Fokker V9

  The order to commence work on the Fokker V9 (Works Number 1831) experimental biplane was placed to the Fokker experimental workshop on 24 August 1917, just as the first Fokker Triplanes (then still carrying the F.I designation) were about to reach the front.
  The fuselage design of the V9 mirrored that of the Triplane; the fuselages of both aircraft were almost identical and they were powered by the same engine. Had both aircraft been developed at the same time, it would not be wrong to say that the V9 was the cantilever biplane fraternal twin of the F.I/Dr.I.
  As it was, the V9 was completed in October 1917, when production of the Dr.I was getting into full swing. It participated in the First Fighter Competition at Adlershof in January 1918, still powered by the 110 hp Oberursel Ur.II rotary engine.
  The biplane configuration reduced drag compared to the Dr.I, so was a bit faster. Its performance, particularly at high altitude, was limited by use of the low-power rotary engine, and the fact that the low-compression Oberursel engine lost power with altitude faster than the inline engines then available in Germany. More advanced rotary engines, such as the Siemens-Halske Sh.III, which retained much of its power at increasing altitudes, were not yet cleared to enter mass-production. The aircraft’s low aspect-ratio wings, while very sturdy, also increased induced drag, further limiting performance at altitude.
  After some further development of the wing and strut design, it was later entered into production under the military designation Fokker D.VI.

Fokker V9 Specifications
Engine: 110 hp Oberursel Ur.II
Wing: Span 7.70 m
Area 16.5 m2
General: Length 5.90 m
Height 2.80 m
Empty Weight 381 kg
Loaded Weight 572 kg
Climb: 1000m 2.5 min
2000m 4.7 min
3000m 7.7 min
4000m 11.0 min
5000m 15.5 min



Fokker V12

  The Fokker V12 (Works Number 1980) was delivered without engine and armament to Austria-Hungary on 3 January 1918 and was equipped at MAG with the 150 hp Steyr-Le Rhone. The probable military number of the V12 in Austro-Hungarian service was 90.04. In June, based on the good flight results of the V12, the LFT ordered 14 series D.VIs from Fokker in Schwerin, seven of which were delivered. Works Number 1980 participated as “MAG-Fokker 150 hp Le Rhone biplane” in the Austro-Hungarian fighter competition in Aspern in July. In the accounts of the disbanded Austro-Hungarian air force after the end of the war, Works Number 1980 was designated V12. When it was commissioned on 22 October 1917, it was still running as a V13 with a 160 hp Siemens Sh.III engine. At that time, on 29 October 1917, another machine V12 [Works Number 1982] was ordered as a biplane with 110 hp Ur.II. In a Fokker compilation of May 1919, Works Number. 1982 was then designated V13, which was sent to Budapest together with the V7 [Works Number 1981] on 3 January 1918. It is unclear whether the contradictory information is only a spelling error in the little documentation available or was as convoluted as described, whereby no systematic designations of prototypes seem to be recognizable.
Fokker V12 Specifications
Engine: 110 hp Oberursel Ur.II
Wing: Span 7.68 m
Area 24.0 m2
General: Length 7.50 m
Height 3.05 m
Empty Weight 592 kg
Loaded Weight 821 kg
Climb: 1000m 3 min
2000m 6.5 min
3000m 11 min
4000m 17.3 min
5000m 22.5 min
  


Fokker V13

  At least three different biplanes carried the V13 designation, possibly only temporarily. Probably some of these are errors in the surviving Fokker documents. Works Number 1980 was sent together with the V7 (Works Number 1981) to Budapest for MAG on 3 January 1918, where both received the Steyr-built Le Rhone. In the 1919/1920 period, Works Number 1980 was also referred to as the V12. Works Numbers 1983 and 2054 flew as the V13-I and V13-II at the First Fighter Competition at Adlershof in January 1918, the latter with a pre-series 160 hp Siemens & Halske Sh.III engine. Works Number 1983 was originally ordered on 2 November 1917 as the V14 with 160 hp Le Rhone. The order for Works Number 2054 as the V13 biplane was placed on 26 November 1917. On the first day of the Adlershof competition (21 January 1918), Anthony Fokker impressed the Idflieg representatives with a dramatic aerobatic flight in the V13-I. When the official climb measurements by Idflieg began on January 25, the V13-I went out of control while the pilot was adjusting its prototype Ur.III engine and rammed the Fokker V18, but the damage to its lower wing was quickly repaired. On January 26,1918, Fokker pilot Schutzenmeister reached an altitude of 6000 meters on the V13-I in 22.7 minutes. However, the engines of the two V13s in the competition, which had not yet been officially approved for production, caused many an aborted flight. In terms of construction, the V13 was a V9 with a slightly extended fuselage.
Fokker V13-I Specifications
Engine: 145 hp Oberursel Ur.III
Wing: Span 6.75 m
Area 17.4 m2
General: Length 6.35 m
Height 2.82 m
Empty Weight 472 kg
Loaded Weight 644 kg
Climb: 2000m 4.5 min
3000m 7.7 min
4000m 11.0 min
5000m 16.2 min

Fokker V13-II Specifications (as V13-I except)
Engine: 160 hp Oberursel Ur.III
Height 3.20 m
Loaded Weight 669 kg


  
Fokker V14

  Works Number 1983 was ordered on 2 November 1917 with the designation V14. V14 was a biplane with UR.III rotary and participated as a V13 in the first fighter competition at Adlershof.



Fokker V15

  There is no data available on the V15.



Fokker V16

  The design of the V16 was similar to the V7 triplane with the middle wings omitted to explore the flight characteristics; the upper and lower wings were enlarged.
  V16, w/n 2085, was ordered on 3 December 1917 with a 110 hp Oberursel UR.II rotary engine. The wings were cantilever and their surface area was specified as 16.6 m2 in the documentation, slightly smaller than the 18.66 m2 of the production Dr.I.
  The purpose of V16 was to investigate the aerodynamic effect of a larger wing gap. The result was deterioration and flight testing was stopped.



