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Dewoitine D.520

The Dewoitine D.520 is a French fighter aircraft that entered service in early 1940, shortly after the beginning of the Second World War.

The D.520 was designed in response to a 1936 requirement from the French Air Force for a fast, modern fighter with a good climbing speed and an armament centred on a 20 mm cannon. At the time the most powerful V-12 liquid-cooled engine available in France was the Hispano-Suiza 12Y, which was less powerful, but lighter than contemporary engines such as the Rolls-Royce Merlin and Daimler-Benz DB 601. Other fighters were designed to meet the specifications but none of them entered service, or entered service in small numbers, too late to play a significant role during the Battle of France.

Unlike the Morane-Saulnier M.S.406, which was at that time the most numerous fighter in the French Air Force, the Dewoitine D.520 came close to being a match for the latest German types, such as the Messerschmitt Bf 109. It was slower than the Bf 109E but superior in manoeuvrability. Because of production delays, only a small number were available for combat against the Luftwaffe. The D.520 proved to be relatively capable as a dogfighter against the Luftwaffe's inventory, but lacked sufficient numbers to make a difference.

Following the armistice of 1940, the D.520 continued to be used, being operated by both the Free French Air Force and the Vichy French Air Force. The type was also returned to production during 1942, although it was manufactured at a lower rate than it had been during 1940. Additional examples were operated by the Luftwaffe, Regia Aeronautica Italiana, and the Bulgarian Air Force. The D.520 saw combat service in North Africa, Bulgaria, and the Eastern Front, as well as use in France and Germany for training and defence purposes. During the type's later life, it was used as a trainer aircraft. On 3 September 1953, the last D.520s were finally withdrawn from service.

Background
On 13 July 1934, the French Air Force launched a new technical programme, under which the development of improved fighter aircraft to improve upon the Dewoitine D.510, which was yet to enter service at that point but was already considered to be obsolete in the face of rapid advances being made in several European nations. While French aircraft company Dewoitine initially responded with an improved design based on the D.510, designated as the D.513, this quickly proved to be inferior to the in-development Morane-Saulnier M.S.405, a domestic competitor.

In response to a specification for a new fighter promulgated by the French Air Ministry on 15 June 1936, Émile Dewoitine, owner and founder of Dewoitine, formed a new private design office and ordered the firm's chief engineer, Robert Castello, to immediately study the development of a new fighter. The envisioned aircraft would be as affordable as possible, be powered by the new 900 hp Hispano-Suiza 12Y21 liquid-cooled engine, and be capable of attaining 500 km/h. However, the corresponding design was promptly rejected by the Air Ministry. The design had been rejected by the French Air Ministry, which, after being impressed by the British Hawker Hurricane and Supermarine Spitfire, had decided to respond by uprating the specifications to include a maximum speed requirement of 500 km/h.

Accordingly, work on what would become the D.520 commenced in September 1936; according to aviation author Raymond Danel, the D.520 designation was a deliberate reference to the required speed of the aircraft. During January 1937, this revised design proposal was submitted to the Service Technique Aeronautique (STA); while the STAe found the design to be likely to conform with the specified requirements, no order for prototypes to be built was immediately forthcoming. By this point, official attention was oriented towards the MS.405, which had already been selected for the re-equipment effort.

Specification and rivals
On 12 January 1937, the A.23 technical programme was launched by the Air Ministry. The specifications called for a maximum speed of 520 km/h at 4000 m, the ability to climb to 8000 m in less than fifteen minutes, with takeoff and landing runs not exceeding 400 m. The armament was to be two 7.5 mm machine guns and one 20 mm Hispano-Suiza HS.9 cannon, or two HS.9 cannons.

Other aircraft designed to the same specification included the Morane-Saulnier M.S.450, the Loire-Nieuport 60 (later C.A.O 200), and the Caudron-Renault C.770, none of which either left the drawing board or entered service. Two other concurrent French designs, the Bloch MB.152.01 and Bloch MB.155.C1 series and the Arsenal VG-33 entered service in small numbers with the French Air Force during the Battle of France, but too late to play a significant role.

In addition to the lack of a prototype order, Dewoitine was absorbed into the larger Société nationale des constructions aéronautiques du Midi (SNCAM) state-owned manufacturing consortium. As a result of this organisational restricting, along with continued alterations within the French Air Force's established manufacturing programmes, work on the design of the D.520 was suspended throughout much of 1937, and it was not until January 1938 that a small number of draughtsmen started work on the first detailed drawings for the prototype.

However, Émile Dewoitine, now the deputy managing director of SNCAM, was keen to proceed with the project and decided to proceed to the detail design drawing phase with the aim of producing a pair of prototypes and a single structural test frame, confident that official interest would be found for the type. On 3 April 1938, this private initiative was rewarded with the issuing of Air Ministry contract No. 513/8, which regularised the programme; by this point, the first prototype had almost been completed.

Modifications and first prototypes
On 2 October 1938, the first prototype aircraft, D.520-01, powered by a Hispano-Suiza 12Y-21 engine that temporarily drove a fixed-pitch, two-bladed wooden propeller, performed its maiden flight. Completion of the prototype had been delayed somewhat by the need to incorporate modifications requested by the STAe following their examination of a wooden mock-up of the type. During early flight tests, the first prototype managed to reach only 480 km/h, and suffered from dangerously high engine temperatures.

A large portion of responsibility for the encountered temperature issue was judged to have been a product of greater than expected drag resulting from the underwing radiators, which exhausted across the upper wing surface and were relatively inefficient; this arrangement was replaced with a single radiator unit housed under the fuselage in a streamlined fairing. Other aerodynamic improvements were made around this time, such as the minor enlargement of the fin and rudder, for greater lateral stability.

After sustaining minor damage in a landing accident on 27 November 1938, caused by the failure to deploy the undercarriage, further modifications were made to the prototype. These included changing the engine to a newer -29 model and incorporating exhaust ejectors which provided added thrust, along with a three-blade variable-pitch propeller. These changes were enough to allow the aircraft to reach its design speed, achieving 530 km/h. The maximum diving speed was 825 km/h, as reached on 6 February 1939.

Additional prototypes
During 1939, the first prototype was followed be two further examples: the D.520-02 and the 03, these were first flown on 9 January 1939 and 5 May 1939, respectively. The major differences between the first prototype and the second and third were the adoption of a new sliding canopy, the fitting of a re-designed and larger tail unit, and longer Oleo-manufactured undercarriage legs; they also omitted the Handley Page slats fitted to the outer wings on 01.

These prototypes were also armed with a single 20 mm Hispano-Suiza HS.9 cannon with the barrel was in a sleeve between the cylinder banks and fired through the propeller spinner. and a pair of MAC 1934 7.5 mm machine guns, each initially with 300 rounds per gun, housed in small pods under the wing. The third prototype also introduced a small tailwheel instead of the original skid. The second prototype was later fitted with a Hispano-Suiza 12Y-31 engine and achieved a maximum speed of 550 km/h and reached 8000 m in 12 minutes 53 seconds.

In response to Belgian interest in the D.520, who were at one stage preparing to negotiate for a licence to produce the type, several evaluation flights of the third prototype were flown by Belgian test pilot Captain Arendt. During late September 1939, CEMA took charge of the third prototype to conduct armament trials. Overall, flight tests had proceeded successfully, and resulted in the issuing of a contract in March 1939 for 200 production machines to be powered by the newer -31 engine (later replaced by the -45). A contract for an additional 600 aircraft was issued in June, albeit reduced to 510 in July 1939.

Production
In April 1939, the rate of production of fighter aircraft throughout France was far beneath official expectations. With the outbreak of war, a new contract brought the total of D.520s on order to 1,280, with the production rate to be 200 aircraft per month from May 1940. During January 1940, the Aéronautique Navale placed its own order for 120 aircraft. Another French Air Force order in April 1940 brought the total to 2,250 and increased production quotas to 350 a month. In addition to domestic orders, Poland was interested in acquiring around 160 D.520s in order.

On 2 November 1939, the first-production D.520 conducted its first flight. On this and the other aircraft, the rear fuselage was extended by 51 cm, the engine cowling panels were redesigned, the curved, one-piece windscreen was replaced by one containing an optically flat panel and armour plate was fitted behind the pilot's seat. Most production examples were powered by the 935 CV Hispano-Suiza 12Y-45 with the new Szydlowski-Planiol supercharger, although later production versions used the 960 CV Hispano-Suiza 12Y-49. The production standard armament was a 20 mm HS.404 cannon firing through the propeller hub and four belt-fed MAC 1934 M39 7.5 mm machine guns in the wings.

As the first batch of D.520s rolled off the production line, they failed acceptance tests due to insufficient top speed and troublesome cooling. Redesigned compressor intakes, a modified cooling circuit and propulsive exhaust pipes proved to be effective remedies of these shortcomings, but as early examples had to be retrofitted with these improvements, the type was not declared combat ready until April 1940, at which point the D.520's operational standards had been defined. In order to speed up the redesign process, a total of four production aircraft were handed back to SNCAM to serve as special test machines.

The manufacturing process was deliberately optimized, each aircraft consumed a reduced 7,000 man-hours each to produce, roughly half the time compared to the previous D.510 and MS.406, and far less than many other fighters of the time, such as the MC.200/202 (21,000 hours), but around 50% greater than a Bf 109E (4,500 hours). The French Air Ministry planned for over 300 aircraft a month to be built and managed to reach this goal, especially in June 1940, but it was too late to affect the tide of battle. The armistice greatly curtailed production of D.520, which would have otherwise been a fighter aircraft produced in far greater numbers and with improved models.

Additional plans had included another manufacturing line at Asnières-sur-Seine, Paris, for a lightened version of the aircraft, known as the D.521. An initial batch of 18 pre-production D.521s had been produced at Bagnères-de-Bigorre, Occitanie and had been prepared for their maiden flight when the armistice came into effect. During 1940, negotiations with American manufacturer Ford had been underway with the aim of establishing the licensed production of an Americanised version of the type, designated as the D.522. This model was anticipated to have been powered by an Allison V-1710-C15 engine, capable of generating 1040 hp, instead.

In April 1941, during the aftermath of the armistice with Germany, a new programme was launched in which the production of 1,074 new aircraft were to be manufactured in the unoccupied zone of Vichy France. Of these, 550 were to be D.520s, which were confirmed as ordered under contract No. 157/41 on 8 August 1941. The intention was for the type to replace all other single-engine fighters that remained in service with the Vichy French Air Force and to eventually equip additional units that were to be reformed from September 1942 onwards. An initial batch of 22 D.520s were delivered during August 1941. In total, a further 180 machines were constructed, bringing the production total to 905.

Overview
The Dewoitine D.520 was a French fighter aircraft, intended to be a capable contemporary of types such as the Messerschmitt Bf 109 and Supermarine Spitfire. An all-metal structure was used, except for fabric-covered ailerons and tail surfaces. The wing, even if single-spar, was a solid and rigid unit with a secondary spar and many reinforced parts. The inwardly retracting undercarriage had a broad 2.83 m track, and was fitted with wide, low-pressure tyres.

