Yellow Sun (nuclear weapon)
Yellow Sun was the first British operational high-yield strategic nuclear weapon. The name refers only to the outer casing; the ENI or electronic neutron initiator was Blue Stone. The casing was some 21 feet long, 48 inches in diameter; the Mark 1 version with the Green Grass warhead weighed 7,250 pounds. The Mk.2 version with the lighter 1,700 pounds Red Snow warhead had ballast added to maintain overall weight and aerodynamic properties, avoid further lengthy and expensive testing, changes to the electrical power generating and airburst fuze. Unlike contemporary United States bombs of similar destructive power, Yellow Sun did not deploy a parachute to retard its fall. Instead it had a flat nose which induced drag, thereby slowing the fall of the weapon sufficiently to permit the bomber to escape the danger zone. Additionally, the blunt nose ensured that Yellow Sun did not encounter the transonic/supersonic shock waves which had caused much difficulty with barometric fuzing gates which had plagued an earlier weapon, Blue Danube.
Electrical power was supplied by duplicated ram-air turbines located behind the twin air intakes in the flat nose. The earlier Blue Danube design had relied on lead–acid batteries which had proven to be both unreliable and to require time-consuming pre-flight warming. Yellow Sun Stage 1 and Stage 2 were the original designations. Stage 1 was intended as an interim design to carry a one megaton Green Bamboo warhead of the "layer-cake" type thought similar to the Soviet JOE.4 and the US "Alarm Clock" concepts. These hybrid designs are not now regarded as thermonuclear, but were thought to be a stepping-stone on the route to a fusion bomb. Stage 2 was to follow when a true thermonuclear warhead based on the Granite design became available; the 45-inch diameter of Green Bamboo determined the 48 inch diameter of both Yellow Sun and the Blue Steel missile. After Green Bamboo was abandoned a decision was made to use the Interim Megaton Weapon known as Green Grass in the Yellow Sun casing and designate it as Yellow Sun Mk.1 until better warheads were available for a Mk.2.
Green Grass was of similar layout to Green Bamboo, although it was not thermonuclear, being a large unboosted pure fission warhead, based in part on the core of the Orange Herald device tested at Grapple, with some of the implosion and firing features of Green Bamboo. Twelve Green Grass warheads were fitted in larger, older casings derived from Blue Danube and known as Violet Club; these twelve warheads were transferred to the Yellow Sun Mk.1 casings and supplemented by further warheads totalling 37. Green Grass yield was stated to the Royal Air Force as 500 kilotons of TNT equivalent, but the designers estimate was revised downwards to 400 kt of TNT; the Green Grass warhead was never tested. It used a dangerously large quantity of fissile material – thought to be in excess of 70 kilograms, more than an uncompressed critical mass, it was kept subcritical by being fashioned into a thin-walled spherical shell. To guard against accidental crushing of the core into a critical condition, the shell was filled with 133,000 steel ball-bearings, weighing 450 kilograms.
In a conflict, these would have had to be removed before flight. The RAF thought it unsafe. Red Snow was the US W28 warhead used in the US Mk-28 nuclear bomb; this was anglicised to adapt it to British engineering practices, manufactured in Britain using British fissile materials. For further information see the "Deployment" section below. Deployment started in 1959-60; the RAF Service designations were Bomb, Aircraft HE 7000 lb HC Mk.1 or Bomb, Aircraft HE 7000 lb HC Mk.2. Yellow Sun Mk.1 was intended as an "emergency" weapon, had not been engineered for reliable long-term stockpiling. It was always envisaged that a Mk.2 version would be available fitted with a true thermonuclear warhead derived from the Granite type tested at Grapple, or an American type made available after the 1958 Anglo-US Bilateral Agreement. It was carried only by RAF V bombers. In September 1958 a decision was made to abandon the Granite type warheads intended for Yellow Sun Mk.2 and instead adopt the US W-28 warhead used in the US Mk-28 nuclear bomb.
