В.Обухович, А.Никифоров Самолеты Первой Мировой войны
На основе G.100 в 1917 г. был создан опытный истребитель RG с двигателем Роллс-Ройс «Фэлкон», а также опытные двухместные истребители F.1 и F.2.
На самолете F.1 устанавливался двигатель Роллс-Ройс мощностью 250 л. с. Место пилота находилось в задней кабине. F.2 имел меньшие размеры. Он оснащался двигателем Испано-Сюиза мощностью 200 л. с. Сиденье же пилота было расположено в передней кабине.
В конце 1917 г. был разработан одноместный истребитель F.3. Его размеры были вновь уменьшены. Кабина пилота была оборудована под верхним крылом. На машине устанавливался двигатель RR «Фэлкон» в 275 л. с. Шасси выполнено по типу самолетов фирмы «Сопвич». Серийно этот вариант не производился.
Одноместный истребитель F.4, разработанный в середине 1918 г., по своим скоростным характеристикам превосходил другие машины этого класса. Кабина была сдвинута назад, установлен двигатель H-S мощностью 300 л. с. Выпускался F.4 в стандартной версии Mk.I и в варианте дальнего истребителя Mk.Ia.
Планировалось запустить самолет большой серией, но из-за окончания войны было изготовлено только 370 самолетов. В боевых действиях самолет не участвовал, но после войны находился на вооружении нескольких стран, в том числе СССР, Ирландии, Финляндии, Латвии, Португалии и Испании.
А.Шепс Самолеты Первой мировой войны. Страны Антанты
Мартинсайд F.4 1918 г.
Появление более мощных рядных двигателей в конце войны позволило самолетостроительным фирмам создать машины с лучшими летными характеристиками. Одним из таких самолетов стал истребитель Мартинсайд F4. Этот самолет стал развитием опытных машин фирмы RG и F.3. На фронт несколько самолетов попали перед самым перемирием. Большинство из 370 выпущенных машин разошлись на экспорт по европейским странам: в Польшу, Финляндию, Литву, Португалию, Испанию. Небольшое количество F.4 закупил и СССР.
Это был классический одностоечный биплан смешанной конструкции. Каркас фюзеляжа изготавливался из деревянного бруса и облицовывался в носовой части алюминиевым листом, а сзади - полотном. Над верхней частью фюзеляжа устанавливался полукруглый гаргот. Крылья двухлонжеронные, деревянной конструкции, со стойками из металлических профилированных труб в деревянных обтекателях. Оперение обычного типа. Шасси двухстоечное с резиново-шнуровой амортизацией. Двигатели устанавливались различные: 8цилиндровые жидкостного охлаждения, рядные V-образные «Испано-Сьюиза» 8F мощностью 300 л. с., «Лорен-Дитрих» 8B (230 л. с.) или Роллс-Ройс «Фалкон III» (275 л. с.). Вооружение - 2 синхронных 7,69мм пулемета «Виккерс».
размах крыльев 10,00
Площадь крыла, м2 29,80
максимальный взлетный 1090
мощность, л. с. 300
Дальность полета 450
Потолок практический 7350
Экипаж, чел. 1
Вооружение 2 пулемета
В.Шавров История конструкций самолетов в СССР до 1938 г.
"Мартинсайд" F-4. Это одноместный истребитель с двигателем "Испано-Сюиза" в 300 л. с., выпущенный в июне 1918 г. На фронт он уже не попал и несколько лет состоял на вооружении в Англии. В 1922-1923 гг. Советский Союз приобрел около 100 самолетов "Мартинсайд" F-4 и из них было сформировано несколько эскадрилий. С 1927 г. этот самолет стал заменяться отечественным истребителем И-2 бис.
"Мартинсайд" F-16 - двухместный разведчик с тем же двигателем. От истребителя F-4 отличался, при той же схеме, увеличенным размахом верхнего крыла и Х-образными защитными стойками (из-за сдвига назад нижнего крыла) и большей длиной фюзеляжа. Был приобретен в двух десятках экземпляров, применялся в строевых частях и в школах.
