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, and is called a "star engine" in some other languages.
134-479: The Bristol Mercury is a British nine-cylinder, air-cooled, single-row, piston radial engine . Designed by Roy Fedden of the Bristol Aeroplane Company it was used to power both civil and military aircraft of the 1930s and 1940s. Developed from the earlier Jupiter engine, later variants could produce 800 horsepower (600 kW) from its capacity of 1,500 cubic inches (25 L) by use of
268-400: A Gloster Gladiator I ( G-AMRK ) which can be seen during flying displays at Old Warden Aerodrome , Bedfordshire. The Aircraft Restoration Company based at Duxford Airfield also operate a Mercury powered Westland Lysander ( G-CCOM ) as well as a Bristol Blenheim I ( G-BPIV ) light bomber fitted with two Bristol Mercurys, which can be seen at air displays at IWM Duxford as well as across
402-481: A Staffelkapitän identified as Hauptmann Albrecht von Ankum-Frank. Two other 109s were claimed by Blenheim gunners. Another successful raid on Haamstede was made by a single Blenheim on 7 August which destroyed one 109 of 4./JG 54, heavily damaged another, and caused lighter damage to four more. There were also some missions which produced an almost 100% casualty rate amongst the Blenheims. One such operation
536-411: A 14-cylinder twin-row version of the firm's 80 hp Lambda single-row seven-cylinder rotary, however reliability and cooling problems limited its success. Two-row designs began to appear in large numbers during the 1930s, when aircraft size and weight grew to the point where single-row engines of the required power were simply too large to be practical. Two-row designs often had cooling problems with
670-451: A 9-cylinder 980 cubic inch (16.06 litre) displacement diesel radial aircraft engine, the 225 horsepower (168 kW) DR-980 , in 1928. On 28 May 1931, a DR-980 powered Bellanca CH-300 , with 481 gallons of fuel, piloted by Walter Edwin Lees and Frederick Brossy set a record for staying aloft for 84 hours and 32 minutes without being refueled. This record stood for 55 years until broken by
804-685: A 9-cylinder radial diesel aero engine, was used in the M1A1E1 , while the Continental R975 saw service in the M4 Sherman , M7 Priest , M18 Hellcat tank destroyer , and the M44 self propelled howitzer . A number of companies continue to build radials today. Vedeneyev produces the M-14P radial of 360–450 hp (270–340 kW) as used on Yakovlev and Sukhoi aerobatic aircraft. The M-14P
938-632: A Blenheim from the Fighter Interception Unit (FIU) at RAF Ford achieved the first success on the night of 2–3 July 1940, accounting for a Dornier Do 17 bomber. The Blenheim was replaced by the faster and more heavily-armed Bristol Beaufighter in 1940–1941. On 11 June 1940, only hours after Italy's entry into the war on Germany's side, several Blenheim IVs bombed Italian positions. In mid-1940, reinforcement ferry routes were established throughout Africa, starting in Takoradi on
1072-678: A build-it-yourself kit. Verner Motor of the Czech Republic builds several radial engines ranging in power from 25 to 150 hp (19 to 112 kW). Miniature radial engines for model airplanes are available from O. S. Engines , Saito Seisakusho of Japan, and Shijiazhuang of China, and Evolution (designed by Wolfgang Seidel of Germany, and made in India) and Technopower in the US. Liquid cooling systems are generally more vulnerable to battle damage. Even minor shrapnel damage can easily result in
1206-537: 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, and 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, making the motion more uniform. If an even number of cylinders were used, an equally timed firing cycle would not be feasible. As with most four-strokes,
1340-399: A few French-built examples of the famous Blériot XI from the original Blériot factory — to a massive 20-cylinder engine of 200 hp (150 kW), 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 (and the earliest "stationary" design produced for World War I combat aircraft)
1474-745: A few months. The Mk IF proved to be slower and less manoeuvrable than expected, and by June 1940 daylight Blenheim losses caused concern for Fighter Command. The Mk IF was relegated mainly to night fighter duties where No. 23 Squadron RAF , which had already operated them at night, soon relegated them to night intruder operations as they were not effective as night fighters. In the German night-bombing raid on London on 18 June 1940, Blenheims accounted for five German bombers, thus proving that they were better-suited for night fighting. In July, No. 600 Squadron, by then based at RAF Manston , had some of its Mk IFs equipped with AI Mk III radar. With this radar equipment,
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#17327729961121608-543: A geared supercharger . Almost 21,000 engines were produced, with a number also being built under license elsewhere in Europe. Several examples remain airworthy, with other preserved examples on public display in aviation museums . The Mercury was developed by the Bristol Aeroplane Company in 1925 as their Bristol Jupiter was reaching the end of its lifespan. Although the Mercury initially failed to attract much interest,
1742-597: A huge variety of spare parts, although some of these had been damaged or otherwise destroyed through sabotage . Yugoslavia had ceased production of the Mk I and commenced a production run of Mk IVs just prior to the April 1941 invasion. The British-made Blenheims had RAF green interiors, RAF seat belts and instruments on imperial units, while Finnish-made Blenheims had medium grey interiors, Finnish-style seat belts and metric instruments. The Finnish Blenheims flew 423 missions during
1876-419: A loss of coolant and consequent engine overheating, while an air-cooled radial engine may be largely unaffected by minor damage. Radials have shorter and stiffer crankshafts, a single-bank radial engine needing only two crankshaft bearings as opposed to the seven required for a liquid-cooled, six-cylinder, inline engine of similar stiffness. While a single-bank radial permits all cylinders to be cooled equally,
2010-411: A metal frame covered with fabric. The undercarriage was hydraulically -retracted, with an auxiliary hand-pump for emergency actuation; medium-pressure tyres were used, complete with pneumatically -actuated differentially-control brakes. The Blenheim typically carried a crew of three – pilot, navigator/bombardier and wireless (radio) operator /air gunner. The pilot's quarters on the left side of
2144-677: A number of experiments and modifications) enough cooling air to the rear. This basic concept was soon copied by many other manufacturers, and many late-WWII aircraft returned to the radial design as newer and much larger designs began to be introduced. Examples include the Bristol Centaurus in the Hawker Sea Fury , and the Shvetsov ASh-82 in the Lavochkin La-7 . For even greater power, adding further rows
2278-510: A power-to-weight ratio near that of contemporary gasoline engines and a specific fuel consumption of roughly 80% that for an equivalent gasoline engine. During WWII the research continued, but no mass-production occurred because of the Nazi occupation. By 1943 the engine had grown to produce over 1,000 hp (750 kW) with a turbocharger . After the war, the Clerget company was integrated in
