Nederlandse Modelbouw en Luchtvaartsite

Dutch Modelling and Aviation

In Memoriam

Klaas Willem Jonker
† April 30, 2018

On Monday 30 April 2018, Wilko Jonker died after a long illness at the age of 58. He leaves behind a wife and two children. The Dutch military aviation and plastic modeling were his hobby and on this website he shared all the knowledge he has collected over the years. His hobby has been able to distract him from the persistent disease in his body until the last week of his life. The contacts with other hobbyists were a major support for him.

This website will be maintained by different people for as long as possible, so that other enthusiasts can continue to benefit from extensive content.

Airco DeHavilland DH-9


The Airco DH.9 was designed to succeed the Airco DH-4 in an attempt to solve the shortcomings of this aircraft.
In fact, it was just a refinement of the DH.4, with only the hull was revised.
The pilot seat was moved backwards and the fuel tank was now situated directly behind the engine. The engine was to be a promising BHP rated 300 hp, but because of setbacks in the development of this engine, it was only 230 hp. This had a negative impact on the performance of the new machine, which was now significantly less than that of the DH.4. There were over 4000 in order, based on the expected performance. The first examples were delivered in November 1917, nine squadrons were operational in June.
The replacement engine, actually evolved from BHP, was the lighter Siddeley Puma rated 230 hp, with which most production DH.9s were fitted. This engine proved to be unreliable. Also, the (heavier) Fiat A.12 applied.
Other attempts to improve performance with other engines were not successful.

The aircraft was used on the western front and suffered very significant more losses than DH.4, also by the unreliable engine.
For example, in the Middle East there were less troubles, mainly due to the tact that less resistance was encountered.

Production went on until 1919 and in 1920 the type was taken out of service by the RAF.
After the war, many aircraft were declared surplus and were sold or scrapped.
Because of the large capacity the DH.9 was very useful for the transport of carriage of passengers and goods.
Often, the aircraft was substantially rebuilt and equipped with a passenger compartment.


The original version, 3024 examples built, plus a number under licenses in Belgium and Spain.
better known as the Nine-Ack was designed by Westland to be equipped with the American Liberty L-12 engine rated 400 hp (298 kW). Besides the new engine also slightly larger wings were applied. Because a shortage of these American engine, the plane was put into operation in smaller quantities than hoped. Finally in 2300 examples were built.

Post-war types.

conversion to civilian performance three-seater (one pilot plus two passengers).
Conversion to Civilian four-seat exercise is performed (one pilot plus three passengers).
Modernized version equipped with an Armstrong Siddeley Jaguar III radial engine of 385 hp.
DH.9J M'pala I:
South African, modernized version, equipped with a Bristol Jupiter VI radial engine of 450 hp.
  • M'pala II: Same, but with a Bristol Jupiter VIII radial engine of 480 hp.
  • Mantis: Same, but with a line Wolseley Viper engine of 200 hp.
Handley Page HP.17:
An experimental version with air gaps in the wing.
USD-9 - DH.9s:
1415 examples built in the U.S. by U.S. Army's Engineering Division (1415 built)


Technical Information
Wingspan: 19,92 m Length: 9,27 mm
Height: 3,44 m Wing area: 40,32 m2
Empty weight: 1014 kg Max. start weight: 1723 kg
Max. speed: 187 km/hr Rate of climb:  
Range: 4,5 hr Service ceiling: 4730 m
Engine type: Armstrong Siddeley Puma 230 rated230 hp
Crew: Two men
Armament: 100 kg bombs; one fixed forward firing Vickers machine-gun; One or two movable Lewis machine-gun.