The SNCAO 200 (sometimes written CAO.200) was a prototype French single seat fighter aircraft of the 1930s. It was a single engined monoplane intended to compete with the Dewoitine D.520, but was unsuccessful, only a single example being built. In 1937, the French Air Ministry issued an official specification for a single-engined fighter to follow-on from and replace the Morane-Saulnier M.S.406. The new fighter was to be powered by a single Hispano-Suiza 12Y-51, rated at 1,100 hp (821 kW). Designs to meet this specification were produced by Dewoitine (the Dewoitine D.520), Morane-Saulnier (the Morane-Saulnier M.S.450), the Arsenal de l'Aéronautique (the VG-33) and SNCAO.
SNACO, formed in 1936 when the factories of Loire-Nieuport and Breguet were nationalised, based its design on the Loire-Nieuport 161 fighter design which had been rejected in favour of the M.S.406. The new fighter, the SNCAO 200 was a low-winged monoplane of all-metal construction, with stressed-skin wings, a forward fuselage of steel tubes covered in duralumin skinning, and a duralumin monocoque rear fuselage. It was fitted with leading edge slats, which were linked to trailing edge flaps.
A mock-up of the SNCAO was exhibited at the 1938 Paris Air Show. When the prototype was completed in January 1939, the planned Hispano-Suiza 12Y-51 engine was not yet available, and it was fitted with an 860 hp (640 kW) Hispano-Suiza 12Y-31 engine to make its first flight on 31 January 1939. With this engine, the SNCAO was underpowered, and by the time the prototype was passed to the authorities for official testing in August 1939, the Dewoitine D.520 had already been ordered into large-scale production. Despite this, several sources claim that a batch of 12 aircraft to be powered by 12Y-51 engines were ordered. During the Battle of France, the prototype SNCAO 200 may have been used to defend the SNCAO factory at Villacoublay, and may even have shot down an attacking Heinkel He 111 bomber. The prototype was taken to Germany for evaluation following the 22 June Armistice between France and Germany.
Specifications Crew: 1 Length: 8.90 m Wingspan: 9.50 m Height: 3.50 m Wing area: 13.30 m2 Gross weight: 2,500 kg Powerplant: 1 × Hispano-Suiza 12Y-51 liquid-cooled V12 engine, 640 kW / 860 hp Maximum speed: 550 km/h at 6,000 m Endurance: 2 hours Service ceiling: 4,480 m Time to altitude: 2 min 27 sec to 2,000 m Guns: 1× 20 mm Hispano-Suiza HS.404, + 2× 7.5 mm MAC 1934 mg in wings
The Ambrosini SAI.207 was a light fighter interceptor built entirely from wood and developed in Italy during World War II. Powered by a single 750 hp Isotta-Fraschini Delta, the SAI.207 enjoyed limited success during evaluation of the 12 pre-production aircraft.
The SAI.207 was developed from the Ambrosini SAI.7 racing and sporting monoplane after the light fighter concept had been proven with the Ambrosini SAI.107 prototype. Steffanuti designed the aircraft to have a lightweight structure and light armament to allow lower-powered engines to be used, without unduly reducing performance.
The first of three prototypes was completed and flown in the Autumn of 1940 as the sole SAI.107, which was a minimum change fighter development of the SAI.7, with identical dimensions, apart from length, at 8.02 m and the 402.7 kW / 540 hp Isotta-Fraschini Gamma engine. Weighing only 1,000 kg the Sai.107 reached a speed of 563 km/h in trials held at the Guidonia research establishment and manoeuvrability proved to be excellent. The SAI.107 was lost, along with pilot Arturo Ferrarin, in a crash on 18 July 1941.
Two more fighter prototypes were built as SAI.207s, flying for the first time in the spring of 1941 and 1942.
The SAI.207 was a single-seat, low-wing monoplane with a conventional tail-wheel undercarriage, developed from the Ambrosini SAI.7. Of wooden construction, giving a light structure, power was supplied by 559.3 kW / 750 hp Isotta-Fraschini Delta R.C.40 engine, cooling air entering the engine through a central intake. Armament consisted of two 12.7 mm Breda-SAFAT machine guns.
In level flight the performance of this aircraft was impressive, achieving a speed of 580 km/h and over 800 km/h in a dive. The Ministero dell' Aeronautica soon placed a production order for 2,000 machines, plus a pre-production batch of 12 aircraft for operational testing. After the mixed results of operational evaluation and the signing of the Armistice, no production aircraft were built.
