Walraven aircraft and projects (Netherlands)

Simply fabulous! Thanks for sharing these rare articles with us.
 
Thanks to Jan for this article. I had a quick read of it and it is most interesting. If any of you want an English translation, let me know as I could do that although it might take some weeks as I am kind of busy right now.
 
Bedankt Jan ,

A very welcome addition to the Walraven story.
It seems that you have access to the vintage magazine 'Vliegwereld'..?
 
Reading an article in an older Dutch magazine "A&K-Lucht en Ruimtevaart" January 1982 about the life
and times of Laurens Walter Walraven and his aircraft.Not much new was found , but about the
Walraven W-5 , the author Gr.J.V. Van Lonkhuyzen states that it should be constructed in
two variants. One was for a liason/airtaxi and the other a sportsplane version.
According to the author , his article was based on a two part feature which was published
in Indonesia ,former Dutch Indies, in the magazine "Tong,Tong" issues 5 & 6 of 1977.
 
Translation of the Cockpit article kindly provided by Jan den Das. I'm not a professional translator, I may have fudged some bits. Information in the photo captions is mostly duplicated by the text, apart from the W-2 being painted blue and silver.
Lark has already mentioned W-5 variants; these are confirmed by the text.

A promising Dutch aircraft maker:
L.W. Walraven
by
Hugo Hooftman

COCKPIT thanks Mrs. L.W. Walraven-Boeschoten for allowing us the interview and for allowing publication of the exclusive images and documents provided by her. Furthermore, our thanks to our Cockpitter E.A. Frank from Amsterdam, who introduced us to Mrs. Walraven, and also made his Walraven collection available to COCKPIT.

It is remarkable so relatively little has been published, both by national as well as international aeronautical press, about Dutch aircraft maker Laurens Walraven. Thanks to the cooperation of Mrs. Walraven, we would like to dedicate half a COCKPIT to the Walraven-aircraft, to present our readers with a more or less complete overview of Laurens Walraven's achievements as an aircraft maker. In many ways, Walraven was a pioneer. He built the first aircraft in the then Dutch East Indies. His ideal was the creation of an aircraft industry in that country.

Walraven was a pioneer of the business aircraft. It is a pity he died so young, during the war, as a Japanese prisoner on his way to the Burmah-railroad.
Walraven was planning to go to America after the war. America, the country where business aircraft took great flight after the war. Such a future Walraven could have made for himself there. Alas, this promising aircraft maker departed from us too soon. But the aircraft he designed and built are worthy to be brought to attention again. Therefore we will dedicate a large part of this COCKPIT to Laurens Walraven and his aircraft. After Fokker and Koolhoven, Walraven undoubtedly was our best achieving aircraft maker, even if none of his designs were ever produced in series. We could call Walraven the first Dutch "homebuilder". Because he only built in his spare time...
He was born in 1898, in Amsterdam. Aviation must have attracted him early, because after an initial job as a draftsman with the Schutte en Van Bakel coachworks, in February 1916 he joined Spijker (Trompenburg), where he worked as a draftsman on the Farman, Nieuport and Spijkers. Because the Spijker works were not destined for a long existence, by January 1, 1919, he transferred to Van Berkel's Patent, who, apart from meatgrinders and scales, were also licence-producing Brandenburger WA- and WB-aircraft. The factory's technical manager was Ir. Von Baumhauer, who later became director of the Dutch Aviation Authority and perished in the USA when a Boeing Stratoliner crashed during a test flight. Von Baumhauer gave Walraven evening classes, from which he learned much. When Von Baumhauer left, Walraven succeeded him as plant manager in November 1919. When this aircraft factory also ceased to be, Walraven left for Carley's new factory in Ede, where Carley also had a flying school (sometimes doors for surrounding villas were made here, in stead of aircraft). Here, Walraven was plant manager until May 31, 1921. A twin-engine 16-seater was to be built, but that never happened.
He had always been reprieved of military conscription, but at some moment he had to join the armed forces. He decided to go to the East Indies, and in Bandung he joined the technical service of the young Aviation Division of the KNIL as chief of the drawing office. At first, this was something of a disappointment, as he could not properly deploy as a constructor. However, Walraven drew an aircraft, three Dutch from the Aviation Division and twelve East Indies craftsmen built the aircraft in an iceplant in Bandung. Thus came to be the Pattist-Walraven PW-1.
M.P. Pattist's name is connected, because he came up with the idea to build an aircraft. He later left for KLM to become Acting Chief Flying Services.