The D.520 was designed to be maintained easily with many inspection panels, a rare feature for its time. Recharging the D.520 ammunition was swift and easy; the machine gun magazines required five minutes each and three minutes for the 20 mm cannon. To fill the machine gun ammunition boxes took 15 minutes, while five minutes were needed to empty it as the cartridges were not expelled. The D.520's cockpit was set well back in the fuselage, aft of the trailing edge of the wings. This gave the pilot good downward visibility, but the long nose in front of him was a drawback when taxiing on the ground.

A self-sealing fuel tank with a capacity of 396 L was mounted between the engine and cockpit, along with two wing tanks which, combined, carried another 240 L, for a total of 636 L; this was considerably more than the contemporary Bf 109E, Spitfire I and early Italian fighters, each with about 400 L fuel capacity. The ferry range was from 1300 to 1500 km at 450 km/h which, from June 1940, allowed D.520s to escape to North Africa when France fell.

Engine
The Hispano-Suiza 12Y-45 engine was an underpowered, older design, with 850 CV at takeoff at 2,400 rpm, or 935 CV emergency power at 2,520 rpm and at a height of 1900 m. The Hispano engine had some advantages over some later engines; for example, its weight was only 515 kg, compared to the 620 kg of the Rolls-Royce Merlin III. Development of the engine had not been straightforward, and had delayed production. According to an aviation author, it was alleged by American aviator Charles Lindbergh that secret negotiations were conducted between Dewoitine and Daimler-Benz during 1939 to obtain the DB.601 engine for the D.520, but that these did not come to fruition due to the war.

Fuel was fed via six Solex S.V. 56 carburettors mounted on an inlet manifold which directed compressed air from the supercharger to the engine cylinders; the 12Y-45 and -49s fitted to production D.520s used either 92 or 100 octane fuel. The -45 drove an electrically operated Ratier Type 1606M three-bladed, 3 m, variable-pitch propeller, while D.520s from No. 351 were fitted with the 12Y-49 960 CV engine driving a Chauvière type 3918 pneumatically operated propeller, 3 m in diameter.

By 1940 a version of the 520D was flying with a Rolls-Royce Merlin X engine. Ernest Hives stated that agreement had been reached with the French Government for the manufacture of the Merlin in France. ("The Merlin in perspective" - A Harvey-Bailey -Rolls-Royce Heritage Trust, p130)

Fire suppression system
The D.520 had a fire-suppression system with a fire extinguisher activated from the cockpit. The engine was started by a simple but effective system, operating with compressed air. A Viet 250 air compressor charged several air bottles (one with a 12-litre capacity, as well as another eight litre tank, three smaller one litre units were matched to the weapons). The 12-litre air bottle was used for the brakes and later, for the Chauvière propeller's constant speed adjustment. The small air bottles provided up to 12 seconds at 9000 m or 20 seconds at low level, before the Viet air compressor recharged them. The pilot had a complete set of cockpit instruments, and a ten-litre oxygen bottle located in the fuselage just behind his seat, with either a Munerelle or Gourdou oxygen regulator system mounted on the right instrument panel. Equipment included a Radio Industrie Type Rl 537 radio-receiver set, an OPL RX 39 reflector sight (less effective than the Revi system), a height-adjustable seat, and a sliding canopy with large, clear panels. Except over the long nose, the pilot's view was good, since he was seated quite high over the forward fuselage; however, no rear-facing mirrors were fitted.

Armament
Production-standard armament consisted of a 20 mm HS.404, which had an ammunition capacity of 60 rounds, firing through the propeller hub, and four belt-fed MAC 1934 M39 7.5 mm machine guns in the wings, with 675 rounds per gun. The MAC 1934 machine guns had a high rate of fire of 1,200 rounds per minute (rpm), while the HS.404 had an effective rate of fire of 600 rpm and was accurate up to 500 m; the ammunition capacity meant that the machine guns could be fired for a total of 30 seconds, while the cannon had ten seconds' worth of ammunition.

In combat, the MS.406 had only a pair of 7.5 mm machine guns and was, therefore, at a disadvantage when the HS.404 had used up its ammunition, while a D.520 could continue to fight effectively because it had four fast-firing machine guns (over 80 rounds/sec), with 20-plus seconds of ammunition still available. The D.520 had provisions for two BE33 "illuminating bombs", useful for nocturnal interception missions, but these were seldom used because French fighters rarely flew nighttime missions.

Flight performance
Although employing a modern design philosophy for its time, the D.520 was considered more difficult to fly than the older MS.406. Captain Eric Brown, commanding officer of the Royal Aircraft Establishment's Captured Enemy Aircraft Flight, tested the D.520 at RAE Farnborough, saying that "It was a nasty little brute. Looked beautiful but didn't fly beautifully. Once you get it on the ground, I was told not to leave the controls until it was in the hangar and the engine stopped. You could be taxiing toward the hangar and sit back when suddenly it would go in a right angle."

The handling changed according to the amount of fuel carried; using the fuselage tank alone, fuel consumption had no appreciable effect on handling because the tank was at the centre of gravity, but with full wing tanks, directional control was compromised, especially in a dive. The flight controls were well harmonized and the aircraft was easy to control at high speed. The maximum dive speed tested was 830 km/h with no buffeting and excellent stability both in the dive (depending on fuel load) and as a gun platform.

Battle of France
The Groupe de Chasse I/3 was the first unit to get the D.520, receiving its first aircraft in January 1940. These initial examples were unarmed and used for pilot training. In April and May 1940, operational units received 34 'war-capable' production D.520s; the type quickly proved to be highly popular with pilots and ground crew. During comparative trials on 21 April 1940 at CEMA at Orleans-Bricy against a captured Bf 109E-3, the German aircraft had a 32 km/h speed advantage owing to its more powerful engine. However, the D.520 had superior maneuverability, matching its turning circle, although displaying nasty characteristics when departing and spinning out of the turn repeatedly during the tests. The Bf 109, owing to its slats, could easily sustain the turn on the edge of a stall.

By 10 May 1940, when the Phoney War came to an end as Germany launched the invasion of France and the Low Countries, a total of 246 D.520s had been manufactured, but the French Air Force had accepted only 79 of these, as most others had been sent back to the factory to be retrofitted to the new standard. As a result, only GC I/3 was fully equipped, possessing a force of 36 aircraft. These met the Luftwaffe on 13 May, shooting down three Henschel Hs 126s and one Heinkel He 111 without suffering any losses. The next day, two D.520s were lost while a total of ten Luftwaffe aircraft (4 Messerschmitt Bf 110s, 2 Bf 109Es, 2 Dornier Do 17s, and 2 He 111s) were confirmed to be destroyed.

Four more Groupes de Chasse and three naval Escadrilles rearmed with the type before France's surrender. GC II/3, GC III/3, GC III/6 and GC II/7 later completed conversion on the D.520. A naval unit, the 1er Flotille de Chasse, was also equipped with the Dewoitine. However, only GC I/3, II/7, II/6 and the naval AC 1 saw any action in the Battle of France. GC III/7 converted to the D.520 too late to be involved in any action. In addition, several aircraft were flown by non-operational units, such as the special patrol of the École de l'air military school, as well as a handful flown by Polish and civilian pilots in defence of airstrips and production facilities in the vicinity of Toulouse.

In air combat, mostly against the Italians, the Dewoitine 520s claimed 114 air victories, plus 39 probables. Eighty five D.520s were lost. By the armistice at the end of June 1940, 437 D.520s had been constructed, 351 of these having been delivered. After the armistice, 165 D.520s were evacuated to North Africa. GC I/3, II/3, III/3, III/6 and II/7 flew their aircraft to Algeria to avoid capture. Three more, from GC III/7, escaped to Britain and were delivered to the Free French. A total of 153 D.520s remained in unoccupied mainland France.

One of the most successful D.520 pilots was Pierre Le Gloan, who shot 18 aircraft down (four Germans, seven Italian and seven British), scoring all but two of his kills with the D.520, and ranked as the fourth-highest French ace of the war.

Under Vichy

In April 1941, the German armistice commission authorized Vichy authorities to resume production of a batch of 1,000 military aircraft for their own use, under the condition that 2,000 German-designed aircraft would later be manufactured in France and delivered to Germany. As part of this agreement, 550 examples of the D.520 were ordered to replace all other single-seat fighters in service. However, no D.520 units were to be stationed on the French mainland, thus individual aircraft were instead stored or dispatched to units overseas, such as in North Africa.

The plan was to have the Dewoitine eventually equip a total of 17 Groupes with 442 aircraft, three escadrilles of the Aéronautique navale with 37 aircraft each, plus three training units with 13 aircraft. The agreement stated that aircraft of this new batch were to be similar to the ones already in service. From serial number 543 on, however, D.520s used the 12Y-49 engine that had a slightly higher rated performance than the 12Y-45, although the German Armistice Commission explicitly prohibited replacing the original power plants with the more powerful 12Y51 or 12Z engines.

In 1941, D.520s of GC III/6, II/3 and naval escadrille 1AC fought the Allies during the Syria–Lebanon campaign. The Vichy French Air Force was already relatively strong, but several units were sent to reinforce it. D.520s were the only French single-seat fighters capable of making the trip to Syria. The GC III/6 was sent first. The ferry trip was very difficult for a 1940 interceptor and the pilots pushed their planes as far as their fuel tanks would allow them to. They flew from France to Syria with intermediate stops at Rome, Brindisi or Catania. Another route was available through Germany and Greece (Athens), but it was seldom used. The trip always included a stopover in Rhodes (which had an Italian base at the time), before the final flight to Syria. This meant several thousand kilometers were flown over mountains and sea. The most demanding part was Catania-Rhodes, which entailed no less than 1200 km flown over water. Even the trip from Rhodes to Syria was 800 km. LeO 451s and Martin 167F bombers had few problems, but D.520s were forced to fly a strenuous and dangerous mission, without any help or external assistance. Of the 168 French aircraft (of all types) sent to Syria, 155 accomplished their mission and arrived successfully. The Vichy Air force was numerically strong, but with very few ground crew and spare parts, which meant that the operational flying time for the D.520s was very limited. D.520s of GC III/6 first saw action against British aircraft on 8 June 1941, when they shot down three Fairey Fulmars, losing one D.520 (its pilot was taken prisoner). Over the following days several escort missions were flown to protect Martin, LeO and Bloch 200 (3/39 Esc) bombers from British Royal Navy fighters. Two Hurricanes were shot down (with another D.520 lost) on 9 June.