This was anglicised to adapt it to British engineering practices, manufactured in Britain using British fissile materials and known as Red Snow. Red Snow was more powerful and smaller than Green Grass, it was always envisaged that the Yellow Sun bomb casing would be adapted for successor warheads to minimise unessential development time and cost. Yellow Sun Mk. 2 entered service in 1961, remained the primary air-dropped strategic weapon until replaced with WE.177B in 1966. Although the first British designed thermonuclear weapon to be deployed, Yellow Sun was not the first to be deployed with the RAF. US Mk-28 and Mk-43 thermonuclear bombs and others had been supplied to the RAF for use in V bombers prior to the deployment of Yellow Sun; some bombers of the V-force only used American weapons supplied under dual-key arrangements. Rainbow Codes UK Nuclear and Chemical Weapons site Britain's Nuclear Weapons - note: contains much old inaccurate, information that may have been superseded in the light of subsequent de-classified, documents.
An account of the Green Grass warhead fitted in both Violet Club and Yellow Sun
Argus As 410
The Argus As 410 was a German air-cooled inverted V-12 light aircraft engine, first produced by Argus Motoren in 1938. The engine marked a departure from earlier Argus engines in that it had new construction techniques which gave the engine greater operating speeds and power; the engine featured smaller 105 mm x 115 mm cylinders with deep finned steel cooling slots, aluminum heads, geared supercharger, a steel alloy crankshaft and a magnesium alloy crankcase. The engine weighed 315 kg and produced 465 PS at 3,100 rpm. 28,700 engines were produced. A distinctive feature is the finned spinner ahead of the propeller; this is driven by the airflow as a windmill, used to power the actuator of the variable-pitch propeller. The more powerful and refined Argus As 411 was developed from it. Arado Ar 96 Focke-Wulf Fw 189 Henschel Hs 129A Pilatus P-2 Argus Fernfeuer Type: 12-cylinder air-cooled inverted V engine Bore: 105 mm Stroke: 115 mm Displacement: 11.949 L Dry weight: 315 kg Fuel system: Carburetor Cooling system: air Power output: 465 PS at 3,100 rpm Comparable engines de Havilland Gipsy Twelve Isotta Fraschini Delta Isotta Fraschini Gamma Ranger V-770 Walter SagittaRelated lists List of aircraft engines
Republic F-105 Thunderchief
The Republic F-105 Thunderchief was an American supersonic fighter-bomber used by the United States Air Force. The Mach 2 capable F-105 conducted the majority of strike bombing missions during the early years of the Vietnam War. Designed as a single-seat, nuclear-attack aircraft, a two-seat Wild Weasel version was developed for the specialized Suppression of Enemy Air Defenses role against surface-to-air missile sites; the F-105 was known as the "Thud" by its crews. As a follow-on to the Mach 1 capable North American F-100 Super Sabre, the F-105 was armed with missiles and a rotary cannon. First flown in 1955, the Thunderchief entered service in 1958; the single-engine F-105 could deliver a greater bomb load than some American heavy bombers of World War II such as the Boeing B-17 Flying Fortress and Consolidated B-24 Liberator. The F-105 was one of the primary attack aircraft of the Vietnam War. Although less agile than smaller MiG fighters, USAF F-105s were credited with 27.5 kills. During the war, the single-seat F-105D was the primary aircraft delivering the heavy bomb loads against the various military targets.
Meanwhile, the two-seat F-105F and F-105G Wild Weasel variants became the first dedicated SEAD platforms, fighting against the Soviet-built S-75 Dvina surface-to-air missiles. Two Wild Weasel pilots were awarded the Medal of Honor for attacking North Vietnamese surface-to-air missile sites, with one shooting down two MiG-17s the same day; the dangerous missions required them to be the "first in, last out", suppressing enemy air defenses while strike aircraft accomplished their missions and left the area. When the Thunderchief entered service it was the largest single-seat, single-engine combat aircraft in history, weighing 50,000 pounds, it could reach Mach 2 at high altitude. The F-105 could carry up to 14,000 lb of missiles; the Thunderchief was replaced as a strike aircraft over North Vietnam by both the McDonnell Douglas F-4 Phantom II and the swing-wing General Dynamics F-111 Aardvark. However, the "Wild Weasel" variants of the F-105 remained in service until 1984 after being replaced by the specialized F-4G "Wild Weasel V".