Flight testing revealed some major shortcomings, most of which were not rectified before the Armistice in 1943; the low power and high wing loading resulted in poor climb performance; the light structure prevented more powerful cannon from being used as the recoil forces overstressed the mounting structure; the rear cylinders of the engine overheated during recovery from a dive; the light structure also led to problems, with the second prototype wing exploding during a dive recovery due to internal pressure built up, caused by the lack of internal fairings in the undercarriage bays. The wooden structure was also badly affected by rain or humidity.
The pre-production batch of 12 aircraft served briefly with three squadrons. The first was 83rd Squadriglia, 18 Gruppo, 3 Stormo, led by Guglielmo Specker, one of the Regia Aeronauticas best known "aces", at Cerveteri airfield, near Rome. The aircraft entered service in July 1943, flying a number of combat missions against heavy Allied raids over the Italian capital, but without success. After one month, they were sent to Castiglione del Lago G.Eleuteri airfield (at that time one of the main RA training airbases), where it was planned that 161 and 162nd Squadriglia would take the aircraft into service. Despite its speed, Italian pilots were not impressed by the type and its service in the summer of 1943 quickly ended. The aircraft of 83rd Squadriglia were returned to SAI-Ambrosini to be refurbished, but the Armistice made it impossible for them to return to their squadron. Operators Italian Kingdom Regia Aeronautica
Specifications SAI.207 Crew: 1 Length: 8.0201 m Wingspan: 9.004 m Height: 2.87 m Wing area: 13.90 m2 Empty weight: 1,750 kg Gross weight: 2,415 kg Powerplant: 1 × Isotta-Fraschini Delta inverted V-12 air-cooled piston engine Maximum speed: 641 km/h Cruise speed: 489 km/h Range: 850 km; 459 nmi Service ceiling: 12,000 m Rate of climb: 13.25 m/s Time to altitude: 6,000 m in 7 minutes 33 seconds Armament: 2 × 12.7 mm Breda-SAFAT mg, + (MM8433 only) 2 × 20 mm cannon
The Martin B-10 was the first all-metal monoplane bomber to be regularly used by the United States Army Air Corps, entering service in June 1934. It was also the first mass-produced bomber whose performance was superior to that of the Army's pursuit aircraft of the time. The B-10 served as the airframe for the B-12, B-13, B-14, A-15 and O-45 designations using Pratt & Whitney engines instead of Wright Cyclones. A total of 348 of all versions were built. Biggest users were the USA, with 166, and the Netherlands, with 121.
The B-10 began a revolution in bomber design. Its all-metal monoplane airframe, along with its features of closed cockpits, rotating gun turrets (almost simultaneously to the British Overstrand biplane bomber's own enclosed nose-turret), retractable landing gear, internal bomb bay, and full engine cowlings, would become the standard for bomber designs worldwide for decades. It made all existing bombers completely obsolete. In 1932, Martin received the Collier Trophy for designing the XB-10.
The B-10 began as the Martin Model 123, a private venture by the Glenn L. Martin Company of Baltimore, Maryland. It had a crew of four: pilot, copilot, nose gunner and fuselage gunner. As in previous bombers, the four crew compartments were open, but it had a number of design innovations as well.
These innovations included a deep belly for an internal bomb bay and retractable main landing gear. Its 600 hp (447 kW) Wright SR-1820-E Cyclone engines provided sufficient power. The Model 123 first flew on 16 February 1932 and was delivered for testing to the U.S. Army on 20 March as the XB-907. After testing it was sent back to Martin for redesigning and was rebuilt as the XB-10. The XB-10 delivered to the Army had major differences from the original aircraft. Where the Model 123 had Townend rings, the XB-10 had full NACA cowlings to decrease drag. It also sported a pair of 675 hp (503 kW) Wright R-1820-19 engines, and an 2.4 m increase in the wingspan, along with an enclosed nose turret. When the XB-10 flew during trials in June, it recorded a speed of 317 km/h at 1,830 m. This was an impressive performance for 1932.
Following the success of the XB-10, a number of changes were made, including reduction to a three-man crew, addition of canopies for all crew positions, and an upgrade to 675 hp (503 kW) engines. The Army ordered 48 of these on 17 January 1933. The first 14 aircraft were designated YB-10 and delivered to Wright Field, starting in November 1933, and used in the Army Air Corps Mail Operation. The production model of the XB-10, the YB-10 was very similar to its prototype. In 1935, the Army ordered an additional 103 aircraft designated B-10B. These had only minor changes from the YB-10. Shipments began in July 1935. B-10Bs served with the 2d Bomb Group at Langley Field, the 9th Bomb Group at Mitchel Field, the 19th Bomb Group at March Field, the 6th Composite Group in the Panama Canal Zone, and the 4th Composite Group in the Philippines. In addition to conventional duties in the bomber role, some modified YB-10s and B-12As were operated for a time on large twin floats for coastal patrol.