During the Syria campaign, a total of 266 missions were conducted by the Vichy French Air Force: 99 of them were carried out by D.520s, nine by MS.406s, 46 by Martin 167s and 31 by LeO 451s. The D.520s were therefore the most active of the French aircraft in the campaign, where they claimed 31 kills over British and Australian units while losing 11 of their own in air combat and a further 24 to anti-aircraft fire, accidents and attacks on their airfields. On 10 July, five D.520s attacked Bristol Blenheim bombers from No. 45 Squadron RAF that were being escorted by seven Curtiss Tomahawks from No. 3 Squadron RAAF (3 Sqn). The French pilots claimed three Blenheims, but at least four of the D.520s were destroyed by the Australian escorts, including two by flying officer Peter Turnbull. The following day, a Dewoitine pilot shot a P-40 down from 3 Sqn, the only Tomahawk lost during the campaign. This Dewoitine was in turn shot down by F/O Bobby Gibbes. The initial advantage that the Vichy French Air Force enjoyed did not last long, and they lost most of their aircraft during the campaign. The majority of them were destroyed on the ground where the flat terrain, absence of infrastructure and absence of modern anti-aircraft (AA) artillery made them vulnerable to air attacks. On 26 June, a strafing run by Tomahawks of 3 Sqn, on Homs airfield, destroyed five D.520s of Fighter Squadron II/3 (Groupe de Chasse II/3) and damaged six more.

By the end of the campaign, Vichy forces had lost 179 aircraft from the approximately 289 committed to the Levant. The remaining aircraft with the range to do so, evacuated to Rhodes. The known French losses of fighter aircraft were 26 in air combat and 45 in strafing and bombing actions. The Allies lost 41 planes, 27 of those shot down by French fighters. During Operation Torch (the invasion of North Africa), GC III/3 (previously known as GC I/3), was engaged in combat with the Allies over Oran. Flotille 1F saw action against the United States Navy Grumman F4F Wildcat squadron VF-41 (from the carrier USS Ranger (CV-4)), over Casablanca. One D.520 was among fourteen US victory claims; the only Allied losses were due to ground and friendly fire. Other Dewoitine-equipped units in North Africa such as GC II/7 or GC II/3 did not take part in the fighting. Overall, the known D.520 air strength in North Africa was 173 D.520s (143 combat ready) of GC II/3, III/3, III/6, II/7 and II/5; another 30 were in Senegal with GC II/6. The Navy had Esc 1AC and 2AC. Many D.520s were destroyed on the ground by Allied bombing. The French Air Force lost 56 aircraft, among them 13 D.520s. The Navy lost 19 D.520s. Among the 44 kills that the French scored overall, there were five losses from fighters and flak out of a squadron of eight Fairey Albacores from HMS Furious (47), some of which were shot down by D.520s of GC III/3.

Free French Dewoitines
A very small number of D.520s were briefly operated by Free French Forces for training purposes. Along with the three examples that had flown to Britain in June 1940, two other Dewoitines were recovered from retreating Vichy forces in Rayak, Lebanon. These D.520s were flown by pilots of the Normandie-Niemen unit before it was sent to the USSR, where they flew the Yakovlev Yak-1 that had many similarities with the French aircraft.

With the Allies
In December 1942, as French forces formerly under Vichy sided with the Allies, there were 153 D.520s left in French hands in North Africa. They flew a few patrols during the Tunisia campaign, but were considered obsolete, and their radio sets were incompatible with Allied equipment. From early 1943 on, they were relegated to training duties at the fighter school in Meknes, and progressively replaced by Supermarine Spitfires and Bell P-39 Airacobras in combat units.

During the liberation of France, a few D.520s abandoned by the Germans, were used by ad hoc units in ground attacks against the isolated German pockets of resistance on the Western coast. Around 55 such aircraft were recovered from the Luftwaffe by the rapid advance of the Allies. Commanded by former test pilot Marcel Doret, one such unit attacked German forces at Royan and Pointe de Grave, performing strafing runs upon enemy artillery positions, as well as providing air cover for Allied bombers. After 1 December 1944, the date on which the French Air Force was officially reformed, Doret's unit became G.C.II/18; it continued to operate D.520s for several months before being reequipped with Spitfires on 1 March 1945.

Regia Aeronautica Dewoitines
About 60 D.520s were acquired by the Regia Aeronautica (the Italian Air Force or RA). Italian pilots appreciated the aircraft's capabilities and Hispano-Suiza HS.404 cannon, at least by 1940–1941 standards. The first three D.520s were assigned to 2° Stormo based at the Torino-Caselle airfield, where they were used for the defence of Torino's industrial area. Other D.520s were captured in Montélimar, Orange, Istres and Aix-en-Provence.

At the beginning of 1943, the Italian ace Luigi Gorrini ferried D.520s taken as prizes of war to Italy to be used for defence. "I have collected several dozen Dewoitines from various French airfields and the Toulouse factory", he recalled later. "At the time, when we were still flying the Macchi C.200, it was a good, if not very good, machine. Compared to the Macchi 200, it was superior only in one point: its armament of the Hispano-Suiza HS 404 20 mm cannon." Italian pilots liked the 20 mm gun, the modern cockpit, the excellent radio set and the easy recovery from a spin but they also complained about the weak undercarriage and the small [cannon] ammunition drum capability; the ammunition was not available in quantities (the HS.404 was not compatible with Breda and Scotti 20 mm guns, so everything depended on France's depots). At the end of February the 359a Squadriglia (22° Gruppo), led by Major Vittorio Minguzzi, received eight Dewoitine D.520. At that time, American B-24s frequently bombed Naples, so an effective interceptor was badly needed, and D.520s were all that were available in early 1943. The 359a Squadriglia pilots used Dewoitines with some success.

On 1 March 1943, Maggiore Minguzzi claimed a B-24 while flying a D.520. This claim was initially only claimed as a probable but was later upgraded to a confirmed. This was probably the first Italian claim using this aircraft. On 21 May 1943, the Regia Aeronautica and the Luftwaffe agreed to exchange 39 Lioré et Olivier LeO 451s, captured by the Italians at the SNCASE factory in Ambérieu-en-Bugey (Lyon), with a stock of 30 D.520s. Subsequently, in the spring and summer of 1943, the Dewoitines were used by 161° Gruppo Autonomo, based in southern Italy with 163a Squadriglia in Grottaglie, 162a Squadriglia in Crotone and 164a Squadriglia in Reggio Calabria. On 31 July 1943, the Regia Aeronautica still had 47 Dewoitines in service. After the armistice of 8 September 1943, three D.520s, previously in service with 24° Gruppo, were used by the Aeronautica Nazionale Repubblicana of the Italian Social Republic for training.

Other foreign users
German forces invading Vichy's so-called "free zone" in November 1942, captured 246 D.520s; additionally, a batch of 62 was completed under German occupation. The captured Dewoitines were to be delivered to the Axis Balkan Front, although some were used by the Luftwaffe for training purposes while 60 were transferred to Italy and 96, or 120, to the Bulgarian Air Force for use in combat. However, D.520s reached Bulgaria only in August 1943, as the fighter pilots of that country were still training on the type at Nancy with JG 107.

The following month, the first 48 Dewoitines were taken over in a ceremony on Karlovo airfield. Two months later, on 24 November, the D.520s were used in combat, when 17 out of the 60 B-24 Liberators of the 15th USAAF arrived over the capital, Sofia, to bomb it. Twenty four Dewoitines took off from Vrazhdebna base (along with 16 Bf 109G-2s from Bojourishte) and attacked the bombers and their 35 escorting P-38 Lightnings. The Bulgarian pilots claimed four American aircraft for the loss of one fighter, three more had to force land. American bombers attacked Sofia again, on 10 December 1943. That day, 31 B-24s escorted by P-38s, were intercepted by six Dewoitines of the II/6th Fighter Regiment from Vrazhdebna and 16 D.520s of the I/6th Fighter Regiment from Karlovo (along with 17 Bf 109G-2s). The Americans claimed 11 D.520s for the loss of only one P-38. The later examination of records showed that only one Dewoitine was lost during that air battle.

The Bulgarian Air Force D.520s were again up in force, to face the massive Allied air raid of 30 March 1944. To intercept the 450 bombers (B-17 Flying Fortresses, B-24s and Handley Page Halifaxes) escorted by 150 P-38s, the Bulgarians scrambled 28 Dewoitines from I./6th at Karlovo, six D.520s from II/6th at Vrazhdebna (together with 39 Bf 109G-6s and even Avia 135s). At least ten Allied aircraft (eight bombers and two P-38s) were shot down, while the Bulgarian Air Force lost five fighters and three pilots. Two more Bulgarian aircraft had to force land. During the last Allied raid on Sofia, on 17 April, the II./6th fighter scrambled seven Dewoitines (plus 16 Bf 109s), against 350 B-17s and B-24s escorted by 100 P-51 Mustangs. Bulgarian pilots, who up to that time had encountered only P-38s, mistook the P-51s for their own Bf 109s and before they realized their mistake, seven Bf 109G-6s had been shot down. That day the Bulgarian Air Force suffered the heaviest losses since the beginning of the war: nine fighters shot down and three that had to crash land. Six pilots lost their lives. By 28 September 1944, twenty days after Bulgaria joined the Allies, Dewoitines still equipped an Orlyak (Group) of the 6th Fighter regiment: I Group had a total of 17 D.520s, five under repair and 12 operational, for its three Jato (Squadrons).

Numerous sources have mentioned use of the D.520 by the Romanian Air Force, but no evidence has ever been provided. One source claims the so-called Romanian Dewoitines were, in fact, in transit to Bulgaria and only flew over Romania in order to get to their final destination. This seems the most reliable explanation, viewed against the numbers of Dewoitines actually available. Romania did however use the French Bloch MB.150.

Postwar service
After the war, the D.520s that remained in France were used as trainers; on 1 June 1945, the school base No. 704 was formed at Tours for the purpose of training pilot instructors operating, amongst other types, 17 D.520s. At the encouragement of No. 704's commanding office, one D.520 was field-modified into a two-seater configuration in late 1945, which was subsequently designated as the D.520 DC. In March 1946, after further experiments, the French Air Force ordered a further batch of 20 D.520s to be likewise converted; however, only 13 of these D.520 DC conversions were completed.

The last unit to fly the D.520 was the EPAA (Équipes de présentation de l'armée de l'air), No. 58. In their final years, the remaining examples were often unserviceable due to general wear and tear. The last flight of an operational D.520 was made on 3 September 1953 with EPAA (Équipes de présentation de l'armée de l'air). Initially, this unit had flown Yak-3s, formerly of the Normandie-Niemen fighter squadron; these were later replaced with seven D.520s, three of them being two-seaters.

Variants

 * D.520
 * The main production version, sometimes designated the D.520 S (for série – production) or the D.520 C1 (for chasseur – fighter, single-seat).

Direct derivatives
In 1940, SNCAM had several projects to fit the D.520 airframe with more powerful engines. These developments were halted by the June armistice.
 * D.521
 * engine replaced by a Rolls-Royce Merlin III, one example was built, but the project was cancelled.

 * D.522
 * engine replaced by an Allison V-1710 C-1, project abandoned after the armistice (22 June 1940).

 * D.523
 * engine replaced by slightly different sub-variants of the 820 kW Hispano-Suiza 12Y-51, with Szydlowski-Planiol supercharger. D.523 Prototype was completing pre-production trials in June 1940.

