Fokker D.XXI

The fighter project was developed at the Fokker factory in South Amsterdam under the direction of Erich (Jiri) Shacki under the name Project 112 ( Dutch Ontverp 112 ) and was a combination of new ideas with the most successful solutions of the early designs of the Fokker CX and Fokker D. Xvii .

The glider was designed as a mixed wood-metal structure. This approach made it possible to create a machine that was easy to manufacture, cheap and reliable in operation. The aircraft possessed deliberately lower flight characteristics in comparison with fighters, the projects of which suggested more advanced structural solutions and methods based on new structural materials.

The Dutch Air Force was the main customer, but the number of fighters that were supposed to be purchased was small. Therefore, when the machine was launched into mass production, Fokker planned a new fighter for export. The company management considered that the new projected machine would be able to find sales in small countries that cannot afford to buy expensive and sophisticated modern equipment, but need simple and cheap combat aircraft.

Fokker D.XXI monoplane fighter was created in close collaboration with the British company Rolls-Royce Ltd , which produced aircraft engines.

It was originally envisaged that the power plant of the aircraft would be a 650-horsepower Rolls-Royce Kestrel IV engine with Preston cooling.

It was planned that the fighter would be armed with rifle-caliber machine guns, or 20 mm cannons mounted in the wings and fuselage.

Constructive calculations of flight characteristics were supposed to bring the maximum speed of the aircraft to 410 km / h at an altitude of 4250 m, with a flight range of 888 km and a ceiling of 10,000 meters.

On November 14, 1934, the company presented the Dutch Army Aviation Department with a choice of two aircraft models:

• Fokker D.XXI Monoplane Project
• The prototype Fokker D.XIX, which was a modernized version of the Fokker D.XVII fighter.

According to the Air Force concept, the new combat aircraft was supposed to be used as part of the Dutch East Indies Air Force ( Netherlands. Militaire Luchtvaart van het Koninklijk Nederlands-Indisch Leger, ML-KNIL ). The military needed an inexpensive fighter that made it possible to cover strategic objects that were remote from each other over long distances from the air. Outstanding flight data was not required for the combat vehicle, since the potential enemy did not have modern type aviation in this region.

In early 1935, a contract was signed with the Dutch Army Aviation Department for the construction of a prototype for the purpose of evaluating it for service in the Dutch East Indies.

The aircraft was equipped with an air cooling engine Bristol Mercury VI-S with a capacity of 645 liters. with. enclosed in an elongated hood type NACA with small punching under the cylinder heads. The machine had a two-bladed metal propeller with a step previously changed before the flight.

A 350 liter fuel tank was installed on the plane, located between the engine and the cockpit, but the rear tank and the radio were not mounted on a prototype.

The prototype first flew March 27, 1936 from the Welschap airfield near Eindhoven, piloted by Czech pilot Fokker Emil Meinecke. The first flight showed that the fighter was quite maneuverable, stable and enjoyable in piloting.

By the time the Fokker D.XXI prototype was tested, the concept of using a combat aircraft in the Dutch Air Force had changed. According to the military, instead of fighters scattered across the rare airfields of the vast territory of the East Indies, it was decided to place bombers here capable of delivering a preemptive bomb strike to a potential enemy. As a result, the Air Force abandoned the idea of ​​putting Fokker D.XXI fighters into service in overseas territories and placed an order for the purchase of medium-sized Martin 139WH bombers .

The future of the new fighter hung in the air. The company’s management offered their aircraft to the arsenal of the air forces located in the metropolis, but met with a refusal due to two reasons:

• 1. The flight performance of the aircraft did not meet the requirements of military operations in Europe and was inferior to both fighters of other countries and high-speed bombers, which have already appeared on the arsenal of some states;
• 2. The leadership of the Dutch Air Force was carried away by the idea of ​​multi-purpose aircraft, which could simultaneously serve as a fighter, reconnaissance and bomber.