With an advanced performance, the Martin company fully expected that export orders for the B-10 would come flooding in. The Army owned the rights to the Model 139 design. Once the Army's orders had been filled in 1936, Martin received permission to export Model 139s, and delivered versions to several air forces. For example, six Model 139Ws were sold to Siam in April 1937, powered by Wright R-1820-G3 Cyclone engines; 20 Model 139Ws were sold to Turkey in September 1937, powered by R-1820-G2 engines.
On 19 May 1938, during the Sino-Japanese War, two Chinese Nationalist Air Force B-10s successfully flew to Japan. However, rather than dropping bombs, the aircraft dropped propaganda leaflets. The Dutch Martins fought in the defense of Singapore and the Netherlands East Indies.
At the time of its creation, the B-10B was so advanced that General Henry H. Arnold described it as the airpower wonder of its day. It was half again as fast as any biplane bomber, and faster than any contemporary fighter. The B-10 began a revolution in bomber design; it made all existing bombers completely obsolete. Rapid advances in bomber design in the late 1930s meant that the B-10 was eclipsed by the time the United States entered World War II. The 139s in combat in China and South East Asia suffered the same disadvantages as the other early war medium bombers, i.e. not enough armour and guns, while it couldn't outrun the latest fighters. Nevertheless, the 166 had the highest performance of all the medium bombers in the theatre at the time, early 1942.
An abortive effort to modernize the design, the Martin Model 146, was entered into a USAAC long-distance bomber design competition 1934–1935, but lost out to the Douglas B-18 and much bigger Boeing B-17. The B-18 was hardly superior to the B-10 and actually inferior to the latest B-10 version, the model 166. Model 166 Final version, a.k.a. 139WH-3 and 139WH-3A, 82 built.
Export version for the Netherlands, used in the Netherlands East Indies. Redesigned wings, nose and single 'glass house' canopy, bomb shackles between engines and fuselage, and better engines. The WH-3 had two 900 hp (671 kW) R-1820-G5 (40 built, delivered September 1938), the WH-3A had two 1,000 hp (671 kW) R-1820-G-105A (42 built, delivered March 1940). With the bomb shackles the bomb load could be doubled for a shorter range. A total of 121 of all types were built for the Dutch.
Operators Argentina Army Aviation Service Argentine Navy - The Argentine Naval Aviation received 13 Model 139WAN aircraft. China Chinese Nationalist Air Force The Netherlands Royal Netherlands East Indies Army Air Force Philippines Philippine Army Air Corps Thailand Siam Royal Thai Air Force received six Model 139W aircraft in April 1937 and used them during the French-Thai War of 1940-41, and during the 1942 invasion of Burma. It was given a further nine ex-Dutch aircraft by the Japanese in 1942. They remained in service until 1949. Turkey Turkish Air Force received 20 Model 139W aircraft in September 1937. Soviet Union Soviet Air Force bought one aircraft for evaluation. United States United States Army Air Corps
General characteristics Crew: 3 Length: 13.6 m Wingspan: 21.5 m Height: 4.7 m Wing area: 63 m² Empty weight: 4,391 kg Loaded weight: 6,680 kg Max. takeoff weight: 7,440 kg Powerplant: 2 × Wright R-1820-33 "Cyclone" radials, 775 hp (578 kW) each Maximum speed: 343 km/h Cruise speed: 310.6 km/h Range: 1,996 km Service ceiling: 7,380 m Rate of climb: 420 m/min Wing loading:106 kg/m² Power/mass: 173 W/kg Guns: 3 × 7.62 mm Browning machine guns Bombs: 1,030 kg
The Lebed XII was a Russian military reconnaissance aircraft produced during the First World War for the Imperial Russian Air Force. It was one of the few domestically designed aircraft to see production in Russia during the war, but was based on designs and techniques learned from Lebed's rebuilding of captured German types.
Test flights commenced on 28 December 1915, but were interrupted by bad weather in St Petersburg, where the Lebed factory was located. Testing was therefore moved to Kiev, and then to the Anatra factory at Odessa on 11–15 February 1916. Grand Duke Alexander Mikhailovich ordered 400 aircraft on February 23, but the final contract on 19 April was for 225 aircraft, 245 sets of spare parts and 10 static airframes for a total of 5,153,500 rubles.
