A Townend ring is a narrow-chord cowling ring fitted around the cylinders of an aircraft radial engine to reduce drag and improve cooling. The Townend ring was the invention of Dr. Hubert Townend of the British National Physical Laboratory in 1929. Patents were supported by Boulton & Paul Ltd in 1929. In the United States it was called a "drag ring", it caused a reduction in the drag of radial engines and was used in high-speed designs of 1930-1935 before the long-chord NACA cowling came into general use. Examples of aeroplanes with Townend rings were the Boeing P-26 Peashooter, Douglas O-38, Vickers Wellesley, the Westland Wallace and the Gloster Gauntlet. Early claims portrayed it as a superior design to the NACA cowling, but comparisons proved aircraft performance using a Townend ring was inferior to that of a NACA cowling when flying at airspeeds above 217 kn; the Spotters Glossary North, J D, "Engine Cowling: With Special Reference to the Air-cooled Engine", The Aircraft Engineer, XXIV No. 6: 133–137 North, J D, "Engine Cowling", The Aircraft Engineer, IX No. 2: 174a–174f "Engine Cowling", Flight, XXVI No. 7: 157–158, 15 February 1934
The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders "radiate" outward from a central crankcase like the spokes of a wheel. It resembles a stylized star when viewed from the front, is called a "star engine" in some languages; the radial configuration was used for aircraft engines before gas turbine engines became predominant. Since the axes of the cylinders are coplanar, the connecting rods cannot all be directly attached to the crankshaft unless mechanically complex forked connecting rods are used, none of which have been successful. Instead, the pistons are connected to the crankshaft with a master-and-articulating-rod assembly. One piston, the uppermost one in the animation, has a master rod with a direct attachment to the crankshaft; the remaining pistons pin their connecting rods' attachments to rings around the edge of the master rod. Extra "rows" of radial cylinders can be added in order to increase the capacity of the engine without adding to its diameter.
Four-stroke radials have an odd number of cylinders per row, so that a consistent every-other-piston firing order can be maintained, providing smooth operation. For example, on a five-cylinder engine the firing order is 1, 3, 5, 2, 4, back to cylinder 1. Moreover, this always leaves a one-piston gap between the piston on its combustion stroke and the piston on compression; the active stroke directly helps compress the next cylinder to fire. If an number of cylinders were used, an timed firing cycle would not be feasible; the prototype radial Zoche aero-diesels have an number of cylinders, either four or eight. The radial engine uses fewer cam lobes than other types; as with most four-strokes, the crankshaft takes two revolutions to complete the four strokes of each piston. The camshaft ring is geared to spin slower and in the opposite direction to the crankshaft; the cam lobes exhaust. For example, four cam lobes serve all five cylinders, whereas 10 would be required for a typical inline engine with the same number of cylinders and valves.
Most radial engines use overhead poppet valves driven by pushrods and lifters on a cam plate, concentric with the crankshaft, with a few smaller radials, like the Kinner B-5 and Russian Shvetsov M-11, using individual camshafts within the crankcase for each cylinder. A few engines use sleeve valves such as the 14-cylinder Bristol Hercules and the 18-cylinder Bristol Centaurus, which are quieter and smoother running but require much tighter manufacturing tolerances. C. M. Manly constructed a water-cooled five-cylinder radial engine in 1901, a conversion of one of Stephen Balzer's rotary engines, for Langley's Aerodrome aircraft. Manly's engine produced 52 hp at 950 rpm. In 1903–1904 Jacob Ellehammer used his experience constructing motorcycles to build the world's first air-cooled radial engine, a three-cylinder engine which he used as the basis for a more powerful five-cylinder model in 1907; this was made a number of short free-flight hops. Another early radial engine was the three-cylinder Anzani built as a W3 "fan" configuration, one of which powered Louis Blériot's Blériot XI across the English Channel.
Before 1914, Alessandro Anzani had developed radial engines ranging from 3 cylinders — early enough to have been used on a few French-built examples of the famous Blériot XI from the original Blériot factory — to a massive 20-cylinder engine of 200 hp, with its cylinders arranged in four rows of five cylinders apiece. Most radial engines are air-cooled, but one of the most successful of the early radial engines was the Salmson 9Z series of nine-cylinder water-cooled radial engines that were produced in large numbers during the First World War. Georges Canton and Pierre Unné patented the original engine design in 1909, offering it to the Salmson company. From 1909 to 1919 the radial engine was overshadowed by its close relative, the rotary engine, which differed from the so-called "stationary" radial in that the crankcase and cylinders revolved with the propeller, it was similar in concept to the radial, the main difference being that the propeller was bolted to the engine, the crankshaft to the airframe.