The new requirements of the military seem to be satisfied by the Fokker G.1 combat aircraft being developed at Fokker . However, the design of the proposed machine was still crude and work on its refinement was delayed.

And before the Dutch Air Force, the problem of replacing the obsolete Fokker D.XVI and Fokker D.XVII biplanes already became, therefore, on November 24, 1936, the Ministry of Defense agreed to buy one Fokker D.XXI aircraft for comprehensive flight tests.

Air Force pilots tested the Fokker D.XXI prototype from November 25, 1936 to January 10, 1937 at the Susterberg military airfield. The aircraft was supposed to be compared with the scout Koolhoven FK-58 , which was offered to the military by a competing firm of Kolhoven .

The aircraft Koolhoven FK-58 was designed by Jiri аacki, who by then had already left Fokker and got a job as a designer at Koolhoven.

Thus, a paradoxical and dramatic situation developed: the planes of two competing firms, designed by one designer, entered the competition.

The designed Koolhoven FK-58 reconnaissance aircraft represented a new step in Shatsky's design thinking. The machine had a retractable landing gear, which, along with other improvements, made it possible to declare a design maximum speed of 520 km / h.

However, the design, construction and refinement of the prototype were delayed and the Koolhoven FK-58 reconnaissance aircraft was not ready for the first flight until September 1938.

Under the current conditions, the Dutch Air Force was ready to purchase and put into service a batch of the Fokker D.XXI aircraft already thoroughly tested in the air, but subject to the fulfillment of additional requirements. In order to improve the tactical and technical qualities of the new aircraft, the military offered Fokker the following design improvements:

• introduce dampers in the engine mount;
• improve the finish of exterior surfaces;
• increase the rigidity of the tail wheel strut;
• reinforce the canvas along the leading edges of the keel and stabilizer;
• reinforce cable to steering wheels

as well as some others.

For ease of operation in flight combat units, the propeller engine installation of the lightweight single-seat multipurpose Fokker D.XXI aircraft was proposed to be unified with the Fokker TV bomber being designed, equipping the machine with a choice of 830 liter Bristol Mercury VII or VIII engines. from.

The requirements of the Air Force were quite acceptable and Fokker promised to take into account all the wishes of the military in the modernized aircraft design.

In 1937, the Dutch government allocated funds for the purchase of 36 modernized Fokker D.XXI multipurpose combat aircraft for its own Air Force. The first production car took off in Schiphol on July 20, 1938 ^[4] and was tested by flight instructors as second reserve lieutenant de Zwaan and captain Van Gemern. The last of the 36 vehicles produced was transferred to the Air Force flight units on September 8, 1939 ^[5] . The aircraft carried on-board serial numbers 212-247. After testing, the cars were driven from Schiphol to the Dutch airbase in Susterberg.

In parallel with the sale of aircraft by its own Air Force, Fokker also mastered the export sale of its aircraft.

Denmark

In July 1937, Denmark purchased two copies identical to the prototype, with a Mercury VI-S engine (the aircraft received the designations J-41 and J-42), which arrived in Copenhagen on April 29, 1938. Aircraft differed from each other by screws - the J-41 was equipped with a two-blade, and the J-42 with a three-blade. The Danes also acquired a production license for the Royal Army Aircraft Plant in Copenhagen, which subsequently produced 10 aircraft (J-43 - J-52). The first three Danish aircraft were launched by the end of 1939. Danish-made vehicles were powered by a Mercury VIII engine and carried two 7.9 mm Madsen machine guns manufactured by DISA . One of the aircraft (J-47) was experimentally equipped with two 20-mm Madsen cannons in the underwing gondolas ^[6] .

