В.Кондратьев Самолеты первой мировой войны

"АЛЬБАТРОС" D.V/D.Va / ALBATROS D.V/D.Va

  Очередная версия истребителя "Альбатрос", разработанная Робертом Теленом в апреле 1917 года. Поскольку немецкие двигателисты не успели создать для нее более мощный мотор, конструктору для повышения летных данных пришлось пойти по пути облагораживания аэродинамики и снижения массы конструкции планера. Фюзеляж самолета приобрел овальное сечение, напоминающее вытянутую каплю, более округлой стала форма руля поворота. Однако к заметным улучшениям это не привело.
  Серийное производство D.V развернуто в мае 1917-го, а в июне самолет начал поступать в войска. Первый опыт боевого применения показал, что прочность бипланной коробки машины недостаточна. Отмечались случаи "выворачивания" и разрушения нижнего крыла при пикировании, вызвавшие ряд катастроф.
  В ответ на это в августе появилась субмодификация D.Va с усиленным каркасом несущих поверхностей и дополнительными раскосами, соединяющими межкрыльевые стойки с передней кромкой. Другим внешним отличием большинства D.Va был небольшой обтекатель-заголовник за кабиной пилота.
  Взлетная масса D.Va оказалась даже выше, чем у D.III. Тем не менее, самолет сменил D.V на сборочных линиях заводов "Альбатрос" в Иоханнештале и Шнейдемюле. Серийный выпуск продолжался до весны 1918 года. Всего построено около 900 D.V и 1662 D.Va.
  На фоне новых истребителей стран Антанты D.Va выглядел не столь выигрышно, как его предшественники год назад. Летные данные машины фактически остались на уровне D.III и во многом уступали характеристикам "спадов" и SE.5.
  Тем не менее, осень 1917 года являлась пиком боевого применения "альбатросов". К началу ноября в составе немецких фронтовых эскадр насчитывалось 1540 D.V и D.Va. Отсутствие полноценной замены вынуждало немцев воевать на этих морально устаревших истребителях вплоть до тех пор, когда на фронт стали поступать в больших количествах гораздо более совершенные "фоккеры" D.VII.
  Помимо западноевропейских фронтов, "альбатросы" D.V и D.Va, как и предыдущие модификации, применялись в Македонии и Палестине.
  Многие "пятерки" пережили войну, в 1919 году сменив обозначение на L.24.
  
  
ЛЕТНО-ТЕХНИЧЕСКИЕ ХАРАКТЕРИСТИКИ
  
   D.V D.Va
  Размах, м 9,05 9,05
  Длина, м 7,33 7,33
  Площадь крыла, кв.м 20,86 20,86
  Сухой вес, кг 650 673
  Взлетный вес, кг 908 937
  Скорость максимальная, км/ч 180 175
  Время подъема на высоту
   2000 м, мин.сек 6,0 6,2
  Потолок, м 6200 6250

O.Thetford, P.Gray German Aircraft of the First World War (Putnam)