Двигатель , марка||<Испано-Сюиза>
мощность, л. с.||300
Длина самолета, м||7,75
Размах крыла, м||10,06
Площадь крыла, м2||33,89
Масса пустого, кг||855
Масса топлива+ масла, кг||98+19
Масса полной нагрузки, кг||258
Полетная масса, кг||1113
Удельная нагрузка на крыло, кг/м2||32,7
Удельная нагрузка на мощность, кг/лс||3,71
Скорость максимальная у земли, км/ч||211
Скорость посадочная, км/ч||75
Время набора высоты||
Потолок практический, м||6850
Продолжительность полета, ч.||1,5
Дальность полета, км||330
O.Thetford Aircraft of the Royal Air Force since 1918 (Putnam)
The F.4 Buzzard single-seat fighter was too late to see action in the First World War, but a few served with the R.A.F. after the Armistice. Two were used by the R.A.F. Communication Wing in 1919 for flights between London and Paris during the Peace Conference. The type also participated in the R.A.F. Pageant at Hendon in 1920 and again in 1922. Powered by a 300-h.p. Hispano-Suiza engine, the Buzzard was one of the fastest fighters of its day with a maximum speed of 132 1/2 m.p.h. at 15,000 ft. and 145 m.p.h. at sea level. Loaded weight, 2,390 lb. Span, 32 ft 9 3/8 in. Length, 25 ft. 5 5/8 in.
P.Lewis The British Fighter since 1912 (Putnam)
Following the lack of success with their F.1 and F.2, Martinsyde abandoned the two-seat formula for a fighter and turned with hope to the single-seater again as a proposition likelier to yield more positive results.
The F.3 was ready for testing by November, 1917, and lived up to its parent firm’s expectations. An eminently compact, clean single-bay biplane, it was powered at first by an experimental Rolls-Royce Falcon which delivered 285 h.p., resulting in a useful maximum speed at ground level of 142 m.p.h. and a service ceiling of 24,000 ft. Two Vickers guns fired forwards from beneath the cowling. Martinsyde had the satisfaction of knowing that, according to official reports, in the F.3 a machine had been designed which was considered to be superior to any other contemporary single-seat fighter. The following year production got under way as the F.4, incorporating minor alterations.
By June, 1918, the revised production version of the Martinsyde F.3, designated F.4 and named the Buzzard, was ready for its trials, powered by the 300 h.p. Hispano-Suiza engine. In the Buzzard an improvement in the view for the pilot was effected by moving the cockpit a short distance to the rear. In trials during August, 1918, following the fitting of improved pistons to the engine, the Buzzard Mk.I recorded a maximum speed at ground level of 144-5 m.p.h., earning itself the distinction of being the fastest type of British aircraft in production when the War ended. The machine’s all-round excellence resulted in good orders for it to re-equip fighter squadrons and included a long-range version - the Mk.Ia. However, production was unable to get under way sufficiently during the few remaining months of the War for the Buzzard to enter service and the machine, in view of its fine qualities and advanced conception, was unfortunate in not being selected to continue the single-seat fighter tradition in the peacetime Royal Air Force.
H.King Armament of British Aircraft (Putnam)
F.3. 'A great advance on all existing fighting scouts' was one official pronouncement on this experimental single-seater of 1917 ('Mother' in the Martinsyde family). In addition to two fixed Vickers guns, there was provision, in deference to an Air Board specification then current, for a Lewis gun on the top centre-section. This gun was apparently never fitted. Compared with the R.G., the F.3 had a deeper fuselage forward of the cockpit, and this allowed the guns to be completely cowled in and to fire through ports in the top decking. A single aperture for the ejection of cases and links was located just forward of the rear centre-section strut on each side.
F.4. The F.4, or Buzzard, was built in 1918 and had a generally similar Vickers gun installation to that of the F.3. An important feature, however, was the excellent system devised for accessibility, described and illustrated in connection with the Aircraft Disposal Company's A.D.C.1. Brackets for an Aldis sight were fitted forward of the cockpit and provision was made for a bomb-carrier (four 20-lb) under the fuselage.
A point of some interest is that on the prototype and on the production aircraft illustrated, the ejection aperture was panelled over, but whether with the object of retaining the spent cartridge cases and belt links aboard cannot be determined.
F.4a. This designation was applied to a post-war (1921) two-seater development of the F.4 having a Scarff ring-mounting for a Lewis gun.
L.Andersson Soviet Aircraft and Aviation 1917-1941 (Putnam)
Martinsyde F.4 Buzzard
Designed by G A Handasyde, the Martinsyde F.3 single-seat biplane fighter first flew in November 1917. It was armed with two synchronised machine-guns enclosed by the engine cowling and it was powered by a 275hp Rolls-Royce Falcon III engine. Only seven F.3s were built, but the re-engined F.4 version was ordered in large numbers. This type had a different lower wing of narrower chord and the cockpit had been moved aft to improve downwards view. It was one of the fastest fighters of its time but was not adopted by the RAF and most of the large production contacts were cancelled after the Armistice. The few already delivered to the RAF were used on second-line duties only. The Armistice prevented the Martinsyde fighter from proving itself operationally and most of those built for the RAF were acquired by the Aircraft Disposal Company in 1920 and a number was later sold abroad.