Fokker D.VI

  Between 20 January and 12 February Idflieg held the First Fighter Competition at Berlin-Adlershof, and Fokker demonstrated both inline-engined and rotary-engined prototypes there. Entered by Fokker in the latter category were three biplanes, the V9, powered by the 110 hp Oberursel Ur.II, the V13-I, powered by the eleven-cylinder Oberursel Ur.III, which was rated at 145 hp, and the V13-II, which was powered by the 160 hp eleven-cylinder Siemens & Halske Sh.III engine. Both eleven-cylinder engines were still considered experimental, but were hoped to be ready for mass-production soon.
  The Siemens-Halske Sh.III was demonstrated in several other types by other manufacturers, too, and turned out to be troublesome in most of these at the competition. Yet, it entered production before the Ur.III did, although its initial service would quickly prove the need for further perfection to the engine.
  While being of very similar appearance, the two V 13 prototypes were 33 cm longer than the V 9, while having 5 cm shorter wingspan.
  Of the three engines mentioned, only the Ur.II was already in mass production and frontline use as the powerplant of the Fokker Dr.I triplane. The Fokker Dr.I was introduced into widespread combat use with several elite Jagdstaffeln around the turn of 1917/18. Pilots very much appreciated the superb rate of climb and excellent maneuverability offered by it. However, it quickly became obvious to the men who flew the type that its horizontal speed was insufficient to keep up with many of the enemy fighters it faced in daily combat.
  The triplane design, while offering excellent climb and maneuverability, simply produced too much drag. Since the 110 hp Oberursel Ur.II that powered the Dr.I was in full-scale production, and its more powerful successor, the eleven-cylinder Ur.III, promising to deliver around 145 hp, was still not ready to enter service, a new airframe providing faster speed with the existing engine, had to be designed.
  The V 9 and the two V 13s had performed well enough at the competition for Idflieg to award Fokker a production order for 120 airframes that were officially designated D.VI in March. These were to be powered by the readily available Oberursel Ur.II, so the smaller V 9 served as the base version for the final production version of the D.VI.
  At this point two important factors have to taken into account. First, Fokker Triplane production at Schwerin was rapidly approaching the end. Out of 320 examples that had been ordered in total, only 21 machines remained to be completed after 31 March. With production of the triplane tapering off, a faster rotary-engined successor was needed. Since the D.VI offered better speed and slightly better low-altitude climb than the triplane, it was chosen as the follow-up model in the Schwerin production halls.
  Second, at the same time, another Fokker type had emerged as the winner in the inline-engined category, the Fokker D.VII. This is the type that was truly intended as a replacement for both the outdated Albatros D.V/Va as well as the Fokker Dr.I, as is graphically illustrated by the initial production orders for the D.VII. Right after the end of the competition, in February, 400 D.VIIs were ordered from Albatros, while an initial order for 300 examples was awarded to Fokker. For the Fokker company, this meant that while the Dr.I was being phased out of production, preparations had to be made to begin the manufacture of two different airframe types simultaneously. The fact that these were powered by different engine types complicated matters further.
  Fokker took a very economical approach to face, this challenge. A fuselage very closely based on that of the Dr.I was chosen for the D.VI production version. Length of both fuselages was practically identical (5776 mm for the D.VI versus 5770 mm for the Dr.I). Of course, the fuselage between the cockpit and the engine was modified for the biplane configuration; the attachment for the middle wing was eliminated and the lower wing cutout was enlarged because it had a greater chord. The Dr.I tailplane layout was carried over to the D.VII, too.
  For the production wings of the D.VI an equally clever solution was found. The chord of the lower wings for both the D.VI and the D.VII was identical (1.20 meters), and the same was true for the upper wings of both types (1.60 meters). Consequently, identical wing ribs could be manufactured for both. In fact, when comparing drawings of the wings of the D.VI to those of the wings of the Fokker D.VII, it becomes apparent that the D.VI wing design was nothing but a shortened D.VII wing. The wing ribs were of identical proportions on both types, and even the ailerons were alike.
  These similarities in design considerably eased serial production of the D.VI, and the first example of the new type (D.1631/18) was accepted at Schwerin on 26 April 1918.
  From a logical standpoint, it seems that the D.VI was primarily put into production to make the best use of the UR.II engines as they were coming off the production line. It is likely that Fokker was requested to manufacture airframes at roughly the same rate as he received the rotary engines that powered it, in order not to interfere with Fokker D.VII production, which had absolute priority. This, however, is a mere assumption that is not backed up by available contemporary references.
  An initial order for 120 machines was placed, and this low number clearly indicates that the Fokker D.VI was not intended to serve at the front in large quantities. Eventually, as the development of better-performing types progressed, even this relatively modest production order would be cut in half.
  The first 23 production examples of the D.VI were accepted at Schwerin in May 1918, and a further 26 followed in June, none in July, and the last nine in August. After 60 aircraft were completed, Idflieg terminated half of their production order in favor of the Fokker E.V.
  Both types were powered by the same engine, but the E.V was faster and had a better rate of climb. Being a parasol monoplane, it also offered better downward visibility than a biplane, and the combination of these three factors spelled the end for the D.VI. Additionally, in all probability it was also easier to manufacture than all previous Fokker types. Thus, production of the D.VI turned out to be very shortlived, making room for the E.V as soon as it passed the customary static loads test.
  By the end of June, 21 Fokker D.VI were listed in the front line inventory, this number modestly increasing to 27 at the end of August. Compared to the 407 Fokker D.VIIs already at the front and 118 Fokker Dr.Is still serving with various units on 30 June, it is readily apparent that the D.VI was not intended to play a major role in frontline combat.
  This is proven by the fact that no Jasta which had been previously equipped with the Fokker Dr.I received the D.VI as a replacement. This role was fulfilled by the Fokker D.VII, which had become the favorite mount of the Jasta pilots in a very short time. Instead, The D.VI was supplied to units serving on “quieter” sections of the front, and to home defense units.
  Royal Bavarian Jagdstaffel 80 was one of the former units. At least six examples were supplied to the Jasta in June 1918 to partially replace their older Albatros D.Va fighters. The pilots were pleased with their new planes, which offered good maneuverability and immediate responsiveness to the controls.
  Few reports of pilots having flown the D.VI are known, but they generally praised the type. However, overall performance of the D.VI was not as good as that of the Fokker D.VII, especially at altitude. The low-powered nine-cylinder rotary engine lost performance at altitude, and sincecombats took place at ever increasing altitudes, this was a considerable penalty.
  Small numbers of the D.VI are known to have been delivered, amongst other units, to Jastas 64, 71, and 75, as well as to several Kests. The fast rate of climb of the rotary-powered fighter made them an ideal candidate for the interceptor role, and the engine required almost no warming up, unlike inline engines.
  The Jagdstaffelschulen also received several examples, but the low number of 60 aircraft produced prevented the D.VI from making a lasting impression, either on the German pilots or their opponents. However, it is interesting to note that no example is known to have been captured intact by the Allies before the Armistice.
  As production of the Fokker D.VI was getting underway, the first examples of a more powerful rotary engine became available. The nine-cylinder 170 hp Goebel Goe.III engine had successfully completed the prescribed 50-hours duration test in April, and twelve D.VI (military numbers 1637/18, 1639/18 & 1640/18,1643/18 and 1679/18 - 1676/18) received the new engine. The Goebel had a slightly bigger diameter (1050 mm) than the Ur.II (960 mm), but was also a nine-cylinder engine. Apparently Idflieg intended to use the D.VI as a frontline evaluation mount for the Goebel, which actually delivered between 165-178 hp depending upon altitude. In theory, the increased performance promised to solve the speed issues while giving an even faster rate of climb.
  Unfortunately, no records or reports of this evaluation have been found, but the facts speak for themselves. No examples of the Goebel engine were later seen in the Fokker E.V when it reached the front in August, and it only reappears later in October 1918 in several prototypes during the Third Fighter Competition in Adlershof. Just before the Armistice, it was intended as the standard powerplant for the Kondor E.IIIa parasol fighter, but by then it was too late.
  The fact that no photograph showing a D.VI powered by the Goe.III serving with a Jasta or Kest is known is also noteworthy. Obviously, the engine was not yet ready for frontline service and required further fine-tuning, just as was initially the case with the Siemens-Halske Sh.III.
  In retrospect, the main purpose of the D.VI was to provide an interim solution that would be an improvement over the triplane and that could make good use of the available Oberursel engines. But the appearance of the simpler, better-performing Fokker E.V parasol quickly ended its short career. Yet its basic design would resurface once more in the shape of the Fokker V.33 just before the end of the war.