Walraven performed the calculations for the aircraft and put it on paper. At the time, Jane's "All the world's aircraft" wrote about Walraven:
"He claims to be the only constructor building aircraft in the tropics with the aid of natives."
Indeed, but those Indian boys were craftsmen and did a great job. One day, lieutenant pilot B.H.F. van Lent flew the PW-1 into Andir, the first aircraft built in the Dutch East Indies. That was in 1931. The little crate with its pusher prop on top of the wing and its two open cockpits performed excellently. "It was like a club seat sailing through the air", Mrs. Walraven remembers. When the "Uiver" came to Bandung after its spectacular Melbourne-flight of 1934, PK-SAM - as the PW-1 was registered - flew to meet the "Uiver". The natives called the PW-1 "Kapal Ikan¨, because it strongly resembled a fish.
About 1935 or 1936, PK-SAM came to an unfortunate end, when after flying too high over the mountains, the engined stalled on cooling too much; an emergency landing had to be made on a football pitch where the aircraft came to grief in a bad way. Fortunately without personal injury.
Many members of Bandung's flying club flew the PW-1. Its construction was financed by Walraven himself, construction materials were financed by contibutions from enthusiast friends.
The PW-1 was a braced, high wing monoplane and two open cockpits in tandem, with duplicated controls. Construction was mixed. The wing was of wooden construction, the fuselage of welded steel tube covered with fabric, the nose covered with aluminium and wood.Next, Walraven became Chief of Department "D" drawing office (aeronautical). Later, he was tasked with the inspection of civilian aircraft.

The best known and most successful of the Walraven-aircraft is the Walraven W-2, a twin-engine business aircraft that was designed and built by order from the Chinese sports pilot Khouw Khe Hien, a millionaire with meat- and breadplants on Java, who wished to have a twin-engine aircraft that could also fly on one engine. And so, somewhere in a shed in Bandung, that wooden W-2 was built. The parts went to Andir, where the aircraft was assembled in an air force hangar. Flying instructor C. Terluin - who, as a colonel, perished on February 2, 1948 in a C-47 near Padalarang - tested the W-2 on January 4, 1935 at Andir. The crate was not painted yet. After some short hops Terluin took off straight away. The Walraven W-2 proved very satisfactory.
Khouw Khe Hien - who perished in 1938 in Glenn Martin bomber 506, along with res. lt. J. Hermanides, sub-lt fl. o. Vermeulen, brigadier Van Riel and Aneta-editor De Hondt, during a blackout exercise with five Glenn Martins - could fly his crate within an hour. And so, Java - as early as then - had its first business aircraft. The W-2's performance proved to be so good, that the plan arose to fly it to the Netherlands. For the first time, by sports aircraft from the East Indies to Holland!

It was a bold plan, but Terluin and Khouw Khe Hien became ever more enthusiastic about it, the longer they thought about it. Indeed, the flight was made. In twelve days, in 1935. The Walraven W-2, in 83 flying hours, distributed over eight flying days, covered a distance of 8,900 miles, from Tjililitan to Schiphol. A fantastic achievement. Because the wooden W-2 had no radio yet, no retractable wheels and limited navigational instruments. Both pilots were seated in tandem in the narrow fuselage.

On September 9, 1035, PK-KKH - of Khouw Khe Hien - started from Batavia. On September 27, the aircraft landed at Schiphol. Indeed, the Walraven W-2 was a kind of "homebuild". A real "crate", made from plywood.

The aircraft was built with the assistance of Indonesian craftsmen, who barely knew what an aircraft was. They simply executed Walraven's orders, with dedication and precision, that could be relied on for 100 %.
One of the most important instruments was the driftmeter, a hole in the floor wih two iron wires mounted crosswise. It showed how much side-wind pushed you from track. The flight to the Netherlands was intended as a kind of demonstration flight, to prove how good and reliable the aircraft was.
The brave flyers followed the regular KLM-route. They carried gold ten-guilder pieces to pay for help in faraway airfields, if need be. Until Aleppo everything went well. One hour away from Istanbul the first engine-trouble occurred, because of a leaking oil line. An emergency landing was inevitable. The crate was without a trace for 24 hours, the flyers' next of kin, as well as Walraven were of course mortally afraid. They had landed on the slope of hill near Nifren and had been arrested as they had been taken for spies. After a telephone call to Istanbul, everything proved to be well; to great joy the message was received the brave flyers were found. In twenty minutes, the engine was repaired; the aircraft took off down hill. The reception at Schiphol was magnificent. Walraven had especially flown to the Netherlands by KLM to be present at the W-2's arrival on Schiphol.
Three days had been lost (there had been a delay at Dresden too). The journey could have been completed in 8½ days. The brave flyers were honoured with wreaths on Schiphol. Later, they flew the W-2 back to Bandung, in 71 flying hours. November 1 they left Schiphol, November 12 the slender crate was back at Tjililitan. Khouw Khe Hien - and this less known - also made a flight to China with the Walraven W-2, where the aircraft drew much attention. Khouw Khe Hien too had plans - as a proper businessman - to start an aircraft industry in the East Indies, together with Walraven. The war put an abrupt end to all those plans.