2412-606: A replica of the Electra". It was designated Type 135 . In early 1934, Lord Rothermere , owner of the Daily Mail newspaper, challenged the British aviation industry to build a high-speed aircraft capable of carrying six passengers and two crew members – he referred to the ambition as seeking "the fastest commercial aeroplane in Europe, if not the world". German firms were producing record-breaking high-speed designs, such as
2546-484: A semi-retracting Bristol Type B Mk I dorsal turret firing to the rear. From 1939 onwards, the Lewis gun was replaced by the more modern .303 in (7.7 mm) Vickers VGO machine gun . A 1,000 lb (450 kg) bomb load could be carried in the internal bomb bay set into the centre section of the fuselage. Like most contemporary British aircraft, the bomb bay doors were kept closed with bungee cords and opened under
2680-704: A similarly sized five-cylinder radial four-stroke model engine of their own as a direct rival to the OS design, with Saito also creating a series of three-cylinder methanol and gasoline-fueled model radial engines ranging from 0.90 cu.in. (15 cm ) to 4.50 cu.in. (75 cm ) in displacement, also all now available in spark-ignition format up to 84 cm displacement for use with gasoline. The German Seidel firm formerly made both seven- and nine-cylinder "large" (starting at 35 cm displacement) radio control model radial engines, mostly for glow plug ignition, with an experimental fourteen-cylinder twin-row radial being tried out -
2814-478: A single bank (or row) and an unusual double master connecting rod. Variants were built that could be run on either diesel oil or gasoline or mixtures of both. A number of powerhouse installations utilising large numbers of these engines were made in the U.S. Electro-Motive Diesel (EMD) built the "pancake" engines 16-184 and 16-338 for marine use. Zoche aero-diesels are a prototype radial design that have an even number of cylinders, either four or eight; but this
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#17327729961122948-581: A wider and rapid expansion of the RAF. The first aircraft built of this production model, K7033 , served as the only prototype; on 25 June 1936, K7033 conducted its first flight from Filton. The service name for the aircraft became Blenheim Mk I after the famous battle during the War of the Spanish Succession . On 10 March 1937, production deliveries to the RAF formally started; 114 Squadron became
3082-448: Is also built in three sections, the centre-section of which is bolted and rivetted to the fuselage. The outer wing sections are tapered in chord and thickness. Extensive use of Alclad sheeting is made in elements such as the ribs , skin, flaps , and web reinforcement of the spars . The tail unit is of a cantilever monoplane style, using an all-metal tailplane and fin while the aerodynamically-balanced rudder and elevators use
3216-599: Is also used by builders of homebuilt aircraft , such as the Culp Special , and Culp Sopwith Pup , Pitts S12 "Monster" and the Murphy "Moose" . 110 hp (82 kW) 7-cylinder and 150 hp (110 kW) 9-cylinder engines are available from Australia's Rotec Aerosport . HCI Aviation offers the R180 5-cylinder (75 hp (56 kW)) and R220 7-cylinder (110 hp (82 kW)), available "ready to fly" and as
3350-412: Is not problematic, because they are two-stroke engines , with twice the number of power strokes as a four-stroke engine per crankshaft rotation. A number of radial motors operating on compressed air have been designed, mostly for use in model airplanes and in gas compressors. A number of multi-cylinder 4-stroke model engines have been commercially available in a radial configuration, beginning with
3484-476: The Air Ministry eventually funded three prototypes and it became another winner for the designer Roy Fedden . With the widespread introduction of superchargers to the aviation industry in order to improve altitude performance, Fedden felt it was reasonable to use a small amount of boost at all times in order to improve performance of an otherwise smaller engine. Instead of designing an entirely new block,
3618-677: The British Expeditionary Force of the Army . In May 1940, AASF and BEF Blenheims participated in the Battle of France , being sent against German forces moving towards Brussels , resulting in many aircraft quickly sustaining heavy damage or being lost to enemy fire. German attacks upon the French airfields also damaged a considerable number of Blenheims on the ground. On 14 May, a combined force of Fairey Battles and Blenheims
3752-538: The DFC for his part in the raid. From 5 September 1940 Blenheims of Bomber Command began a bombing campaign targeting German-occupied ports along the English Channel , alongside heavier bomber types. Bomber Command Blenheims also performed anti-shipping patrols due to Coastal Command's own strike squadrons being heavily depleted throughout the latter half of 1940. On 11 March 1940, a Blenheim IV, P4852 , became
3886-555: The Dunkirk evacuation by harassing enemy forces. Rapid advances in technology which had taken place in the late 1930s had rendered the Blenheim mostly obsolete by the outbreak of the war. In particular, it had become heavier as extra service equipment was installed; much of this was found to be necessary through operational experience. This, coupled with the rapid performance increases of the fighters that would oppose it, had eclipsed
4020-671: The Gloster Gauntlet and its successor, the Gloster Gladiator . It was intended that the larger Pegasus would be for bombers , but as the power ratings of both engines rose, the Mercury was used in almost all roles. Perhaps its most famous use was in a twin-engine light bomber , the Bristol Blenheim . In 1938 Roy Fedden pressed the Air Ministry to import supplies of 100 octane aviation spirit from
4154-659: The Gold Coast . By the end of 1940, a total of three RAF squadrons equipped with Blenheim IV aircraft were performing anti-shipping, bombing, and reconnaissance missions in support of Allied ground forces in North Africa. By July 1941, it had been recognised that, in response to the increasing intensity of combat in North Africa and in the Middle East theatres, additional squadrons were urgently required. In
Bristol Mercury - Misplaced Pages Continue
4288-610: The Imperial Japanese main carrier battle group . The Blenheims approached undetected by the A6M2 Zero combat air patrol (CAP) fighters, resulting in a total surprise-attack upon the Japanese carrier battle group. While the bombers were able to drop bombs on fleet carrier Akagi from an altitude of 11,000 feet (3,353 m), they fell off-target without scoring any hits. Four of the Blenheims were shot down over
4422-627: The Kawasaki Ki-100 and Yokosuka D4Y 3. In Britain, Bristol produced both sleeve valved and conventional poppet valved radials: of the sleeve valved designs, more than 57,400 Hercules engines powered the Vickers Wellington , Short Stirling , Handley Page Halifax , and some versions of the Avro Lancaster , over 8,000 of the pioneering sleeve-valved Bristol Perseus were used in various types, and more than 2,500 of