Fokker D.VI Specifications
Engine: 110 hp Oberursel Ur.II
Wing: Span upper 7.20 m
Span lower 5.81 m
Chord upper 1.60 m
Chord upper 1.20 m
Gap 1.25 m
Area 17.1 m2
General: Length 5.78 m
Height 2.65 m
Empty Weight 395 kg
Loaded Weight 588 kg
Climb: 1000 m 2.6 min.
2000 m 5.9 min.
3000 m 10.7 min.
4000 m 17.3 min.
5000 m 28.0 min

Fokker D.VI Production Orders
Order Date Qty Serial Nos. Notes
March 1918 120 D.1630-1749/18 60 aircraft, serials 1630-1689/18, were built. The rest were cancelled to produce the D.VIII that used the same engine.
May 1918 150 Unknown Cancelled to produce the D.VIII.

  “The Fokker D.VI aircraft flown by the Staffel during the month of August experienced frequent cylinder seizures of the Le Rhone 110 hp rotary engine. The Fokker D.VI was very maneuverable at low altitudes, but it took about one hour to reach the altitude of 5000 meters. It was very slow and unmaneuverable at these altitudes. In Fokker D.VI 1679/18, one cylinder had seized, because the pilot did not immediately recognize the error and continued to fly at full throttle, tearing the connecting rod from the pistons and pushing the broken connecting rod between the threads of the cylinder and the casing, causing the cylinder to break loose and break the main spar of the lower wing. The aircraft crashed out of control [steuerlos] from about 1000 meters. The Ricinus substitute oil No. B237 [and] B238 has served well as long as the Staffel has flown the Fokker D VI.”
  Source: The Activity Report of the Wurttbg.Jagstaffel Nr. 64 for the period from August 1 to September 30,1918.



Fokker V33

  The Fokker V33 was a small, rotary-powered biplane fighter derived from the Fokker V9 that was tested at Schwerin in August 1918. It was tested with both the 110 hp Oberursel Ur.II (a 9-cylinder engine) and the 145 hp Ur.III (an 11-cylinder engine). Both versions had the same dimensions, but the Ur.III-powered version was heavier due to its heavier engine. The empty weight of the Ur.III-powered version was 396 kg and the loaded weight was 616 kg.
  Fitted with the 110 hp Ur.II, the V33 climb rate approximated that of the more powerful V29 up to 4000 meters, but fell behind above that altitude. Unfortunately, data for the V33 climb rate when fitted with the 145 hp Ur.III are not available.
  After the war, Fokker flew the V33 in Holland. Dutch newspaper reports mention aerobatic demonstrations of what was then described as a sports plane with an 80 hp Le Rhone engine in the summer of 1919.

Fokker V33 Specifications
Engine: 110 hp Oberursel Ur.II
145 hp Oberursel Ur.III
Wing: Span 7.24 m
Area 13.7 m2
General: Length 5.456 m
Height 2.385 m
Empty Weight 360 kg
Loaded Weight 560 kg
Maximum Speed (Ur.II & Ur.III): 200 km/h
Climb (Ur.II): 3000m 7.5 min
4000m 11 min
5000m 17 min
6000m 24 min
Endurance: 1.5 hrs

Fokker V.11

  Keen to evaluate the potential of the new cantilever wing design, Fokker ordered another biplane fighter from his workshop on 20 September 1917. This particular aircraft was assigned the works number 1883, and was given the Fokker designation V11. The basic design of its airframe very closely resembled that of the V9, being enlarged to make up for the additional size, weight, and power of the inline engine. Available photos taken during construction of V11 show that it was, initially at least, powered by a Mercedes D.III engine, which shows clear signs of previous use. This invites suggestion that this engine may have been second-handed from another Fokker aircraft, possibly a D.IV which had been returned to the factory, or maybe even from the V2, V3, V6, or V8 prototypes.
  The rear fuselages of both the V9 and the initial V11 very closely resembled that of the Fokker Triplane, which seems a reasonable design concept considering the initial successes demonstrated by the two Fokker F.Is at the front.
  Unlike the V9, the V11 sported no undercarriage axle wing, indicating this component may have been considered better-suited for the rotary-engined fighters.
  The first performance and weight figures for this aircraft were recorded at Schwerin as early as mid-October 1917, indicating that the aircraft was completed roughly three to four weeks after the experimental workshop received their order.
  Conventional wisdom has it that the aircraft was shipped to Adlershof to take part in the First Fighter Competition on 18. January 1918, a date confirmed by Fokker records. At the competition it was reportedly test-flown by Manfred Freiherr von Richthofen (and others), who universally praised its performance but criticised its lack of directional stability, especially in a dive, as well as its tendency to swing in flight.
  In order to remedy this deficiency, Fokker supposedly rushed over his most experienced welders from Schwerin in order to lengthen the fuselage “over the weekend”, and voila, the modifications turned Vll into the clear winner of the competition.
  While this makes for an amazing narrative, some indications make this story somewhat hard to believe. To begin with, it would imply that the pretty obvious defects mentioned had escaped the attention of Fokker and his team of test pilots at Schwerin over a period of two months. This seems somewhat unlikely, and even more importantly, all available photos of Vll in its initial shape were taken at Schwerin. No known photo taken at Adlershof shows the aircraft in its initial guise.
  Furthermore, when comparing photos of the freshly-completed V11-I to the modified V11-II, which was photographed at Adlershof, it becomes obvious that the modifications did not just comprise of lengthening and deepening the rear fuselage. The wing area was reduced by integrating the ailerons into the wing, adding a cut-out to the wing centre-section, and possibly reducing the chord of the wings. A larger-capacity radiator was fitted, and a 170 hp Mercedes D.IIIa engine now powered the aircraft - the upright air pump ahead of the first cylinder is now clearly visible. The familiar “streaked” camouflage scheme had been applied, but no works number is visible.
  A look at a graph documenting the wing loads of Fokker aircraft shows that a wing load of approximately 34,2 kg/m2 was recorded for V11 in mid-October 1917. By early January, before the aircraft was shipped to Adlershof, a wing loading of around 41,29 kg/m2 was recorded for V11. This clearly indicates that by then, the lengthened fuselage and reduced wing area (now 20.2 m2) had been applied to the aircraft, resulting in V11-II. Interestingly, the wing area of V1-II was now exactly that of the D.VII production aircraft.
  Taking all this into account, the aircraft appeared markedly different from its first appearance, and to this day it is not entirely clear if the photos show a radically-rebuilt airframe or two completely different planes. Certainly, Fokker records only mention the works number 1883 for V11, implying that it was indeed just one aircraft.
  On the other hand, the sheer extent of modifications, which literally cover almost the entire airframe, suggests the existence of two aircraft under the V11 designation.
  After Fokker received his initial production order for the D.VII, V11 was included into this batch of 300 aircraft where it was assigned the military number 227/18. This way, Fokker obtained payment from the authorities for an experimental aircraft which he had originally financed out of his own pocket. All indications are that V11 was destroyed during the type-test procedure at Adlershof in February 1918, where load-tests were carried out on the airframe, proving it to exceed all specified load factors.
  The question whether the V11 or the V18 was the true prototype of the D.VII is impossible to answer. While the V11-II was picked as the winner of the First Fighter Competition, the production D.VII inherited features from both of these aircraft, and a few entirely new details as well. In a way, the V11 and V18 were two parallel paths that eventually merged into the Fokker D.VII by late February 1918.


