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Typenumber F.IX
Type of aircraft
Country The Netherlands
Date first flight 23 August 1929
number of passengers 18

The F.IX also served with the Czech Air Force not as a commercial airliner but as a bomber. The Czech aircraft manufacturer Avia acquired license rights to the type and immediately developed a bomber version under the esignation F.39.

How many F.39's Avia built is uncertain. Two military registrations have been identified and a photo exists which appears to show five F.39's. The English magazine Air Enthusiast of February 1973 referred to twelve F.39's for the Czech Air Force plus two for the Yugoslav Air Force, and illustrated a Yugoslavian F.39. Avia also built two F.IX's as commercial aircraft.

Equipped with three Czech Walter Pegasus II engines, these were sometimes referred to as F.IXDs (D = Daprovni = Transport). Avia delivered the first aircraft to the Czech state airline company CSA (Ceskoslovenske Stetne Aerolinie). This machine crashed on 11 September 1937 and was replaced by another aircraft, probably a rebuilt bomber.

The second commercial aircraft delivered was captured by the Germans in 1939 and was provided with a German registration. One aircraft (probably another rebuilt bomber), did service as the personal transport of Air Force General Ing. Jaroslav Fajfr. In addition to the bomber version, Avia in 1933 had developed a further special variant.

This aircraft, identified on drawings as the Avia B.139, was designed to be powered by only two engines. The design did not get beyond the drawing board.

Fokker F.IX

In October 1929 the F.IX PH-AGA received its certificate of airworthiness following which Fokker immediately flew to London with his latest commercial aircraft

Fokker F.9 at Waalhaven, just prior to take-off

Comfortably-upholstered interior of the Fokker F.9

Military version of the F.IX, build in Thechoslowakia as Avia F.39

An F.IX bomber built by Avia and also designated F.39

Victim of the crises years

A good aircraft for its time, but unfortunately the time itself was not so good. This could be said to suitably describe the fate of the F.IX. It was the largest three-engined aircraft to be built by Fokker in Holland, and the general economic situation resulted in it being too big for the airlines.

Only two F.IX's were built and the real interest in the aircraft came from Czechoslovakia where the type was put into service mainly as a bomber.

Looking back to 1924 when the F.VII HN-ACC first flew, there was still a long way to go before there would be talk of a regular service between Holland and the Dutch East Indies.

It was to be the end of 1930 before the KLM 'life line' (as the route was called) became a reality.

It was not just a matter of technology because aircraft had meanwhile advanced sufficiently to be technically capable of bridging such distances.

It was much more a matter of the enormous organization required at the many airfields along the Indies route where aircraft had to make intermediate stops. Spare parts had to be available and passenger handling facilities had to be provided.

All this meant that KLM had to look out for trained personnel, hangar space and suppliers of fuel, oil and catering services. Albert Plesman knew what was needed to enable KLM to capitalize on the great possibilities offered by the Indies route.

He foresaw that the various versions of F.VII would soon be too small and so as early as 1925 he asked Fokker for a larger aircraft. He wanted a twenty-seater and this led to protracted negotiations.

KLM exercised considerable influence on the design and this did not always make life easy for Fokker's designers. They fully realized however the importance of taking the wishes of KLM into account. And the aircraft would hopefully be of interest to other airlines as well. Fokker test pilot Meinecke took the F.IX off on its first flight on 23 August 1929.

As early as 26 August, I.A. Aler of KLM and H.J. van der Maas of the Dutch government's Study Department for Aviation made a series of nine flights, each time with a heavier load onboard.

The three-page test report was remarkably lenient in what it said. It contained no major criticisms but only such comments as the steering wheel should be slightly larger, an adjustable stabilizer was recommended, and the rudder bar was rather too low etc.


In October 1929 the F.IX PH-AGA received its certificate of airworthiness following which Fokker immediately flew to London with his latest commercial aircraft. There, the compass of the F.IX was checked for deviation, involving placing the aircraft on a large turntable such as was not available at Schiphol.
This visit to London was also used to catch the attention of the airlines and press. Although the F.IX attracted plenty of praise, it did not win any orders. In fact this was not the fault of the aircraft: 30 October 1929 was the date of the great New York Stock Exchange crash and the start of the crisis years. Economical uncertainties made airline managements cautious about investing in new equipment. Technically the F.IX was not revolutionary.

At first sight the design seems little more than an enlarged F.VIIb-3m. With the F.IX, wooden wings covered with plywood were again used, and the fuselage was a welded-steel tubular structure with fabric covering.


The cabin accommodated three rows of seats - a single row on the left and a double row on the right. The comfortable interior was designed by the firm Mutters.

The undercarriage had a track width of 23 ft in to provide ample stability on the rough airfields that were to be expected along the KLM Indies route.