The Martinsyde F.4 was powered by a 300hp Hispano-Suiza 8Fb eight-cylinder water-cooled engine driving a 2.7m diameter Lang two-blade wooden propeller. A frontal radiator was fitted and fuel capacity was 173 litres. The fuselage was made in two parts. The structure of the forward section consisted of solid hickory longerons and spruce spacers and it was covered by birch three-ply, the rear section having spruce longerons and fabric covering. Two fixed forward-firing 7.7mm Vickers machine-guns were located ahead of the cockpit, housed within the top fuselage decking which had gun muzzle blast troughs.
The wing spars were built of three laminations of spruce. Each wing panel had four box compression ribs and numerous former ribs. The tail unit was of fabric-covered wood. The narrow undercarriage consisted of V-struts made of spruce with rubber chord shock absorbers.
About 330 Martinsyde F.4s were built before production was halted in 1919. A contract for 1,500 Liberty-powered Martinsyde F.3s had been placed by the American authorities but this order was also soon cancelled. One F.4 was taken to Japan by a British aviation mission in 1921 and two other examples were presented to Poland and Portugal in 1921. The Martinsyde company tried to survive for some time and made a racing version of the F.4, a number of two-seat conversions and other variants, but it soon had to close down. The F.4 was then marketed by the Aircraft Disposal Company. Portugal bought three in 1923 and Spain acquired at least 25. Four were sold to Ireland, two to Lithuania and one to Finland for evaluation, followed by another fourteen in 1927. In 1926 Uruguay received one and Latvia bought one normal F.4 and seven ADC Is, which were conversions of the F.4 powered by an Armstrong Siddeley Jaguar radial engine. A few F.4s were also flown in British civil markings.
The RKKVF authorities acquired the Martinsyde F.4 for re-equipment of some of its fighter units. Twenty were ordered by the Soviet Government from the Aircraft Disposal Company and arrived in Leningrad on board the Miranda in May 1922, followed by another twenty-one in the autumn of 1923. The RAF serial numbers of these aircraft were D4271-4273, D4276, D4277, D4280, D4282, D4283, D4288, D4289, D4291, D4292, D4304, H7633, H7685, H7686, H7690, H7691, H7693, H7698, H7703, H7706-7712, H7715, H7720, H7723, H7724, H7728, H7735, H7749, H7751, H7757, H7758, H7774, H7775 and H7794. Twenty- five were in service by September 1923 and a year later thirty-eight were on charge. When the original Hispano-Suiza engines became worn out after some time they were replaced by the Soviet-built 290hp M-6 copy.
The Martinsyde fighters were assigned to the 2nd Otdel'naya Istrebit'elnaya Aviaeskadril'ya based at Ukhtomskaya, near Moscow, and served with this unit until withdrawn from operational use when the unit was disbanded in 1926-27. After having been in service for two-and-a-half years thirty-one of the Martinsydes were presented to the VVS in connection with an official ceremony at the Central Airport in Moscow on 17 May 1925. Soviet railway and waterway workers had formed a special committee for an aviation fund in 1924, which had supervised the subscription of some 750,000 roubles. This money was to be used for the establishment of a VVS eskadril'ya to be named Dzerzhinsky after F E Dzerzhinsky, who is known as the first chief of the Cheka (or ChK - Chrezvychainaya komissiya, Special Commission), the secret political police which became the GPU in 1922. Dzerzhinsky had also held the People's Commissar for Communiations post from 1921.
In what might be described as something of a giant propaganda bluff some 35,000 people were gathered at the Moscow airport to inspect the 'new' Martinsyde fighters which had been given individual names including Proletarskaya oborona, Proletarii, Krasnyi zheleznodorozhnik, Krasnyi gorets, Krasnyi severyanin, Kras- novostochnyi, Strazh revolyutsii, Vsegda golov, Chekist, Serg Ordzhonikadze, Jan Tomp, Pavel Vavilov (Proletarian Defence, Proletarian, Red Railway Worker, Red Mountaineer, Red Northerner, Red Easterner, Revolution Guard, Always Ready, Chekist).
