard (RAE) to Ministry of Aircraft Production, 27 November 1940. PRO AVIA 15/590, Enclosure 12A.
- '. . . the only way of using the complete Manchester production organisation . . . when production of Vulture engines ceases.' Minute, N. E. Rowe (for Deputy Director/RDA) to Director of Technical Development, 25 August 1940. PRO AVIA 15/590, Minute 2.
- William Green, Famous Bombers of the Second World War, Volume 2. (Doubleday & Company Inc, Garden City, New York, 1967). P. 86.
- Ibid., p. 87.
- Bruce Robertson, Halifax Special. (London, Ian Allan Ltd, 1990). p. 69.
- Gee used transmissions from ground stations in Britain to fix the position of an aeroplane without ref-erence to stars or surface features and entered service, with a range of 350 miles, in February 1942, in about one-third of all Bomber Command aircraft. AP 103D, Volume 1, Chapter 4, Aircraft Navigation Aids. London, Air Ministry; also Denis Richards, The Hardest Victory. (London, Hodder & Stoughton Ltd, 1994). p. 114.
- Radar which mapped ground features on a cathode ray tube display in the aeroplane.
- Roy Chadwick, Avro Chief Designer, realised that the Manchester would be overweight and the Vulture unsatisfactory; he therefore initiated design of a four-engined development. Harald Penrose, Architect of Wings (Airlife Publishing, Shrewsbury, 1985), pp. 185–187.
- Chadwick emphasized this feature when describing the Lancaster to the aeronautical press in 1942. "The Avro Lancaster", Flight, August 13, 1942, reproduced in Lancaster Portfolio (London, Brooklands Books/Aeroplane Monthly, 1990), p. 10.
- The Lancaster structure accounted for about 30% of the maximum weight.
- AP 2062 A,C,F-PN, Pilot's and Flight Engineer's Notes, Lancaster Mark I, Mark III & Mark X. (Air Ministry, London, May 1944). pp. 10 & 11.
- Known initially as the Lancaster Mark IV
- A version with Rolls Royce Clyde turboprop engines was proposed but not built. Mason, op. cit., p. 353.
- Aspect ratio is wing span divided by mean chord; cruise performance of aeroplanes, particularly near the service ceiling, is improved by increasing the aspect ratio but the choice of aspect ratio is also influenced by other considerations; e.g., wings of higher aspect ratio tend to be heavier.
- A 'quango' set up after the First World War to advise the Air Ministry on aeronautical research.
- Commonly known by its initials, NACA, the Committee changed its name, with the inception of the American space programme, to the National Aeronautics and Space Agency.
- The pitch of a 'constant speed' propeller varied to maintain a pre-set engine speed; a further develop-ment allowed 'feathering' of the blades, i.e., turning them to lie in line of flight, when an engine was shut down in flight.
- Michael J. F. Bowyer, The Stirling Bomber. (Faber & Faber, London, 1980), pp. 32, 41, 43, 54, 56, 92, 105, 110 and 154.
- 'Generally considered, with proper training, it would be possible to be pretty certain of being within one's objective by a distance of ten to fifteen miles, even if one could not see the ground'. Sir Henry Tizard, quoted in Ronald W. Clark, lizard. (Methuen, London, 1965). p. 190.
- Blue Danube was about 24 feet long and 5 feet 8 inches in diameter and weighed about 15,000 lb.
- Described by Handley Page in 1952 as a 'crescent' wing. Andrew Brookes, Postwar Military Aircraft 6: Handley Page Victor. (Ian Allan Ltd, Shepperton, 1988), p. 14.
- Barry Jones, "Short's Chameleon", Aeroplane Monthly, July 1995, p. 13.
- Kuchemann or Whitcomb bodies.
- Metal foil strips cut to reflect radar transmissions and impede radar surveillance.
- In order of building, Avro 707, Avro 707B, Avro 707A (two built) and Avro 707C (a two seat variant).
- Brookes, op cit., pp. 18–20.
- Brookes, op. cit., pp. 52–54.
- Vulcan Mark II Aircrew Manual, quoted in: Tim Laming, The Vulcan Story. (Arms and Armour Press, London, 1993), pp. 186–188; also Brookes, op. cit., p. 51.
- Blue Steel was a small, unmanned aircraft, powered by a liquid fuel rocket motor and carrying a nuclear warhead; its range after release was about 100 miles.
- Mach Number is airspeed divided by the speed of sound; Mach 2.5 implied an airspeed of about 1650 mph.
- i.e., thin skins separated by a metal foil honeycomb, placed endwise and bonded to them.
- Author's experience.
- The policy was declared in the 1957 Defence White Paper.
- Minute and response, both dated 21 September 1932. PRO AIR 2/850, Enclosure 7A.
- Specification B3/34, 3 July 1934. PRO AIR 2/729, Enclosure 21A.
- Minute from 'Plans' (Gp Capt A. T. Harris) to 'F01', 6 March 1934. PRO AIR 2/729, Minute 4.
- Minute from Deputy Director, Operational Requirements to Deputy Chief of the Air Staff, 3 May 1936, covering the first draft of Spec B12/36. PRO AIR 2/2629, Minute 1.
- Notes of a Conference held on 12 February 1937. PRO AIR 2/2734, Enclosure 2A.
- Notes of a Conference held on 12 March 1937. PRO AIR 2/2734, Enclosure 2B.
- From issue of the first specification to first flight of the prototype.
- From first flight to entry into service.
- From entry into service to withdrawal from bombing duties.
- The Ilya Mourometz Type B spanned 101 ft-6 in and maximum weight was 10,600 lb.
- Wing span of the R-VI was 138 ft-3 in and maximum weight was 26,900 lb.
- The Tupolev TB-3, which served from 1932 until the beginning of the Second World War, had a wing span of 120 ft-0 in and carried a maximum bomb load of 3300 lb at 155 mph.
- Registered as a trade mark in the USA.
- United States Army Air Force.
- Achieved by the use of highly supercharged engines.
- The B-17C had one 0.303 inch and six 0.5 inch machine guns; the later B17E had three 0.303 inch and eight 0.5 inch guns.
- Unless otherwise stated, data is taken from the appropriate pages of Mason, op. cit.
- Date of withdrawal as a bomber; some aircraft served after this date in other roles.
- Numbering of specifications was rationalised as a serial number, starting with '1 ' each year, and two digits indicating the year of issue.
- 'HP 33' designated the prototype Hinaidi and a small number of Mark I aeroplanes converted from Hyderabads; 'HP 36' designated new build Mark II aeroplanes.
- A letter preceding the serial number indicated the class of aeroplane covered by the specification, e. g., 'B' for bomber, 'C' for bomber/transport.
- The prototype was designated 'HP 38'; production aircraft were designated 'H P 50'.
- Vickers gave a different type number to each Wellington and Warwick Mark; the first and last only are noted.
- Handley Page also gave a different type number to each Mark; the first and last only are noted.
- Three prototype aircraft only were completed, each allocated a different type number.
- Operational Requirement, the basis of any subsequent specification.
- This prototype (a modified Hyderabad) flew before the formal specification was issued.