4556-710: The RAF Advanced Air Striking Force (AASF) was deployed to numerous airfields in France, allowing for shorter range bombing missions against German targets, including industries. Several squadrons of Blenheim IVs were assigned to the AASF, being frequently used against targets in France and the Low Countries once the Battle of France had begun. Blenheims were also assigned to the air component of
4690-479: The Rutan Voyager . The experimental Bristol Phoenix of 1928–1932 was successfully flight tested in a Westland Wapiti and set altitude records in 1934 that lasted until World War II. In 1932 the French company Clerget developed the 14D, a 14-cylinder two-stroke diesel radial engine. After a series of improvements, in 1938 the 14F2 model produced 520 hp (390 kW) at 1910 rpm cruise power, with
4824-638: The SNECMA company and had plans for a 32-cylinder diesel engine of 4,000 hp (3,000 kW), but in 1947 the company abandoned piston engine development in favour of the emerging turbine engines. The Nordberg Manufacturing Company of the United States developed and produced a series of large two-stroke radial diesel engines from the late 1940s for electrical production, primarily at aluminum smelters and for pumping water. They differed from most radials in that they had an even number of cylinders in
4958-583: The Type 142 , a civil airliner, after a challenge from the newspaper proprietor Lord Rothermere to produce the fastest commercial aircraft in Europe. The Type 142 first flew in April 1935, and the Air Ministry , ordered a modified design as the Type 142M for the Royal Air Force (RAF) as a bomber. Deliveries of the new Blenheim to RAF squadrons commenced on 10 March 1937. In service the Type 142M became
5092-499: The Westland Lysander , Bristol Blenheim , and Blackburn Skua . In the years leading up to World War II, as the need for armored vehicles was realized, designers were faced with the problem of how to power the vehicles, and turned to using aircraft engines, among them radial types. The radial aircraft engines provided greater power-to-weight ratios and were more reliable than conventional inline vehicle engines available at
5226-590: The fall of France in June 1940, the Free French Air Force was formed at RAF Odiham , Hampshire , in the form of Groupe Mixte de Combat (GMC) 1, consisting of a mixed bag of Blenheims and Westland Lysander liaison/observation aircraft, which were later dispatched to North Africa and saw action against Italian and German forces. Blenheim units operated throughout the Battle of Britain , often taking heavy casualties, although they were never accorded
5360-442: The main spar to accommodate a sizeable bomb bay. Other modifications included the addition of a bomb-aimer's position and a Browning machine gun in the port wing along with provisions for a semi-retractable gun turret in the dorsal position. In September 1935, an initial contract for 150 aircraft was placed. The Air Ministry had chosen to order the type directly from the drawing board, having been urgently sought as one piece of
5494-670: The American Pratt & Whitney company was founded, competing with Wright's radial engines. Pratt & Whitney's initial offering, the R-1340 Wasp , was test run later that year, beginning a line of engines over the next 25 years that included the 14-cylinder, twin-row Pratt & Whitney R-1830 Twin Wasp . More Twin Wasps were produced than any other aviation piston engine in the history of aviation; nearly 175,000 were built. In
Bristol Mercury - Misplaced Pages Continue
5628-673: The American Evolution firm now sells the Seidel-designed radials, with their manufacturing being done in India. Bristol Blenheim I The Bristol Blenheim is a British light bomber designed and built by the Bristol Aeroplane Company , which was used extensively in the first two years of the Second World War , with examples still being used as trainers until the end of the war. Development began with
5762-607: The American single-engine Vought F4U Corsair , Grumman F6F Hellcat , Republic P-47 Thunderbolt , twin-engine Martin B-26 Marauder , Douglas A-26 Invader , Northrop P-61 Black Widow , etc. The same firm's aforementioned smaller-displacement (at 30 litres), Twin Wasp 14-cylinder twin-row radial was used as the main engine design for the B-24 Liberator , PBY Catalina , and Douglas C-47 , each design being among
5896-664: The Blenheim IV continued until June 1943, when newcomers such as the Beaufort -derived Beaufighter had succeeded the type. A total of 3,307 were produced. A long-range fighter version, the Blenheim Mk IF, was also developed. For this role, about 200 Blenheims were fitted with a gun pack under the fuselage for four .303 in (7.7 mm) Brownings. Later, the Airborne Intercept (AI) Mk III or IV radar
6030-532: The Blenheim Mk II, which increased tankage from 278 to 468 imp gal (1,260 to 2,130 L; 334 to 562 US gal). Only one Blenheim Mk II was completed, as flight tests revealed the increase in speed to be marginal and not warranting further development. Another modification resulted in the Blenheim Mk III, which lengthened the nose, dispensing with the "stepless cockpit" format of
6164-589: The Blenheim Mk IV. In early 1939, the first batch of Blenheim Mk IVs were accepted into service; these lacked outer fuel tanks but were accepted due to the urgent demand for the type. Early Blenheim Mk IVs were also equipped with the Mercury VIII engine, most were fitted with the more powerful Mercury XV or Mercury 25 models. Further aircraft deliveries were made to the production standard and were primarily manufactured by Avro and Rootes. Production of
6298-618: The Blenheim Mk IV. The Mercury was also the first British aero engine to be approved for use with variable-pitch propellers. The Bristol company and its shadow factories produced 20,700 examples of the engine. Outside the United Kingdom, Mercury was licence-built by Państwowe Zakłady Lotnicze in Poland and used in the PZL P.11 fighters. It was also built by NOHAB in Sweden and used in
6432-472: The Blenheim Mk.I had been subject to considerable criticism, prompting the development of an improved model to rectify the shortcomings. On 24 September 1937, an experimental Blenheim Mk.I, modified with an extended forward fuselage beyond its original stepless cockpit , smooth-fronted nose enclosure, made its first flight from Filton. Formal work on an extended-range reconnaissance version started as
6566-559: The Blenheim Mk.I which would be developed into the long-nosed Type 149, the Blenheim Mk.IV, except in Canada where Fairchild Canada built the Type 149 under licence as the Bolingbroke. The Type 160 Bisley was also developed from the Blenheim but was already obsolete when it entered service. Both versions were converted into heavy fighters by the addition of a gun pack with four Browning .303 in (7.7 mm) machine guns mounted under