Finland

On November 18, 1936, the Finnish government requested the sale of 7 D.XXI, equipped with a Bristol Mercury VIII engine and armed with 4 machine guns (2 in the wing and 2 in the fuselage) and to provide a license for the manufacture of 14 fighters. On May 7, 1937 the contract was signed, and on June 15 it was supplemented with a license for another 21 aircraft. The first batch of 7 cars, the Finns assigned the numbers FR-76 - FR-82. The first Dutch-built machine was ready in August 1937 and showed superiority over the prototype, which in turn also influenced the decision of the Dutch Air Force to replace the engine on their machines.

Since October 1938, when the first Finnish aircraft was assembled, the D.XXI licensed building was unfolded at the Valtion Lentokonetehdas state aircraft plant in Tampere . Finnish experts were attracted primarily by the technological simplicity of the machine, for the production of which expensive equipment, sophisticated equipment and a large number of highly qualified specialists were not required. At the same time, they made further changes to the design of the machines. Instead of a single strut mount stabilizer installed double V-shaped. An extra rectangular transparent panel has appeared on the outboard garrotta to improve the overview of the rear hemisphere. The upper steering wheel suspension assembly has also changed somewhat. The aircraft were equipped with a modern reflex sight Revi 3 ^[7] , unlike the Dutch, equipped with a collimator (ring with a front sight). Also, Finnish-made Mercury VII engines were installed on the aircraft. The cars were produced in two series: with the numbers FR-83 - FR-96 in November 1938 - March 1939 and FR-97 - FR-117 in March - July 1939 (a total of 35 pieces). The last of them left the assembly shop on July 27, 1939.

After the production of the licensed aircraft, the Finns purchased an additional license for the production of another 50 aircraft. This series was produced from January 1940 to March 1941. Since the capacities of the Tampere plant were small and, in addition to the Fokker fighters, he released a licensed version of the British Bristol Blenheim , which also uses Bristol Mercury VIII engines, the Finns faced the problem of a lack of these engines. Then they decided to produce the entire batch of American engines Pratt & Whitney R-1535 Twin Wasp Junior , available in sufficient quantities. A bulky engine modified the plane. In addition to the changed engine hood, on which adjustable blinds and exhaust pipes appeared on both sides of the engine (before that they were only on the right), the following changes were introduced on the machines of this series: all four machine guns were now located in the wings; new forms of fairings were used, a new form of the steering wheel and the carburetor air intake was changed. At the same time, the aircraft became heavier by almost 100 kilograms and the flight characteristics of the aircraft decreased. The speed was only 438 km / h, climb and maneuverability worsened. Machines of this party received the numbers FR-118 - FR-167. On two aircraft (FR-117 and FR-167), a retractable landing gear was mounted experimentally ^[6] .

The last fifth Finnish series was made from existing backlogs in August - November 1944, consisting of 5 pieces. These aircraft received the numbers FR-171 - FR-175. They were identical to the aircraft of the 4th series, although some sources claim that they were equipped with Bristol Pegasus X engines.

Spain

The Republican government of Spain also purchased a production license for the Fokker D.XXI, after which about 50 gliders were assembled in Spain. At the same time, since the Netherlands strictly complied with the embargo imposed by the League of Nations on the supply of arms to Spain, apparently no technical assistance was provided. The Spanish D.XXI was equipped with a Messier chassis, later deployed on a Hispano-Suiza HS-42 trainer. In Spanish documents it is mentioned that at least one aircraft under the control of the pilot Mariano Palacios Menendez flew in August - October 1938 over the factory airfield in El Carmoli , with the Soviet M-25 engine mounted on it - a copy of the American Wright Cyclone, and armament of 4 ShKAS machine guns . But soon the Republicans were forced to retreat, and upon retreating from El Carmoli, they blew up the aircraft factory, destroying all the documentation on the Fokkers. Attempts to resume the production of "fokkers" in Spain were not made.