 * D.524
 * Version powered by Hispano-Suiza 12Y-89ter engine. One prototype built, but it never flew.

 * D.525
 * development version of the D.523

 * D.530
 * planned version with a 1044 kW Rolls-Royce Merlin or a 1342 kW Hispano-Suiza 12Y.

Related prewar projects

 * HD.780
 * Floatplane derivative of the D.520, one prototype built, but it never flew, the development was cancelled with the armistice.

 * D.790
 * Carrier-borne derivative project, none built.

 * D.550
 * Unarmed aircraft built for speed record attempt, with an airframe loosely based on the D.520, but using weight-saving construction techniques. One example was built.

 * D.551 and D.552
 * Military developments of the D.550. 12 examples were built, but none flew. The development was resumed in 1941, but was quickly terminated by the Germans.

Post-armistice developments
Several projects were initiated after the June 1940 armistice. They were all terminated with the German occupation of Southern France in November 1942.
 * D.520 amélioré
 * Single production D.520 experimentally fitted with minor improvements to improve top speed with an unchanged engine.

 * D.520 Z
 * D.520 airframe with 12Z engine and minor improvements. One example was built. The development resumed after the war (as SE.520Z), but was eventually cancelled in 1949.

 * M.520 T
 * Different airframe loosely based on the D.520. None built.

Postwar derivative

 * D.520 DC (double commande – dual control)
 * Two-seat trainer conversion, at least 13 built.

Markings
Apart from the first prototype and postwar examples, D.520s sported the usual French camouflage of dark blue-grey, khaki, and dark brown with light blue-grey undersurfaces. The camouflage pattern was not standardized. National markings were the standard light-blue-white-red roundels on the wingtips, as well as on the rear fuselage, and the rudder flag.

Specific markings were applied during the Vichy era, consisting of white outlined fuselage roundels with a white fuselage stripe, and from mid-1941 on, the infamous "slave's pajamas" with red and yellow stripes on the engine cowling and tail surfaces.

Operators
Main operators
 * Kingdom of Bulgaria
 * Bulgarian Air Force

 * undefined
 * French Air Force
 * Aéronautique navale

 * Vichy France
 * Vichy French Air Force

 * Free France:
 * Free French Air Force

 * Nazi Germany
 * Luftwaffe

 * Kingdom of Italy
 * Regia Aeronautica

Intended operators Royal Romanian Air Force
 * Kingdom of Romania

Surviving aircraft

 * n°603 – D.520 on display at the Conservatoire de l’air et de l’espace d'Aquitaine in Bordeaux–Mérignac.
 * n°650 – D.520 under restoration at the Musée National de la Marine in Rochefort.
 * n°862 – D.520 on display at the Musée de l’air et de l’espace. It is painted as n°277, which was used by GC III/6 in June 1940.

title: Dewoitine D.520


text:
M/S

m/s is the symbol for metre per second, a unit of both speed and velocity.

example: speed of sound=340 m/s.

M/S or m/s may also refer to:

 * Motor ship, also MS, MV, M/V, or motor vessel, a maritime prefix
 * M/S stereo coding (Mid/Side stereo encoding), in audio engineering
 * Master/slave (BDSM)
 * Messrs., especially in India as a prefix to a firm or company name.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: M/S


text:
Dornier Do 335

The Dornier Do 335 Pfeil (Arrow) is a heavy fighter built by Dornier for Germany during World War II. The Pfeil's performance was predicted to be better than other twin-engine designs due to its unique push-pull configuration and the lower aerodynamic drag of the in-line alignment of the two engines. It was Nazi Germany's fastest piston-engined aircraft of World War II. The Luftwaffe was desperate to get the design into operational use, but delays in engine deliveries meant that only a handful were delivered before the war ended.

What made the Do 335 unique was due to its initial planning of a Schnellbomber, it had two engines. These engines were the Daimler-Benz DB 605 at the front, and its counterpart DB 605 QA at the back.

This design allowed the Pfeil to reach high speeds of almost 500 mph sometimes in level flight, and outrun most of the military aircraft in service at the time, with only first generation jet fighters being faster.

Design and development
The origins of the Do 335 trace back to World War I when Claude Dornier designed a number of flying boats featuring remotely driven propellers and later, due to problems with the drive shafts, tandem engines. Tandem engines were used on most of the multi-engine Dornier flying boats that followed, including the highly successful Do J Wal and the gigantic Do X. The remote propeller drive, intended to eliminate parasitic drag from the engine entirely, was tried in the innovative but unsuccessful Do 14, and elongated, tubular drive shafts as later used in the Do 335 saw use in the rear engines of the four-engined, twinned tandem-layout Do 26 flying boat.

There are many advantages to this design over the more traditional system of placing one engine on each wing, the most important being power from two engines with the frontal area (and thus drag) of a single-engine design, allowing for higher performance. It also keeps the weight of the twin powerplants near, or on, the aircraft centerline, increasing the roll rate compared to a traditional twin. In addition, a single engine failure does not lead to asymmetric thrust, and in normal flight there is no net torque, so the plane is easy to handle. The four-surface set of cruciform tail surfaces in the Do 335's rear fuselage design included a ventral vertical fin–rudder assembly that projected downwards from the extreme rear of the fuselage, to protect the rear propeller from an accidental ground strike on takeoff. The presence of the rear pusher propeller also mandated the provision for an ejection seat for safe escape from a damaged aircraft, and designing the rear propeller and dorsal fin mounts to use explosive bolts to jettison them before an ejection was attempted – as well as twin canopy jettison levers, one per side located to either side of the forward cockpit interior just below the sills of the five-panel windscreen's sides, to jettison the canopy from atop the cockpit before ejection.

In 1939, Dornier, reviving a principle he patented in 1937, was busy working on the P.59 high-speed bomber project, which featured the tandem engine layout. In 1940, he commissioned a test aircraft, closely modeled on the airframe of the early versions of the Dornier Do 17 bomber but only 40% of the size of the larger bomber, with no aerodynamic bodies of any sort on the wing panels (the original Do 17 had twin engine nacelles on its wings) and fitted with a retractable tricycle landing gear to validate his concept for turning the rear pusher propeller with an engine located far away from it, through the use of a long tubular driveshaft. This aircraft, the Göppingen Gö 9 (D-EBYW), showed no unforeseen difficulties with this arrangement, but work on the P.59 was stopped in early 1940 when Hermann Göring ordered the cancellation of all projects that would not be completed within a year or so.

In May 1942, Dornier submitted an updated version with a 1000 kg bombload as the P.231, in response to a requirement for a single seat, Schnellbomber-like high-speed bomber/intruder. The P.231 proposal was selected as the winner after beating rival designs from Arado, Junkers, and Blohm & Voss. A development contract was awarded, by the RLM issuing the Dornier firm the airframe approval number 8-335, for what would become known as the Do 335. In autumn 1942, Dornier was told that the Do 335 was no longer required, and instead a multi-role fighter based on the same general layout would be accepted. This delayed the prototype delivery as it was modified for the new role.

The use of a nose-mount annular radiator for the forward engine (much like a Jumo 211-powered Ju 88, or Jumo 213-powered Focke-Wulf Fw 190D-9) and a ventral-fuselage mount airscooped radiator installation for cooling the rear engine made the aircraft look distinctive. When fitted with DB 603A engines delivering 1,750 PS it had a pair of the largest inverted V12 aircraft engines mass-produced during the Third Reich's existence. The Do 335 V1 first prototype, bearing the Stammkennzeichen (factory radio code) of CP+UA, flew on 26 October 1943 under the control of Flugkapitän Hans Dieterle, a regular Heinkel test pilot and later primary Dornier test pilot. However, several problems during the initial flight of the Do 335 would continue to plague the aircraft through most of its short history. Issues were found with the weak landing gear and with the main gear's wheel well doors, resulting in them being removed for the remainder of the V1's test flights. The Do 335 V1 made 27 flights, flown by three different pilots. During these test flights the second prototype, V2 (Werk Nr 230002) CP+UB, was completed and made its first flight on 31 December 1943, again under the control of Dieterle. New to the V2 were upgraded DB 603A-2 engines, and several refinements learned from the test flights of the V1 as well as further windtunnel testing. On 20 January 1944, the Do 335 V3 (W.Nr. 230004), CP+UC was completed and flown for its first time by Werner Altrogge. The V3 was powered by the new pre-production DB 603G-0 engines which could produce 1900 PS at take-off and featured a slightly redesigned canopy which included twin rear-view mirrors in blisters, one in each of two matching side panels of the well-framed, eleven-panel main canopy's openable section. Following the flights of the V3, in mid January 1944, RLM ordered five more prototypes (V21–V25), to be built as night fighters. By this time, more than 60 hours of flight time had been put on the Do 335 and reports showed it to be a good handling, but more importantly, very fast aircraft, described by Generalfeldmarschall Erhard Milch himself as "...holding its own in speed and altitude with the P-38 and it does not suffer from engine reliability issues". The Do 335 was scheduled to begin mass construction, with the initial order of 120 preproduction aircraft to be manufactured by Dornier-Werke Friedrichshafen (DWF) to be completed no later than March 1946. This number included a number of bombers, destroyers (heavy fighters), and several yet to be developed variants. At the same time, Dornier-Werke München (DWM) was scheduled to build over 2,000 Do 335s in various models, due for delivery in March 1946 as well.

On 23 May 1944, Hitler, as part of the developing Jägernotprogramm (Emergency Fighter Program) directive, which took effect on 3 July, ordered maximum priority to be given to Do 335 production. The main production line was intended to be at Manzell, but a bombing raid in March destroyed the tooling and forced Dornier to set up a new line at Oberpfaffenhofen. The decision was made, along with the rapid shut-down of many other military aircraft development programs, to cancel the Heinkel He 219 night fighter, which also used the DB 603 engines (in well-unitized installations), and use its production facilities for the Do 335 as well. However, Ernst Heinkel managed to delay, and eventually ignore, its implementation, continuing to produce examples of the He 219A.

At least 16 prototype Do 335s were known to have flown (V1–V12, W.Nr 230001-230012 and Muster-series prototypes M13–M17, W.Nr 230013–230017) on a number of DB603 engine subtypes including the DB 603A, A-2, G-0, E and E-1. The first preproduction Do 335 (A-0s) starting with W.Nr 240101, Stammkennzeichen VG+PG, were delivered in July 1944. Approximately 22 preproduction aircraft were thought to have been completed and flown before the end of the war, including approximately 11 A-0s converted to A-11s for training purposes. One such aircraft was transferred to the Royal Aircraft Establishment at Farnborough, and later, after a rear-engine fire burnt through the elevator controls during a flight, crashed onto a local school.