6700-576: The Blenheim's speed advantage. In January 1941, the Air Staff classified the Blenheim as inadequate in terms of performance and armament for current operations. The light armament was seldom able to deter fighter opposition. Squadrons were forced to use several different improvisations in an attempt to provide better defensive armament, until officially sanctioned modifications were able to be introduced in early 1940. The Blenheim also proved to be vulnerable to anti-aircraft artillery , especially around
6834-557: The Blenheim, including Romania , Greece and Turkey . By September 1939, orders for the Blenheim had risen to 2,088 aircraft. Total production of the Blenheim Mk I in England was 1,351 aircraft prior to the end of the production run in 1939; production had been terminated in favour of more advanced variants. The Blenheim production programme saw several shifts in requirements and in capacity. A modified Blenheim design, given
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#17327729961126968-446: The Blenheim, ordering 18 Blenheim Mk Is, which were delivered from Britain between June 1937 and July 1938. Two years later, Finland obtained a manufacturing licence for the Blenheim. Before any aircraft could be manufactured at the Valtion lentokonetehdas (State Aeroplane Factory) in Finland, the Winter War broke out, forcing the Finns to order more aircraft from the UK. A further 24 British-manufactured Blenheims were ordered during
7102-407: The Blenheims once again proved to be too slow and vulnerable against Luftwaffe fighters and they took constant casualties. On 12 August 1941, an action described by The Daily Telegraph in 2006 as being the "RAF's most audacious and dangerous low-level bombing raid, a large-scale attack against power stations near Cologne" took place. The raid was a low-level daylight raid by 54 Blenheims under
7236-500: The Centaurus and rapid movement to the use of turboprops such as the Armstrong Siddeley Python and Bristol Proteus , which easily produced more power than radials without the weight or complexity. Large radials continued to be built for other uses, although they are no longer common. An example is the 5-ton Zvezda M503 diesel engine with 42 cylinders in 6 rows of 7, displacing 143.6 litres (8,760 cu in) and producing 3,942 hp (2,940 kW). Three of these were used on
7370-692: The German single-seat, single-engine Focke-Wulf Fw 190 Würger , and twin-engine Junkers Ju 88 . In Japan, most airplanes were powered by air-cooled radial engines like the 14-cylinder Mitsubishi Zuisei (11,903 units, e.g. Kawasaki Ki-45 ), Mitsubishi Kinsei (12,228 units, e.g. Aichi D3A ), Mitsubishi Kasei (16,486 units, e.g. Kawanishi H8K ), Nakajima Sakae (30,233 units, e.g. Mitsubishi A6M and Nakajima Ki-43 ), and 18-cylinder Nakajima Homare (9,089 units, e.g. Nakajima Ki-84 ). The Kawasaki Ki-61 and Yokosuka D4Y were rare examples of Japanese liquid-cooled inline engine aircraft at that time but later, they were also redesigned to fit radial engines as
7504-498: The Gnome and Le Rhône rotary powerplants, and Siemens-Halske built their own designs, including the Siemens-Halske Sh.III eleven-cylinder rotary engine , which was unusual for the period in being geared through a bevel geartrain in the rear end of the crankcase without the crankshaft being firmly mounted to the aircraft's airframe, so that the engine's internal working components (fully internal crankshaft "floating" in its crankcase bearings, with its conrods and pistons) were spun in
7638-405: The Japanese O.S. Max firm's FR5-300 five-cylinder, 3.0 cu.in. (50 cm ) displacement "Sirius" radial in 1986. The American "Technopower" firm had made smaller-displacement five- and seven-cylinder model radial engines as early as 1976, but the OS firm's engine was the first mass-produced radial engine design in aeromodelling history. The rival Saito Seisakusho firm in Japan has since produced
7772-478: The Jupiter. Although other piston configurations and turboprops have taken over in modern propeller-driven aircraft , Rare Bear , which is a Grumman F8F Bearcat equipped with a Wright R-3350 Duplex-Cyclone radial engine, is still the fastest piston-powered aircraft . 125,334 of the American twin-row, 18-cylinder Pratt & Whitney R-2800 Double Wasp , with a displacement of 2,800 in (46 L) and between 2,000 and 2,400 hp (1,500-1,800 kW), powered
7906-527: The Middle East and Far East – received this variant but operated them generally only for a few months. One Blenheim Mk IV left in Java by the retreating British forces in 1942 ended up in the hands of the fledgling Indonesian Air Force (AURI). They repaired it, installed 950 hp (699 kW) Nakajima Sakae engines, painted it in their colours, and flew it around Yogyakarta on at least three occasions. On 9 April 1942, nine Blenheims from 11 Squadron RAF attacked Admiral Chuichi Nagumo's Kidō Butai ;
8040-408: The Middle East were relocated from the theatre to the Far East in response to the new threat from Japanese forces. Blenheims continued to operate widely in many combat roles until about 1943, equipping RAF squadrons in the UK and at British bases in Aden , India, British Malaya , Singapore, and the Dutch East Indies . Many Blenheims were lost to Japanese fighters during the Malayan Campaign and
8174-430: The Mk.I, introducing a true windscreen in front of the pilot, to provide more room for the bomb aimer. This required the nose to be "scooped out" in front of the pilot to maintain visibility during takeoff and landing. Both modifications were combined, along with a newer version of the Mercury engine with 905 hp (675 kW). The turret acquired a pair of Brownings in place of the original single Vickers K gun, creating
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#17327729961128308-410: The RAF's biplane fighters in the late 1930s but advances soon left it vulnerable if flown in daylight, though it proved successful as a night fighter. The Blenheim was effective as a bomber but many were shot down. Both Blenheim types were used by foreign operators and examples were licence built in Yugoslavia and Finland, in addition to Canada. In 1933 Frank Barnwell , Bristol's chief designer, went to
8442-444: The Swedish Gloster Gladiator fighters and in the Saab 17 dive-bomber. In Italy, it was built by Alfa Romeo as the Mercurius. In Czechoslovakia it was built by Walter Engines . In Finland, it was built by Tampella and mainly used on Bristol Blenheim bombers. Note: (1937) 820 hp (610 kW) Note: The Shuttleworth Collection operates two Bristol Mercury powered aircraft: A Westland Lysander III ( G-AZWT ) and
8576-419: The UK. The Fighter Collection, also currently based at Duxford Airfield, operate a 1939 Gloster Gladiator II ( G-GLAD ) powered by a Bristol Mercury XX. The Canadian Warplane Heritage Museum has a Lysander IIIA in flying condition as does the Vintage Wings of Canada . Data from Lumsden Related development Comparable engines Related lists Radial engine The radial configuration
8710-413: The US. This new fuel would allow aero engines to run at higher compression ratios and supercharger boost pressure than the existing 87-octane fuel, thus increasing the power. The Mercury XV was one of the first British aero engines to be type-tested and cleared to use the 100-octane fuel in 1939. This engine was capable of running with a boost pressure of +9 lbs/sq.in (0.62 bar) and was first used in