The problem of the cooling of the cylinders, a major factor with the early "stationary" radials, was alleviated by the engine generating its own cooling airflow. In World War I many French and other Allied aircraft flew with Gnome, Le Rhône, Bentley rotary engines, the ultimate examples of which reached 250 hp although none of those over 160 hp were successful. By 1917 rotary engine development was lagging behind new inline and V-type engines, which by 1918 were producing as much as 400 hp, were powering all of the new French and British combat aircraft. Most German aircraft of the time used water-cooled inline 6-cylinder engines. Motorenfabrik Oberursel made licensed copies of the Gnome and Le Rhône rotary powerplants, Siemens-Halske built their own designs, including the Siemens-Halske Sh. III eleven-cylinder rotary engine, unusual for the period in being geared through a bevel geartrain in the rear end of the crankcase without the crankshaft being mounted to the aircraft's airframe, so that the engine's internal working components (fully in
The Saunders A.10 was a private venture four-gun fighter. It was a single-seat, single-engined biplane with poor handling serving as a gun-testing aircraft. After their first aircraft, the T.1, Saunders did not build another landplane until 1928 when the Saunders A.10 single-seat fighter appeared. The original design was a private venture, its distinguishing feature its four-gun armament at a time when two machine guns were standard; because of this the A.10 was sometimes referred to as the "Multi-gun". E. Saunders Ltd had been bought out by A. V. Roe and John Lloyd it is sometimes known as the Saunders/Saro A.10 or the Saro A.10. Air Ministry specification F.20/27 was issued during the design process and Saunders decided to submit the A.10 though that specification only called for two guns and suggested the use of the radial Bristol Mercury rather than the inline Rolls-Royce F. XIS that designer Harry Knowler had chosen; the Air Ministry provided an unsupercharged F. XI engine and the A.10 first flew on 27 January 1929.
It was a compact single bay sesquiplane with a duraluminum airframe, fabric covered throughout apart from the forward fuselage. The fuselage was built from tubular members, bolted together; the pilot sat with the upper wing at eye level to optimise the view both above and below, helped by cut-outs in the lower plane roots and a thinner aerofoil in the upper centre section. The breeches of all four guns were accessible to him, with two in the forward decking and two in the fuselage sides; the water-cooled engine's chin radiator sat behind a roller blind shutter, close to the twin-bladed propeller. The simple single axle undercarriage was mounted on a pair of inverted V-struts joining the fuselage ahead and aft of the lower wing; the broader chord, greater span upper wing carried the ailerons unbalanced but modified to Frise hinged type to lighten the feel. Stagger was exaggerated by the smaller chord of the lower wing, mounted on the bottom of the fuselage; the rudder and elevators, the latter mounted on a cantilever tailplane were unbalanced.
After the first flight and the aileron modifications, flight testing recommenced in March. In July it was decided to submit the aircraft under Air Ministry specification F.10/27 as well as F.20/27, the earlier specification calling for a six gun fighter. In armament terms, the A.10 fitted neither. In August 1929 it went to the Aeroplane and Armament Experimental Establishment for tests under F.20/27, armed with just two guns. The reports were critical: the A.10 suffered from longitudinal instability and was impossible to hold at constant speed in dives or in the climb. Ground handling was said to be difficult; these trials ended in January 1930 and the A.10 went back to Saro's for modification. Changes included a 3 in shift aft of the main undercarriage to improve ground handling, a 1 ft 9 in fuselage extension and revised empennage; the tailplane now had a straight, rather than swept leading edge. When it went back to the A&AEE in September most of the old faults remained and no more were ordered.
