Kit No. 436
Decals: One version – Air ambulance serving with the British “Z” Force in Somaliland, 1919-1920
Comments: Detailed kit; contains all parts for DH.9 bomber version; Red Cross covering not included; only a very basic rigging diagram
The Airco DH.9 ( after 1920, the de Havilland DH.9) was a British bomber flown during the First World War by the Royal Flying Corps and — by war’s end — the Royal Air Force. Intended as a replacement for Airco’s earlier, highly successful DH.4, it was ordered in very large numbers, with over 2,000 in RAF service by November 1918. Unfortunately, it was not only inferior to the DH.4, but its performance was so poor that it cost a great many Allied airmen their lives.
The idea was for the DH.9 to have similar performance to the DH.4, but longer range, helping to form Britain’s first strategic bomber force. But in reality, the DH.9’s performance was not similar to that of the DH.4; far from it. Originally intended to be fitted with an American-supplied Liberty V-12 engine, the DH.9 was instead mated with a BHP 230 hp engine, due to delays in production that rendered the Liberty unavailable. But the BHP was the engine that was fitted to the DH.4 at the prototype stage, and later replaced by the Rolls Royce Eagle, a superior engine capable of 250 hp. Unfortunately, a Rolls Royce powerplant was not in the DH 9’s future. It entered service saddled with the underpowered, unreliable BHP. The alternative of a Rolls Royce engine was not an option due to the limitations on production capacity and priorities for its use in other aircraft – including the DH.4.
The DH.9 was designed by Geoffrey de Havilland for the Aircraft Manufacturing Company (Airco) in 1916. It used the wings and tail unit of the DH.4 but had a new fuselage, enabling the pilot to sit closer to the gunner/observer and away from the engine and fuel tank. The other major change from the DH.4 was the choice of the promising new BHP/Galloway Adriatic engine, predicted to produce 300 hp (224 KW) and so give the new aircraft an adequate performance to match enemy fighters. But in flight tests beginning at Hendon in July 1917 the BHP proved disappointing, having such difficulty consistently delivering the initially rated 300 hp that it was de-rated to 230 hp (186 kW) in order to improve reliability. This rendered the DH.9 inferior to the DH.4 it was intended to replace, particularly at high altitude, with all too often with fatal results.
The DH. 9 design altered the DH4 two-seater bomber in two ways: First, it moved the pilot’s cockpit rearwards, just behind the trailing edge of the wing, making space for an internal bomb bay in the fuselage. Second, the engine centre line was raised and the nose radiator replaced by a vertical water tank and a radiator in the bottom of the fuselage. Compared to the DH4, the total empty weight was reduced by 100 lbs, the fuel tank size increased and the bomb load increased by 500 lbs, at the cost of “a slight loss of speed and climb and an increase in the landing speed.” The design had the advantage of closing of the gap between the pilot and the observer/gunner, improving communication between them during combat. However, when fully loaded, the DH. 9’s service ceiling was about 14,000 ft., some 2,000 ft. lower than the DH4. The deficiencies in its powerplant combined with its heavier bomb load meant that in combat, enemy fighters would be able to reach and attack the DH.9 formations more easily. Authorities had evidence early on that the slower, lower flying DH.9 would have to fight its way through enemy fighters before reaching its targets, whereas the earlier DH.4 was able to avoid many such attacks due to its superior speed. Despite this, plans went ahead to put the new type into service — perhaps with a thought of fitting it with a improved powerplant as soon as possible — but at the cost of many Allied airmen’s lives.
Entering service in November 1917, the deployment of the DH.9 to France was a disaster, frequently resulting in heavy losses, due mainly to the poor performance of the BHP engine. For Major General Hugh Trenchard, commanding officer of the Royal Flying Corps on the Western Front from 1915-1917, the events of 31 July 1918 confirmed his early prejudices about the DH.9. A formation of a dozen aircraft from No. 99 Squadron set out to bomb the town of Mainz. Three aircraft dropped out with engine trouble before crossing the lines; nine aircraft continued but due to enemy opposition attacked Saarbrucken instead. Four aircraft were brought down before reaching the target, and of the five remaining, a further three were shot down by the time the raid was completed. This one action resulted in the loss of 14 aircrew, eight of whom never got near their target.
By the end of August 1918 Maj. Gen. Trenchard, by then recalled to London to take up the post of Chief of the Air Staff for the recently created Royal Air Force, decided that the DH.9’s were unfit for front-line service “and that the losses which must be expected they would suffer did not justify again sending them over the lines.” He accordingly withdrew the type from front-line service, and it was thereafter used for transport or liaison duties.
Elsewhere the DH.9 continued in service until the Armistice. Despite its limitations, when flown in a tight defensive formation, the DH.9 could hold off attackers with some success and squadrons claimed a number of victories against attackers. The DH.9 saw service in France with Nos 27, 49, 98, 99, 103, 104, 107, 108, 206, 211 and 218 Squadron. Some 2,166 DH.9’s were delivered for RAF service by the end of October 1918 and a total of 3,204 were produced.