A number of Martinsydes also served in the fighter trainer role with the 1st Higher School of Military Pilots in Moscow and the Strel'bom school at Serpukhov, later moved to Orenburg. At the end of 1928 the Akademiya VVF had one, the 1st and 2nd Schools of Military Pilots each had two, while the 3rd School of Military Pilots (previously Military School of Aerial Combat and Strel'bom) had ten. Those with the 3rd School were withdrawn from use in 1930, but the 1st School still had two on charge in July 1931.
On 29 June 1928 the Nil VVS received s/n 4280 from Zavod 39 in Moscow, where it had been rebuilt after a crash. At the end of that year some twenty Martinsydes remained and the last three were retired in 1931. Eleven were handed over to Osoaviakhim, but they were probably used as instructional airframes and were not flown.
V B Shavrov mentions in his Istoriya konstruktsii samoletov v SSSR do 1938 a two-seat reconnaissance 'Martinsyde F 16', about which he writes that it had increased span on the upper wing, and that twenty were purchased, but no trace of this type has been found in any original documents.
300hp Hispano-Suiza 8Fb (290hp M-6)
Span 10.06m; length 7.76m; height 2.65m; wing area 29.76sq m
Empty weight 855kg; loaded weight 1,113kg
Maximum speed 212km/h; landing speed 75km/h; climb to 1,000m in 2.2min; ceiling 6,850m; endurance 1 1/2hr; range 330km
Jane's All The World Aircraft 1919
THE MARTINSYDE F3 & F4 BUZZARD
The Martinsyde F3 single-seater scout biplane was designed in 1917. and, although it was far superior to any other machine of the period in speed and climb, was not put into production, owing to the difficulty in obtaining engines, in this case, the Rolls Royce " Falcon," which were earmarked by the Air Ministry for other machines actually in use.
It was then adapted to take the 300 h.p. Hispano-Suiza, and was put into production as the F-4, but its appearance on active service was preceded by the Armistice.
The fuselage is very deep and carries enclosed in the cowling twin Vickers sychronised guns. One set of interplane struts are carried on either side of the fuselage, and are splayed outwards from the base.
The pilot is set well back, and fairly high in the fuselage, the upper plane being cut away and the lower plane staggered back, thereby giving him a good view both upward and downward.
THE MARTINSYDE F4.
Type of machine F 4.
Purpose for which intended Fighter.
Span Top plane. 32 ft. 9 3/8 in.;
bottom, 31 ft. 2 3/8 In.
Gap. maximum and minimum 5 ft. 2 5/8 In.
Overall length 25 ft. 5 5/8 in.
Maximum height 10 ft. 4 in.
Chord Top plane, 6 ft. 0 1/2 in. ;
bottom plane, 5 ft. 6 1/4 in.
Total surface of wings 320 sq. ft. (all in).
Span of tail 11 ft 1 1/2 in. (over elevators).
Total area of tail 36 3/4 sq. ft. (tailplane and elevators).
Area of elevators 8 1/4 sq. ft. each.
Total 16 1/2 sq. ft.
Area of rudder 9 3/4 sq. ft.
Area of fin 6 1/2 sq.ft.
Area of each aileron Top, 11 3/4 sq. ft. each;
Bottom, 9 1/4 sq. ft. each.
total area Total, 42 sq. ft.
Engine type and h.p. Hispano-Suiza. 300 h.p.
Airscrew, diameter and pitch and revs. Dia., 8 ft. 8 7/8 in.;
Pitch, 6 ft. 6 in.;
Revs. 1850 r.p.m.
Weight of machine empty 1710 lbs.
Load per sq. ft. 7 lbs
Weight per h.p. 7 1/2 lbs
Tank capacity in hours 3 hours.
Tank capacity in gallons 43 gallons.
Speed low down 145 m.p.h.
Speed at 10,000 feet 143 m.p.h.
Speed at 20,000 feet 126 m p.h.
Landing speed 45 m.p.h.
To 5,000 feet 3.0 mins.
To 10,000 feet 6.30 mins.
To 20,000 feet 19.30 mins.
Total weight of machine loaded 2280 lbs.