The fuselage was a plywood structure of rectangular cross-section with seating for the pilot and observer in tandem, open cockpits. The wings were built around a pine spar and covered in fabric, and the empennage (tail assembly) was of welded steel tube with fabric covering. Before production began, a number of handling difficulties noted by the test pilots were being corrected in the design, along with a new set of problems caused by a change in powerplant. The prototypes had been flown with 97 kW (130 hp) engines, but the production contract called mostly for 112 kW (150 hp) engines, plus some machines equipped with 104 kW (140 hp) engines for training. These heavier powerplants shifted the aircraft's centre of gravity, and the mountings for the engine and cooling system had to be revised before a final round of tests began in October. Serial production finally commenced in November and delivery to squadrons soon afterwards.
The Lebed XII started appearing on the front line in quantity in early 1917, but problems quickly became apparent. In particular, a number of engine fires and crashes due to structural defects led to deliveries of the type being suspended by mid-year while an investigation was held. Army test pilots concluded that the version with the more powerful engine was unfit for frontline service, and recommended that it be relegated to training use only, while the lower-power version was regarded as not even fit for training.
Lebed disputed the findings, blaming the poor results on the inexperience of the test pilots and on poor weather while the tests were conducted. The Army therefore held a second inquiry. On 2 October 1917, this panel concluded that the type was obsolete and unfit for service, recommending that production be halted and the type withdrawn altogether. However, due to a shortage of aircraft, production continued into 1918, and eventually 214 of the original order were delivered. The Lebed XII saw limited frontline service in the North and North-western parts of the front with Germany, equipping four air divisions of the 38th Corps, 5th Army. Aircraft delivered in the second half of 1917 went mostly to training units, however. These included the Imperial aviation school, the Gatchinskoy military flying school, the Odessa flying school, Kiev school for pilots and observers and the flying school of the Caucasus. Over 50 were supplied to the Navy's school of air combat in Krasnoye Selo alone.
Operators Estonian Air Force - One aircraft only. Imperial Russian Air Force Soviet Air Force - Taken over from the Imperial Russian Air Force.
Specifications Crew: Two, pilot and observer Length: 7.96 m Wingspan: 13.15 m Height: 3.25 m Wing area: 42.0 m2 Empty weight: 820 kg Gross weight: 1,350 kg Powerplant: 1 × Salmson water-cooled radial engine, 115 kW (150 hp) Maximum speed: 135 km/h Endurance: 3 hours 0 min Service ceiling: 3,500 m Armament: 1 × machine gun on flexible mount for observer
The Arsenal-Delanne 10 was an experimental fighter aircraft of French origin. The plane had a rear cockpit and a distinctive tandem wing. The Arsenal-Delanne 10-C2 two-seat fighter, designed by Maurice Delanne and built by the Arsenal de l'Aéronautique, was of so-called Nenadovich biplane or tandem wing configuration, the tandem-mounted wings providing a continuous slot effect and offering exceptional center of gravity range.
The fighter was of all metal stressed-skin construction, which used a sandwich technique, with a smooth dural skin welded to a corrugated sheet. Pilot and gunner sat in tandem under a single canopy at the rear of the fuselage, which was level with the rear wing, which carried twin tailplanes.
This arrangement gave the gunner a clear field of fire for his planned armament of two 7.5 mm machine guns, which was to be supplemented by a 20 mm cannon firing through the propellor hub and two more machine guns in the wing. The aircraft was fitted with a retractable tailwheel undercarriage and was powered by a single 860 hp (641 kW) Hispano-Suiza 12Ycrs 12-cylinder liquid-cooled engine.
The Arsenal-Delanne 10-C2 prototype was virtually complete at Villacoublay when German forces occupied the factory in June 1940. Work on the aircraft continued in a desultory fashion and the first flight test was made in October 1941. After completion of the initial test programme, the aircraft was ferried to Germany for further trials.
General characteristics Crew: 2 Length: 7.328 m Wingspan: 10.11 m Height: 3.00 m Wing area: 22.50 m2 Powerplant: 1 × Hispano-Suiza 12Ycrs liquid-cooled v12 engine, 640 kW / 860hp Maximum speed: 550 km/h at 5,415 m Endurance: 1.5 hr Service ceiling: 10,000 m Time to altitude: 6.5 min to 5,000 m Guns: 1× fixed forward firing 20 mm cannon and 2× wing mounted 7.5 mm MAC 1934 machine guns, 2× flexibly mounted 7.5 mm machine guns in rear cockpit
The AGO C.I was a First World War German pusher reconnaissance biplane that used a pod-and-boom configuration. The crew and pusher engine shared a central nacelle, and the twin booms carried the tail and the four-wheeled landing gear.
