Okay, a compromise ... partial spats
Interim Fokker Fighters - the Fokker D.26 4e Serie and SD.1 Combat TrainersRepublican Spain had purchased a production license to produce the Fokker D.XXI. This D.XXI variant differed from most in its choice of engine. In place of the usual Bristol
Mercury, Spanish D.XXIs were to be powered by the Wright
Cyclone - either US-built 775 hp powerplants or Soviet 710 hp M-25 radials. Production was begun at La Hispano Aviaciòn’s San Vincente del Raspeig facility near Alicante. Only one Hispano-built D.XXI was ever flown (its further fate going unrecorded). The remainder of this initial batch were still on the production line when the factory was overrun by advancing Nationalist forces in 1938.
Through circuitous contacts, NV Ned. Vliegtuigenfabriek cautiously approached the Spanish Nationalists about purchasing the Hispano parts. In early 1939, an offer was made to purchase all Spanish-built D.XXI components through a Mexican intermediary. A deal was struck and remaining Hispano components were crated and sent to the port of Alicante for shipment. To skirt Dutch embargo regulations, the crated D.XXI components were loaded aboard a Mexican-flagged cargo ship bound for Cuba. [1] In Havana, the parts were transferred to a Dutch-registered cargo vessel sailing home from the Dutch West Indies.
'Improvements?' - Renovating la Caza de FokkerHispano had planned to built 24 D.XXIs for Spain's Republican government. Only one Spanish aircraft was completed and flown (but its subsequent fate goes unrecorded). Of the remaining components, several airframes were incomplete and no
Cyclone (or Soviet M-25) engines were included in the sale. Fokker's original intentions for the Spanish components were a little fuzzy. The initial concept was to complete the airframes as Wright-powered D.XXIs for quick export (by the beginning of 1939, many European air forces were desperate to re-equip with modern fighters). But plans shift ...
Fokker was over-loaded with work in 1939 and the MvD was becoming impatient with both the delivery rate of D.26 fighters and the repair schedule for several damaged LVA D.XXIs. In meetings between MvD officials and Fokker staff, it was agreed that the Spanish components would be redirected to the LVA. The two most complete Spanish-built airframes were fitted with
Mercury engines as interim LVA D.XXI replacement aircraft. Other components were used to more quickly repair three damaged LVA D.XXIs.
'Laagdekker jachtvliegtuig met intrekbaar landingsgestel' - the Fourth FokkerSix semi-finished Spanish airframes would be completed with new wings as D.26 4
e Serie fighters. [2] These aircraft were more closely related to the 1
e Serie than to the later-model D.26s. Minor differences in the 4
e Serie resulted mainly from the use of Hispano's parts. The engine installation was identical to the 1
e Serie D.26 but to speed development, the 4
e Serie aircraft only mounted two machine guns. [3]
There were individual differences within the D.26 4
e Serie batch as well. The first two 4
e Serie fighters received reconditioned Mercury VII engines with added interrupter gears (the rest got
Mercury VIIIs). D.26 4
e Serie nr. 256-259 were armed with twin 7,9 mm FN-Browning guns. The final pair -
nr. 260-261 - got two 13,2 mm FN-Brownings (weapons intended to arm 3
e Serie fighters) as well as reflector gun sights. All of the 4
e Serie D.26s were equipped for radio transmitters but none actually received an R/T set before 10 May 1940.
All six D.26 4
e Serie fighters were delivered to the 3
e Jachtvliegtuig Afdeling replacing D.XXIs. Moving from Soesterberg to Ypenburg, 3e JaVa became a mixed squadron. Despite its 'fighter squadron' designation, part of 3e JaVa was on hastily imported Northrop 8A1 attack aircraft. Introduction of the D.26 brought 3e JaVa back to real fighters but the Fokkers' primary role would be to escort the Northrops. This was made difficult with the lack of radios but that (and the reduced) armament also made the D.26 4
e Serie a lighter, more spritely fighter.
(
Bottom) D.26 4
e Serie of 3e JaVa deployed to the emergency airfield at Ockenburg in early March 1940. Note that the 'Neutrality' markings prescribed in November 1939 have yet to be completely applied. The '4e' cowling marking was to alert armourers to 13,2 mm ammunition requirements.
Les- is More -- the Fokker SD.1 Lesvliegtuig (Lesson Plane)The decision to complete Spanish-built D.XXI airframes as D.26s left Fokker with surplus wings and fixed undercarriages. Ir. Alfred Gassner had already begun design work on a D.XXI-derived 2-seat trainer.
Ontwerp 197 was to be a general trainer powered by a 400 hp Wright R-975
Whirlwind. For this design to work as a fighter-trainer, it was decided that more power was needed. Accordingly the
Ontwerp 197 (B) was evolved, powered by a more powerful 600 hp Pratt & Whitney R-1340
Wasp S1H1-G radial.
Originally, the
Ontwerp 197 (B) was approved for LVA use as the Fokker S.11. However, before the prototype could fly, a new designation was adopted - SD.1, for the first dedicated fighter-trainer type. Being constructed almost entirely from modified Spanish parts, SD.1 production was quickly accomplished. [4] Six SD.1s were delivered to the LVA at Soesterberg by May 1940. All were then dispatched to De Zilk to serve as lead-in trainers for 5e JaVa.
In a change of plans, it was concluded that the SD.1s should be based at the training base at
Vliegpark Vlissingen alongside Fokker S.IV and S.IX biplane trainers. This move was scheduled to begin on 15 May 1940, with the SD.1s resuming operations by the end of the month. Fate, however, would intervene ...
(
Top) Fokker SD.1 two-seat trainer, attached to 5e JaVa, De Zilk in Zuid-Holland, 01 May 1940. The overall orange colour scheme of SD.1s was intended as an obvious 'Neutrality' marking.
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[1] Through this ruse, NV Ned. Vliegtuigenfabriek was able to legally 'buy' these components from a Cuban handler.
[2] The fourth series was out of numerical sequence because the MvD had already issued orders for improved 2e and 3e Serie D.26 fighters for the LVA. The serials for the D.26 4
e Serie aircraft were originally assigned to a third batch of 1
e Serie (which was cancelled in favour of the 4
e Serie).
[3] It was concluded that changes needed to introduce gun bays into the lower fuselage sides would result in excessive delays in service entry.
[4] The follow-on 2
e Serie, the SD.1A, were to be built entirely from Dutch-made parts. Twelve SD.1A were ordered by the MvD in April 1940 but production work had yet to commence when the German invasion began.
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