8844-486: The United Kingdom the Bristol Aeroplane Company was concentrating on developing radials such as the Jupiter, Mercury , and sleeve valve Hercules radials. Germany, Japan, and the Soviet Union started with building licensed versions of the Armstrong Siddeley, Bristol, Wright, or Pratt & Whitney radials before producing their own improved versions. France continued its development of various rotary engines but also produced engines derived from Bristol designs, especially
8978-429: The United States to collect first-hand information on their latest twin-engined, low-wing monoplane airliners. When he returned home he discussed one of them, the Lockheed Electra 12A , with Roy Fedden and prepared a design to match it using Fedden's Bristol Aquila engine which produced 500 hp, the same power as the engine used in the Electra. Sir Archibald Russell described Barnwell's design as "close to being
9112-446: The Winter War and were delivered from the RAF's own stocks. In the aftermath of the Winter War, 55 Blenheims were constructed in Finland, the final aircraft being completed in September 1944; this brought the total number of Blenheims in Finnish service to 97 (75 Mk Is and 22 Mk IVs). The Finns also received 20 half-completed ex-Yugoslavian Mk IV Blenheims captured by Germany, together with manufacturing tools, production equipment, and
9246-591: The Winter War, and close to 3,000 missions during the Continuation War and Lapland War . Blenheim machine-gunners also shot down eight Soviet aircraft. Thirty-seven Blenheims were lost in combat during the wars. The Finnish Blenheims were divided on six series ( sarja ): Series I with doorless bomb bays could carry 1,800 lb (800 kg) bomb load in the bomb bay and up to 220 lb (100 kg) in wing cells. Series II, V and VI could carry 1,800 lb (800 kg) load on bomb bay and 379 lb (172 kg) on wing cells and fuselage racks. Series III and IV had
9380-422: The aircraft was faster than the fighters in service with the Royal Air Force (RAF), having a top speed of 307 mph (494 km/h). Rothermere presented the aircraft to the nation for a formal evaluation as a potential bomber. By June 1935, the Air Ministry had become interested in the project due to its high performance. On 9 July 1935, a design conference was held by Bristol at the ministry's request into
9514-446: The animated illustration, four cam lobes serve all 10 valves across the 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 which is concentric with the crankshaft, with a few smaller radials, like the Kinner B-5 and Russian Shvetsov M-11 , using individual camshafts within
9648-620: The basis for the Beaufort torpedo bomber , which led to the Beaufighter, with the lineage performing two evolutions of bomber-to-fighter. The Bristol Blenheim was a twin-engine high performance all-metal medium bomber aircraft, powered by a pair of Bristol Mercury VIII air-cooled radial engines , each capable of 860 hp (640 kW). Each engine drove a three-bladed controllable-pitch propeller , and were equipped with both hand-based and electric engine starters. To ease maintenance,
9782-449: The basis for, a bomber aircraft. Rothermere became aware of Bristol's Type 135 proposal and on 3 March 1934, Barnwell issued him with a quote of the specification and performance statistics of the design, including an estimated top speed of 240 mph (390 km/h) at 6,500 ft (2,000 m). The Aquila engine had been shelved in favour of the supercharger -equipped, poppet-valve Bristol Mercury engine. Deeming it suitable for
9916-399: The battles for Singapore and Sumatra . By that point, the traditional daylight light bomber role was more effectively carried out by suitable fighter-bombers, and the surviving examples were relegated to training duties. Nonetheless, the Blenheim played a role in preventing India from falling and in recapturing Burma , destroying over 60 aircraft on the ground in raids on Bangkok early in
10050-512: The campaign. One Blenheim pilot, Squadron Leader Arthur Scarf , was posthumously awarded the Victoria Cross for an attack on Singora , Thailand , on 9 December 1941. Another bomber of No. 60 Squadron RAF was credited with shooting down Lt Col Tateo Katō 's Nakajima Ki-43 fighter and badly damaging two others in a single engagement on 22 May 1942, over the Bay of Bengal . Katō's death
10184-589: The carriers by CAP Zeroes (two of which were claimed by ace-fighter pilot Kaname Harada from the Soryu ), and by other Japanese aircraft returning from the earlier-strike on HMS Hermes , shooting down two Zeroes in return. This was the first time a Japanese carrier force had faced a concerted air attack in the Pacific War . In 1936, the Finnish Air Force became the first export customer for
10318-624: The challenge, the design of Type 135 was further adapted to produce the Type 142 to meet the requirements outlined by Rothermere. In late March 1934, Rothermere placed an order for a Type 142 aircraft, under which he paid for half of the estimated £18,500 cost up front and the remainder upon the aircraft's first flight in the following year. On 12 April 1935, the Type 142 , named Britain First , conducted its maiden flight from Filton Aerodrome , South Gloucestershire . Flight tests soon proved that
10452-607: The command of Wing Commander Nichol of No. 114 Squadron RAF . They hit their targets (Fortuna Power Station in Oberaußem-Fortuna and the Goldenberg Power Station in Hürth-Knapsack ), but twelve of the Blenheims were lost during the raid, 22% of those that took part, which was far above the sustainable loss rate of less than 5%. The England cricketer Squadron leader Bill Edrich was awarded
10586-460: The compression stroke, this liquid, being incompressible, stops piston movement. Starting or attempting to start the engine in such condition may result in a bent or broken connecting rod. Originally radial engines had one row of cylinders, but as engine sizes increased it became necessary to add extra rows. The first radial-configuration engine known to use a twin-row design was the 160 hp Gnôme "Double Lambda" rotary engine of 1912, designed as
10720-502: The crankcase and cylinders revolved with the propeller. It was similar in concept to the later radial, the main difference being that the propeller was bolted to the engine, and 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 , Clerget , and Bentley rotary engines,
10854-572: 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 (39 kW) at 950 rpm. In 1903–1904 Jacob Ellehammer used his experience constructing motorcycles to build
10988-408: The crankshaft takes two revolutions to complete the four strokes of each piston (intake, compression, combustion, exhaust). The camshaft ring is geared to spin slower and in the opposite direction to the crankshaft. Its cam lobes are placed in two rows; one for the intake valves and one for the exhaust valves. The radial engine normally uses fewer cam lobes than other types. For example, in the engine in
11122-468: The day that war was declared on Germany, a Blenheim Mk IV, N6215 , piloted by Flying Officer Andrew McPherson was the first British aircraft to cross the German coast to perform a high altitude reconnaissance mission upon the German Navy in the vicinity of Wilhelmshaven , Lower Saxony . The following morning, 15 Blenheims from three squadrons set off on one of the first bombing missions to attack