Republic Aviation started the Thunderchief as an internal project to replace the RF-84F Thunderflash, which first used the characteristic wing-root air intakes to make room for cameras in the nose section. The design team led by Alexander Kartveli examined some 108 configurations before settling on a large, single-engine AP-63FBX AP-63-31; the new aircraft was intended for supersonic, low altitude penetration to deliver a single, internally carried nuclear bomb. The emphasis was placed on low-altitude speed and flight characteristics and payload; the aircraft would be fitted with a large engine, a small wing with a high wing loading for a stable ride at low altitudes, less drag at supersonic speeds. Traditional fighter attributes such as maneuverability were a secondary consideration. Enthusiastic at first, the United States Air Force awarded Republic with a contract for 199 aircraft in September 1952. However, by March 1953, the USAF had reduced the order to 37 fighter-bombers and nine tactical reconnaissance aircraft, citing the approaching end of the Korean War.
By the time the F-105 mock-up had been completed in October 1953, the aircraft had grown so large that the Allison J71 turbojet intended for it was abandoned in favor of the more powerful Pratt & Whitney J75. Anticipating a protracted development of the engine, it was expected that the first aircraft would use the smaller Pratt & Whitney J57. Near the end of 1953, the entire program was canceled by the USAF due to a number of delays and uncertainties regarding the aircraft. However, on 28 June 1954, the USAF ordered 15 F-105s under the Weapon System designation WS-306A; the YF-105A prototype first flew on 22 October 1955, with the second YF-105A following on 28 January 1956. In spite of being powered by a less potent J57-P-25 engine with 15,000 pounds-force of afterburning thrust, the first prototype attained the speed of Mach 1.2 on its maiden flight. Both aircraft featured conventional wing root air intakes and slab-sided fuselages typical of the early jets. Insufficient power and aerodynamic problems with transonic drag, as well as Convair's experience with their F-102, led to a redesign of the fuselage to conform to the area rule, giving it a characteristic "wasp waist".
In combination with the distinctive forward-swept variable-geometry air intakes which regulated airflow to the engine at supersonic speeds and the J75 engine, this redesign enabled the F-105B to attain Mach 2.15. In March 1956, the USAF placed a further order for 17 RF-105Bs. In order to conduct the nuclear mission, an MA-8 fire control system, AN/APG-31 ranging radar, K-19 gunsight to allow for toss bombing were integrated; the first pre-production YF-105B flew on 26 May 1956. Five of the F-105C trainer variant were added to the procurement plan in June 1956, before being canceled in 19
An aircraft is a machine, able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines. Common examples of aircraft include airplanes, airships and hot air balloons; the human activity that surrounds aircraft is called aviation. The science of aviation, including designing and building aircraft, is called aeronautics. Crewed aircraft are flown by an onboard pilot, but unmanned aerial vehicles may be remotely controlled or self-controlled by onboard computers. Aircraft may be classified by different criteria, such as lift type, aircraft propulsion and others. Flying model craft and stories of manned flight go back many centuries, however the first manned ascent – and safe descent – in modern times took place by larger hot-air balloons developed in the 18th century; each of the two World Wars led to great technical advances. The history of aircraft can be divided into five eras: Pioneers of flight, from the earliest experiments to 1914.
First World War, 1914 to 1918. Aviation between the World Wars, 1918 to 1939. Second World War, 1939 to 1945. Postwar era called the jet age, 1945 to the present day. Aerostats use buoyancy to float in the air in much the same way, they are characterized by one or more large gasbags or canopies, filled with a low-density gas such as helium, hydrogen, or hot air, less dense than the surrounding air. When the weight of this is added to the weight of the aircraft structure, it adds up to the same weight as the air that the craft displaces. Small hot-air balloons called sky lanterns were first invented in ancient China prior to the 3rd century BC and used in cultural celebrations, were only the second type of aircraft to fly, the first being kites which were first invented in ancient China over two thousand years ago. A balloon was any aerostat, while the term airship was used for large, powered aircraft designs – fixed-wing. In 1919 Frederick Handley Page was reported as referring to "ships of the air," with smaller passenger types as "Air yachts."