The observer sat at the nose and was armed with a machine-gun. It was produced in both two bay and three bay versions. A single example was fitted with floats for coastal patrol duties for the Imperial German Navy (designation C.I-W).
Operators German Empire Luftstreitkrafte Kaiserliche Marine
General characteristics Crew: two, pilot and observer Length: 9.0 m Wingspan: 15.0 m Wing area: 41.5 m2 Powerplant: 1 × Mercedes D.III, 117 kW (158 hp) Maximum speed: 140 km/h Range: 480 km Service ceiling: 4,800 m Armament: 1 × 7.92 mm Parabellum machine gun
The Sopwith 5F.1 Dolphin was a British fighter aircraft manufactured by the Sopwith Aviation Company. It was used by the Royal Flying Corps and its successor, the Royal Air Force, during the First World War. The Dolphin entered service on the Western Front in early 1918 and proved to be a formidable fighter. The aircraft was not retained in the postwar inventory, however, and was retired shortly after the war.
In early 1917, Sopwith's chief engineer Herbert Smith began designing a new fighter (internal Sopwith designation 5F.1) powered by the geared 200 hp Hispano-Suiza 8B. The resulting Dolphin was a two-bay, single-seat biplane. The upper wings were attached to an open steel cabane frame above the cockpit. To maintain the correct centre of gravity, the lower wings were positioned 13 inches forward of the upper wings, creating the Dolphin’s distinctive negative wing stagger.
The pilot sat with his head raised through the frame, where he had an excellent field of view. This configuration sometimes caused difficulty for novice pilots, who found it difficult to keep the aircraft pointed at the horizon because the nose was not visible from the cockpit. The cockpit was nevertheless warm and comfortable, in part because pipes ran alongside the cockpit walls to the two side-mounted radiator blocks. Shutters in front of each radiator core allowed control of engine temperature. --------------
General characteristics Crew: 1 Length: 6.78 m Wingspan: 9.91 m Height: 2.59 m Wing area: 24.4 m² Empty weight: 641 kg Max. takeoff weight: 890 kg Powerplant: 1 × Hispano-Suiza 8B, 149 kW (200 hp) Maximum speed: 211 km/h at sea level Range: 315 km Service ceiling: 6,100 m Rate of climb: 12 min 5 sec to 3,048 m Wing loading: 36.5 kg/m² Power/mass: 0.232 kW/kg Armament: 2× 7.7 mm Vickers machine guns, up + to 2× 7.7 mm Lewis guns Bombs: Four x 12,5 kg bomb.
Operators Canadian Air Force Second Polish Republic Ukraine1918. Ukrainian People's Republic Ukrainian Air Force (postwar, two aircraft loaned by Poland in October 1920, returned to Poland in February 1921) United Kingdom Royal Flying Corps/Royal Air Force American Expeditionary Force United States Army Air Service
----------------------- The first Dolphin prototype was powered by a geared 150 hp Hispano-Suiza 8 and featured a deep "car-type" frontal radiator. Test pilot Harry Hawker carried out the maiden flight on 23 May 1917. In early June, the prototype was sent to Martlesham Heath for official trials. On 13 June, the prototype flew to Saint-Omer, France, where the aircraft's unfamiliar shape prompted Allied anti-aircraft gunners to fire on it. Several pilots, including Billy Bishop of No. 60 Squadron, evaluated the prototype and reported favorably on it. On 28 June 1917, the Ministry of Munitions ordered 200 Dolphins from Hooper & Co. Shortly thereafter, the Ministry ordered a further 500 aircraft from Sopwith and 200 aircraft from Darracq Motor Engineering Co.
The second prototype introduced upper wing radiators in lieu of the frontal radiator and large cut-outs in the lower wing roots to improve the pilot's downward vision. These features proved unsuccessful and were omitted from subsequent aircraft. The third and fourth prototypes incorporated numerous modifications to the radiator, upper fuselage decking, fin and rudder. The fourth prototype was selected as the production standard. Series production commenced in October 1917, with 121 Dolphins delivered by the end of the year. The Dolphin Mk I became operational with Nos. 19 and 79 Squadrons in February 1918. Nos. 87 and 23 Squadrons followed in March. The Dolphin’s debut was marred by several incidents in which British and Belgian pilots attacked the new aircraft, mistaking it for a German type. For the next few weeks, Dolphin pilots accordingly exercised caution near other Allied aircraft.