A sister of Khouw Khe Hien lives in Utrecht, the wife of an eye-doctor. She used to be a sports pilot in the East Indies. In 1935, this Khouw King Hien was the first woman in Asia with a pilot's licence. She was 22 years old at the time, had studied medicine and was co-director of the family-owned multi-million company "Merbaboe". Her private aircraft, a Bellanca, carried the name "Merbaboe 11" on its engine cover. With it, together with her sister, she made many flights to the plants and ventures of the Merbaboe-companies that were spread from Batavia to Bali and from Deli to Makassar.

On the Walraven W-2's arrival at Schiphol, Anthony Fokker also came to watch. He thought that W-2 to be a nice crate. According to messages from the day, construction of the W-2 had cost less than 6,000 guilders...
It has never been published that Plesman wanted to buy the licence-rights of the Walraven W-2 to turn it into a bigger airtaxi for KLM. COCKPIT - thanks to Mrs. Walraven - has an important scoop here. Mrs. Walraven allowed me to read the letter, written by Plesman on May 8, 1935, to Walraven, in which he asked if the W-2 could be turned into an airtaxi; also if Walraven was inclined to possibly grant KLM licence-rights for Holland, or, eventually, for all of Europe. Plesman wanted to know exactly what performance was like, takeoff- and landing-distance, whether the aircraft was equipped with brakes, its ceiling on one engine...

This letter was adressed to "Luchtvaartkundig Ingenieursbureau [Aeronautical Engineering Bureau] Walraven, N. Merdeka 14, Bandoeng"

In fact, Walraven designed his W-3 more or less for Plesman, a four-seater that could serve as an airtaxi. It remained a design, the W-3 was never built. Whether the plan foundered because of money...? Plesman had seen a twin-pusher design, published in The Aeroplane of February 27, 1935. This in particular interested Plesman.
The W-3 was to have received two 135 hp engines.
Also, it is not known whether an American Journalist wanted to have a W-2. Mrs. Walraven let me read the letter, written in Paris March 5, 1935, by Karl H. von Wiegand, European correspondent and represenative of the Hearst Newspapers. In it, this American wrote he had read articles about the W-2 in Flight and Aeroplane. He asked whether the crate was to be produced in Holland, and what its price would be.
Verbatim, he wrote:
"If your monoplane lives up to the figures given in the aero journals, it seems to be what many private owners like myself are looking for."

It is assumed the Walraven W-2 was destroyed on the ground during the Japanese invasion of Java. Alas...
We also wonder what happened to the aircraft after Khouw Khe Hien perished with the Glenn Martin "506"...
At the time, the W-2 has been compared to the wooden De Havilland DH-88 Comet, which won the Melbourne-race.
The W-2 was designed earlier than the Comet. The W-2 was designed in April 1934, when nothing was known about the Comet. Remarkable in this, the comparison came from the English. After its Tjililitan-Schiphol flight, the W-2 stayed in London for two weeks, with Khouw Khe Hien and Terluin. At Lympne, they received a very bad weather report, where in reality the weather was fine. "Surely a weather report from a month ago", Khow Khe Hien remarked...
The third Walraven-aircraft to be built was the W-4, a sports aircraft in the same category as the well-known German Klemms. About February 1, 1938, the aircraft was transferred to the Aviation Division to be covered and painted. On April 14, 1938, captain-instructors Terluin and Te Roller took it for its first flight. (Possibly, this was the second W-4, because, according to Mrs. Walraven, the first W-4 made its first flight on September 10, 1937, her youngest son's birth date!) Once again, the test pilots were enthusiastic, "for certain, the 160 km/h maximum speed will be exceeded, a fine achievement with a 60 HP engine!", we can read in "Luchtvaart" of June 1938. The journal continues: "Landing was truly sensational. A loitering speed of 80 km/h and a landing speed of less than 50 km/h, while the aircraft remains entirely controllable until the last moment. The flying club really has cause to be grateful to Mr. Walraven, for all his cares and troubles, because in no way would we have been able to acquire a performance-aircraft of this kind at such a low price. We heartily congratulate Mr. Walraven with this exceptionally successfull design and hope that many sports flyers In the Indies will decide to buy this ultra-modern little aircraft." The PK-SAU - as the W-4 was registered - was fitted with hydraulic brakes. A second W-4, the PK-SAI, was built by the Bandung Flying Club itself.