In the 1930s, large intercontinental flying boats were sometimes referred to as "ships of the air" or "flying-ships". – though none had yet been built. The advent of powered balloons, called dirigible balloons, of rigid hulls allowing a great increase in size, began to change the way these words were used. Huge powered aerostats, characterized by a rigid outer framework and separate aerodynamic skin surrounding the gas bags, were produced, the Zeppelins being the largest and most famous. There were still no fixed-wing aircraft or non-rigid balloons large enough to be called airships, so "airship" came to be synonymous with these aircraft. Several accidents, such as the Hindenburg disaster in 1937, led to the demise of these airships. Nowadays a "balloon" is an unpowered aerostat and an "airship" is a powered one. A powered, steerable aerostat is called a dirigible. Sometimes this term is applied only to non-rigid balloons, sometimes dirigible balloon is regarded as the definition of an airship.
Non-rigid dirigibles are characterized by a moderately aerodynamic gasbag with stabilizing fins at the back. These soon became known as blimps. During the Second World War, this shape was adopted for tethered balloons; the nickname blimp was adopted along with the shape. In modern times, any small dirigible or airship is called a blimp, though a blimp may be unpowered as well as powered. Heavier-than-air aircraft, such as airplanes, must find some way to push air or gas downwards, so that a reaction occurs to push the aircraft upwards; this dynamic movement through the air is the origin of the term aerodyne. There are two ways to produce dynamic upthrust: aerodynamic lift, powered lift in the form of engine thrust. Aerodynamic lift involving wings is the most common, with fixed-wing aircraft being kept in the air by the forward movement of wings, rotorcraft by spinning wing-shaped rotors sometimes called rotary wings. A wing is a flat, horizontal surface shaped in cross-section as an aerofoil. To fly, air must generate lift.
A flexible wing is a wing made of fabric or thin sheet material stretched over a rigid frame. A kite is tethered to the ground and relies on the speed of the wind over its wings, which may be flexible or rigid, fixed, or rotary. With powered lift, the aircraft directs its engine thrust vertically downward. V/STOL aircraft, such as the Harrier Jump Jet and F-35B take off and land vertically using powered lift and transfer to aerodynamic lift in steady flight. A pure rocket is not regarded as an aerodyne, because it does not depend on the air for its lift. Rocket-powered missiles that obtain aerodynamic lift at high speed due to airflow over their bodies are a marginal case; the forerunner of the fixed-wing aircraft is the kite. Whereas a fixed-wing aircraft relies on its forward speed to create airflow over the wings, a kite is tethered to the ground and relies on the wind blowing over its wings to provide lift. Kites were the first kind of aircraft to fly, were invented in China around 500 BC.
Much aerodynamic research was done with kites before test aircraft, wind tunnels, computer modelling programs became available. The first heavier-than-air craft capable of controlled free-flight were gliders. A glider designed by Geo
The empennage known as the tail or tail assembly, is a structure at the rear of an aircraft that provides stability during flight, in a way similar to the feathers on an arrow. The term derives from the French language word empenner which means "to feather an arrow". Most aircraft feature an empennage incorporating vertical and horizontal stabilising surfaces which stabilise the flight dynamics of yaw and pitch, as well as housing control surfaces. In spite of effective control surfaces, many early aircraft that lacked a stabilising empennage were unflyable. So-called "tailless aircraft" have a tail fin. Heavier-than-air aircraft without any kind of empennage are rare. Structurally, the empennage consists of the entire tail assembly, including the tailfin, the tailplane and the part of the fuselage to which these are attached. On an airliner this would be all the flying and control surfaces behind the rear pressure bulkhead; the front section of the tailplane is called the tailplane or horizontal stabiliser and is used to provide pitch stability.
The rear section is called the elevator, is hinged to the horizontal stabiliser. The elevator is a movable aerofoil that controls changes in pitch, the up-and-down motion of the aircraft's nose; some aircraft employ an all-moving stabiliser and elevators in one unit, known as a stabilator or "full-flying stabiliser". The vertical tail structure has a fixed front section called the vertical stabiliser, used to restrict side-to-side motion of the aircraft; the rear section of the vertical fin is the rudders, a movable aerofoil, used to turn the aircraft's nose to one side or the other. When used in combination with the ailerons, the result is a banking turn referred to as a "coordinated turn"; some aircraft are fitted with a tail assembly, hinged to pivot in two axes forward of the fin and stabiliser, in an arrangement referred to as a movable tail. The entire empennage is rotated vertically to actuate the horizontal stabiliser, sideways to actuate the fin; the aircraft's cockpit voice recorder, flight data recorder and Emergency locator transmitter are located in the empennage, because the aft of the aircraft provides better protection for these in most aircraft crashes.