Curiously, in view of the A&AEE's comments on the problems the A.10's longitudinal instability would pose it as a gun platform, it was used by the Establishment to explore the effects of multi-gun armament, trials involving the Gloster SS.19. These lasted until December 1930 after a period of unserviceability, from 1932 to 1933. Data from London 1988, p. 92. General characteristics Crew: 1 Length: 24 ft 5 in Wingspan: 32 ft 0 in Height: 9 ft 9 in Wing area: 273 ft2 Empty weight: 2,674 lb Gross weight: 3,467 lb Powerplant: 1 × Rolls-Royce F. XI 12-cylinder water-cooled inline, 480 hp Performance Maximum speed: 200 mph Service ceiling: 29,000 ft Armament 2×0.303 in Vickers machine guns Notes Bibliography
An aileron is a hinged flight control surface forming part of the trailing edge of each wing of a fixed-wing aircraft. Ailerons are used in pairs to control the aircraft in roll, which results in a change in flight path due to the tilting of the lift vector. Movement around this axis is called'rolling' or'banking'; the modern aileron was invented and patented by the British scientist Matthew Piers Watt Boulton in 1868, based on his 1864 paper On Aërial Locomotion. Though there was extensive prior art in the 19th century for the aileron and its functional analog, wing warping, in 1906 the United States granted an expansive patent to the Wright Brothers of Dayton, for the invention of a system of aerodynamic control that manipulated an airplane's control surfaces. Considerable litigation ensued within the United States over the legal issues of lateral roll control, until the First World War compelled the U. S. Government to legislate a legal resolution; the name "aileron", from French, meaning "little wing" refers to the extremities of a bird's wings used to control their flight.
It first appeared in print in the 7th edition of Cassell's French-English Dictionary of 1877, with its lead meaning of "small wing". In the context of powered airplanes it appears in print about 1908. Prior to that, ailerons were referred to as rudders, their older technical sibling, with no distinction between their orientations and functions, or more descriptively as horizontal rudders. Among the earliest printed aeronautical use of'aileron' was that in the French aviation journal L'Aérophile of 1908. Ailerons had more or less supplanted other forms of lateral control, such as wing warping, by about 1915, well after the function of the rudder and elevator flight controls had been standardised. Although there were many conflicting claims over who first invented the aileron and its function, i.e. lateral or roll control, the flight control device was invented and described by the British scientist and metaphysicist Matthew Piers Watt Boulton in his 1864 paper On Aërial Locomotion. He was the first to patent an aileron control system in 1868.
Boulton's description of his lateral flight control system was both complete. It was "the first record we have of appreciation of the necessity for active lateral control as distinguished from.... With this invention of Boulton's we have the birth of the present-day three torque method of airborne control" as was praised by Charles Manly; this was endorsed by C. H. Gibbs-Smith. Boulton's British patent, No. 392 of 1868, issued about 35 years before ailerons were "reinvented" in France, became forgotten and lost from sight until after the flight control device was in general use. Gibbs-Smith stated on several occasions that if the Boulton patent had been revealed at the time of the Wright brothers' legal filings, they might not have been able to claim priority of invention for the lateral control of flying machines; the fact that the Wright brothers were able to gain a patent in 1906 did not invalidate Boulton's lost and forgotten invention. Boulton had described and patented ailerons in 1868 and they were not used on manned aircraft until they were employed on Robert Esnault-Pelterie’s glider in 1904, although in 1871 a French military engineer, Charles Renard and flew an unmanned glider incorporating ailerons on each side, activated by a Boulton-style pendulum controlled single-axis autopilot device.
The pioneering U. S. aeronautical engineer Octave Chanute published descriptions and drawings of the Wright brothers' 1902 glider in the leading aviation periodical of the day, L'Aérophile, in 1903. This prompted Esnault-Pelterie, a French military engineer, to build a Wright-style glider in 1904 that used ailerons in lieu of wing warping; the French journal L’Aérophile published photos of the ailerons on Esnault-Pelterie’s glider which were included in his June 1905 article, its ailerons were copied afterward. The Wright brothers used wing warping instead of ailerons for roll control on their glider in 1902, about 1904 their Flyer II was the only aircraft of its time able to do a coordinated banked turn. During the early years of powered flight the Wrights had better roll control on their designs than airplanes that used movable surfaces. From 1908, as aileron designs were refined it became clear that ailerons were much more effective and practical than wing warping. Ailerons had the advantage of not weakening the airplane's wing structure as did the wing warping technique, one reason for Esnault-Pelterie's decision to switch to ailerons.