As early as May 1937, The Dutch East Indies Flying Club had decided to buy new training aircraft, and the instructors formulated a number of demands that the new aircraft - from an instructional point of view - had to comply with. The demands, among others, were for:
- great economy, which would allow the members to fly at low cost;
- good aerobatic qualities;
- landing flaps and wheel brakes;
- a practical ceiling of no less than 4000 meters in consideration of the high mountains and high clouds in the tropics;
- low landing speed and cruising speed of at least 160 km/h.
No aircraft was available on the worldmarket that fitted these demands, and Mr. Walraven was invited to build this aircraft for the Flying Club. The invitatation was accepted and the W-4 was built in the Flying Club's sheds. One of the W-4's characteristics was that its wing had a so-called "fixed-pressurepoint profile" which was very beneficial to stability. The tail surfaces were offset relative to each other, to prevent them from blanking each other off during aerobatics, as particularly during tail-spins loss of control could be caused.
Apart from the wooden wing, the aircraft was of steel tube construction. The ailerons were duraluminium. Thanks to split landing flaps, a low landing speed of 50 km/h was possible. As an interesting peculiarity, on extending the landing flaps, both ailerons automatically moved down to some extent, also functioning as flaps. Maximum speed was claimed at 185 km/h. Fuel consumption amounted to just 14.5 liters/hour, so 12 km could be flown on one liter of petrol, at a cruising speed of 160 km/h. The seat was adjustable and could accomodate a parachute. The tail wheel could swing through 360 degrees. Duplicated controls were fitted.
Test flights with W-4 were conducted by, among others, Lt. Van der Schroef, test pilot of the Technical Service of Military Aviation, and by the well-known Ir. Oyens. Best time-to-climb, fully loaded, from 1,000 meters to 1,500 meters was 6 minutes, horizontal speed at 1,000 meters as high as 190 km/h. Takeoff run, fully loaded was 190 meters, a height of 25 meters was reached after 600 meters, and landing distance with flaps was 101 meters.
Without flaps, letting go of the elevator control caused the aircraft to speed up to 155 km/h, after which it would level itself. Flaps out, the aircraft would speed up to 208 km/h before leveling itself. Six tail-spins to the right, nine to the left were performed. Upon forcing the stick forward, the aircraft would jump out of the spin with, at most, an additional quarter turn. Loopings were performed at 200 km/h! All in all, the Military Aviation's test pilot judged the flying qualities to be very good.
It is a pity no more W-4s have been built for the East Indies flying clubs. On Monday, December 11, 1939, at six in the evening near Bandung , one W-4 stalled from a height of approximately 70 meters and was completely destroyed. The aircraft was flown by Ir. Oyens with an 18-year old colllege student as a passenger. The pilot was slightly injured, the college-student unfortunately died in hospital.
The complete destruction of the aircraft was a big loss for the Bandung flying club. The crashed W-4 was most likely the PK-SAI.
There was a Walraven W-5 on paper. That design has never been published, and with it, we have another scoop. Mr. Walraven designed the W-5 while being imprisoned by the Japanese. He drew the aircraft in the prison camp, on paper used for judicial reports... A scale model was supposed to be made from food tins. His W-5 was to be a twin-tail private aircraft with a pusher propellor; an aircraft somewhat like the later Difoga and Fokker Promotor. Mr. Walraven foresaw two variants, a Sport Type with 90 hp engine an a Travel Type with 120 hp. Span was to be 11.25 meters, length 6.60 meters. In fact, the W-5 was developed from the W-1, with the engine mounted significantly lower.
Flying Lt. G.T. Uitzetter later took the papers from the prison camp. In the camp, a model of the W-5 was made by him from food tins, but this was lost. Laurens Walraven was taken away on the ship Takoma Maru to Burmah, where he was to work on the famous, notorious railroad.
It was never to be. On November 6, 1942, he died of dysentery on board the ship, after five days of illness. While his wife, with four boys and a girl, remained in a Japanese camp on Java he drew his last breath. His body, after a brief burial ceremony, as per tradition, was entrusted to the waves. Laurens Walraven was only 44 years old. His wife told us he planned to stay in Government Service until 45, and then start his own business. Khouw Khe Hien and Chang Kai-shek would have him in China, to start an aircraft industry there. We already saw how he thought about going to America too. On August 17, 1940, from London, he had received a Royal Honour. He was a Knight in the Order of Orange-Nassau.
Thus came to an end the life of a great aircraftmaker, a man who could have done much for the Dutch aircraft industry. His four sons all have something of the inventor in them. But they did not venture into aviation.
Laurens Walraven's name is etched forever into the history of Dutch aircraft building. In golden letters.
 
Many thanks, Arjen, for this translation.
Very interesting subject, indeed.
 
Hugo Hooftman mentions in which issue the pusher W-3 was shown - The Aeroplane of February 27, 1935.
 

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