Flight tests

The first 10 Do 335 A-0s were delivered for testing in May 1944. Do 335 V3, (T9+ZH), W.Nr. 230003 was delivered to the Luftwaffe's experimental reconnaissance unit, 1./Versuchsverband OKL, in late May. However, it suffered constant problems and was returned to Dornier in September. By late 1944, the Do 335 A-1 was on the production line. It was similar to the A-0 but with the uprated DB 603E-1 engines of some 1324 kW take-off power rating apiece on 87 octane "B4" lignite-derived synthetic fuel, and two underwing hardpoints for additional bombs, drop tanks or guns. It had a maximum speed of 763 km/h at   6500 m with MW 50 boost, or 686 km/h without boost, and climbed to 8000 m in under 15 minutes. Even with one engine out, it reached about 563 km/h.

Operational History
Delivery commenced in January 1945. When the United States Army overran the Oberpfaffenhofen factory in late April 1945, only 11 Do 335 A-1 single-seat fighter-bombers and two Do 335 A-12 trainers had been completed. The two-seater trainer version was called Ameisenbär ("anteater").

French ace Pierre Clostermann claimed the first Allied combat encounter with a Pfeil in April 1945. He described leading a flight of four Hawker Tempests from No. 3 Squadron RAF over northern Germany when they came across an unknown aircraft whose description matched the Do 335's, flying at maximum speed at treetop level. Detecting the British aircraft, the German pilot reversed course to evade. Two pilots fired on the Dornier but Clostermann, despite the Tempests' considerable low altitude speed, decided not to attempt to chase it as it was obviously much faster.

On 26 April 1945, the Do 335 V9, which was still at Rechlin, was test-flown by Oberleutnant Heinrich Schild. Later that day he escorted Hanna Reitsch and Genral der Flieger Robert von Greim's Junkers Ju 188 flight to Berlin-Gatow. After arriving at Gatow, Reitsch and von Greim comandeered a Fieseler Fi 156 Storch and flew to Hitler's bunker. Also on 26 April, Fliegerstabsing. Heinz Fischer attempted to fly Do 335 V9 from Rechlin to Switzerland. Due to a compass failure, he strayed over France and ran out of fuel. Both the ejector seat and the tail jettison mechanism failed and he had to bail out over the Vosges mountains.

Do 635
In 1944, Junkers helped Dornier with work on the Do 335 Zwilling or Dornier Do 635. A meeting was arranged between Junkers and Heinkel engineers, and after the meeting, they began work on the project, named 1075 01–21. The designer, Professor Heinrich Hertel, planned a test flight in late 1945. At the end of 1944, the Germans reviewed aircraft designs with the Japanese military. Among other projects, the Do 635 impressed the Japanese military with its capabilities and design. This design consisted of two Do 335 fuselages, joined by a common centre wing section, with two Rb 50 cameras in the port fuselage for aerial photography. Armament was confined to provision for five 60 kg photo-flash bombs. The mainwheels were common with Ju 352 wheels. It was also intended that two monopropellant Walter Starthilfe RATOG units would be fitted. In early 1945, a wind-tunnel model was tested, and a cockpit mockup was constructed. Following an order from the Rüstungsstab on the 15 March, it was decided that Junkers continue with the project, but only by using the simplest production solutions. However, none were completed by wars end.

P 256
The P 256 was to meet a Luftwaffe requirement issued 27 February 1945. It was designed to carry a crew of three (pilot, radar operator, and navigator), with pilot and radar operator together under the canopy, while the navigator was in the fuselage, an idea copied from Arado. Departing from centerline thrust, it was to have two Heinkel HeS 011 engines of 12.7 kN each, podded under the wings in the fashion of the Me 262. The low-mounted wing was unswept, and had an aspect ratio of 5.8:1. Designed armament was four 30 mm MK 108 cannon in the nose. A field conversion kit was to retrofit two MK 108s in a Schräge Musik configuration. A fighter-bomber variant would have carried two 500 kg bombs. Its loaded weight would have included 3750 kg of fuel, giving a wing loading of 276 kg/m2. Maximum speed was achieved at 8000 m, maximum range at 6000 m. Endurance with 4000 kg fuel was calculated as 2.6 hours. Its electronics would have included FuG 24SE with ZVG 24, FuG 29, FuG 25a or c, and FuG 244 Bremen with Gnome weapon triggers. Criticized for having poor cross-sectional area and unduly large tail surfaces, it was not adopted.

Variants

 * Built
 * Do 335 A-0 : 10 pre-production aircraft.
 * Do 335 A-1 : Single-seat fighter-bomber aircraft.
 * Proposed
 * Do 335 A-2: single-seat fighter-bomber aircraft with new weapon sights, later proposed longer wing and updated 1471 kW DB603L engines.
 * Do 335 A-3: single-seat reconnaissance aircraft built from A-1 aircraft, later proposed with longer wing.
 * Do 335 A-4: single-seat reconnaissance aircraft with smaller cameras than the A-3
 * Do 335 A-5: single-seat night fighter aircraft, later night and bad weather fighter with enlarged wing and DB603L engines.
 * Do 335 A-6: two-seat night fighter aircraft, with completely separate second cockpit located above and behind the original.
 * Do 335 A-7: A-6 with longer wing.
 * Do 335 A-8: A-4 fitted with longer wing.
 * Do 335 A-9: A-4 fitted with longer wing, DB603L engines and pressurized cockpit.
 * Do 335 A-10: two seat trainer
 * Do 335 A-12: two seat trainer
 * Do 335 B-1: abandoned in development.
 * Do 335 B-2: single-seat destroyer aircraft. Fitted with 2 additional MK 103 in the wings and provision to carry two standard Luftwaffe 300 litre (80 US gal) drop tanks. Only two prototypes competed and were known as the Do 335 M13 and M14
 * Do 335 B-3: updated B-1 but with longer wing.
 * Do 335 B-4: update of the B-1 with longer wing, DB603L engine.
 * Do 335 B-6: night fighter.
 * Do 335 B-12: dual-seat trainer version for the B-series aircraft.
 * Do 435: a Do 335 with the redesigned, longer wing. Allied intelligence reports from early May 1945 mention spotting a Do 435 at the Dornier factory airfield at Lowenthal.
 * Do 535: actually the He 535, once the Dornier P254 design was handed over to Heinkel in October 1944; fitted with jet engine in place of rear piston engine
 * Do 635: twin-fuselaged long-range reconnaissance version. Also called Junkers Ju 8-635 or Do 335Z. Mock up only.
 * P 256: turbojet nightfighter version, with two podded HeS 011 turbojet engines, based on Do 335 airframe.

Surviving aircraft
Only one Do 335 survives, the second preproduction Do 335 A-0, designated A-02, with construction number (Werknummer) 240 102, and factory radio code registration, or Stammkennzeichen, of VG+PH. The aircraft was assembled at the Dornier plant in Oberpfaffenhofen, Bavaria on 16 April 1945. It was captured by Allied forces at the plant on 22 April. VG+PH was one of two Do 335s to be shipped to the United States aboard the Royal Navy escort carrier HMS Reaper (D82), along with other captured German aircraft, to be used for testing and evaluation under a USAAF program called "Operation Lusty". One Do 335 (registration FE-1012) went to the USAAF and was tested in early 1946 at Freeman Field, Indiana, USA. Its fate is not recorded.

VG+PH went to the Navy for evaluation and was sent to the Test and Evaluation Center, Patuxent River Naval Air Station, Maryland, USA. Following testing from 1945 to 1948, the aircraft languished in outside storage at Naval Air Station Norfolk. In 1961, it was donated to the Smithsonian's National Air Museum, though it remained in deteriorating condition at Norfolk for several more years before being moved to the National Air and Space Museum's storage facility in Suitland, Maryland. In October 1974, VG+PH was returned to the Dornier plant in Oberpfaffenhofen, Germany (then building the Alpha Jet) for a complete restoration. In 1975, the aircraft was restored by Dornier employees, many of whom had worked on the airplane originally. They were surprised that the explosive charges built into the aircraft to blow off the dorsal fin and rear propeller prior to pilot ejection were still intact.

Following restoration the completed Do 335 was displayed at the Hannover, Germany Airshow from 1 May to 9 May 1976. After the air show, the aircraft was loaned to the Deutsches Museum in Munich, where it was on display until 1988, when it was shipped back to Silver Hill, Maryland. VG+PH can be seen today in the Steven F. Udvar-Hazy Center of the National Air and Space Museum alongside other unique late-war German aircraft that accompanied the Do 335 aboard Reaper nearly eight decades earlier, such as the only known example of the Arado Ar 234 B-2 Blitz jet reconnaissance-bomber, and the fully restored fuselage and tail surfaces of the only complete surviving Heinkel He 219A Uhu (Eagle-Owl) night fighter (the wings and engines/nacelles are still undergoing restoration).

title: Dornier Do 335


text:
Ilyushin Il-4

The Ilyushin Il-4 (DB-3F) (Ильюшин Ил-4 (ДБ-3Ф); NATO reporting name: Bob) was a Soviet twin-engined long-range bomber and torpedo bomber, widely used by the Soviet Air Force and Soviet Naval Aviation during World War II.

Design and development
In 1938, the Ilyushin design bureau redesigned the Ilyushin DB-3 to ease production and improve its performance, the revised version receiving the designation DB-3F (Forsirovanniye or "boosted"). The aircraft's internal structure, particularly the wings, was extensively changed, eliminating the need for hand finishing of the structure, and with duralumin replacing the large scale use of steel in the earlier version. The aircraft's fuel system was redesigned, increasing its internal capacity while reducing the number of fuel tanks. The fuselage nose was lengthened to give more room for the navigator/bombardier while reducing drag. The prototype DB-3F, powered by the same 708 kW Tumansky M-87B engines of the DB-3M, was piloted on its maiden flight by Vladimir Kokkinaki on 21 May 1939. It successfully passed through state acceptance tests and entered production in January 1940, with the 1100 hp Tumansky M-88 quickly replacing the M-87. The DB-3F was redesignated Il-4 in March 1942. Some series had wooden outer wings and front fuselages to conserve metals, and throughout the production, engines and fuel tanks were upgraded for improved performance while retaining the same range. However the most notable change was the addition of larger defensive guns in the turret, using the 12.7 mm (0.5 in) UBT machine gun in place of the earlier 7.62 mm (0.3 in) weapons. In addition, it was found that the gunners were attacked first, so blocks of armor were placed around the gunner positions.

This extra weight was not offset by the newer engines however, and the Il-4 proved to be slower than the earlier versions at only 404 km/h (251 mph). An attempt to improve performance was made as the Il-6, adding large diesel engines and heavier armament. The engines proved unreliable and production was never started. The Il-4 remained in production until 1945, when just over 5,200 had been built.

Soviet Union
Although the Il-4 was only a medium bomber, it had the range to be used on strategic missions. The use of the bombers in this role was not a priority for the VVS, but nevertheless the Il-4 was used on several long-range bombing raids against Berlin in 1941. Most would be used on much shorter range missions, often adding another 1,000 kg (2,204 lb) of bombs under the wings, in addition to the internal 2,500 kg (5,512 lb).