W.Green, G.Swanborough The Complete Book of Fighters
MARTINSYDE BUZZARD UK
Widely considered to have been one of the best single-seat fighters to emerge during World War I, the Buzzard began life as a private venture design by G H Handasyde designated F.3. A single-bay staggered biplane of conventional wooden construction with fabric skinning and powered by a Rolls-Royce Falcon engine of 285 hp, the F.3 appeared in the autumn of 1917. It underwent its first official trials on 3 October, six further prototypes being ordered and a decision to manufacture the F.3 in quantity being taken before the end of 1917. The F.3 was powered by the 275 hp Falcon III engine, but priorities in Falcon engine supplies enjoyed by the Bristol Fighter led to the reworking of the F.3 for the 300 hp Hispano-Suiza 8Fb. With this it was redesignated F.4 and (from September 1918) officially named Buzzard. It is uncertain just how many of the original batch of 150 aircraft were completed as Falcon-engined F.3s, but most were certainly finished as HS 8Fb-engined F.4s, the first of the latter being tested at Martlesham Heath in June 1918. Additional contracts for the F.4 were placed with the parent company (300), Boulton & Paul (500), Hooper (200) and Standard Motor (300). Armed with two synchronised 0.303-in (7,7-mm) Vickers guns, the F.4 differed from the F.3, apart from power plant, in having revised fuselage decking contours and more extensive plywood skinning. Belated engine deliveries and other factors delayed production, only seven having been handed over by November 1918, and, in the event, no RAF squadron was to be equipped with the type. Production of the F.4 by the parent company continued for a time after the Armistice (no other contractor apparently producing any complete Buzzards) and more than 370 airframes were built, some being fitted with Falcon engines. A number of F.4 Buzzards was sold abroad by the Aircraft Disposal Company, the principal recipients being Finland (15), Portugal (4), Spain (20) and the USSR, the last-mentioned procuring 100 aircraft of this type. A two-seat variant, the F.4A, was produced in 1920, a much-modified derivative with two-bay wings of increased span appearing in the following year. This had a Lewis gun in the rear cockpit and several were supplied to Spain in June 1921, both single- and two-seat Buzzards being referred to as F.4As in Spanish service. The following data relate to the standard F.4 Buzzard.
Max speed, 132 mph (212 km/h) at 15,000 ft (4 570 m).
Time to 10,000 ft (3 050 m), 7.9 min.
Empty weight, 1,811 lb (821 kg).
Loaded weight, 2,398 lb (1088 kg).
Span, 32 ft 9 1/2 in (9,99 m).
Length, 25 ft 5 1/2in (7,76 m).
Height, 8 ft 10 in (2,69 m).
Wing area, 320 sq ft (29,73 m2).
A.Jackson British Civil Aircraft since 1919 vol.3 (Putnam)
Immediately after the 1914-18 war, Martinsyde Ltd. produced several civil types, most of which were derived from the F.4 single seat fighter, a fabric covered, wooden biplane designed by G. H. Handasyde, with wire braced, box girder fuselage and two spar, single bay wings. Some 280 were constructed, of which only about 50 were delivered to the R.A.F., the remainder, brand new, being stored at the firm’s Brooklands works. Their unusually deep and capacious fuselages and relatively high cruising speed made them eminently suitable for civil adaptation as a means of keeping Martinsyde Ltd. in business during peace-time. Piloted by R. H. Nisbet, K-152, the first demilitarised F.4, powered by a 275 h.p. Rolls-Royce Falcon III, gained second place in the Aerial Derby at Hendon on 21 June 1919, at an average speed of 124-61 m.p.h. It was followed by four standard F.4 fighters G-EANM, ’UX, ’YK and ’YP, which received temporary civil status for overseas demonstration. The first left Brooklands piloted by F. P. Raynham on 6 October 1919, performed in Madrid, and on arrival at Lisbon on 11 November was named ‘Vasco da Gama’ to become the first British aircraft ever to fly in Portugal and the first of a number of F.4s supplied to its air force.
Martinsyde pilot R. H. Nesbit was 6th in the 1920 Aerial Derby in the first F.6, G-EAPI, before it was sold to the Canadian Government and taken on charge at Camp Borden for No.3 Squadron, R.C.A.F. on 9 October 1922 as G-CYEQ. The second F.6, G-EATQ, was almost certainly the aircraft sold to Bishop-Barker Aeroplanes Ltd., Toronto and flown by Lt. Col. W. A. Bishop V.C. who was uninjured when it crashed at Armour Heights Aerodrome, Toronto, on 25 October 1920 before it had been allotted a Canadian registration.