11256-400: The demand, secondary assembly lines were established at Chadderton by Avro and at Speke by Rootes Securities . The aircraft was built under licence by foreign countries, including Finland , who completed a total of 55 aircraft, and Yugoslavia , which completed 16 aircraft with a further 24 in advanced stages of completion when Germany invaded Yugoslavia . Other countries also procured
11390-486: The early 1920s Le Rhône converted a number of their rotary engines into stationary radial engines. By 1918 the potential advantages of air-cooled radials over the water-cooled inline engine and air-cooled rotary engine that had powered World War I aircraft were appreciated but were unrealized. British designers had produced the ABC Dragonfly radial in 1917, but were unable to resolve the cooling problems, and it
11524-401: The engine mountings were designed with a split-segment to facilitate rapid engine removal without disturbing the carburettors . A pair of fuel tanks, each containing up to 140 gallons, were housed within the centre-section of the fuselage. The fuselage of the Blenheim employed a light- alloy monocoque structure using open-section stringers , and was constructed in three sections. The wing
11658-470: The existing Jupiter parts were re-used with the stroke reduced by one inch (25 mm). The smaller capacity engine was then boosted back to Jupiter power levels, while running at higher rpm and thus requiring a reduction gear for the propeller . The same techniques were applied to the original Jupiter-sized engine to produce the Pegasus . The Mercury's smaller size was aimed at fighter use and it powered
11792-566: The fast Osa class missile boats . Another one was the Lycoming XR-7755 which was the largest piston aircraft engine ever built in the United States with 36 cylinders totaling about 7,750 in (127 L) of displacement and a power output of 5,000 horsepower (3,700 kilowatts). While most radial engines have been produced for gasoline, there have been diesel radial engines. Two major advantages favour diesel engines — lower fuel consumption and reduced fire risk. Packard designed and built
11926-566: The first RAF aircraft to sink a U-boat , having scored two direct hits on U-31 in the Schillig Roads . In April 1941, a campaign aiming to completely close off the Channel to enemy shipping was launched using an initial flight of Blenheims stationed at RAF Manston . Between April and June that year, a total of 297 Blenheims of No 2. Group attacked German shipping at sea, losing 36 aircraft, while Coastal Command launched 143 attacks in
12060-428: The first squadron to receive the Blenheim. On 13 January 1938, the Blenheim entered service with No. 30 Squadron , the first overseas squadron to receive the type; in early 1939, the first Blenheims arrived in India. From July 1936 onwards, various additional orders were placed for the Blenheim Mk I , including multiple orders for the export market. By the end of 1936, 1,568 aircraft were on order. In order to meet
12194-470: The form of a "stepless cockpit" that used no separate windscreen panels for the pilot, a notable feature of a substantial majority of German bomber designs, first conceived during the war years. Both fixed and sliding window panels were present, along with a transparent sliding roof. Other onboard equipment included a radio , cameras , navigation systems, electric lighting , oxygen apparatus, and stowage for parachutes and clothing. In September 1939,
12328-630: The four-engine Boeing B-29 Superfortress and others. The Soviet Shvetsov OKB-19 design bureau was the sole source of design for all of the Soviet government factory-produced radial engines used in its World War II aircraft, starting with the Shvetsov M-25 (itself based on the American Wright Cyclone 9 's design) and going on to design the 41-litre displacement Shvetsov ASh-82 fourteen cylinder radial for fighters, and
12462-409: The fuselage. The Mk.IV was also used as a maritime patrol aircraft and both aircraft were also used as bombing and gunnery trainers once they had become obsolete as combat aircraft. The Blenheim was one of the first British aircraft with an all-metal stressed-skin construction, retractable landing gear , flaps , a powered gun turret and variable-pitch propellers . The Mk.I was faster than most of
12596-620: The largest-displacement production British radial from the Bristol firm to use sleeve valving, the Bristol Centaurus were used to power the Hawker Tempest II and Sea Fury . The same firm's poppet-valved radials included: around 32,000 of Bristol Pegasus used in the Short Sunderland , Handley Page Hampden , and Fairey Swordfish and over 20,000 examples of the firm's 1925-origin nine-cylinder Mercury were used to power
12730-528: The last flight of a Finnish Blenheim taking place on 20 May 1958. The usual nickname of Blenheim in the Finnish Air Force was Pelti-Heikki ("Tin Henry"). In Finland, the sole surviving original Blenheim in the world, a Mk IV registered as BL-200 of the Finnish Air Force, has been completely restored and is now on display at the Aviation Museum of Central Finland at Tikkakoski. An airworthy Blenheim
12864-447: The late-war Hawker Sea Fury and Grumman F8F Bearcat , two of the fastest production piston-engined aircraft ever built, using radial engines. Whenever a radial engine remains shut down for more than a few minutes, oil or fuel may drain into the combustion chambers of the lower cylinders or accumulate in the lower intake pipes, ready to be drawn into the cylinders when the engine starts. As the piston approaches top dead center (TDC) of
12998-603: The latter half of 1941, several Blenheim squadrons were flown out to Malta , many being stationed there into early 1942 before mainly being absorbed in the Western Desert air operations. As Bomber Command gradually took Blenheims out of the Northern Europe theatre, they were often dispatched to other areas such as North Africa. Upon the outbreak of the Pacific War in December 1941, some Blenheim squadrons in
13132-487: The massive, 58-litre displacement Shvetsov ASh-73 eighteen-cylinder radial in 1946 - the smallest-displacement radial design from the Shvetsov OKB during the war was the indigenously designed, 8.6 litre displacement Shvetsov M-11 five cylinder radial. Over 28,000 of the German 42-litre displacement, 14-cylinder, two-row BMW 801 , with between 1,560 and 2,000 PS (1,540-1,970 hp, or 1,150-1,470 kW), powered
13266-473: The month in which the Second World War broke out, the Blenheim Mk I equipped two home-based squadrons and 11 overseas squadrons in locations such as Egypt , Aden , Iraq , India , and Singapore . Further RAF squadrons had received, or were in the process of converting to, the more capable Blenheim Mk IV; 168 Blenheim Mk IV aircraft had entered RAF operational strength by the outbreak of war. On