Finland
Finland bought four captured DB-3Fs from German stocks. These were given the Finnish Air Force serials DF-22 to DF-25 and flown from Bryansk, Russia to Finland (one aircraft, DF-22, was destroyed en route and crashed near Syeschtschinskaya airfield). The aircraft were later flown by No. 48 Sqn during 1943 (DF-23, DF-24 and DF-25), No. 46 Sqn during 1944 (DF-23 and DF-24) and No. 45 Sqn for a short time in 1945 (DF-23), until the last remaining serviceable aircraft went into depot on 23 February 1945. After the war, DF-25 was lost in a snowstorm, landed on the ice and crashed into the woods in Öja near the city of Kokkola. Most parts of the plane were rescued and taken to a depot.

Operators

 * Chinese Nationalist Air Force 24 aircraft
 * Finnish Air Force 11 aircraft of the type DB-3M and four aircraft of the type DB-3F (Il-4)
 * 🇩🇪 Germany
 * Luftwaffe (tests only)
 * Soviet Air Force
 * Regiments as at 1945-46:
 * 10th Guards Bomber Aviation Regiment
 * 290th Bomber Aviation Regiment
 * 303rd Bomber Aviation Regiment (Zavitinsk, Amur Oblast)
 * 442nd Bomber Aviation Regiment (Belogorsk, Amur Oblast) with Il-4
 * other regiments
 * 303rd Bomber Aviation Regiment (Zavitinsk, Amur Oblast)
 * 442nd Bomber Aviation Regiment (Belogorsk, Amur Oblast) with Il-4
 * other regiments

 * Soviet Naval Aviation

title: Ilyushin Il-4


text:
Simeon

Simeon is a given name, from the Hebrew שמעון (Biblical Šimʿon, Tiberian Šimʿôn), usually transliterated as Shimon. In Greek, it is written Συμεών, hence the Latinized spelling Symeon. It is a cognate of the name Simon

Meaning
The name is derived from Simeon, son of Jacob and Leah, patriarch of the Tribe of Simeon. The text of Genesis (29:33) argues that the name of Simeon refers to Leah's belief that God had heard that she was hated by Jacob, in the sense of not being as favoured as Rachel.

Implying a derivation from the Hebrew term shama on, meaning "he has heard"; this is a similar etymology as the Torah gives for the theophoric name Ishmael ("God has heard"; Genesis 16:11), on the basis of which it has been argued that the tribe of Simeon may originally have been an Ishmaelite group (Cheyne and Black, Encyclopaedia Biblica). Alternatively, Hitzig, W. R. Smith, Stade, and Kerber compared שִׁמְעוֹן Šīmə‘ōn to Arabic سِمع simˤ "the offspring of the hyena and the female wolf"; as supports, Smith points to Arabic tribal names Simˤ "a subdivision of the defenders (the Medinites)" and Samˤān "a subdivision of Tamim".

In classical rabbinical sources, the name is sometimes interpreted as meaning "he who listens [to the words of God]" (Genesis Rabbah 61:4), and at other times thought to derive from sham 'in, meaning "there is sin", which is argued to be a prophetic reference to Zimri's sexual miscegenation with a Midianite woman, a type of relationship which rabbinical sources regard as sinful (Jewish Encyclopedia).

In the Bible

 * Simeon (son of Jacob), in the Hebrew Bible
 * Tribe of Simeon, one of the twelve tribes of Israel
 * Simeon the Just (3rd century BC?) a Jewish High Priest, also called "Simeon the Righteous" (not the same as the New Testament figure, below)
 * Simeon (Gospel of Luke), figure in the New Testament who blessed Jesus and his parents in the Jerusalem temple
 * Simeon Niger, person in the Book of Acts

Up to 1700 AD

 * Ordered chronologically.

 * Simeon of Jerusalem (15–14 BC–c. 107 or 117), 2nd Bishop of Jerusalem, perhaps one of the Seventy Apostles sent out by Jesus
 * Simeon ben Gamliel, Nasi of the Sanhedrin in 50 AD
 * Simeon ben Gamliel II, Nasi of the Sanhedrin in c. 118 AD
 * Simeon Bar Kokhba, leader of the Bar Kokhba revolt
 * Simeon bar Yochai, rabbi of the Tannaim period, possibly the author of the Zohar
 * Simeon Stylites (c. 388–459 AD), Christian pillar-hermit from Sisan, Syria
 * Simeon Stylites III, 5th-century pillar-hermit
 * Simeon Stylites the Younger (521–597 AD), hermit and pillar-hermit from Antioch
 * Simeon, the name of one priest and one deacon martyred with Abda and Abdjesus
 * Simeon the Holy Fool, 6th-century Christian saint and hermit
 * Simeon I of Bulgaria (866–927), Bulgarian tsar
 * Symeon Metaphrastes (10th century?), Byzantine hagiographer
 * Symeon the New Theologian (949–1022), Eastern Orthodox saint
 * Simeon (abbot) (994–1094), Abbot of Ely Cathedral
 * Simeon Seth (fl. 1070), Jewish Byzantine physician, writer, and grand chamberlain from Antioch
 * Simeon of Mantua (died 1016), Armenian monk
 * Symeon of Durham (died after 1129), English chronicler and monk of Durham Priory
 * Stefan Nemanja (1113–1199), canonized as Saint Simeon, Serbian ruler and saint of the Serbian Orthodox Church
 * Simeon of Moscow, 14th-century Grand Prince of Moscow
 * Simeon Uroš, 14th-century ruler of Epirus and Thessaly
 * Simon of Trent, 15th-century boy supposedly killed by Jews, and formerly a martyr of the Catholic Church
 * Patriarch Symeon I of Constantinople, or Symeon of Trebizond, reigned three times: 1466, 1471–1475 and 1482–1486
 * Simeon Bekbulatovich, de jure Tsar of Russia (1575–1576)
 * Symeon of Polotsk (1629–1680), Russian poet, dramatist, churchman, and enlightener

Since 1700 AD

 * Ordered alphabetically by last name.

 * Semyon Belits-Geiman (born 1945), former Soviet Olympic freestyle swimmer
 * Semyon Budyonny (1883–1973), Soviet military commander
 * Simeon Coxe (usually known only as Simeon), American musician, singer and synth player of Silver Apples
 * Simeon Jocelyn (1799-1879), minister and abolitionist
 * Simeon Mangiuca (1831–1890), Austro-Hungarian Romanian folklorist
 * Simeon V. Marcelo (born 1953), Filipino lawyer and former Ombudsman and Solicitor-General of the Philippines
 * Simeon North (1765–1852), American gunmaker
 * Siméon Denis Poisson (1781–1840), French mathematician
 * Simeon Rice (born 1974), American football player
 * Simeon Woods Richardson (born 2000), American professional baseball player
 * Simeon Saxe-Coburg-Gotha (born 1937), Tsar of Bulgaria (1943–1946), prime minister of Bulgaria (2001–2005)
 * Semyon Sereda (1871–1933), Soviet politician
 * Simeon Thomas (born 1993), American football player
 * Simeon Tienpont (born 1982), Dutch sailor
 * Semyon Varlamov (born 1988), Russian ice hockey player
 * Simeon S. Willis (1879–1965), American lawyer, judge, and politician from Kentucky

title: Simeon


text:
Simon

Simon may refer to:

People

 * Simon (given name), including a list of people and fictional characters with the given name Simon
 * Simon (surname), including a list of people with the surname Simon
 * Eugène Simon, French naturalist and the genus authority Simon

 * Tribe of Simeon, one of the twelve tribes of Israel

Places

 * Şimon (Simon), a village in Bran Commune, Braşov County, Romania
 * Șimon, a right tributary of the river Turcu in Romania

Films

 * Simon (1980 film), starring Alan Arkin
 * Simon (2004 film), Dutch drama directed by Eddy Terstall
 * Simón (2018 film), Venezuelan short film directed by Diego Vicentini
 * Simón (2023 film), Venezuelan feature film directed by Diego Vicentini

Games

 * Simon (game), a popular computer game
 * Simon Says, children's game

Literature

 * Simon (Sutcliff novel), a children's historical novel written by Rosemary Sutcliff
 * Simon (Sand novel), an 1835 novel by George Sand
 * Simon Necronomicon (1977), a purported grimoire written by an unknown author, with an introduction by a man identified only as "Simon"

Music

 * Simon (album), an album by the band Gruvis Malt
 * Simon (EP), an EP by Dirty Little Rabbits

Television

 * Simon (French TV series), a 2016 French animated children's television series
 * Simon (American TV series), a 1995 American sitcom
 * Simon & Simon, 1980s television series with brother detectives
 * Simon (The Walking Dead), a fictional character from the television series The Walking Dead

Other arts, entertainment, and media

 * Simon's Cat, an animated cartoon and book series
 * WSMW, aka Simon FM, a radio station in Greensboro, North Carolina

Brands and enterprises

 * La Maison Simons, a Quebec department store
 * Simon Property Group

Electronics and technology

 * Simon (cipher)
 * Simon (computer), a 1950s personal computer
 * IBM Simon the first smartphone
 * SIMON breach grenade, a door breaching rifle grenade

Other uses

 * Simon (cat), a ship's cat who was awarded the Dickin Medal

title: Simon


text:
Junkers Ju 388

The Junkers Ju 388 Störtebeker is a World War II German Luftwaffe multi-role aircraft based on the Ju 88 airframe by way of the Ju 188. It differed from its predecessors in being intended for high altitude operation, with design features such as a pressurized cockpit for its crew. The Ju 388 was introduced very late in the war, and production problems along with the deteriorating war conditions meant that few were built.

Background
The Reichsluftfahrtministerium (RLM), the Reich Aviation Ministry, first learned of the American Boeing B-29 Superfortress heavy bomber in late 1942. Serious concerns as to B-29 capability developed in early 1944, when YB-29 "Hobo Queen" made a well-publicised appearance at RAF Bovingdon, which had been cryptically hinted-at in an American-published Sternenbanner German language propaganda leaflet from Leap Year Day in 1944, meant to be circulated within the Reich.

The performance estimates of this aircraft were a cause for great unease in the Luftwaffe. The B-29 had a maximum speed of around 560 km/h (350 mph), and would attack in a cruise of about 360 km/h (225 mph) at 8,000 - 10,000 m, an altitude where no current Luftwaffe aircraft was effective, and for which the only effective Wehrmacht anti-aircraft gun was the rarely-deployed 12.8 cm FlaK 40, which could effectively fire to an altitude of 14,800 m.

To counter the B-29, the Luftwaffe would need new day fighters and bomber destroyers with greatly enhanced performance at extreme-altitude. The fighter chosen was the Focke-Wulf Ta 152H. The Ta 152 was a derivative of the Fw 190D with a longer wingspan and powered by the new high-altitude model "E" of the Junkers Jumo 213 engine. An alternative was the Messerschmitt Me 155B, a long-winged development of the Bf 109 which had already undergone several stages of design and would ultimately be built in prototype form by Blohm & Voss. The centre-line thrust, twin-engined Dornier Do 335, powered with two of the competing Daimler-Benz DB 603 engines also offered a service ceiling of some 11,400 m (37,500 ft), but the promising Dornier heavy fighter and zerstörer was still under development with only prototype airframes flying, and the first production examples expected to enter operational service late in 1944.