By 1911 most biplanes used ailerons rather than wing warping—by 1915 ailerons had become universal on monoplanes as well. The U. S. Government, frustrated by the lack of its country's aeronautical advances in the years leading up to World War I, enforced a patent pool putting an end to the Wright brothers patent war; the Wright company changed its aircraft flight controls from wing warping to the use of ailerons at that time as well. Others who were thought to have been the first to introduce ailerons included: American John J. Montgomery included spring-loaded trailing edge flaps on his second glider: these were operable by the pilot as ailerons. In 1886 his third glider design used rotation of the entire wing rather than just a trailing edge portion for roll control. By his own accounts all of these changes in addition to his use of an elevator for pitch control provided "entire control of the machine in the wind, preventing it from upsetting." New Zealander Richard Pearse reputedly made a power
Hawker Sea Fury
The Hawker Sea Fury is a British fighter aircraft designed and manufactured by Hawker Aircraft. It was the last propeller-driven fighter to serve with the Royal Navy, one of the fastest production single reciprocating engine aircraft built. Developed during the Second World War, the Sea Fury entered service two years, it proved to be a popular aircraft with a number of overseas militaries, was used during the Korean War in the early 1950s, as well as against the 1961 Bay of Pigs Invasion of Cuba. The Sea Fury's development was formally initiated in 1943 in response to a wartime requirement of the RAF, thus the aircraft was named Fury; as the Second World War drew to a close, the RAF cancelled their order for the aircraft. Development of the Sea Fury proceeded, the type began entering operational service in 1947; the Sea Fury has many design similarities to Hawker's preceding Tempest fighter, having originated from a requirement for a "Light Tempest Fighter". Production Sea Furies were fitted with the powerful Bristol Centaurus engine, armed with four wing-mounted Hispano V cannons.
While developed as a pure aerial fighter aircraft, the definitive Sea Fury FB 11 was a fighter-bomber, the design having been found suitable for this mission as well. The Sea Fury attracted international orders as land-based aircraft; the type acquitted itself well in the Korean War, fighting even against the MiG-15 jet fighter. Although the Sea Fury was retired by the majority of its military operators in the late 1950s in favour of jet-propelled aircraft, a considerable number of aircraft saw subsequent use in the civil sector, several remain airworthy in the 21st century as heritage and racing aircraft; the Hawker Fury was an evolutionary successor to the successful Hawker Typhoon and Tempest fighters and fighter-bombers of the Second World War. The Fury's design process was initiated in September 1942 by Sydney Camm, one of Hawker's foremost aircraft designers, to meet the Royal Air Force's requirement for a lightweight Tempest Mk. II replacement. Developed as the "Tempest Light Fighter", the semi-elliptical wing of the Tempest was incorporated, but was shortened in span by eliminating the central bay of the wing centre-section, the inner part of the undercarriage wells now extending to the aircraft centreline, instead of being situated level with the fuselage sides.
The fuselage was broadly similar in form to that of the Tempest, but was a monocoque structure, while the cockpit level was higher, affording the pilot better all-round visibility. The project was formalised in January 1943 when the Air Ministry issued Specification F.2/42 around the "Tempest Light Fighter". This was followed up by Specification F.2/43, issued in May 1943, which required a high rate of climb of not less than 4,500 ft/min from ground level to 20,000 feet, good fighting manoeuvrability and a maximum speed of at least 450 mph at 22,000 feet. The armament was to be four 20mm Hispano V cannon with a total capacity of 600 rounds, plus the capability of carrying two bombs each up to 1,000 pounds. In April 1943, Hawker had received Specification N.7/43 from the Admiralty, who sought a navalised version of the developing aircraft. Around 1944, the aircraft project received its name. Six prototypes were ordered. Hawker used the internal designations P.1019 and P.1020 for the Griffon and Centaurus versions, while P.1018 was used for a Fury prototype, to use a Napier Sabre IV.
The first Fury to fly, on 1 September 1944, was NX798 with a Centaurus XII with rigid engine mounts, powering a Rotol four-blade propeller. Second on 27 November 1944 was LA610, which had a Griffon 85 and Rotol six-blade contra-rotating propeller. By now, development of the Fury and Sea Fury was interlinked so that the next prototype to fly was a Sea Fury, SR661, described under "Naval Conversion." NX802 was the last Fury prototype, powered by a Centaurus XV. LA610 was fitted with a Napier Sabre VII, capable of developing 3,400 to 4,000 hp. With the end of the Second World War in Europe in sight, the RAF began cancelling many aircraft orders. Thus, the RAF's order for the Fury was cancelled before any production examples were built because the RAF had excessive numbers of late Mark Spitfires and Tempests and viewed the Fury as an additional overlap with these aircraft. Although the RAF had pulled out of the programme, development of the type continued as the Sea Fury. Many of the Navy's carrier fighters were either Lend-Lease Chance-Vought Corsair aircraft and thus to be returned, or in the case of the Supermarine Seafire had considerable drawback