New pilots also voiced concern over the Dolphin’s wing arrangement, fearing serious injury to the head and neck in the event of a crash. Early aircraft were often fitted with improvised crash pylons consisting of steel tubes over the cockpit to protect the pilot's head. Operational usage eventually showed that fears of pilot injury from overturning were largely unfounded. Crash pylons thereafter disappeared from front line aircraft, though they were often retained on training aircraft. Night-flying Dolphins of No. 141 Squadron, a Home Defence unit, had metal loops fitted above the inner set of interplane struts.
Despite early problems, the Dolphin eventually proved successful and generally popular with pilots. The aircraft was fast, maneuverable, and easy to fly, though a sharp stall was noted. When functioning properly, the Hispano-Suiza afforded the Dolphin excellent performance at high altitude. Accordingly, the Dolphin was often deployed against German reconnaissance aircraft such as the Rumpler C.VII, which routinely operated at altitudes above 20,000 ft. No. 87 Squadron explored the use of equipment to supply pilots with oxygen at high altitude, but the experiment was abandoned after trials showed that the oxygen tanks exploded when struck by gunfire.
The highest-scoring Dolphin unit was No. 87 Squadron, which shot down 89 enemy aircraft in the type. Pilots of No. 79 Squadron shot down 64 enemy aircraft in the eight and one half months that the aircraft was at the front.[17] The top two Dolphin aces served in No. 79 Squadron. Captain Francis W. Gillet, an American, scored 20 victories in the type. Lieutenant Ronald Bannerman, a New Zealander, scored 17 victories. The third-ranking Dolphin ace was Captain Arthur Vigers of No. 87 Squadron, who attained all 14 of his victories while flying the same aircraft. Another notable ace, Major Albert Desbrisay Carter of No. 19 Squadron, obtained approximately 13 of his 29 confirmed victories in the Dolphin. Captain Henry Biziou scored eight victories in the type.
Four Royal Air Force squadrons operated the Dolphin as their primary equipment, while other squadrons used it in small numbers. No. 1 (Fighter) Squadron, a Canadian Air Force unit, formed with Dolphins at RAF Upper Heyford. The unit became operational shortly after the Armistice. In October 1918, the American Expeditionary Force purchased five standard Mk Is for evaluation, sending four back to the United States. The scarcity and unreliability of the French-built Hispano-Suiza 8B engine proved to be the most serious problem in the deployment and use of the Dolphin. Use of insufficiently hardened metal in the pinion gears led to numerous failures of the reduction gearing, particularly in engines built by the French firm Brasier. The engine also suffered persistent lubrication problems. Limited production capacity for the Hispano-Suiza engine, and the priority afforded to French aircraft like the SPAD S.XIII slowed Dolphin deliveries. Availability of the Hispano-Suiza improved in early 1918 as the French firm Emile Mayen began deliveries on an order placed by the British Admiralty.
The official armament of the Dolphin was two fixed, synchronized Vickers machine guns and two Lewis guns mounted on the forward cabane crossbar, firing at an upward angle to avoid the propeller disc. The mounting provided three positions in elevation and limited sideways movement. In service, however, the Lewis guns proved unpopular, as they were difficult to aim and tended to swing into the pilot's face. Pilots also feared that the gun butts would inflict serious head injuries in the event of a crash. Most pilots therefore discarded the Lewis guns, though a minority retained one or both guns specifically for attacking high altitude reconnaissance aircraft from below. Pilots of No. 87 Squadron, including Arthur Vigers, experimentally fitted some aircraft with two forward firing, unsynchronized Lewis guns mounted on top of the lower wing, just inboard of the inner wing struts. These guns could fire incendiary ammunition, which could not be used with the synchronized Vickers guns. However, the 97-round ammunition drums could not be changed once empty, nor could the pilot clear gun jams. This field modification did not become standard. Dolphins were quickly retired after the war. Nos. 19 and 87 Squadrons demobilized in February 1919, followed by No. 23 Squadron in March. The last RAF unit to operate Dolphins was No. 79 Squadron, based at Bickendorf, Germany, as part of the army of occupation. The squadron demobilized in July 1919. The Dolphin was declared obsolete on 1 September 1921.