Fokker V11-II Specifications
Engine: 160 hp Mercedes D.III
Wing: Span 8.72 m
Area 24.0 m2
General: Length 6.90 m
Height 3.05 m
Empty Weight 592 kg
Loaded Weight 821 kg
Climb: 1000m 3 min
2000m 6.5 min
3000m 11 min
4000m 17.3 min
5000m 22.5 min



Fokker V18

  The Fokker V18 experimental aircraft, given the Fokker works number 2116, was closely related to the Vll and must be seen as the second prototype ancestor to the aircraft that eventually entered serial production under the military designation Fokker D.VII.
  From the start, this machine had a taller rear fuselage that already closely resembled that of the later D.VII. Importantly for its flying qualities, it had much enlarged vertical tail surfaces for better stability. The leading edge of the horizontal tailplane was curved, resembling the shape of the component on the early Fokker F.Is. As was the case on the Triplane, the curved leading edge of the horizontal tail surfaces was not adopted for production aircraft.
  The construction order for the Fokker V18 was dated 12 December 1917; work on the aircraft proceeded quickly. It was sent to Adlershof on 17 January 1918, actually a day before the V11 was, in order to participate in the First Fighter Competition. Once again, Fokker records document the aircraft had a 160 hp Mercedes D.III, while photos prove it was in fact powered by a D.IIIa.
  Without a doubt, Fokker wanted to assure that his latest designs were powered by the better-performing engine during the competition.
  On 25 January 1918, V18 was damaged as a result of an accident. As the result of an Oberursel maintenance man making a mistake while adjusting the engine of Fokker V13, which was parked nearby, the rotary-engined prototype made a sudden hop that was halted by the tip of the lower left wing of V18. However, the damage was quickly repaired, and testing of V18 resumed on 27 January.
  Like Vll, the aircraft was missing the axle wing that was a standard component on the Fokker Dr. I, as well as on all of Fokker's 1918 production aircraft.
  After Fokker received his initial production order for the D.VII, the V18 prototype was absorbed into this batch of 300 aircraft, where it was assigned the military number 228/18. However, it is unknown if it was ever fully brought up to D.VII production standards, or if this inclusion into the first batch was merely intended to assure that Fokker would receive payment for his prototype investment.

Fokker V18 Specifications
Engine: 170 hp Mercedes D.IIIa
Wing:
Span 8.72 m
Area 23.1 m2
General: Length 7.03 m
Height 2.9 m
Empty Weight 634 kg
Loaded Weight 860 kg
Climb: 2000m 5.3 min
3000m 10.5 min
4000m 17.3 min
5000m 26.0 min



Fokker V21

  For many years, the true identity of the Fokker V21 had researchers puzzled. It was known that this aircraft had been assigned the Fokker Works Number 2310, but since a rudder showing just this works number was seen on a Mercedes-powered mid-wing monoplane, it was determined that this must have been the V21. Thanks to the research of the much-missed historian Alex Imrie we know that this mid-wing monoplane was, in fact, Fokker V23, Works Number 2443. When said photograph was taken, V23 mounted a “comma"-shaped rudder which was originally fitted to the real V21, and this component was marked with the Fokker Works Number 2310.
  The true Fokker V21 was, in fact, the Fokker D.VII production prototype, and it is termed exactly that in official Fokker records. Unfortunately, the few available photographs of V21 only show it being fitted with the final tail-plane, featuring the tall rudder complete with the fin as seen on the production Fokker D.VIIs.
  In these photos the aircraft is painted in the overall “streaked” scheme known so well from the Fokker Dr.I, which was still in full production at Schwerin when the V21 first appeared in February 1918. Records documenting wing data and engine performance mention the D.VII for the first time during this month, and in this context it is possible to determine that V21 was indeed the D.VII “pattern aircraft”.
  It is noteworthy that the Iron Cross markings were also applied in an identical way to that seen on the Dr.I, being marked on a rectangular white background, a style of application that had become obsolete by an Idflieg instruction dating back as far as October 1916!
  The fact that the initial small rudder, which was apparently first fitted to V21, was then transplanted to V23 proves that even by early February the final D.VII production configuration had not yet been determined. Last-minute modifications were still being carried out then.
  Streaky fabric covering aside, the details seen on V21 match those of the first production D.VIIs, including the wing layout and the type of radiator fitted to the airframe. Some very minor details differed, but on the whole it can be seen as the true “pre-production” Fokker D.VII.
  Unsurprisingly, the overall dimensions recorded for V21 match those of the D.VII.
  On 22 May, V21 aka Werknummer 2310, was sent to Flz.A.Gr 6 (the aircraft testing department) at Adlershof, in order to participate in the upcoming Second Fighter Competition.
  We hear about it one more time on 17 October, when it was sent to the Central Acceptance Commission at Berlin-Johannisthal.