For the bomber destroyer and night fighter roles, the all-wood Focke-Wulf Ta 154 and metal-structured Heinkel He 219 had the performance needed to catch the bomber; however, both designs only gained that performance by mounting low aspect ratio wings which were inadequate for flight at high altitude and resultingly produced too high a wing loading. The Junkers Ju 88 had already been modified for high-altitude with as the S and T models, but these did not have the performance needed. Similar high-altitude modifications to the Ju 188, with its complex stepless cockpit glazing comprising some three dozen framed window panels in all, were being looked at as the projected Ju 188J, K and L models, which included a simplified "stepless" pressurized cockpit that fully enclosed the entire nose using fewer glazed panels in comparison to the Ju 188's glazing design, and wing and elevator de-icing equipment for extended flights at very high altitude. These were selected for development, and renamed Ju 388.

Development
In order to improve performance, the Ju 388 was stripped of almost all defensive armament. Whereas the Ju 88 included a number of manually operated guns in ports around the cockpit area, on the Ju 388 they were replaced by a single remote-control turret in the tail containing two 13 mm (.51 in) MG 131 machine guns, aimed via a periscope in the cockpit, mounted one-above-the-other, as had been done experimentally with a few Heinkel He 177A heavy bombers' manned tail defensive gun positions. The Ju 388's remote tail turret had an excellent field of fire and could shoot directly to the rear, so the Bola streamlined  defensive armament position under the nose of Ju 88s and 188s was omitted, improving the aerodynamics.

The aircraft was to be delivered using the same naming as the three original Ju 188 experimental versions: the J, K, and L. The J model was a fighter with two 30 mm (1.18 in) MK 103 cannons and two 20 mm MG 151/20 cannons in a solid nose for use as a daytime bomber destroyer. For use as a night fighter, the long-barreled MK 103s were replaced by the smaller and lighter 30 mm MK 108s, while a second pair of upward firing MK 108s were added in a Schräge Musik installation behind the cockpit. The K model was a pure bomber, with a pannier under the plane increasing the size of the bomb bay. The L photo-reconnaissance model put its cameras in the pannier along with additional fuel tanks for long-range missions.

Three sub-models of each variant were planned, different only in the engine installation. The -1 would mount the 1,331 kW (1,810 PS) output BMW 801J, a turbocharged version of the basic BMW 801 air cooled radial, each engine installed as a unitized Triebwerksanlage engine installation. The -2 would use the 46.4 litre displacement, 1,864 kW (2,500 hp) Jumo 222A/B 24-cylinder six-bank liquid-cooled engines, or the identical displacement 222E/F versions with an improved two-speed supercharger with triple intercoolers on each engine. The -3 would mount the Junkers Jumo 213E liquid-cooled inverted V12, which included a supercharger similar to the 222E/F's. Since the 24-cylinder Jumo 222 engine never progressed beyond development and testing with just under 300 units ever built, the only powerplants actually used for the Ju 388 would be the BMW 801 radial and Jumo 213 series V12s.

With the BMW 801J or Jumo 213E, the fighter versions flew at 616 km/h (383 mph) when equipped as a destroyer, losing about 25 km/h (16 mph) due to the eight-dipole Hirschgeweih antenna array used for late-war, VHF-band Neptun radar and Schräge Musik when equipped as night fighters. This was similar in speed to existing Luftwaffe night fighters, but the Ju 388 maintained this speed at much higher altitudes. With the Jumo 222 engine, the aircraft was estimated to be capable of reaching around 700 km/h (435 mph), again about 25 km/h (16 mph) less in night fighter versions. The bomber versions flew at roughly the same speeds depending on bombload, while the reconnaissance versions would have been about 25 km/h (16 mph) faster.

The first prototype, Ju 388 L-0/V7, mainly built from Ju 188 series production components, made its first flight on December 22, 1943. It demonstrated much better handling at altitude than the Ju 88S due to an increase in tail surface area, as the streamlined-nose Ju 88S, also omitting the Bola gondola, still used the original Ju 88A vertical tail surface design. This was followed by six new prototypes. It was some time before deliveries of the production models started due to engine delivery delays. By the time the engines were widely available, it was clear that B-29 bombers were actually being sent to the Asia and the Pacific and would not be operating over Germany anytime soon. German photo-reconnaissance efforts had practically disappeared due to the increased performance of the Allied defenses, so production mostly concentrated on the L model.

Deliveries started in August 1944 but few Ju 388s were completed. About 47 L models seem to have been built, the majority as -1s with the BMW 801J engine, and just three -3s with the Jumo 213E. Fifteen K-1s were built; and only three J-1 models were produced.

Production
The exact number of Ju 388s built is difficult to determine. One of the reasons is that various pre-series aircraft were used as prototypes, and some were damaged or destroyed by Allied bombs before completion. Furthermore, several official records terminate before the end of production or contradict each other.

Based on available documentation and research the following can be assumed as proven:

 * 6 Ju 388 prototypes, 2 each for J-1, K-1 and L-1
 * 20 Ju 388L-0, including prototypes V7, V8, V30 - V34
 * 10 Ju 388K-0, first batch, including two converted to the Ju 488 V401/V402 prototypes (never flown)
 * 1 Ju 388K-1 manufactured by ATG for static tests in July 1944
 * 46 Ju 388L-1 manufactured by ATG in 1944
 * 8+ Ju 388L-1 manufactured by ATG in 1945
 * 10 Ju 388L-1 (max.) manufactured by Weserflug (WFG), initially planned as K-1

More aircraft and prototypes were planned and partially completed:
 * 10 Ju 388K-0, second batch, some prototypes, partially completed
 * 30 Ju 388K-0, third batch, planned, only few units completed

Also, an unknown number of Ju 388L-1 and Ju 388J were in advanced stages of production by the end of the war.

Proposed export to Japan
In August 1944, Japanese Major-General Osamu Otani, a member of one of the commissions related to the Tripartite Pact and serving in Berlin, expressed interest in a license production of the Ju 388. Complete drawing sets for the Ju 388 were handed over to the Japanese as well as the rights for licensed production. No evidence exists that any documents were ever delivered. Otani was captured by allied forces in Berlin in May 1945.

Variants

 * Ju 388J
 * Heavy fighter / night fighter.

 * Ju 388K
 * High-altitude bomber.

 * Ju 388L
 * Photo-reconnaissance aircraft.

 * Ju 388M
 * Proposed torpedo bomber based on the Ju 388K.

 * '145'
 * A captured Ju 388L modified with an early 'fly by wire' control system in support of the development of the Soviet OKB-1 150 jet bomber.

Operators

 * Nazi Germany
 * Luftwaffe
 * Erprobungsstelle Rechlin
 * Erprobungsstelle Werneuchen
 * Erprobungskommando Ju 388
 * 3./Versuchsverband O.K.L. operated Ju 388 V32, W.Nr 300 295, T9+DL.
 * Nachtjagdgeschwader 2 operated four Ju 388J-0 nachtjager during April/May 1945, under operational trial/evaluation conditions. Aircraft were pre-production prototypes.

Surviving aircraft

One Ju 388 survives today. The Ju 388L-1 reconnaissance version with construction number (Werknummer) 560049 was the eighth of the series manufactured at Weser Flugzeugbau's Nordenham plant. Parts of the airframe were also built at ATG in Altenburg and at Niedersächsische Metallwerke Brinckmann & Mergell in Hamburg-Harburg. The aircraft was completed early in 1945. It was captured by U.S. troops in May 1945 at the Junkers plant in Merseburg, then flown to Kassel/Waldau.

The aircraft was examined and test flown by "Watson's Whizzers", led by United States Army Air Forces (USAAF) Colonel Harold E. Watson, as part of Operation Lusty and it is believed that Watson himself flew in the aircraft in preparation for flying it directly back to the U.S. Instead, on 17 June 1945 the aircraft was flown to Cherbourg, France where it was shipped to the United States aboard the Royal Navy escort carrier HMS Reaper (D82) together with other captured German aircraft for detailed evaluation in the U.S.

The aircraft was flown to Freeman Field in Indiana for evaluation, and in September 1945 made a flight demonstration for the press. The Ju 388 was flown for 10 hours of flight tests at Wright Field near Dayton, Ohio with the "foreign evaluation" serial number FE-4010 (later changed to T2-4010). Following these tests the aircraft was displayed at the Dayton, Ohio Air Show at Wright Field in 1946 along with other captured German aircraft.

On 26 September 1946, 560049 was transferred to Orchard Place Airport in Park Ridge, Illinois, near the present O'Hare International Airport. This temporary storage facility was a vacant U.S. Government-owned factory previously used by the Chrysler Corporation to build the Douglas C-54. The Ju 388 was donated to the Smithsonian Institution's National Air Museum on 3 January 1949 and arrived at Silver Hill, Maryland, for storage in November 1954.

Today the aircraft is disassembled and remains in generally good condition, having never been stored outside. The cockpit area is in particularly good condition and complete with all instruments. The aircraft is just one of several unique German aircraft still awaiting restoration at the National Air and Space Museum's Paul E. Garber Preservation, Restoration, and Storage Facility in Silver Hill, Maryland, all intended to be transferred in the coming years to the Steven F. Udvar-Hazy Center's restoration annex of the Smithsonian, on the Dulles International Airport property.

title: Junkers Ju 388


text:
List of winners of the Boston Marathon

The Boston Marathon, one of the six World Marathon Majors, is a 26.2 mile race which has been held in the Greater Boston area in Massachusetts since 1897, making it the oldest annual marathon in the world. The event is held on Patriots' Day, which was April 19 (or April 20 if April 19 was a Sunday) until the implementation of the Uniform Monday Holiday Act in 1971. Since 1971, except in 2020 (race not held) or 2021 (Columbus Day holiday), the Boston Marathon is held on the third Monday in April. Various factors meant that until 1957 the course varied in length, due to which the marathon recognizes several course records that are slower than previous records due to being run on longer courses. The first Boston Marathon included only 15 runners, all of whom were men, and was won by John McDermott. The race was cancelled twice, in 1918 because of World War I, where a ekiden-style relay was conducted of military teams, and in 2020, when Massachusetts authorities refused to allow the event to be conducted due to the COVID-19 pandemic. The winners have represented 27 different countries: Americans have won the marathon the most, doing so on 108 occasions; Kenyans have won 34 times; and Canadians 21 times. Ernst van Dyk is the most successful individual athlete, having won the men's wheelchair division ten times. The current course records are held by Geoffrey Mutai, Buzunesh Deba, Marcel Hug and Manuela Schär.