• D.XXI-1, 1936. Bristol Mercury VI-S motor (645 hp) manufactured: prototype under registration number FD-322 and 2 aircraft for the Danish Air Force (registration numbers J-41 and J-42)
• D.XXI-2, 1937. Motor Bristol Mercury VIII (760 hp) aircraft for the Dutch Air Force - 36 units (registration numbers 212-247) and Finland Air Force - 7 units (registration numbers FR-76 - FR-82)
• D.XXI, 1938. The Spanish version with the Soviet engine M-25 - number and numbers are not known
• D.XXI, 1939-1940. Danish licensed model. Bristol Mercury VIII motor (760 hp), 10 units manufactured (registration numbers J-43 - J-52)
• D.XXI-3, 1938-1939. Finnish licensed model. Motor Bristol Mercury VIII (760 hp) In 1939, 35 were built (registration numbers FR-83 - FR-117)
• D.XXI-E1, 1938. Bristol Mercury VIII (760 hp) - an experimental version with a pronounced narrowing of the wing to the end, possibly based on a production aircraft
• D.XXI-4, 1941. Finnish licensed model. Motor Pratt & Whitney R-1535 Twin Wasp Junior (825 hp) built 50 units (registration numbers FR-118 - FR-167)
• D.XXI-5, 1944. Finnish licensed model. Motor Pratt & Whitney R-1535 Twin Wasp Junior (825 hp) built 5 pieces (registration numbers FR-171 - FR-175)

Netherlands Air Force

Danish Air Force

When German troops invaded Denmark in April 1940, the 8th Fokker D.XXI were in service with the 2nd Squadron of the Army Aviation Corps , which, along with the 4th Squadron, armed with the Fokker CV , was part of the Jutland Group. They were based at the Vaerlose airfield, near Copenhagen, where all the few Danish aircraft were concentrated.

The participation of Danish aircraft was minimal. On April 9, at 4 a.m., the duty officer at the airfield received a telephone message from the air defense post stating that a large group of German planes had crossed the border and were moving to Copenhagen. An alert was immediately announced. At 4:15 the first Danish fighter took off, but at that moment “Messerschmitts” Bf.110 from I. / ZG1 appeared over the airfield, who shot down it and began to storm the rest of the cars, which only warmed up the engines. Already at 4:30 the Danish Air Force actually ceased to exist. None of the remaining “fokers” could take off. Three hours later, there was a call from the Ministry of Defense. The officer transmitted the king’s order of surrender, which ended the resistance of the Danish armed forces of the Nazi occupation, as well as the career of Fokker D.XXI in Denmark.

Finnish Air Force

Fokker during the Winter War

By the beginning of the Winter (Soviet-Finnish) war, it was Fokker D.XXI who turned out to be the main and newest fighter of the Finnish Air Force. At the end of November 1939, there were 31 single-seat monoplanes of this type in the combat structure of the Air Force. Of these, General J. F. Lundquist , Commander of the Finnish Air Force, formed the 24th Fighter Squadron, based in Imola on the Karelian Isthmus. Fokker D.XXI entered the battle on December 1, 1939, on the second day of the war. Первым пилотом совершившим успешный боевой вылет стал в этот же день капитан ВВС Финляндии Эйно Лююкканен, сбивший советский бомбардировщик СБ-2 . Некоторые «Фоккеры» были оснащены лыжами, что давало возможность использовать их в прифронтовой полосе, где часто самолётам приходилось приземляться на заснеженный лёд. Прочие были снабжены обычными неубирающимися шасси, поэтому посадка в глубокий снег была для них достаточно опасным делом.

Наиболее результативным пилотом «Фоккера» стал лейтенант Йорма Сарванто — 13 подтверждённых побед и 4 неподтверждённые. 6 января 1940 года Сарванто вступил в бой с семью советскими бомбардировщиками ДБ-3 и за 6 минут сбил шесть из них, использовав весь боекомплект в 2000 патронов. Все самолёты упали на финской территории и были обнаружены (два члена экипажа пленены) ^[8] .