Fokker V21 Specifications
Engine: 160 hp Mercedes D.III
Wing:
Span 8.90 m
Area 20.2 m2
General: Length 6.945 m
Height 2.945 m
Empty Weight 652 kg
Loaded Weight 870 kg
Climb: 2000m 7.0 min
3000m 12.0 min
4000m 19.5 min
5000m 27.0 min



Fokker V22

  After the victory of Fokker’s new D.VII fighter in the First Fighter Competition, Austrian pilots were given the opportunity to fly the first prototype. Fokker wrote to the Austro-Hungarian Fliegerarsenal (Flars) as early as 19 February 1918 that he could deliver 40 D.VIIs a month to Austria if he could get the necessary quota of steel tubes. In four weeks, he wanted to have two samples of the D.VII ready for the LFT. The first was the V22, powered by the 200 hp (19000 series) Austro-Daimler engine and a four-bladed Jaray propeller and steel tube fuselage.
  The V22 carried the Fokker Works number 2342, and this reveals that it was “sandwiched” into the early Fokker D.VII fighters, between 256/18 (w/n 2341) and 257/18 (w/n 2343). As such, it was a series-production airframe that was adapted for installation of the Austrian engine and armament. This is an important fact that has to be kept in mind when reading the later objections brought up by the Austrian authorities against license manufacture of the aircraft.
  A second projected prototype was to have a plywood fuselage, intended as a fallback solution in case a lack of steel tubing would prevent serial production either in Austro-Hungaria or in Schwerin as an “export” version. However, as early as March 1918, Idflieg officer Oblt. Reichelt indicated that a number of wagon-loads of steel tube could be supplied to ensure production at or for the Austro-Hungarian empire. On 2 March, Fokker requested the delivery of two 8 mm Schwarzlose M16s for the V22, which was to receive the latest version of Fokker’s central control system. He had agreed to deliver the V22 readily-equipped to full military standards. Of course, this would allow for an evaluation of the type under realistic circumstances.
  On 15 and 16 March 1918, Austrian Stabsfeldwebel Franz Kuttner flew the V22 at Schwerin-Gorries. Kuttner had previously been a Fokker flight instructor. During these evaluations, a climb time to 3000 meters was recorded in 8 to 9 Minutes, while 5000 meters were reached in 17 1/2 to 19 minutes. The aircraft was reported to have very good flight characteristics, offered remarkably good visibility as was very maneuverable.
  In early April, the Austrian War Ministery purchased the aircraft, which was delivered to MAG on 24 April 1918. Fokker invoiced Flars via MAG on 13 June, the price of the airframe was 30.000 Marks.
  Thorough testing by the Fliegerasenal at Wien-Aspern followed under Austrian military serial number 90.05. Flars representatives were initially opposed to serial production of the aircraft, expecting equal or better performance from their own new or improved fighter designs.
  An Austrian report dated 20 April listed seven points that supposedly prevented production of the type by an Austro-Hungarian manufacturer under licence. These points document an obvious ignorance of facts that can only be explained by a massive bias of the Austro-Hungarian authorities against the Fokker design. For this reason, they are repeated in full here:
  “The aircraft presented cannot be considered to enter series production with us.
  1) The performance should be equalled by our new single-seaters (powered) by the 225 hp Daimler and 240 hp Hiero (engines), possibly even exceeding it. (author's note: This is a reference to the Oeffag D.III, Berg D.I, Phoenix D.III, and WKF D.I fighters)
  2) By the time license manufacture is fully underway (5 months or more) our new single-seaters are already available.
  3) 19000-engines (i.e. the 200 hp variant of the Austro-Daimler fitted to the V22) are no longer in production.
  4) Range is less than that of our single-seaters. In that context, useful load must be reduced in order to increase the fuel capacity.
  5) In spite of the lower useful load, 190 kg versus 240 kg in our planes, the total weight is higher than that of the Berg single-seater.
  6) In terms of structural strength, the Fokker will likely lag far behind our single-seaters.
  7) Installation of machine guns and visibility, especially ahead at eye level, are impeccable, but should be ideally equalled by our new single-seaters.”
  Regarding point 1: For the most part, this remark can be interpreted as wishful thinking. The Oeffag D.III was a licence-built version of the Albatros D.III, a 1916-vintage design that can be considered completely outdated by April 1918. The Berg was structurally weak, even when powered by lighter, less powerful versions of the Austro-Daimler. Finally, the Phoenix was also a design that had reached the limits of further development.
  Regarding 2: As it turned out, the only new design hinted at, the WKF D.I, would not enter frontline service before the end of the war. The other three designs, powered by the 225 hp Daimler and 240 hp Hiero engines, did see service, but were merely evolutions of old and, more or less, proven designs.
  Regarding 3: This objection cheerfully ignores the fact that 225 hp Daimler engine could have been easily installed in the V22 - had an example of it been made available to Fokker. That was not the case at the time. Flars officials obviously feared that it would give the Fokker an improved performance that could not be matched even by the new domestic designs powered by the same engine.
  Regarding 4: The only new design hinted at, the WKF D.I, would not enter frontline service before the end of the war. The other three designs, powered by the 225 hp Daimler and 240 hp Hiero engines, did see service, but were evolutions of old designs
  Regarding 5: Available records indicate that the V22 was indeed tested with a useful load of 190 Kg. Endurance of the WKF D.I was 2 hours and 30 minutes, one hour more than that of the V22, but it weighed 1005 Kg, almost 100 KG more than the V22.
  Regarding 6: By that time, the D.VII had passed all mandatory German load tests with flying colors, and since the V22 was nothing but a modified D.VII these results could be applied to the V22 as well. In spite of this, as late as 09 July, the Austrian authorities noted that the V22 was not cleared to be flown by frontline pilots since calculations concerning structural strength were not (yet) available.
  The Berg D.I had suffered from structural failure of its wings during its entire frontline life, the Oeffag D.III featured a single-spar lower wing versus the V22's double spar lower wing. All Austro-Hungarian designs had wooden fuselages that offered inferior survivability for the pilot in case of a crash compared to the steel-tube fuselage used by Fokker design.
  Regarding 7: Positioning the radiator in the nose of the D.VII meant that no water pipes coming down from the upper wing obstructed the forward view for the pilot, as was the case of several of the competing designs. Mounting the machine guns on top of the fuselage alone did not ensure good forward visibility from the cockpit.
  Aside from the points quoted, this report completely ignores the most important technical advance of the V22: its cantilever wing that rendered rigging wires completely obsolete. In this context it is worth mentioning that all domestic designs that are hinted at in the report (Oeffag D.III, Berg D.I, Phoenix D.III, and WKF D.I) still featured the now obsolete thin airfoil rigged wings.
  V22 took part in the fighter evaluation flight in Wien-Aspern from July 9 to 23, 1918, where LFT pilots were forbidden to fly it, due to a lack of documents proving the structural integrity of the aircraft. This happened at a time when hundreds of D.VIIs were serving without any sign of structural defects in dozens of Fliegertrupper Jagdstaffeln on the Western Front! Therefore, Fokker’s MAG-Chief Seekatz organized a presentation of the aircraft by German Lt. Mallinckrodt to the LFT chief. By August the examination of the Fokker D.VII, as it was now referred to, had been successfully concluded, and orders for Austro-Hungarian use could be placed, at last.

