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Type	F.XIII.
Type of aircraft	Passengerplane on floates
Country	The Netherlands
Date	1928/1929, drawing, not build
Crew	2
Number of passengers	10
Wingspan	25.80 m
Lenght	17.20 m
Height	4.30 m
Enginetype	2 x Bristol Jupiter
Engine power	450 hp
Cruise speed	150 km/h
Max take-off weight	6700 kg
Empty weight	4500 kg
Range	650 km

Fokker F.XIII

Airliner on floats

In the 'twenties, many factory premises were located near water. Trucks were not yet in widespread use and boats were the most convenient means of transportation for raw materials and finished goods.

It was natural that businessmen who visited the enterprises, traveled overland. In principle though, these businessmen could equally well have journeyed by air, using water-based aircraft. Between 1920 and 1930, this possibility triggered the development of several types of flying boats and floatplanes. Demand proved to be rather limited however and the majority of these business planes achieved little or no success. Anthony Fokker was not an enthusiast for water-based planes.

This view was strengthened by his earlier fruitless efforts to sell float versions of his F.VIII and F.IX. But he felt that the Netherlands East Indies with its many islands and long distances could be a potential market. The F.XIII was designed with this particular application in mind. The oldest remaining document on the F.XIII, dated 21 May 1928, is shown on this page.

The drawing depicts a high wing machine powered by two Bristol Jupiter engines. It was only logical that Fokker chose a floatplane configuration rather than a flying boat: floatplanes are supported on the water by their floats, but flying boats, with no floats, have their fuselage, or hull, directly in the water.

This would have caused problems with the then-standard Fokker fuselage comprising a steel tube structure covered by fabric. Fokker could of course have introduced new ways to build his fuselages but the costs would not have been recovered by the - at best - limited production that was to be expected.

The wing of the F.XIII was to be in keeping with Fokker traditions: an allwood structure covered with plywood. To keep the tail surfaces free of water spray, they were (in the words of a Fokker brochure) 'pulled up'.

In America some Fokker Universals and Super-Universals had been floatequipped. Based on experience with these aircraft, it was decided that the F.XIII would have a fullyenclosed two-man cockpit.

Nacelles

The short stubby nacelle of the F.XIII engines was a rather odd design feature, looking old-fashioned even in those days.

The nacelles have a distinct similarity to those that were originally envisaged in 1925 for the F.VIIa when that aircraft was to be converted to the trimotor F.VIIa-3m. At that time, Reinhold Platz, Fokker's chief designer considered them too risky aerodynamically.

Had the F.XIII been built, it is doubtful that this would have been the definitive nacelle configuration, but the floatplane never passed the design stage.

There probably never were any serious discussions with potential customers and no documents remain to suggest there were.

The design performance of the F.XIII was not up to that of even the Fokker F.VIIb-3m.
No doubt because of its floats, the F.XIII was heavier and slower, and its fuel consumption would have been higher, making it a not very attractive proposition. Aside from that, the Fokker factory had plenty of other work in hand at the time the F.XIII was designed. With hindsight the floatplane can be seen to have been what today would be called a design study by the Fokker preliminary design.