The cockpit was fully enclosed, although the side windows were not installed during the initial flight.

At the aft end of the cockpit the lower side of the wing leading edge was cut away to accommodate fuel gauges and shut-off valves.

In its day, the aircraft was regarded as very attractive.

At the 1930 Paris Air Show the F.IX won the 'beauty' contest - or as it was officially termed "Grand Prix de Comfort et d'Elegance d'Avions de Transport".

The aircraft won 17 out of the maximum of 20 points the public could award.


Despite the considerable influence that KLM had on the design, airlines were not generous with their orders. At Fokker, Bruno Stephan showed his displeasure in a letter to KLM in November 1935, writing "As early as 1925 you were saying that KLM needed an aircraft seating 20 passengers and equipped with three 450 hp engines. After several designs had been discussed, technical agreement was reached in 1926 on the F.IX type.

When the aircraft was ready in 1929, you asked us to let you know the price and advised us that you wanted to have a further two F.IX's available by around 15 April 1930. During a meeting that followed, you informed us that in the course of 1930 you would be ordering five more F.IX's. Although after modification of the luggage space the F.IX was a very good and effective aircraft, you finally ordered only one F.IX".

At the beginning it had all looked so favorable.


Not only the previously-mentioned test reports from Aler and van der Maas gave confidence but Plesman also boosted the optimism by announcing, during a press conference in 1929, the possible purchase of ten F.IX for 'his' Indies route. However, things never got as far as that. KLM had to take the consequences of the depression into account which meant that the F.IX was too big for the airline. After acquiring two aircraft, further purchases were superfluous.

Nor did it pay to have a large stock of spare parts and other equipment along a route operated by only two aircraft. With this, the ambitious plans of KLM for this Fokker 'bird' on the Indies route completely fell through. Both F.IX's came to be used on the European network. KLM did not accept Fokker's offer in 1931 to supply the F.IX with Pratt & Whitney Hornet engines. And Plesman would have been the last person to be interested in an F.IX with floats - for which there are drawings in the Fokker archives.

Indies route

Despite all of this, both of the KLM F.lX's made one flight each to the Indies. The first, PH-AGA named 'Adelaaf' (Eagle), departed on 13 November 1930 on a 13-day flight to Batavia. The crew consisted of pilots Smirnoff and Aler, radio operator Strijkers and flight engineers Westrate and Waalewijn. On 5 February 1931, PH-AFIC followed with Hondong and Pellens on board as pilots, and Weber and de Jong as flight engineers. The radio operators were Hegener of the Nederlandsche Seintoestellen Fabriek (NSF), and Pronk of Radio Holland.

This second aircraft returned to Schiphol on 20 March 1931 after having overcome a series of technical snags. Bulky radio equipment was carried onboard both flights, enabling extensive transmission tests to be successfully performed. The papers reported that "signals were received at either Schiphol or Bandoeng, Java each day". On 4 August 1931, PH-AFK crashed at Waalhaven. Shortly after the aircraft had taken-off, the left engine stopped.

The pilot Pellens endeavored to return to the airfield but unfortunately impacted with a tall airfield lighting structure. Although the machine was damaged beyond repair, only two out of the 13 passengers were slightly injured.

The sister aircraft PH-AGA continued in existence and was frequently operated on the Amsterdam-London route through to 1936. KLM had meanwhile replaced the elderly Jupiter power units with Pratt & Whitney Hornets. In 1934 the center engine was temporarily replaced by a Wright Cyclone to provide experience with this type of engine.


In the course of this latter change, the EEK was fitted with a 3 ft 3.5 in longer nose such as the PH-AFK had had from the beginning.

This enabled an extra luggage compartment to be fitted between the fireproof bulkhead and the cockpit. An added bonus of this modification was a more favorable positioning of the center of gravity. KLM further replaced the tail skid with a wheel. In 1936 KLM got rid of its remaining F.IX to a Frenchman, Alain Pilain. In the Dutch press, notices appeared to the effect that the aircraft had been sold to Air Tropique, a French company which in fact did not exist.

Pilain was acting on behalf of SFTA (Société Française de Transports Aériens). This organization was a cover for the purchasing agency of Spanish Republicans in Paris who had an urgent need for aircraft. In October 1936, the F.IX together with an F.XII, F.VIII and an F.XX, was seen at Le Bourget airfield near Paris. To keep up the masquerade, the Spaniards gave the F.IX a French registration.

Even so, in France it was definitely known by insiders and almost certainly in the Netherlands too that Spain was the intended destination for PH-AGA.

The Spanish Republicans equipped the aircraft with bomb racks and machine guns, and used it in the bloody Civil War against Franco's Nationalists. The F.IX survived the war and after defeat of the Republicans by the Nationalists, did service with Franco's Gruppo 45.