Fokker V22 Specifications
Engine: 200 hp Austro-Daimler (MAG)
Wing: Span 8.90 m
Area 20.2 m2
General: Length 6.945 m
Height 2.945 m
Empty Weight 689 kg
Loaded Weight 908 kg
Max Speed 210 km/h
Climb: 2000m 5.0 min
3000m 9.0 min
4000m 13.5 min
5000m 19.0 min



Fokker V24

  The Fokker V24, Works Number 2612, was a version of the D.VII with a heavier, more powerful, overcompressed 200 hp Benz Bz.IVu engine. After acceptance flights by pilot Gross on 26 April 1918, the V24 took part in the Second Fighter Competition at Adlershof.
  This same engine was also tested in the Pfalz D.XIV, a slightly enlarged derivative of the Pfalz D.XII. However, unlike Pfalz, the Fokker V24 had the same wings as the standard Fokker D.VII. The V24 and Pfalz D.XIV were compared with one another during the Second Fighter Competition. In four climb flights between May 27 and June 13, the Pfalz D.XIV, with a starting weight of 1032 kg, averaged 24.2 minutes climb to 5,000m and the V24, at a starting weight of 1006 kg, averaged 22.3 minutes, results that were roughly equivalent.
  The additional weight of the Benz Bz.IVu offset the advantage of its greater power, and both performance and maneuverability with the Benz Bz.IVu were not as good as with the 185 hp BMW IIIa. Combined with the need for the Bz.IVu for two-seaters, this eliminated further consideration of the Benz engine for fighter use.
  After the climb competition with the Pfalz D.XIV, the V24 was converted to a BMW IIIa engine and after conversion was delivered to ZAK on 17 October 1918.

Fokker V24 Specifications
Engine: 200 hp Benz Bz.IVu
Wing: Span 8.90 m
Area 20.2 m2
General: Length 7.14 m
Height 3.15 m
Empty Weight 750 kg
Loaded Weight 989 kg
Climb: 2000m 6.0 min
3000m 8.5 min
4000m 12.5 min
5000m 16.3 min

Fokker V17

  Fokker’s first cantilever monoplane fighter, the V17, Works Number 2147, was the final rotary-powered Fokker entry in the First Fighter Competition. The construction order of 28 December 1917, issued only three weeks earlier, lists the 110 hp Le Rhone engine as the powerplant. The idea for the development of cantilever monoplanes certainly came from Fokker’s experience flying the breakthrough all-metal J2 monoplane in December 1916 and the two-seat all-metal Junkers J8 a year later on December 16,1917.
  Only three weeks after construction began, the V17 went to the first fighter competition at Adlershof on January 17, 1918, but was subsequently not pursued further. Fokker was able to dispel the pilots’ initial distrust of the monoplane with his aerobatic demonstrations on the V17 at Adlershof.
  The wooden wing had a box spar covered in plywood, giving it a smooth finish and reasonable torsional stiffness for effective aileron control. Powered by the same 110 hp Oberursel UR.II engine used in the Fokker Dr.I Triplane, it was reportedly the fastest fighter at the First Fighter Competition, and was described by pilots as “exceptionally maneuverable”. It also had an excellent climb rate; however, its wing obscured the pilot’s field of view downward, particularly important during takeoff and landing, and it was officially rejected for that reason. A more important reason may have been that monoplanes, especially cantilever monoplanes, were viewed as structurally suspect. On 17 October 1918, after repairs, the aircraft was delivered to ZAK at Johannisthal.

Engine: 110 hp Oberursel UR.II
Wing: Span 8.375 m
Area 11.6 m2
General: Length 5.80 m
Height 2.80 m
Empty Weight 356 kg
Loaded Weight 535 kg
Climb: 1000 m 3.2 min.
2000 m 6 min.
3000 m 9 min.
4000 m 13 min.
5000 m 19 min.



Fokker V19

  According to the Fokker type list, the V19 was a single-seat monoplane with 110 hp UR.II, about which no further information is given.



Fokker V20

  The V20, Works Number 2219, was a mid-wing cantilever monoplane with Mercedes D.III engine for better high-altitude performance. Fokker reports that he ordered the V20 as a variant of the V17 with the more powerful in-line engine in his experimental department only in the course of the first Adlershof competition and that it was built within only one week under the direction of Reinhold Platz in Schwerin and delivered to Berlin, where Fokker demonstrated it.
  According to Platz’s recollections, Fokker called him from Berlin on a Saturday (26 January 1918) and on the following Saturday (2 February 1918) the plane was ready and was flown in by pilot Weidner due to Fokker’s absence. The Idflieg monthly report for March 1918 mentions a Fokker monoplane with an inline engine in flight testing, but states: “The aircraft in its present configuration cannot be used as a front-line aircraft, as the visibility is too poor. For the cantilevered wooden wing with one spar, Fokker documents also state 16.0 m2 wing area.

Fokker V20 Specifications
Engine: 160 hp Mercedes D.III
Wing: Span 9.29 m
Area 15.2 m2
General: Length 7.135 m
Height 3.0 m
Empty Weight 620 kg
Loaded Weight 821 kg
Climb: 2000 m 6.7 min.
3000 m 11.7 min.
4000 m 18.0 min.
5000 m 26.7 min.



Fokker V23

  The Fokker V23, Works Number 2443, was another midwing monoplane design similar to the V20, which had first appeared at the First Fighter Competition at Adlershof in January 1918. Unlike the V20, it had a two-spar wooden wing, but the ailerons were inset into the wings and did not have aerodynamic balances. It was hoped that a new wing profile would improve performance over the V20, but this was not achieved to any great extent. The V23 participated in the Second Fighter Competition in May 1918, where it was shipped on 28 May 1918. In July 1918, Idflieg declined to place a series order for the V23, as it had for the V20. In spite of showing excellent speed and climb, the then-fashionable reservations against mid-wing monoplanes prevented approval for production. On 17 October, after the completion of unspecified repairs, it was delivered to the ZAK (Central Acceptance Commission) in Johannisthal.
  In available photos of V23, the Works Number 2310 is visible on the rudder. As related in the V21 text, this was actually the Werknummer of the V21 prototype. Thus, it appears that the V 21 was initially test-flown without a tail fin. After it was modified accordingly, the surplus comma-shaped rudder was then given a second life on the V23 prototype, Works Number 2443. Obviously nobody saw the need to apply the correct works number to this component since the aircraft had no prospects of being chosen for production. At the time, no one thought of the confusion caused by this small oversight decades later.