13400-535: The more capable Beaufighter derivative. About 60 Mk IVs were also equipped with the gun pack as the Mk IVF and were used by Coastal Command to protect convoys from German long-range bombers. The last bomber variant was conceived as an armoured ground attack aircraft , with a solid nose containing four more Browning machine guns. Originally known as the Bisley, (after the shooting competitions held at Bisley Ranges ),
13534-483: The name Bolingbroke , was manufactured under licence in Canada by Fairchild Aircraft . The Bolingbroke, which had been developed in response to Air Ministry Specification G.24/35 to procure a coastal reconnaissance/light bomber as a replacement for the Avro Anson , had substantial improvements that would serve as the basis for improved variants of the Blenheim. Both the navigator's station and range limitations of
13668-611: The northern areas of the British mainland, such as RAF Lossiemouth , flying for extended periods over the North Sea led to the weather posing almost as much of a risk as enemy combatants, particularly as most of the Blenheim IVs lacked any heating or deicing systems; in response, some aircraft were later equipped with boilers fixed onto the starboard engine exhaust. A sizeable number of losses occurred, caused by both enemy action and mid-air engine failures due to icing . After
13802-406: The nose were so cramped that the control yoke obscured all flight instruments while engine instruments eliminated the forward view on landings. Most secondary instruments were arranged along the left side of the cockpit, essential items such as the propeller pitch control were actually placed behind the pilot where they had to be operated by feel alone. The navigator/bombardier was seated alongside
13936-548: The opposing direction to the crankcase and cylinders, which still rotated as the propeller itself did since it was still firmly fastened to the crankcase's frontside, as with regular umlaufmotor German rotaries. By the end of the war the rotary engine had reached the limits of the design, particularly in regard to the amount of fuel and air that could be drawn into the cylinders through the hollow crankshaft, while advances in both metallurgy and cylinder cooling finally allowed stationary radial engines to supersede rotary engines. In
14070-573: The original RAF bomb bays and racks and could carry only 1,000 lb (450 kg) load on bomb bay and 200 lb (91 kg) on wing cells. The bomb bays, bomb bay doors and bomb racks of various series were modified on major overhauls to host bigger bombs. After the war, Finland was prohibited from flying bomber aircraft by the Paris Peace Treaty , with Finland's Blenheims being placed into storage in 1948. However, in 1951, five Blenheims were re-activated for use as target tugs , with
14204-409: The pilot, and made use of a sliding/folding seat whilst performing the bomb aiming role. Dual flight controls could be installed. The wireless operator/air gunner was housed aft of the wing alongside the aircraft's dorsal gun turret. Armament comprised a single forward-firing .303 in (7.7 mm) Browning machine gun outboard of the port engine and a .303 in (7.7 mm) Lewis Gun in
14338-493: The production aircraft were renamed Blenheim Mk V and featured a strengthened structure, pilot armour, interchangeable nose gun pack or bomb-aimer position and another Mercury variant with 950 hp (710 kW). The Mk V was ordered for conventional bombing operations, with the removal of armour and most of the glazed nose section. The Mk V (Type 160) was used primarily in the Middle East and Far East. The Blenheim served as
14472-595: The production leaders in all-time production numbers for each type of airframe design. The American Wright Cyclone series twin-row radials powered American warplanes: the nearly-43 litre displacement, 14-cylinder Twin Cyclone powered the single-engine Grumman TBF Avenger , twin-engine North American B-25 Mitchell , and some versions of the Douglas A-20 Havoc , with the massive twin-row, nearly 55-litre displacement, 18-cylinder Duplex-Cyclone powering
14606-420: The publicity of the fighter squadrons. From July to December 1940, Blenheims raided German-occupied airfields both in daylight and at night. Although most of these raids were unproductive, there were some successes; on 1 August five out of twelve Blenheims sent to attack Haamstede and Evere ( Brussels ) were able to bomb, damaging (50%, 40% and 10%) three Bf 109Es of II./JG 27 at Leuwarden and apparently killing
14740-413: The question of converting the Type 142 into a medium bomber. The Air Ministry quickly formalised Specification B.28/35 for prototypes of a bomber version; the Type 142M (M for military). One change between the Type 142M bomber and its Type 142 predecessor was the repositioning of the wing from a low-wing to a mid-wing position, which allowed for more internal space within the fuselage underneath
14874-409: The rear bank of cylinders, but a variety of baffles and fins were introduced that largely eliminated these problems. The downside was a relatively large frontal area that had to be left open to provide enough airflow, which increased drag. This led to significant arguments in the industry in the late 1930s about the possibility of using radials for high-speed aircraft like modern fighters. The solution
15008-551: The rear fuselage. Flexible, self-sealing liners had been fitted to the fuel tanks but they were still not fully protected against the 0.79 in (20 mm) MG FF cannon carried by the Luftwaffe ' s Bf 109 and Bf 110 fighters. Blenheim squadrons were still in immediate and high demand after their withdrawal from France as part of the British action during the Norwegian campaign . Typically operating from bases in
15142-465: The same is not true for multi-row engines where the rear cylinders can be affected by the heat coming off the front row, and air flow being masked. A potential disadvantage of radial engines is that having the cylinders exposed to the airflow increases drag considerably. The answer was the addition of specially designed cowlings with baffles to force the air between the cylinders. The first effective drag-reducing cowling that didn't impair engine cooling
15276-568: The same period, losing 52 aircraft; by the end of the year, 698 ships had been attacked and 41 of these sunk for the loss of 123 aircraft. The Bristol Blenheim was used by both Bomber and Fighter Commands . About two hundred Mk I bombers were modified into Mk IF long-range fighters with 600 (Auxiliary Air Force) Squadron , based at Hendon , the first squadron to take delivery in September 1938. By 1939, at least seven squadrons were operating them as fighters, increasing to about 60 squadrons within
15410-419: The ships spotted on the previous day. The raid was a failure, only nine aircraft attacked, and only superficial damage was done to the cruiser Emden , when one of No. 107 Squadron's Blenheims crashed into the cruiser, killing 11 crewmen. RAF Coastal Command were soon using the Blenheim with the stated mission of protecting British shipping convoys off the east coast. Shortly after the conflict's start,
15544-480: The single-engined Heinkel He 70 , and Rothermere wanted the prestige of being able to claim to have the fastest civilian aircraft. Rothermere also intended to encourage businesses and key figures to make greater use of civil aviation and to demonstrate to the British Air Ministry how their fighter aircraft may not be able to match modern transport aircraft, which may be easily converted to, or used as