Albatros D V and Va

  In answer to the ascendancy which the S.E. 5s and Spads of the Allies were gaining over the Albatros D IIIs, the mid-summer of 1917 saw the introduction of the D V from the Albatros stable. In the event, the D V did not prove to have sufficient increase in performance to restore the balance of power in favour of the German Air Corps. Nevertheless, orders were put in hand for vast quantities, presumably on the theory that sufficient numbers would overwhelm any opposition, even if of superior calibre. In the autumn of 1917 the supply of D Vs was supplemented, and eventually replaced, by the D Va, which (as will be explained) differed very little from its predecessor.
  In an endeavour to obtain an increased performance from a more-or-less standardised airframe,a major re-design of the fuselage was undertaken. This dispensed with the flat sides of the D I/D III series and introduced a more truly elliptical section, endowing the fuselage with a more refined and pleasing appearance. An additional longeron was necessary along the centre-line on each side of the fuselage, which was wider than on the D III. A spinner of increased diameter was also fitted. A headrest was incorporated in the design of the new fuselage, but as it tended to restrict rearward vision, it was often removed on active service. The prototype D V had a D III type rudder, but thereafter the more familiar rounded rudder was fitted. The tailplane and elevator were interchangeable with those of the D III, but the under-fin was modified, its trailing edge being raked back at some 45° instead of vertical as before.
  The ailerons of the D V also departed from previous practice. The cables now ran through the top wing (and not the bottom as before), where they angled back through 90° and were locked on to pulleys to the aileron leading edge. Small shrouds covered the cables where they emerged through the wing surface. The wing itself was otherwise identical in shape, dimensions and construction with that of the D III, retaining the Teeves and Braun radiator in the starboard side of the centre-section.
  The D Va revived the D III type aileron modus operandi, with the cables running through the lower wing, the only difference being a slightly shortened operating crank. The wings were, in fact, interchangeable with those of the D III. As in the D V, D Vas were seen both with and without headrests, and the only certain means of distinguishing one from the other was by the location of the aileron control wires.
  As compared with the D III type, the gap of the D V and Va types was reduced by some 4 in.; the wing structures were otherwise the same except in the aileron operation. The unfortunate tendency to break up in a prolonged dive remained, and at the time the reason for this was not fully understood. Although static load tests confirmed that the structural strength of the lower wings was more than sufficient, it was found at a later date that the single spar was positioned too far aft. This caused vibrations which, in a long dive, increased proportionately, eventually resulting in wing failure. A partial cure, or at least an increased safety margin, was achieved by lifting a short auxiliary strut from the leading edge to the vee interplane strut. Even then, pilots were advised not to over-dive their Albatroses. The effect upon morale of such a restriction on a vital combat manoeuvre may well be imagined.
  The Albatros D V first entered service in May 1917, and from the middle of 1917, as the number of Jagdstaffeln increased, so they were equipped with Albatros types except for the units that also had Pfalz D III and Fokker Dr Is on their strength. Of all the Jastas that were eventually raised in readiness for the March 1918 offensive, it may be safely said that all, at one time or another, flew either Albatros D III, D V or D Va, some having a "mixed bag" of all types. Vast numbers were operated and, as if to counteract their structural shortcomings, many were adorned with bizarre insignia and garish colour schemes to bolster their pilot's morale. Lt. von Hippel of Jasta 5, who once miraculously crash-landed his D Va safely after the lower wing came away at 16,000 ft., had a fire-breathing black dragon emblazoned along the fuselage. Lt. Hermann Goring (later to become the infamous head of Hitler's Luftwaffe) led his Jasta 27 in a black fuselaged D V with nose and tail portions painted white.
  Richthofen was shot down in the D V 1177/17 on 6th July 1917 and later flew another, 4693/17, during the Battle of Cambrai. The leader of Jasta 21, von Schleich, was known as the "Black Knight" because of his all-black Albatros D V, which he flew on the French Front. The Albatroses of Jasta 21 shot down forty-one French aircraft during September 1917.
  And so the ubiquitous Albatros lighters continued to fly on all Fronts. Manufacture was finally discontinued in 1918 in favour of the Fokker D VII, but they remained in action in considerable numbers right up to the end of hostilities. In September 1918 some 327 D V and D Vas were in front-line service - the peak figure was in May 1918, when 131 D Vs and 928 D Vas were with the various Jastas in all theatres of operations.

TECHNICAL DATA
  Purpose: Single seat fighting scout.
  Manufacturers:
   Albatros Werke G.m.b.H. (Alb.).
   Ostdeutsche Albatros Werke, Schneidemuhl (O.A.W.).
  Power Plant: 180 and 200 h.p. Mercedes D IIIa 6-cylinder in-line water-cooled. (Basically 160 h.p. Mercedes with high compression and oversize cylinders fitted.)
  Dimensions: Span, 9.05 m. (29 ft. 8 1/4 in.). Length, 7.33 m. (24 ft. 0 5/8 in.). Height, 2.7 m. (8 ft. 10 1/4 in.). Wing area, 212 sq.m. (229 sq.ft.).
  Weights: Empty, 687 kg. (1,511 lb.) includes 30 kg. (66 lb.) cooling water. Loaded, 937 kg. (2,061 lb.)
  Performance: Maximum speed, 186 km.hr. (116 m.p.h.) Initial climb, 1,000 m. (3,280 ft.) in 4 min. Ceiling, 5,700 m. (20,000 ft.). Duration, 2 hr.
  Armament: Two fixed Spandau machine-guns synchronised to fire through airscrew.

  N.B. One Albatros D Va serial 7117; 17 experimentally fitted with a 185 h.p. B.M.W. IIIa achieved a ceiling of 10,500 m. on 6th February 1918, although this was with an uncorrected barograph.