Clarence DeMar won the men's open race seven times, more than any other runner, achieving his first victory in 1911 and his last in 1930. Women were only officially allowed to run the race beginning in 1972, though female runners had unofficially participated beginning in 1966 despite breaching the rules of the Amateur Athletic Union. The first six victories in the women's open division, between 1966 and 1971, were officially recognized in 1996. Bobbi Gibb was the first woman to finish the race in 1966, while Nina Kuscsik was the first official winner in 1972. Catherine Ndereba's four victories between 2000 and 2005 are the most in the women's open division. The Boston Marathon became the first major marathon to include a wheelchair division, in 1975, which was won by Robert Hall, though the first person to complete the race in a wheelchair had been Eugene Roberts in 1970. The first female wheelchair finisher, Sharon Rahn, came in 1977. Ernst van Dyk's ten wins in the men's wheelchair division are the most of any athlete at Boston, while Jean Driscoll leads the women's wheelchair division with seven wins, and holds the overall record for the most consecutive victories, also seven. A handcyclist division was recognized for the first time in 2017, though handcyclists had been taking part prior to that. Tom Davis has won the first three men's handcyclist races since it was officially recognized in 2017, and still holds the course record as of 2024. Alicia Dana has won the women's handcycle race three times, as of 2024, and set a course record each time.

The course was designed to replicate the original marathon in Greece; a hilly point-to-point race, and as such has not been the venue for many world records. Suh Yun-bok set the only World Athletics-ratified men's open division world record in 1947, in a time of 2:25:39. Two apparent world record times set between 1951 and 1956 by Keizo Yamada and Antti Viskari were later struck when the course was found to be over 1,000 yards short. In 1975, Liane Winter took advantage of a 25 mph following wind to set a world record in the women's open race of 2:42:24, and eight years later, Joan Benoit beat a world record that had only been set the day before at the London Marathon, finishing in 2:22:43. Since 1990, the Boston Marathon has been ineligible for world records, as the start and finish are too far away from each other, and the race is a net downhill. In 2011, Geoffrey Mutai won the race in 2:03:02, which was the world's fastest time for the marathon, beating the official world record by 57 seconds.

Winners

 * All Editions Results

title: List of winners of the Boston Marathon


text:
Screaming jelly babies

"Screaming Jelly Babies" (British English), also known as "Growling Gummy Bears" (American and Canadian English), is a classroom chemistry demonstration which is practiced in schools around the world. It is often used at open evenings to show the more engaging and entertaining aspects of science in secondary education settings.

The experiment shows the amount of energy there is in a piece of candy. Jelly babies or gummy bears are often used for theatrics. Potassium chlorate, a strong oxidising agent, rapidly oxidises the sugar in the candy causing it to burst into flames. The reaction produces a "screaming" sound as rapidly expanding gases are emitted from the test tube. The aroma of caramel is given off. Other carbohydrate or hydrocarbon containing substances can be dropped into test tubes of molten chlorate to produce similar results.

Net Reaction

4 KClO3 (s) + C12H22O11 (s) + 6 O2 (g) → 4 KCl + 12 CO2 (g) + 11 H2O (g)

== Mechanism == The solid potassium chlorate is melted into a liquid.

KClO3 (s) + energy → K+ClO3- (l)

The liquid potassium chlorate decomposes into potassium perchlorate and potassium chloride.

4 KClO3 → KCl + 3 KClO4

The potassium perchlorate decomposes into potassium chloride and oxygen.

KClO4 → KCl + 2 O2

The sugar in the candy reacts with oxygen, forming water and carbon dioxide. The reaction is exothermic and produces heat, smoke, and fire.

C12H22O11 (s) + 12 O2 (g) → 12 CO2 (g) + 11 H2O (g) + energy

Safety Measures
Care should be taken in performing this experiment, which should only be attempted by a professional. Potassium chlorate is a strong oxidizer and can cause fire or explosions. It is toxic by inhalation or ingestion and is hazardous to aquatic environments. Reagent grade potassium chlorate should be used. Upon completion of the demonstration, all chemicals should be disposed of in designated chemical waste containers to prevent harm to people or the environment.

All participants in the experiment should wear personal protective equipment, including eye protection, and should stand a safe distance away from the demonstration. A face-shield and heat resistant gloves should be worn by the person adding the jelly baby to the molten potassium chlorate.

Variations
Deviation from the experiment is not recommended, and has been linked with accidents. Candy with low moisture content or high surface area may cause explosions.

title: Screaming jelly babies


text:
Food energy

Food energy is chemical energy that animals (including humans) derive from their food to sustain their metabolism, including their muscular activity.

Most animals derive most of their energy from aerobic respiration, namely combining the carbohydrates, fats, and proteins with oxygen from air or dissolved in water. Other smaller components of the diet, such as organic acids, polyols, and ethanol (drinking alcohol) may contribute to the energy input. Some diet components that provide little or no food energy, such as water, minerals, vitamins, cholesterol, and fiber, may still be necessary to health and survival for other reasons. Some organisms have instead anaerobic respiration, which extracts energy from food by reactions that do not require oxygen.

The energy contents of a given mass of food is usually expressed in the metric (SI) unit of energy, the joule (J), and its multiple the kilojoule (kJ); or in the traditional unit of heat energy, the calorie (cal). In nutritional contexts, the latter is often (especially in US) the "large" variant of the unit, also written "Calorie" (with symbol Cal, both with capital "C") or "kilocalorie" (kcal), and equivalent to 4184 J or 4.184 kJ. Thus, for example, fats and ethanol have the greatest amount of food energy per unit mass, 37 and 29 kJ/g, respectively. Proteins and most carbohydrates have about 17 kJ/g, though there are differences between different kinds. For example, the values for glucose, sucrose, and starch are 15.57, respectively. The differing energy density of foods (fat, alcohols, carbohydrates and proteins) lies mainly in their varying proportions of carbon, hydrogen, and oxygen atoms. Carbohydrates that are not easily absorbed, such as fibre, or lactose in lactose-intolerant individuals, contribute less food energy. Polyols (including sugar alcohols) and organic acids contribute 10 kJ/g and 13 kJ/g respectively.

The energy contents of a complex dish or meal can be approximated by adding the energy contents of its components.

Direct calorimetry of combustion
The first determinations of the energy content of food were made by burning a dried sample in a bomb calorimeter and measuring the temperature change in the water surrounding the apparatus, a method known as direct calorimetry.

The Atwater system
However, the direct calorimetric method generally overestimates the actual energy that the body can obtain from the food, because it also counts the energy contents of dietary fiber and other indigestible components, and does not allow for partial absorption and/or incomplete metabolism of certain substances. For this reason, today the energy content of food is instead obtained indirectly, by using chemical analysis to determine the amount of each digestible dietary component (such as protein, carbohydrates, and fats), and adding the respective food energy contents, previously obtained by measurement of metabolic heat released by the body. In particular, the fibre content is excluded. This method is known as the Modified Atwater system, after Wilbur Atwater who pioneered these measurements in the late 19th century.

The system was later improved by Annabel Merrill and Bernice Watt of the USDA, who derived a system whereby specific calorie conversion factors for different foods were proposed.

Dietary sources of energy
The typical human diet consists chiefly of carbohydrates, fats, proteins, water, ethanol, and indigestible components such as bones, seeds, and fibre (mostly cellulose). Carbohydrates, fats, and proteins typically comprise ninety percent of the dry weight of food. Ruminants can extract food energy from the respiration of cellulose because of bacteria in their rumens that decompose it into digestible carbohydrates.

Other minor components of the human diet that contribute to its energy content are organic acids such as citric and tartaric, and polyols such as glycerol, xylitol, inositol, and sorbitol.

Some nutrients have regulatory roles affected by cell signaling, in addition to providing energy for the body. For example, leucine plays an important role in the regulation of protein metabolism and suppresses an individual's appetite. Small amounts of essential fatty acids, constituents of some fats that cannot be synthesized by the human body, are used (and necessary) for other biochemical processes.

The approximate food energy contents of various human diet components, to be used in package labeling according to the EU regulations and UK regulations, are:

(1) Some polyols, like erythritol, are not digested and should be excluded from the count.

(2) This entry exists in the EU regulations of 2008, but not in the UK regulations, according to which fibre shall not be counted.

More detailed tables for specific foods have been published by many organizations, such as the United Nations Food and Agriculture Organization also has published a similar table.

Other components of the human diet are either noncaloric, or are usually consumed in such small amounts that they can be neglected.

Energy usage in the human body
The food energy actually obtained by respiration is used by the human body for a wide range of purposes, including basal metabolism of various organs and tissues, maintaining the internal body temperature, and exerting muscular force to maintain posture and produce motion. About 20% is used for brain metabolism.

The conversion efficiency of energy from respiration into muscular (physical) power depends on the type of food and on the type of physical energy usage (e.g., which muscles are used, whether the muscle is used aerobically or anaerobically). In general, the efficiency of muscles is rather low: only 18 to 26% of the energy available from respiration is converted into mechanical energy. This low efficiency is the result of about 40% efficiency of generating ATP from the respiration of food, losses in converting energy from ATP into mechanical work inside the muscle, and mechanical losses inside the body. The latter two losses are dependent on the type of exercise and the type of muscle fibers being used (fast-twitch or slow-twitch). For an overall efficiency of 20%, one watt of mechanical power is equivalent to 4.3 kcal/h. For example, a manufacturer of rowing equipment shows calories released from "burning" food as four times the actual mechanical work, plus 300 kcal per hour, which amounts to about 20% efficiency at 250 watts of mechanical output. It can take up to 20 hours of little physical output (e.g., walking) to "burn off" 4000 kcal more than a body would otherwise consume. For reference, each kilogram of body fat is roughly equivalent to 32,300 kilojoules of food energy (i.e., 3,500 kcal/lb).

Recommended daily intake
Many countries and health organizations have published recommendations for healthy levels of daily intake of food energy. For example, the United States government estimates 2000 and 2600 kcal needed for women and men, respectively, between ages 26 and 45, whose total physical activity is equivalent to walking around 1+1/2 to 3 mi per day in addition to the activities of sedentary living. These estimates are for a "reference woman" who is 5 ft tall and weighs 126 lb and a "reference man" who is 5 ft tall and weighs 154 lb. Because caloric requirements vary by height, activity, age, pregnancy status, and other factors, the USDA created the DRI Calculator for Healthcare Professionals in order to determine individual caloric needs.

According to the Food and Agriculture Organization of the United Nations, the average minimum energy requirement per person per day is about 1800 kcal. Although the U.S. has changed over time with a growth in population and processed foods or food in general, Americans today have available roughly the same level of calories as the older generation.

Older people and those with sedentary lifestyles require less energy; children and physically active people require more. Recognizing these factors, Australia's National Health and Medical Research Council recommends different daily energy intakes for each age and gender group. Notwithstanding, nutrition labels on Australian food products typically recommend the average daily energy intake of 2100 kcal.

The minimum food energy intake is also higher in cold environments. Increased mental activity has been linked with moderately increased brain energy consumption.

Nutrition labels

Many governments require food manufacturers to label the energy content of their products, to help consumers control their energy intake. To facilitate evaluation by consumers, food energy values (and other nutritional properties) in package labels or tables are often quoted for convenient amounts of the food, rather than per gram or kilogram; such as in "calories per serving" or "kcal per 100 g", or "kJ per package". The units vary depending on country:

title: Food energy