Van Berkel W - B The Van Berkel W - B was a single engine Dutch long range reconnaissance seaplane built in the early 1920s for work in the Dutch East Indies . Six were operated by the Dutch Naval Aviation Service ( MLD ) with disappointing results , though the last two were not decommissioned until 1933 . Design and development . As neutrals in World War I , the Dutch armed forces experienced difficulties in obtaining military aircraft from abroad . To ease the problems of both the Dutch Army Aviation Group ( LVA ) and the MLD , in August 1917 the Ministry of War encouraged companies like the car makers Spyker to become involved in aircraft production . The only other manufacturer to volunteer was Van Berkel ' s Patent Company Ltd , formed to make meat processing cutters . They began by building the Hansa - Brandenburg W . 12 floatplane fighter under licence as the Van Berkel W - A , then in 1919 the MLD invited to company to design and build a long range reconnaissance floatplane for use in the Dutch East Indies , based on the Hansa - Brandenburg W . 29 . The resulting Van Berkel W - B was broadly similar to the W . 29 but both larger and more powerful : its span was increased by more than 40 % and it had a 360 hp rather than a 150 hp engine . The W - B was a braced low - wing monoplane with wings of constant chord . These were braced from below with pairs of parallel steel tube lift strut s on each side , assisted by small jury strut s , connecting the wing to the top of the appropriate float . Each float was mounted on the fuselage lower longerons by basically N - form struts , the leading member doubled into a narrow V , sharing common junctions with both the wing struts and two horizontal cross braces between the floats . Two more V - form struts linked the centres of the cross members vertically upwards to the lower fuselage . The floats , with rounded noses , three steps and vertical stern posts were made of aluminium alloy since wood degraded rapidly in tropical waters . The fuselage was of simple , rectangular cross section . The 270 kW ( 360 hp ) Rolls - Royce Eagle VIII water - cooled V - 12 engine was installed in the nose with its upper cylinders exposed and a long external exhaust down the fuselage starboard side . Underneath the nose there were two " lobster pot " style Lamblin radiators . The pilot sat in an open cockpit just aft of the engine , with a second cockpit for the gunner some way behind . The fuselage remained deep and high sided back to the tail , possibly offering some directional stability in the absence of a fixed fin . The tailplane was mounted on top of the fuselage just ahead of the extreme tail , where an unusual rudder which extended both above and below the fuselage was hinged . This was one of the features that visually distinguished the W - B from the W . 29 , on which the rudder was entirely below the top of the fuselage . The aviation department of Van Berkel Patent was closed in June 1921 and the proposed civilian version of the W - B , the W - F was never built . Operational history . The W - B flew for the first time on 3 September 1920 . After testing , which showed that the specification parameters were met , six production aircraft were delivered to the MLD . The last went to the Priok Naval Air Station in Indonesia in December 1923 . Their performance in operational conditions was disappointing , with poor flight characteristics and the first four were withdrawn from service in 1926 ; the last two remained in use for another seven years .