Fokker V23 Specifications
Engine: 160 hp Mercedes D.III
Wing: Span 9.01 m
Area 13.6 m2
General: Length 7.81 m
Empty Weight 658 kg
Loaded Weight 877 kg
Maximum Speed: 210 kmh
Climb: 1000m 2.5 min
2000m 8.5 min
3000m 12.0 min
4000m 17.0 min
5000m 23.0 min



Fokker V25

  The Fokker V25, Works Number 2732, was derived from the V17 that had demonstrated such excellent performance at the First Fighter Competition. The V17 wing was mounted in the middle of the fuselage, and to improve the pilot’s downward view the V25’s wing was mounted at the bottom of the fuselage.
  The V25 was entered in the Second Fighter Competition with the 110 hp Oberursel UR.II and was also tested with the more powerful 170 hp Goebel Goe.III engine. Even the 110 hp engine gave it good performance, but again the pilot’s field of view was not considered satisfactory and it was not developed further.
  Dimensions of the V25 with Goebel engine were the same as with the Oberursel but the Goebel engine increased the empty weight to 396 kg and loaded weight to 661 kg. Unfortunately, performance with the Goebel engine is not available. After being overhauled at Fokker, the V25 was sent again to ZAK III at Johannisthal on 17 October 1918.

Fokker V25 Specifications
Engine: 110 hp Oberursel UR.II
Wing: Span 8.13 m
Area 9.7 m2
General: Length 5.89 m
Height 3.02 m
Empty Weight 365 kg
Loaded Weight 565 kg
Maximum Speed: 200 km/h
Climb: 1000 m 1.5 min.
2000 m 3.3 min.
3000 m 6.5 min.
4000 m 9.5 min.
5000 m 13.3 min.

Fokker V26
  
  There is almost no record of the V26 in Fokker or Idflieg orders documented at the time, so its identity is as yet unclear. It is possible that the V26 carried Works Number 2733, which lies between the V25 (Works Number 2732) and V27 (Works Number 2734). Perhaps the V26 was the machine that was used in the period from June 7 to 12,1918, as part of the Typenprufung (Type Test).



Fokker V28

  With the Fokker V28, Works Number 2735, Fokker finally produced another design destined for production as the Fokker E.V. The V28 shared its parasol monoplane configuration with the V27, but was a smaller, lighter machine that was tested with a variety of rotary engines. Its parasol wing solved the pilot’s field of view problem that had led to rejection of the earlier Fokker monoplane fighter prototypes at the cost of somewhat increased drag. Like the V27, the wing was moved above the fuselage just above the pilot’s eye level, giving the pilot exceptional fields of view both above and below the wing.
  The V28 was tested with three different engines during the Second Fighter Competition; the 110 hp Oberursel Ur.II, the 145-160 hp Oberursel Ur.III, and the 160 hp Goebel Goe.III. At this time only the Oberursel Ur.II was in production; the other engines were still in development. The V28 was the winner of the Second Fighter Competition despite its low-power 110 hp Oberursel Ur.II, the same engine that had powered the Dr.I Triplane. Despite its low-power the V28 was fast and maneuverable, and had an exceptional field of view for the pilot.
  From May 27 to 29, the V28 equipped with the Ur.II engine recorded climb times between 19.3 and 21.6 minutes to 5000 meters. On June 6, the V28 equipped with Ur.III reached 5000 meters in 13.4 to 14 minutes. From June 8 to 12, the V28 equipped with the Geo.III engine reached 5000 meters in 10.4 to 15.7 minutes.
  A second V28 [W/N 2738] fuselage went to the Flugzeugmeisterei for strength testing on 17 October 1918. A third V28 [W/N 3860] with the Sh.III Rhemag motor took part in the Third Fighter Competition in October at Adlershof.
  The first mention of an unbraced Fokker monoplane with a 160 hp Gobel engine is in the April report of Idflieg, which notes that the aircraft climbed to 5000 m in 11 minutes according to factory data. Since the use of the Goe.III rotary engine in a monoplane is so far only known for the V28, it must have been this model, although no further information was found on the attempt.
  Already in the next Idflieg monthly report in May, it was decided to build the Fokker Parasol monoplane with 110 hp Ur.II engine as the E.V instead of the 60 D.VIs not yet delivered from the order for 120.

Fokker V28 Specifications
Engine: 110 hp Oberursel UR.II
145-160 hp Oberursel UR.III
160 hp Goebel Goe.III
160 hp Rhemag Sh.III
Wing: Span 8.34 m
Area 10.7 m2
General: Length 5.865 m
Height 2.82 m
Empty Weight 360 kg
Loaded Weight 560 kg
Maximum Speed (UR.II): 200 km/h
Climb (UR.II): 3000 m 7.5 min.
4000 m 10.5 min.
5000 m 14.7 min.
6000 m 19.5 min.

Fokker V27

  The Fokker V27, Works Number 2734, was another attempt to achieve the performance benefits of the monoplane configuration while solving the pilot’s field of view problem that had led to rejection of the earlier Fokker monoplane fighter prototypes. In the V27, the wing was not mounted on the fuselage, which minimized aerodynamic drag, but was moved above the fuselage just above the pilot’s eye level, giving the pilot exceptional fields of view both above and below the wing.
  The V27 was powered by the experimental 195-200 hp Benz Bz.IIIbo ungeared V-8 engine. It had good performance but the experimental V-8 engine was not yet reliable enough for production and the V27 remained a prototype. Built in April 1918, the V27 was sent to the Second Fighter Competition and was assessed as the best fighter at the competition using the 200 hp Benz Bz.IIIbo. However, vibration prevented production of this engine to the Armistice.
  The V27 was shipped to Idflieg department A3 after it was repaired.
  Interestingly, the Fokker V29, one of the winners of the Third Fighter Competition, used the same configuration as the V27; the main difference was that the V29 used the reliable, production BMW IIIa engine instead on an experimental Benz V-8 engine.
  Low drag was the key benefit of cantilever monoplane wings, and the parasol configuration combined that with exceptional field of view. The drawback was that the cantilever wing, even if strong enough to safely support the aerodynamic loads, was not as stiff in torsion as the biplane wing cellule with N-struts, with the result that aileron effectiveness was not as good as that of a biplane.