In some aircraft trim devices are provided to eliminate the need for the pilot to maintain constant pressure on the elevator or rudder controls. The trim device may be: a trim tab on the rear of the elevators or rudder which act to change the aerodynamic load on the surface. Controlled by a cockpit wheel or crank. an adjustable stabiliser into which the stabiliser may be hinged at its spar and adjustably jacked a few degrees in incidence either up or down. Controlled by a cockpit crank. A bungee trim system. Controlled by a cockpit lever. An anti-servo tab used to trim some elevators and stabilators as well as increased control force feel. Controlled by a cockpit wheel or crank. A servo tab used to move the main control surface, as well as act as a trim tab. Controlled by a cockpit wheel or crank. Multi-engined aircraft have trim tabs on the rudder to reduce the pilot effort required to keep the aircraft straight in situations of asymmetrical thrust, such as single engine operations. Aircraft empennage designs may be classified broadly according to the fin and tailplane configurations.
The overall shapes of individual tail surfaces are similar to wing planforms. The tailplane comprises the tail-mounted fixed horizontal movable elevator. Besides its planform, it is characterised by: Number of tailplanes - from 0 to 3 Location of tailplane - mounted high, mid or low on the fuselage, fin or tail booms. Fixed movable elevator surfaces, or a single combined stabilator or flying tail; some locations have been given special names: Cruciform tail - The horizontal stabilisers are placed midway up the vertical stabiliser, giving the appearance of a cross when viewed from the front. Cruciform tails are used to keep the horizontal stabilisers out of the engine wake, while avoiding many of the disadvantages of a T-tail. Examples include Douglas A-4 Skyhawk. T-tail - The horizontal stabiliser is mounted on top of the fin, creating a "T" shape when viewed from the front. T-tails keep the stabilisers out of the engine wake, give better pitch control. T-tails have a good glide ratio, are more efficient on low speed aircraft.
However, the T-tail has several disadvantages. It is more to enter a deep stall, is more difficult to recover from a spin. For this reason a small secondary stabiliser or tail-let may be fitted lower down where it will be in free air when the aircraft is stalled. A T-tail must be stronger, therefore heavier than a conventional tail. T-tails tend to have a larger radar cross section. Examples include the Gloster Javelin and McDonnell Douglas DC-9; the fin comprises rudder. Besides its profile, it is characterised by: Number of fins - one or two. Location of fins - on the fuselage, tail booms or wingsTwin fins may be mounted at various points: Twin tail A twin tail called an H-tail, consists of two small vertical stabilisers on either side of the horizontal stabiliser. Examples include the Antonov An-225 Mriya, B-25 Mitchell, Avro Lancaster, ERCO Ercoupe. Twin boom A twin boom has two fuselages or booms, with a vertical stabiliser on each, a horizontal stabiliser between them. Examples include the P-38 Lightning, de Havilla
Messerschmitt Me 163 Komet
The Messerschmitt Me 163 Komet was a German rocket-powered interceptor aircraft. Designed by Alexander Lippisch, it is the only rocket-powered fighter aircraft to have been operational and the first piloted aircraft of any type to exceed 1000 km/h in level flight, its performance and aspects of its design were unprecedented. German test pilot Heini Dittmar in early July 1944 reached 1,130 km/h, an unofficial flight airspeed record unmatched by turbojet-powered aircraft for a decade. Over 300 Komets were built, but the aircraft proved lackluster in its dedicated role as an interceptor and destroyed between 9 and 18 Allied aircraft against 10 losses. Aside from combat losses many pilots were killed during training. Work on the design started around 1937 under the aegis of the Deutsche Forschungsanstalt für Segelflug —the German Institute for the study of sailplane flight, their first design was a conversion of the earlier Lippisch Delta IV known as the DFS 39 and used purely as a glider testbed of the airframe.