2 февраля 1940 года советский воздушный ас Антонов Яков Иванович в воздушном бою сбил ^[9] истребитель Fokker D.XXI. По финским данным, 2 февраля 1940 года в бою с И-16 из 25-го ИАП над посёлком Рауха был сбит один Fokker D.XXI из 4/LLv24. его пилот — датский доброволец лейтенант Фритц Расмуссен ( дат. Fritz Rasmussen ) — погиб. 21 марта 1940 года за мужество и отвагу, проявленные в схватках с врагами, Антонов Яков Иванович удостоен звания Героя Советского Союза.

При подведении итогов Зимней войны генералу Лундквисту было доложено, что только одни «Фоккеры» сбили 120 советских бомбардировщиков, потеряв при этом 12 самолётов (из общего количества потерь финских ВВС в 62 самолёта) и всего 8 пилотов. Таким образом, именно в составе Финских ВВС истребитель Fokker D.XXI показал свою реальную достаточно высокую боеспособность, правда, против устаревших, но значительно численно превосходивших советских самолётов образца начала-середины 1930-х годов и достойно вошёл в историю мировой военной авиации.

13 февраля 1940 года советский лётчик-истребитель Я. Ф. Михин во время воздушного боя таранил и сбил финский истребитель «Gloster Gladiator», ударив его крылом по килю, а затем сумел посадить свой самолёт. Пилот Карл-Кнут Калмберг погиб, а за совершение тарана Михин был награждён орденом Красного Знамени ^[10] . До последнего времени сбитым самолётом считали «Fokker D.XXI», который пилотировал финский ас (6 побед), лейтенант Тату Гуганантти . Самолёт якобы обнаружен, но восстановлению не подлежал ^[11] .

«Фоккеры» в Советско-финской войне (1941—1944)

Фюзеляж

Каркас фюзеляжа состоял из сварной фермы из хромомолибденовых труб, выполненной вцело с моторамой. Обшивка передней части — съёмные панели дюралевого сплава «электон», задней — полотно. В передней части фюзеляж имел круглое сечение, в задней — эллиптическое. Кабина лётчика располагалась посередине машины. Она отапливалась горячим воздухом от двигателя и полностью закрывалась прозрачным фонарём из триплекса и плексигласа . Средняя секция фонаря раскрывалась по продольной оси: левая часть откидывалась на петлях вниз. В полёте фонарь не открывался, но в аварийной ситуации он сбрасывался. За сиденьем пилота несущая ферма фюзеляжа была развита вверх, образуя противокапотажную раму.

Двигатель

На самолёте предусматривалась установка множества разнообразных двигателей воздушного охлаждения. На самолётах голландского производства устанавливались британские двигатели Бристоль «Меркюри» VII воздушного охлаждения и трёхлопастные металлические винты «Ратье» изменяемого шага. Машины, строившиеся по лицензии в Дании и Финляндии, оснащались двигателем «Меркюри» VIII. Начиная с июля 1940 года на финские самолёты устанавливали американские четырнадцати цилиндровые двухрядные моторы воздушного охлаждения Пратт-Уитни «Твин Уосп Джуниор». Винты применялись изменяемого шага, как металлические, так и деревянные, с полусферическим коком, предохранявшим механизм установки шага от замерзания. Центровка самолёта из-за различия масс двигателей изменялась вариацией объёма и установки топливных и масляных баков (перед и за кабиной). Дополнительный бак можно было разместить в левом крыле. Проектом предусматривалось протектирование всех бензобаков.

Крыло

Крыло цельнодеревянное двух лонжеронное с фанерной работающей обшивкой трапециевидной формы и округлыми законцовками. Силовой набор крыла составляли два коробчатых лонжерона из бруса (орегонской сосны) и 18 наборных реечных фанерных нервюр (часть из них — кессонного типа). Обшивка носка крыла выполнялась из «электона» а дальше — из фанеры, пропитанной бакелитовой смолой. К заднему лонжерону крепились дюралевые посадочные щитки и элероны с металлическим каркасом и полотняной обшивкой. На элеронах стояли флеттнеры. Стык крыла и фюзеляжа закрывали развитые дюралевые зализы.