Between May and November 1918, two squadrons on the Western Front (Nos. 99 and 104) lost 54 DH.9’s shot down, and another 94 written off in accidents. DH.9’s were more successful against the Turkish forces in the Middle East, where they faced less opposition, and were also used extensively for coastal patrols, to deter U-boat operations. The DH.9’s combat record in France was a key reason it was re-deployed to these duties. After the war, a single DH 9 was rebuilt as an air ambulance, requiring a modification of the fuselage by placing a special installation behind the cockpit over what had been the gunner’s postion. This was the widest part of the fuselage, where stretchers could be fitted to keep the injured in a stable position. Only one DH 9 was so modified, as larger, twin-engined aircraft became available for this duty in the 1920’s.
While attempts were made to provide the DH.9 with an adequate engine, with aircraft being fitted with the Siddeley Puma, a lightened and supposedly more powerful version of the BHP, and also with the Fiat A12 engine, and finally with a 430 hp (321 kW) Napier Lion engine, these were generally unsuccessful (although the Lion-engined aircraft did set a World Altitude Record of 30,500 ft (13,900 m) on 2 January 1919). Ultimately, it required a redesign into the DH.9A to transform the aircraft.
Type: tactical bomber/patrol aircraft/air ambulance
Designed by: Geoffrey de Havilland
First flight: July 1917
Primary users: Royal Air Force, RNAS, RFC.
Number Built: 4091
Variants: DH.9A, DH.9C, Westland Walrus
Length: 30 ft 5 in (9.27 m)
Wingspan: 42 ft 4½ in (19.92 m)
Height: 11 ft 3½ in (3.44 m)
Wing area: 434 ft² (40.3 m²)
Empty weight: 2,360 lb (1,014 kg)
Max takeoff weight: 3,790 lb (1,723 kg)
Powerplant: 1 × Armstrong Siddeley Puma piston engine, 230 hp (172 kW)
Maximum speed: 98 kn (113 mph, 182 km/h)
Endurance: 4½ hours
Service ceiling: 15,500 ft (4,730 m)
Climb to: 10,000 ft 18 min 30 sec
Armament: One forward firing .303 Vickers machine gun; one or two rear .303 Lewis guns on Scarff ring
Reviewing the record nearly a century later, one wonders why the DH.9 was allowed to enter service at all with a clearly inferior powerplant, which literally meant the difference between life and death for many British airmen. It is curious that, given the initial specifications laid down for the new bomber, it was not given an equally successful if not identical powerplant to the aircraft it was intended to replace. It is equally curious that, when its designated powerplant was proven deficient prior to its deployment to France, arrangements were not made to increase production of the Rolls Royce Eagle engine which had made the DH.4 such a successful aircraft, or to scrap the DH.9 altogether in favor of increasing production of the DH.4. Was it simply a case of political pressure to give the Royal Flying Corps its first strategic bomber, regardless of the cost, with national prestige so tied up in the project that failure could not be conceded? In any event, the DH. 9 was a great deal more successful as liaison aircraft and air ambulance than as a bomber.
Comparisons in performance between the DH.4 and DH.9
The Official History of the War in the Air makes particular reference to the performance of the DH4 and DH9 bombers during the Battle of Amiens, illustrating the poor performance of the newer aircraft.
” The DH4 fitted with the 275 horse power Rolls Royce (Eagle VI) engine was splendidly reliable. In the four days of intensive fighting from 8-11 August inclusive the DH4’s of 205 Squadron were in the air for a total of 324 hours 13 minutes, and dropped sixteen tons of bombs. Every aeroplane returned from its mission and no more than one had to be struck off the strength of the squadron.”
” By way of comparison, a typical DH9 squadron flew a total of 115 hours in the same period and dropped four and a half tons of bombs. During the operations seven of the DH9’s were lost and two others were wrecked, and ten pilots had to leave formation without dropping their bombs, through engine trouble.”
Roden’s Airco DH 9 is injection molded in grey and consists of 274 parts. A whopping 138 of these parts — roughly half — are not to be used at all, according to the instructions. This is because Roden provides all parts necessary to built the DH. 9 in its initial configuration as a bomber, despite the fact that this kit is for the air ambulance version. The military version includes six Lewis guns with separately mounted ammunition drums, a pair of .303 Vickers water-cooled machine guns, and two other machine guns of unknown origin. There are also four fairly large bombs along with 22 anti-personnel bomblets, small enough to have been thrown by hand.
The kit is quite detailed; the engine alone consists of a dozen parts, along with three additional parts for the engine mount. The fuselage bears interior sidewall detail for the cockpit, as well as external panel line and raised stitching detail. The cockpit is fairly well detailed, but despite the fact that this kit depicts an air ambulance, no stretcher is provided, nor it is clear from the instructions how patients were loaded and off-loaded. There are a number of details that add to the kit’s accuracy, including an external coolant or fuel line for the engine, a ladder, and loop skids that are fitted beneath the lower wings to prevent damage in the event of ground loops. Stressed fabric effects on the wings, elevators, and rudder are subtle, noticeable but not overdone.
Decals are provided for a single version, an air ambulance operating with “Z” Force in British Somaliland during 1919-1920. The decals have excellent color and are fully in register. The paint scheme called for is Matt WWI Green over Matt Linen, and the instructions specifically reference Model Master colors.
This kit will require some initiative. If you opt to build the air ambulance, the modeler will have to provide his or her own fabric depicting the red cross draped over the rear fuselage in the box art. A rigging diagram is provided, but it is pretty basic and does not address the myriad of wires clearly running to the rear fuselage, as seen in the box art. Overall, an interesting kit representing an effort to get the maximum use out of an unsuccessful wartime airframe design.