A larger follow-on version with a small propeller engine started as the DFS 194. This version used wingtip-mounted rudders, which Lippisch felt would cause problems at high speed. Lippisch changed the system of vertical stabilization for the DFS 194's airframe from the earlier DFS 39's wingtip rudders, to a conventional vertical stabilizer at the rear of the aircraft; the design included a number of features from its origins as a glider, notably a skid used for landings, which could be retracted into the aircraft's keel in flight. For takeoff, a pair of wheels, each mounted onto the ends of a specially designed cross-axle, were needed due to the weight of the fuel, but the wheels, forming a takeoff dolly under the landing skid, were released shortly after takeoff; the designers planned to use the forthcoming Walter R-1-203 cold engine of 400 kg thrust, which like the self-contained Walter HWK 109-500 Starthilfe RATO booster rocket unit, used a monopropellant consisting of stabilized HTP known by the name T-Stoff.
Heinkel had been working with Hellmuth Walter on his rocket engines, mounting them in the He 112R's tail for testing - this was done in competition with Wernher von Braun's bi-propellant, alcohol/LOX-fed rocket motors with the He 112 as a test airframe - and with the Walter catalyzed HTP propulsion format for the first purpose-designed, liquid-fueled rocket aircraft, the He 176. Heinkel had been selected to produce the fuselage for the DFS 194 when it entered production, as it was felt that the volatile monopropellant fuel's reactivity with organic matter would be too dangerous in a wooden fuselage structure. Work continued under the code name Projekt X; the division of work between DFS and Heinkel led to problems, notably that DFS seemed incapable of building a prototype fuselage. Lippisch asked to leave DFS and join Messerschmitt instead. On 2 January 1939, he moved with his team and the completed DFS 194 to the Messerschmitt works at Augsburg; the delays caused by this move allowed the engine development to catch up.
Once at Messerschmitt, the team decided to abandon the propeller-powered version and move directly to rocket-power. The airframe was completed in Augsburg and in early 1940 was shipped to receive its engine at Peenemünde-West, one of the quartet of Erprobungsstelle-designated military aviation test facilities of the Reich. Although the engine proved to be unreliable, the aircraft had excellent performance, reaching a speed of 550 km/h in one test. In the Me 163B and -C subtypes, a ram-air turbine on the extreme nose of the fuselage, the backup lead-acid battery inside the fuselage that it charged, provided the electrical power for the radio, the Revi16B, -C, or -D reflector gunsight, the direction finder, the compass, the firing circuits of the cannon, some of the lighting in the cockpit instrumentation. There was an onboard lead/acid battery, but its capacity was limited, as was its endurance, no more than 10 minutes, hence the fitted generator; the airspeed indicator averaged readings from two sources: the pitot tube on the leading edge of the port wing, a small pitot inlet in the nose, just above the top edge of the underskid channel.
There was a further tapping-off of pressure-ducted air from the pitot tube which provided the rate of climb indicator with its source. In early 1941 production of a prototype series, known as the Me 163, began. Secrecy was such that the RLM's "GL/C" airframe number, 8-163, was that of the earlier Messerschmitt Bf 163. Three Bf 163-prototypes were built, it was thought that intelligence services would conclude any reference to the number "163" would be for that earlier design. In May 1941, the first prototype Me 163A, V4, was shipped to Peenemünde to receive the HWK RII-203 engine. By 2 October 1941, Me 163A V4, bearing the radio call sign letters, or Stammkennzeichen, "KE+SW", set a new world speed record of 1,004.5 km/h, piloted by Heini Dittmar, with no apparent damage to the aircraft during the attempt. Some postwar aviation history publications stated that the Me 163A V3 was thought to have set the record; the 1,004 km/h record figure was only surpassed after the war, by the American Douglas D-558-1 on 20 August 1947.
Ten Me 163As were built for further tests. During testing, the jettisonable main landing gear arrangement, of a differing design to that used on the B-series production aircraft, was a serious problem; the A-series dolly landing gear caused many aircraft to be damaged on takeoff when the wheels rebounded and crashed into the aircraft due to the sizable springs and shock absorbers on the A-series dolly devices which possessed well-sprung independent suspension systems for each mai