No. 1 (Fighter) Squadron of the Canadian Air Force, which operated Dolphins and S.E.5as, Sopwith Snipes and captured Fokker D.VIIs, was disbanded on 28 January 1920. Although retired from Canadian Air Force service, a small number of Dolphins were sent back to Canada. One Dolphin was converted for civilian use. In 1920, Handley Page Ltd. obtained D5369 and operated it as a demonstrator under the civil registration G-EATC. This aircraft was sold in 1923. The Polish Air Force operated 10 Dolphins during the Polish-Soviet War. From August 1920, these aircraft were primarily used for ground attack duties in the Battle of Warsaw and other actions. They were soon grounded due to lack of spare parts. In October 1920, two Polish Dolphins were loaned to the Ukrainian Air Force (1. Zaporoska Eskadra Ukraińska) for use against the Soviets. Both aircraft were returned to the Poles in February 1921 A total of 2,072 Dolphin Mk I aircraft were produced by Sopwith, Darracq Motor Engineering Co. and Hooper & Co. Approximately 1,500 Dolphins were stored awaiting engines at the time of the Armistice. These incomplete airframes were eventually scrapped. Two developments of the Dolphin were planned. The French firm SACA (Société Anonyme des Constructions Aéronautiques) commenced licensed production of the Dolphin Mk II in 1918. The RAF expressed no interest in this variant, which was intended for the French Aéronautique Militaire and the US Army Air Service. The Mk II's 300 hp direct-drive Hispano-Suiza 8F gave a maximum speed of 225 km/h (140 mph) and a ceiling of 8,047 m (24,600 ft). The new engine had a displacement of 18.5 litres (1,129 in3) and required an enlarged, bulbous cowling that fully enclosed the guns. The Mk II also featured an additional fuel tank, a variable incidence tailplane, strengthened airframe and longer exhaust pipes. The Air Service anticipated delivery of over 2,000 Mk II aircraft by the summer of 1919, but only a few were delivered before the Armistice. Meanwhile, persistent difficulties with the geared 200 hp Hispano-Suiza 8B prompted development of the Dolphin Mk III, which used a direct-drive version of the 200 hp engine. The Mk III first flew in October 1918 and went into production just as hostilities ended. Many existing Dolphins were also converted to Mk III standard at aircraft repair depots by removing the reduction gearing and fitting a modified cowling to accommodate the resultant lowered thrustline
The Gloster E.28/39, (also referred to as the "Gloster Whittle", "Gloster Pioneer", or "Gloster G.40") was the first British jet-engined aircraft to fly. It was designed to test the Whittle jet engine in flight, leading to the development of the Gloster Meteor. In September 1939, the Air Ministry issued a specification to Gloster for an aircraft to test one of Frank Whittle's turbojet designs in flight. The E.28/39 name comes from the aircraft having been built to the 28th "Experimental" specification issued by the Air Ministry in 1939. The E.28/39 specification required the aircraft to carry two .303 Browning machine guns in each wing, with 2,000 rounds of ammunition, but these were never fitted. Paragraph 2 of the contract for the first aeroplane stated.
The primary object of this aeroplane will be to flight test the engine installation, but the design shall be based on requirements for a fixed gun interceptor fighter as far as the limitations of size and weight imposed by the power unit permit. The armament equipment called for in this specification will not be required for initial trials but the contractor will be required to make provision in the design for the weight and space occupied by these items..." Gloster's chief designer, George Carter, worked closely with Whittle, and laid out a small low-wing aircraft of conventional configuration. The jet intake was in the nose, and the single tail-fin and elevators were mounted above the jet-pipe, although due to uncertainty about the spinning characteristics of a jet aircraft, in an earlier design stage twin fins and rudders were considered.
Two jet pipe/rear fuselage arrangements were also originally considered due to the potential loss of thrust through the jet pipe itself: a 'short jet' with a cutaway rear fuselage and short exhaust necessitating the tailplane to be carried on booms, and a 'long jet' with a fully enclosed jet pipe; the 'long jet' was subsequently selected. A contract for two prototypes was signed by the Air Ministry on 3 February 1940, and the first of these was completed by April 1941. Manufacturing started at Brockworth near Gloucester, but was later moved to Regent Motors in Regent Street Cheltenham (now the site of Regent Arcade), which was considered a location safer from bombing.