W.Green, G.Swanborough The Complete Book of Fighters

ALBATROS D V Germany
  
  At the same time as the OAW received its first contract for the D III in April 1917, Albatros received an order from Idflieg for 200 DVs, referred to as "lightened D IIIs". The DV retained the wings of the DIII (although the aileron cables were led through the upper wing), was powered by the high-compression Mercedes D IIIa with oversize cylinders and offering 180 hp, and mounted twin 7,92-mm synchronised LMG 08/15 machine guns. The D V experienced a recurrence of the wing failures (previously suffered by the D III) as early as May 1917. Four hundred more D Vs were ordered, nevertheless, in May 1917 and 300 in July, after which the Idflieg terminated production in favour of the D Va which reverted to the D III-type aileron control cable arrangement and was reinforced throughout. The last Albatros fighter to see operational use in World War I, the D Va arrived at the Front in October 1917, by which time 1,612 fighters of this version had been ordered. Service of the D Va peaked in May 1918 when there were 928 (plus 131 D Vs) in operational use.

Max speed, 115 mph (185 km/h).
Time to 3,280 ft (1000 m), 4.35 min.
Endurance, 2.0 hrs.
Empty weight, 1,515 lb (687 kg).
Loaded weight, 2,066 lb (937 kg).
Span, 29 ft 8 in (9,04 m).
Length, 24 ft 0 5/8 in (7,33m).
Height, 8ft 10 1/4 in (2,70m).
Wing area, 228.19 sq ft (21,20 m2).

J.Herris Albatros Aircraft of WWI. Vol.4: Fighters (A Centennial Perspective on Great War Airplanes 27)

Albatros D.V & D.Va

  The Albatros company continued rapid development of the basic design and the next new type, the Albatros D.V, started arriving at the front in May. The D.V looked very similar to the earlier D.III and was a refinement of the earlier design that took the basic Albatros concept to the limit of its development. The major change, difficult to see at a distance, was the cross section of the fuselage, which in the earlier fighters had been a flattened oval; in the D.V it was elliptical to further reduce drag and somewhat lightened for improved performance.
  A rounded trailing edge to the rudder differentiated it from the early D.III, but later D.III fighters used the same rounded rudder. To compensate for the reduced keel area of the elliptical fuselage the fin holding the tail skid was enlarged slightly, and the different angle of the rear of that under-fuselage fin is the key distinguishing feature between the D.III and D.V from a distance. Some early D.V fighters also had a streamlined headrest for the pilot, but this obscured rearward vision and was soon discarded.
  The tail, wings, engine, and guns of the D.III were carried over into the D.V, although the wings had detail changes at the wing root to attach to the differently-shaped D.V fuselage. Also, the control cables to the ailerons were now routed through the upper wing to eliminate the aileron control wires running between the wings in previous designs, which was a source of drag.
  As a result of all the attention given to drag reduction, the D.V was one of the most streamlined biplanes of the war. Due to the lack of a better fighter from a competing manufacturer for many months coupled with the great production capacity of the Albatros company and the urgent need for more fighters to counter the growing numbers of Allied aircraft, the Albatros D.V and its D.Va development were built in large numbers and were the dominant German fighters at the front from the summer of 1917 until July/August of 1918 when the superior Fokker D.VII eclipsed it as the most numerous German fighter at the front.
  The D.V, shapely as it was, was a disappointment. Not only was its performance barely better than the D.III it was meant to replace, the structural lightening and revised lower wing root design led to a great rate of structural failures than with the D.III. The weakness of the lower wing first noticed in the D.III became much more serious in the more lightly-built D.V.
  Although the D.III and D.V both passed their static structural load tests, the basic problem was the single-spar lower wing. The lower wing could withstand the static loads that could be tested on the ground. However, dynamic flight loads rotated the wing around the spar and the single-spar wing was weak in torsion. Static tests did not detect this issue, which was greatly aggravated by the spar being located too far aft. Flight loads are generally concentrated at 25% of the chord aft of the leading edge; that is, right at or in front of the spar. Therefore, any change in lift on the lower wing tended to rotate the wing around the spar. During high-G maneuvering or steep, fast dives the lower wing could start twisting rapidly back and forth, a phenomenon unknown at the time but now known as flutter. Any aerodynamic surface that is subject to flutter can soon be torn off the airframe, and in the V-strutter Albatros fighters, especially the D.V, this was a serious problem that remained unsolved throughout the war because it was not understood.
  All this was an unpleasant shock for the German fighter pilots, who went from technical superiority in April 1917 to inferiority in May/June 1917 at a time when their aircraft became increasingly subject to structural failure and more and better aircraft equipped the Allied air units.
  Basically, Albatros and Idflieg failed with the D.V, which despite its problems went on to substantial production (900 aircraft) due to the lack of a better fighter. With the D.III dominant at the front, Albatros had tinkered with the basic design to wring the last bit of performance from it instead of trying significantly new and different concepts. For its part, Idflieg acquiesced with that limited vision and failed to drive development of fighter engines vigorously enough. No wonder the D.V was a disappointment; it arrived at the front using the same engine, guns, and technology as the D.I; The D.V even lacked the D.I's robustness. One notable indication of the D.V's mediocrity is that the D.III continued on in production alongside the D.V for months.
  Albatros immediately started working to address the pilots' many complaints about the D.V, but again could only modify the basic design instead of develop something really new. The revised D.Va appeared at the front in the early autumn of 1917; the airframe was strengthened (stronger wing spars and ribs), the aileron control system was returned to its original configuration in the D.III, and a slightly more powerful version of the Mercedes engine, the 170 hp D.IIIa, was fitted, which helped the heavier D.Va at least maintain performance parity with the mediocre D.V. Moreover, wing-tip support cables and auxiliary struts to link the wing leading edge to the forward interplane strut were fitted to many aircraft to further strengthen the wing cellule. Despite its mediocrity, no truly better fighter was available for production for months, and 1,662 D.Va fighters were built to fulfill the front's demand for more fighters.
  The D.V/D.Va debacle was due to both Albatros and Idflieg running out of good ideas and other German manufacturers failing to fill in the gap. Roland designs of 1917 did not have the flying qualities of the Albatros, and the more robust Pfalz D.III and D.IIIa did not offer better performance. Significantly, both used similar technology and engines to Albatros. Only Fokker's light, rotary-powered triplane offered any real advantages over the Albatros with its much superior climb and maneuverability, but its debut was marred by structural failures that greatly impeded its buildup at the front, and it was slow.
  Albatros's fighter reputation never recovered from the disappointment of the D.V. Despite much fighter prototype development work in 1918, Albatros's major accomplishment after the D.V was mass production of the far superior Fokker D.VII under license.