Хвостовое оперение

Хвостовое оперение обычного типа с металлическим каркасом и целиком полотняной обтяжкой. Стабилизатор крепился к фюзеляжу снизу с помощью трубчатых одинарных (на финских и датских машинах — двойных, V-образных) подкосов и сверху с помощью тросовых расчалок. Проводка рулей полускрытая мягкая. На рулях высоты устанавливались триммеры , а на руле поворота — флеттнер. У машин голландского производства рули высоты оснащались выносными весовыми балансирами.

Шасси

Шасси не убирающееся трёхопорное консольного типа с ориентирующимся хвостовым колесом. Свободнонесущие стойки с масляно-пневматической амортизацией были укреплены на переднем лонжероне. Дюралевые капоты, закрывающие стойки и частично — колеса, придавали хорошо обтекаемые формы. Колеса прикрывались каплевидными обтекателями с небольшой подножкой для механика. На самолётах датского производства центральные секции капотов, прикрывающие гидроцилиндры амортизаторов, обычно не устанавливались. Хвостовое колесо во всех случаях не убиралось. Оно имело механическую связь с рулем поворота и амортизировалось пакетом резиновых пластин.

Приведённые ниже характеристики соответствуют модификации D.XXI-2 :

Источник данных: GH Kamphuis The Fokker D.XXI //Aircraft profile 63. 1968 год

Specifications

• Экипаж : 1 пилот
• Длина : 8,2 м
• Размах крыла : 11,0 м
• Высота : 2,92 м
• Площадь крыла: 16,2 м²
• Масса пустого: 1450 кг
• Нормальная взлётная масса: 2050 кг
• Объём топливных баков: 350 л
• Силовая установка : 1 × воздушный Bristol Mercury VIII
• Мощность двигателей: 1 × 760 л.с. (1 × 559 кВт)

Лётные характеристики

• Максимальная скорость: 435 км/ч
• Крейсерская скорость : 365 км/ч
• Практическая дальность: 950 км
• Практический потолок : 9500 м
• Нагрузка на крыло: 126,5 кг/м² (расч.)
• Тяговооружённость : 272,7 Вт/кг (расч.)

Armament

• Стрелково-пушечное:
  • 2 × 7,69 мм пулемёта FN-Browning М.36 с 500 сн. на ствол в фюзеляже
  • 2 × 7,69 мм пулемёта FN-Browning М.36 с 300 сн. на ствол в крыле

• GH Kamphuis. The Fokker D.XXI (англ.) // Aircraft profile 63. : Перевод А. Плахова, редакция В. Моисеева. — 1968. Архивировано {a.
• Skulski, Przemysław. Fokker D.21 (Seria «Pod Lupą» 10) (in Polish, with English summary). Wrocław, Poland: Ace Publication, 1999. ISBN 83-86153-79-2 .
• Котельников Владимир. Фоккер D.XXI (рус.) // Мир Авиации : журнал. — 1993. — № 4, 5 . — ISSN 0869-7450 .
• Харук А.И. Истребители Второй Мировой. Самая полная энциклопедия. — М. : Яуза, ЭКСМО, 2012. — 368 с. — 1500 экз. — ISBN 978-5-699-58917-3 .
• Энгл Э., Паанен Л. Советско-финская война. Прорыв линии Маннергейма 1939-1940 = The Winter War. The Soviet attack on Finland 1939-1940 : перевод с англ.. — Москва: Центрполиграф, 2006.

• Fokker D.XXI (рус.) . Уголок неба - Большая авиационная энциклопедия . Дата обращения 31 августа 2009.
• Jarmo Lindberg. D.XXIs to Finland (англ.) . Дата обращения 15 мая 2011. Архивировано 6 апреля 2012 года.
• forum. Fokker D.XXI in Dutch service (англ.) . Дата обращения 15 мая 2011. Архивировано 6 апреля 2012 года.