Although the initial flight tests were relatively early in the Second World War, the German Heinkel He 178 had been first test-flown on 27 August 1939, at Rostock-Marienehe on the Baltic Coast, days before the outbreak of the war. The E.28/39 was delivered to Brockworth for ground tests beginning on 7 April 1941, using a non-flightworthy version of the Power Jets W.1 engine. These included some short "hops" of about 6 ft in height from the grass airfield. With these initial tests satisfactorily completed, the aircraft was fitted with a flightworthy engine rated for 10 hours use, and then transferred to Cranwell which had a long runway. On 15 May 1941, Gloster's Chief Test Pilot, Flight Lieutenant Gerry Sayer flew the aircraft under jet power for the first time from RAF Cranwell, near Sleaford in Lincolnshire, in a flight lasting 17 minutes. In this first series of test flights, a maximum true speed of 350 m.p.h. was attained, in level flight at 25,000 ft. and 17,000 r.p.m. turbine revolutions.
General characteristics Crew: One Length: 7.74m Wingspan: 8.84 m Height: 2.70 m Wing area: 13.6 m² Airfoil: G.W.2-section Empty weight: 1,309 kg Loaded weight: 1,700 kg Powerplant: 1 × Power Jets W.1 turbojet, 860 lbf (3.8 kN) Fuel capacity: 81 gallons Maximum speed: 544 km/h at 3,050 m Range: 656 km Endurance: 56 minutes Service ceiling: 9,755 m Rate of climb: 5.9 m/s Thrust/weight: 0.21 Guns: None fitted, but provision for four 7.7 mm Browning machine guns
Over the following months, tests continued with increasingly refined versions of the engine. Later in the test program small, auxiliary fins were added near the tips of the tailplanes to provide additional stability in high-speed flight. John Grierson, in 1971, called these "end-plates", and wrote that their purpose was to increase the fin area due to the problem of rudder blanking in a side-slip. On 21 October 1942, Sayer disappeared during an acceptance test flight in a Hawker Typhoon, presumed killed in a collision, and his assistant, Michael Daunt, took over testing of the E.28/39. The oil system had been changed before he flew; after it was proven, the aircraft was handed over to the RAE for testing by service pilots.
The second prototype E.28/39 (W4046) - initially powered by a Rover W2B engine - joined the test programme on 1 March 1943. Testing had revealed problems with engine oil and lubricants. Flying of W4046 was by Gloster test pilots John Grierson and John Crosby Warren, because Michael Daunt was then involved with the F.9/40 (the Meteor). In April 1943, W4046 flew to Hatfield for a demonstration in front of the Prime Minister and members of the Air Staff. It was taken to Farnborough and fitted with a 1,500 lbf (6.7 kN) W2.B. It achieved 466 mph. On 30 July 1943, while on a high-altitude test flight, the second prototype was destroyed in a crash resulting from an aileron failure. The accident was attributed to the use of the wrong type of grease in the aileron controls; one aileron had "stuck in position, sending the aircraft out of control". The test pilot, Squadron Leader Douglas Davie, successfully bailed out from 33,000 ft, suffering frostbite on the way down.
The first prototype was fitted with the 1,700 lbf (7.6 kN) thrust W2/500. It was flown successfully to 42,000 ft, but level speed at altitude was not attempted due to fuel shortage. The pilot commented in his report on a need for cockpit heating and a larger fuel tank. It continued flight tests until 1944. By that time, more advanced turbojet-powered aircraft were available. The Gloster E.28/39 was later able to achieve high speeds, highest being 505 mph at 30,000 feet with a W.2/700 engine, and it proved to be a capable experimental platform and exhibited a "good climb rate and ceiling". Experience with the E.28/39 paved the way for Britain's first operational jet fighter aircraft, the Gloster Meteor. The Meteor used the Rolls-Royce Welland engine, the next stage from the Power Jets W.1. Of the E.28/39 Grierson wrote: "The very favourable impressions of jet propulsion obtained ... have all been endorsed by subsequent flights ... The E.28 is a most pleasant little aeroplane to handle, particularly on account of the excellent field of vision from the pilot's seat ... "
In 1946, the first prototype (W4041) was placed in the Science Museum in Central London, where it is exhibited today in the Flight Gallery. A full-size replica has been placed on an obelisk on a roundabout near the northern perimeter of Farnborough Airfield in Hampshire, as a memorial to Sir Frank Whittle. A similar full-size model is on display in the middle of a roundabout at Lutterworth in Leicestershire (pictured below), where the aircraft's engine was produced. A full-scale model taken from the same moulds, with authentic paint scheme and detailing, has been built by members of the Jet Age Museum in Gloucestershire. It has recently been on display in Brockworth, Gloucester, Kemble (at both the Kemble Air Day and the MVT Show), and formed part of the display for the Sir Frank Whittle Centenary commemorations at RAF Cranwell in June 2007.