Albatros Fighter Production Orders
Date Ordered Type Qty Serials
Apr. 1917 D.V 200 D.1000-1199/17
May 1917 D.V 400 D.1962-2361/17
July 1917 D.V 300 D.4403-4702/17
Aug. 1917 D.Va 262 D.5165-5426/17
Sept. 1917 D.Va 250 D.5600-5849/17
Oct. 1917 D.Va 550 D.7000-7549/17
Sep./Oct. 1917 D.Va(OAW) 600 D.6400-6999/17
Notes:
  4. D.V total 900, D.Va total 1662 (1,062 by Albatros & 600 by OAW). Total of all Albatros fighters 4,227.


Albatros Fighter Specifications
D.III(OAW) D.V D.Va D.Va(OAW)
Engine 160 hp Mercedes D.III 160 hp Mercedes D.III 170 hp Mercedes D.IIIa 170 hp Mercedes D.IIIa
Span (Upper) 9.00 m 9.00 m 9.00 m 9.00 m
Span (Lower) 8.81 m 8.73 m 8.73 m 8.73 m
Chord (Upper) 1.5 m 1.5 m 1.49 m 1.49 m
Chord (Lower) 1.1 m 1.0 m 1.0 m 1.0 m
Wing Area 20.9 m2 20.86 m2 20.50 m2 20.50 m2
Length 7.33 m 7.36 m 7.33 m 7.33 m
Height 2.90 m 2.75 m 2.70 m 2.70 m
Empty Weight 603.5 kg 680 kg 717 kg 730.5 kg
Useful Load 227.5 kg 235 kg 220 kg 220 kg
Loaded Weight 891 kg 915 kg 937 kg 950.5 kg
Wing Loading 47.7 kg/m2 41.1 kg/m2 45.7 kg/m2 46.4 kg/m2
Power Loading 5.57 kg/hp 5.72 kg/hp 5.51 kg/hp 5.59 kg/hp
Max. Speed 175 km/h 170 km/h 172 km/h 172 km/h
Climb, 1,000 m - 4 min. 20 sec. 4 min. -
Climb, 2,000 m - 8 min. 50 sec. 8 min. 48 sec. -
Climb, 3,000 m - 14 min. 30 sec. 14 min. 47 sec. -
Climb, 4,000 m - 22 min. 40 sec. 22 min. 45 sec. -
Climb, 5,000 m - 35 minutes 35 minutes -
Type-Test Accept. June 1917 April 1917 December 1916 January 1918
Notes: All were armed with two machine guns. D.Va ceiling 5,800 m.