Fokker V27 Specifications
Engine: 195-200 hp Benz Bz.IIIbo
Wing: Span 9.68 m
Area 14.3 m2
General: Length 6.34 m
Height 3.0 m
Empty Weight 602 kg
Loaded Weight 840 kg
Maximum Speed: 200 km/h



Fokker V29

  After winning the first two fighter competitions, Fokker entered the Third Fighter Competition in the best position of any manufacturer. The Fokker D.VII was the mainstay of the German fighter units and the BMW-powered version was generally acknowledged as the best all-around fighter in combat. Fokker’s D.VII was being built not only by Fokker but by two other manufacturers under license. After a rocky start due to two fatal wing failures, Fokker D.VIII production was back in full swing.
  Fokker’s entries in the third competition built on these successes. The V28 was a D.VIII prototype with the more powerful 160 hp Siemens-Halske rotary, the V36 was a modified D.VII, and the V29 (Works Number 2736) was a parasol monoplane derivative of the D.VII that was a high-altitude fighter.
  As early as June 1918 the V29 was mentioned in the Idflieg monthly report as it was undergoing flight testing equipped with the BMW IIIa engine. In July Idflieg stated that, according to the results of the flight tests, the aircraft in its present form was not yet suitable as a replacement for the Fokker D.VII with BMW engine. The V29 was tested with two different wings of 13.3 and 14.3 square meters wing area.
  Using the same basic configuration as the production D.VIII, the V29 was evaluated at the Third Fighter Competition with both the over-compressed BMW IIIa and Mercedes D.IIIau engine for excellent high-altitude performance and was one of the winners of the competition, the other being the Rumpler D.I. However, with fresh memories of the D.VIII wing debacle and with the robust, proven D.VII still superior, Idflieg was in no hurry to order the V29 into production and had not done so by the Armistice. Similarly, the troubled Rumpler D.I never reached mass production.
  
Fokker V29 Specifications
Engine: 185 hp BMW IIIa
Wing: Span 9.68 m
Area 14.3 m2
General: Length 7.02 m
Height 2.93 m
Empty Weight 632 kg
Loaded Weight 861 kg
Maximum Speed: 200 km/h
Climb: 3000m 7.5 min
4000m 10.5 min
5000m 14.7 min
6000m 19.7 min



Fokker V30

  The V30 was a cantilever parasol monoplane (w/n 2737) with a plywood wing powered by Benz Bz.IIIbm geared V-8 motor of 195-200 hp.
  The V30 was sent to Adlershof on July 25, 1918 for evaluation and went there again in October for strength testing. According to the Fokker factory, the V30 was also tested with two different sized wings of 13.3. and 14.3 square meters wing area.
  No photo of the aircraft has been found. Its description sounds much like the V27 only powered by the geared version of the experimental Benz V-8

Fokker V30 Specifications
Engine: 195-200 hp Benz Bz.IIIbm V-8
Wing: Span 9.68 m
Area 13.3 m2
General: Length 6.535 m
Height 3.075 m
Empty Weight 652 kg
Loaded Weight 882 kg
Maximum Speed: about 200 km/h
Duration: 1.5 hr


  
Fokker V31

  A Fokker document “New Constructions and Test Machines” written during the war refers to the V31 as a two-seat parasol monoplane with wing area of 16.5 square meters and 185 hp BMW IIIa engine. No more data has been found.
  The V31 sounds like it may have been an enlarged, two-seat derivative of the V29.



Fokker V32

  No documented information is known.



Fokker V37
  
  Derived from the earlier Fokker V27, and like it powered by a 195 hp Benz Bz.IIIb liquid-cooled V-8 engine, the Fokker V37 was an armored fighter designed for low-level fighting and ground attack.
  Clearly the radiator had to be protected from ground fire to make an effective armored airplane, and the V37’s solution was clever. The radiator was mounted behind the propeller and protected by a disk of armor. The propeller was given a large spinner for streamlining, and air was forced through the radiator by six fan blades mounted in the plane of the propeller. The spinner was made of aluminum sheet and an armor plate disk. Fokker received Reichs patent No. 335745 on 2 October 1918 for an armored propeller spinner with ventilator-like slots.
  The entire forward fuselage, including the engine and cockpit, was protected by steel armor plate 2.5mm thick. The armor behind the pilot even extended up behind his head and was faired into a headrest.
  Had the V37 design progressed, it would certainly have been fitted with the standard fighter armament of two synchronized machine guns. However, the V37 arrived too late to be evaluated, let alone produced in quantity, so its performance and flying qualities are not known. Even its dimensions are unknown.

Fokker V37 Specifications
Engine: 195 hp Benz Bz.IIIb V-8
Wing: Area 17.0 m2

Fokker V34
  
  The Fokker V34, Works Number 3254, was a refined, slightly smaller development of the Fokker D.VII to improve its performance. Its oval radiator and two distinct designs of rudder are its most easily noticed differences, but perhaps the most important was reduced wingspan and reduced chord upper wing that eliminated the need for a center-section cutout. It was built in September 1918 and on October 10 was sent to participate in the Third Fighter Competition, but it was not selected as the winner, indicating it was not a significant improvement over the standard D.VII, which remained in production until the end of the war. Power was provided by the BMW IIIa, the best inline engine available at this time.

Fokker V34 Specifications
Engine: 185 hp BMW IIIa
Wing: Span 8.45 m
Area 17.6 m2
General: Length 6.76 m
Height 3:01 m
Empty Weight 628 kg
Loaded Weight 864 kg
Maximum Speed: 200 km/h




Fokker V36

  Analysis of the information available on the V36, Works Number 3256, indicates that it was as closely related to the V34 as the V18 was to the Vll, and the V27 was to the V28 and V29. Following the adoption of the cantilever wing, Fokker had obviously become inclined to develop pairs or even trios of prototypes that were closely related to one another.
  Visually, the V36 was closely related to the D.VII. The rear fuselage, including the horizontal tail surfaces, fin and rudder were almost identical, but the fuselage was about half a meter shorter compared to the D.VII. The forward fuselage, with its oval engine cowling and radiator, closely resembled that of the V34. The lower wings appeared to retain the layout seen on the D.VII, while the upper wing had a reduced chord, resulting in a smaller wing area.
  The fuel tank was relocated into the undercarriage axle wing fairing, which was intended to reduce the fire hazard to the pilot. Like the V34, it was built in September 1918, and together they were shipped on 10 October 1918 to participate in the Third Fighter Competition. Again, detailed information concerning the assessment of the type by the participating pilots is not available, but it was not selected as one of the winning designs.

Fokker V36 Specifications
Engine: 185 hp BMW IIIa
Wing: Span 8.935 m
Area 17.6 m2
General: Length 6.46 m
Height 3.045 m
Empty Weight 637 kg
Loaded Weight 871 kg
Maximum Speed: 200 km/h
Climb: 1000m 1.75 min
2000m 4 min
3000m 6.75 min
4000m 10 min
5000m 13.5 min
6000m 18.25 min
Endurance 1.5 hr.