Despite the sale of many F.4s to foreign air forces, by 1921 Martinsyde Ltd. found itself in difficulties, a victim of the post-war slump. Its last aeroplane was a low powered F.6, built for F. P. Raynham and fitted with a 200 h.p. Wolseley Viper for more economical private use. First flown at Brooklands on 29 September 1921, the machine later became G-EBDK and was converted into a single seater for racing purposes, coming second in the King’s Cup Race of 8-9 September 1922, and competing in the 1924 race piloted by J. King. Its subsequent owners, all well known, were L. C. G. M. Le Champion of Brooklands 1924-25, Leslie Hamilton of Croydon 1925-26 and Major J. C. Savage, Hendon 1927. This famous aircraft was dismantled in Dudley Watt’s shed at Brooklands in April 1930 and its remains lingered there for several years.
The final chapter in F.4 history opened in 1921, when Martinsyde Ltd. went into liquidation. All surviving airframes were then acquired by the Handley Page controlled Aircraft Disposal Co. Ltd. and went by road to Croydon to join the surplus R.A.F. F.4s already held by the company. Four of the latter had lately become civil aircraft in the usual racing and demonstration roles, G-EAXB and ’TD being flown by Major E. L. Foote and R. H. Stocken in the 1921 and 1922 Aerial Derbys respectively. By 1927 a considerable proportion of the F.4 stock had been sold to foreign air forces, 41 going abroad with civil Cs. of A. and two more, G-EBDM and ’FA, in civil marks. To G-EBMI, one of the last to be made airworthy, fell the honour of becoming the only privately owned F.4, property of E. D. A. Biggs at Woodley in March 1930. It crashed a few months later due to failure of the tailplane spar, with the loss of instructor S. W. ‘Pat’ Giddy.
Martinsyde Ltd., Maybury Hill, Woking, and Brooklands Aerodrome, Byfleet, Surrey; The Aircraft Disposal Co. Ltd., Regent House, Kingsway, W.C.2, and Croydon Aerodrome, Surrey.
One 275 h.p. Rolls-Royce Falcon HL
One 300 h.p. Hispano-Suiza.
(Martinsyde F.4 A and A.V.l)
One 300 h.p. Hispano-Suiza.
One 300 h.p. Hispano-Suiza.
One 200 h.p. Wolseley Viper.
F.4 and F.4A F.6
Span 32 ft. 9 3/8 in. 31 ft. 11 1/4 in.
Length 25 ft. 5 5/8 in. 24 ft. 6 in.
Height 9 ft. 6 in. 9 ft. 1 1/4 in.
Wing area 328'5 sq. ft. 320 sq. ft.
Tare weight 1,811 lb. -
All-up weight 2,300 lb. 2,300 lb.
Maximum speed 145 m.p.h. -
Initial climb 1,600 ft./min. -
Ceiling 24,000 ft. -
Duration 3 hours 3 hours
(a) Martinsyde F.4
Eleven British civil conversions and 29 reworked for export to foreign air forces with Cs. of A. 24.9.23 (17 aircraft for Finland); 7.10.23 (4); 2.2.24 (1); 15.10.24 (5); 4.3.27 (2).
(b) Martinsyde F.4A
Five British registered aircraft shown in Appendix E.
(c) Martinsyde F.6
Three British registered aircraft shown in Appendix E.
Flight, June 26, 1919.
THE AERIAL DERBY
No. 10. - The Martinsyde, F 4, 275 h.p. Rolls-Royce Falcon
In the main the Martinsyde biplane flown by Lieut. Robert Nisbet was the standard F4, which type has to its credit the fastest climb and speed at great heights, as well as the speed record for the Paris-London flight (1 hr. 15 mins.). The F . 4 is one of the most beautiful aeroplanes we have ever seen, quite apart from her qualities as a flying machine. There is positively not an ugly line or curve in her. As all the Martinsyde productions, she is beautifully finished in every detail, yet the construction is such as to be a sound production job. The body, which is very deep in front, is covered with three-ply in front, and shows the numerous external duralumin fittings which one always associates with the Martinsyde machines. The deep coaming in front of the pilot has "tumble-home" sides, and as the body is not very wide the pilot's view forward is not restricted to nearly the extent that might be expected. The top fairing of the fuselage behind the pilot comes to a sharp edge, which adds greatly to the appearance of the machine. A feature of all the Martinsyde biplanes is the manner of attaching the bottom plane to the fuselage. There are short wing roots permanently attached to, and situated below, the bottom of the fuselage. To these roots are attached the two bottom wings. The break in the lines caused by the bottom spars below the body is faired off with an aluminium plate which is so bent as to carry the fuselage bottom along from the nose to the pilot's seat in easy curves. All these things may appear of little importance, but they contribute their share towards the graceful appearance of the machine, and, incidentally, they probably have quite a lot to do with the performance.