15678-600: The time. This reliance had a downside though: if the engines were mounted vertically, as in the M3 Lee and M4 Sherman , their comparatively large diameter gave the tank a higher silhouette than designs using inline engines. The Continental R-670 , a 7-cylinder radial aero engine which first flew in 1931, became a widely used tank powerplant, being installed in the M1 Combat Car , M2 Light Tank , M3 Stuart , M3 Lee , and LVT-2 Water Buffalo . The Guiberson T-1020 ,
15812-492: The ultimate examples of which reached 250 hp (190 kW) although none of those over 160 hp (120 kW) 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 (300 kW), and were powering almost 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
15946-402: 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
16080-408: The weight of the released bombs. Because there was no way to predict how long it would take for the bombs to force the doors open, bombing accuracy was consequently poor. The bomb bay could be loaded using a hand-operated winch incorporated into the fuselage. To achieve its relatively high speed, the Blenheim used a very small fuselage cross-section, with its upper front glazing all at one angle in
16214-559: 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 installed in his triplane and made a number of short free-flight hops. Another early radial engine was the three-cylinder Anzani , originally 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 (spaced 120° apart) — early enough to have been used on
16348-599: Was a severe blow to the Imperial Japanese Army Air Force . The Air Ministry's replacement for the Blenheim as a daylight bomber, another Bristol design, the Buckingham , was overtaken by events and changes in requirements, and considered inferior to the de Havilland Mosquito , and as such did not see combat. The final ground-attack version – the Blenheim Mk V – first equipped 139 Squadron in June 1942. Eventually thirteen squadrons – mainly in
16482-512: Was carried out in the US, and demonstrated that ample airflow was available with careful design. This led to the R-4360 , which has 28 cylinders arranged in a 4 row corncob configuration. The R-4360 saw service on large American aircraft in the post- World War II period. The US and Soviet Union continued experiments with larger radials, but the UK abandoned such designs in favour of newer versions of
16616-420: Was commonly 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,
16750-683: Was developed in 1922 with Navy funding, and using aluminum cylinders with steel liners ran for an unprecedented 300 hours, at a time when 50 hours endurance was normal. At the urging of the Army and Navy the Wright Aeronautical Corporation bought Lawrance's company, and subsequent engines were built under the Wright name. The radial engines gave confidence to Navy pilots performing long-range overwater flights. Wright's 225 hp (168 kW) J-5 Whirlwind radial engine of 1925
16884-446: Was dispatched on a counter-attack upon German forces as they broke through defensive lines: 40 out of 71 aircraft were lost in this sortie. This is claimed to be the highest ever losses known to the RAF. Further action by Blenheims of Bomber Command that day sustained a 25% aircraft loss despite a high level of British fighter cover. Shortly thereafter, the mostly-depleted squadrons were withdrawn to Britain. Around 50 Blenheims supported
17018-405: Was fitted to some aircraft in use as night fighters; these were the first British fighters to be equipped with radar. The Blenheim had been selected as the first aircraft to be adapted for this role as its fuselage was sufficiently roomy to accommodate the additional crew member and radar apparatus. Their performance was marginal as a fighter but they served as an interim type pending availability of
17152-453: Was introduced with the BMW 801 14-cylinder twin-row radial. Kurt Tank designed a new cooling system for this engine that used a high-speed fan to blow compressed air into channels that carry air to the middle of the banks, where a series of baffles directed the air over all of the cylinders. This allowed the cowling to be tightly fitted around the engine, reducing drag, while still providing (after
17286-513: Was mounted on 13 August 1940 against a Luftwaffe airfield near Aalborg in north-western Denmark by twelve aircraft of 82 Squadron . One Blenheim returned early (the pilot was later charged but was killed on another operation before a court martial was held); the other eleven, which reached Denmark, were shot down, five by flak and six by Bf 109s. Blenheim units had also been formed to carry out long-range strategic reconnaissance missions over Germany and German-occupied territories. In this role,
17420-483: Was not considered viable due to the difficulty of providing the required airflow to the rear banks. Larger engines were designed, mostly using water cooling although this greatly increased complexity and eliminated some of the advantages of the radial air-cooled design. One example of this concept is the BMW 803 , which never entered service. A major study into the airflow around radials using wind tunnels and other systems
17554-746: Was not until the 1920s that Bristol and Armstrong Siddeley produced reliable air-cooled radials such as the Bristol Jupiter and the Armstrong Siddeley Jaguar . In the United States the National Advisory Committee for Aeronautics (NACA) noted in 1920 that air-cooled radials could offer an increase in power-to-weight ratio and reliability; by 1921 the U.S. Navy had announced it would only order aircraft fitted with air-cooled radials and other naval air arms followed suit. Charles Lawrance 's J-1 engine
17688-545: Was the Salmson 9Z series of nine-cylinder water-cooled radial engines that were produced in large numbers. Georges Canton and Pierre Unné patented the original engine design in 1909, offering it to the Salmson company; the engine was often known as the Canton-Unné. 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
17822-709: Was the British Townend ring or "drag ring" which formed a narrow band around the engine covering the cylinder heads, reducing drag. The National Advisory Committee for Aeronautics studied the problem, developing the NACA cowling which further reduced drag and improved cooling. Nearly all aircraft radial engines since have used NACA-type cowlings. While inline liquid-cooled engines continued to be common in new designs until late in World War II , radial engines dominated afterwards until overtaken by jet engines, with
17956-474: Was widely claimed as "the first truly reliable aircraft engine". Wright employed Giuseppe Mario Bellanca to design an aircraft to showcase it, and the result was the Wright-Bellanca WB-1 , which first flew later that year. The J-5 was used on many advanced aircraft of the day, including Charles Lindbergh 's Spirit of St. Louis , in which he made the first solo trans-Atlantic flight. In 1925
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