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Airco (de Havilland) D.H.9A

As a result of the daylight bombings of London, the British government sought to bolster the strength of the RAF with new, longer-range bombers. Production facilities were in place for the D.H.4, and so attempts were made to create this new aircraft with as many parts of the existing D.H.4 aircraft as possible. The result was the D.H.9. The plane was to feature a new, lightweight 224-kW engine designed by Siddeley. Unfortunately, this engine proved unreliable at that output, and was redesigned to produce a more reliable 172-kW. As might be expected, the plane's resulting performance suffered, and the D.H.9 experienced severe losses when introduced in April 1918. Nevertheless, over 3,200 D.H.9s were produced, and rather than replacing the D.H.4, the D.H.9 merely supplemented them.

Clearly, the best option to improve the D.H.9 was to improve the engine. With British factories already taxed, the American-made Liberty 12 engine was selected. Westland Aircraft Works (which made the D.H.4 and D.H.9 under license) was given the task of fitting the new engine into the old airframe, and the resulting modifications produced the outstanding D.H.9A strategic bomber. Some 885 examples were built beginning in 1918 and extending into the post war years. The biplane saw service in Iraq and India until as late as 1931, when it was withdrawn from service.

The plane has a historical endurance of 5 hours; it burns 14.9 gallons of aviation fuel per hour at routine usage. A full load of fuel and ammo (excluding bombs) costs $37.40.

 

Airco de Havilland DH.9A

Subassemblies: Light Fighter chassis +3; Heavy Fighter wings with Biplane option +2; 2 fixed wheels +0.

Powertrain: 298-kW aerial HP gasoline engine with 298-kW old prop and 112-gallon standard fuel tank [Body].

Occ.: 2 XCS Body

Cargo: 5.5 Body

 

Armor F RL B T U

Body: 2/2W 2/2W 2/2W 2/2W 2/2W

Wings: 1/2C 1/2C 1/2C 1/2C 1/2C

Wheels: 2/3 2/3 2/3 2/3 2/3

 

Weaponry:

Aircraft LMG/.303 Vickers [Body:F] (500 rounds).

2xAircraft LMG/.303 Lewis [Body:B] (500 rounds each).*

660 lbs. of Bombs [Body and Wings:U].

*Linked.

 

Equipment:

Body: 660-lb. Hardpoint [Body and Wings:U], Casemate and high-angle mount for rear guns.

 

Statistics:

Size: 30'x46'x11' Payload: 0.92 tons Lwt.: 2.32 tons

Volume: 144 Maint.: 62 hours Cost: $10,270

HT: 6. HPs: 25 Body, 180 each Wing, 8 each Wheel.

aSpeed: 123 aAccel: 3 aDecel: 28 aMR: 7 aSR: 1

Stall Speed: 43 mph. Take Off Run: 205 yards. Landing Run: 185 yards.

gSpeed: 181 gAccel: 9 gDecel: 10 gMR: 0.5 gSR: 2

Ground Pressure: Very High. 1/8 Off-Road Speed.

 

Design Notes:

Historical wing area was 487 sf. Chassis and wing weight, costs, and HPs were halved to lower design weight; it was increased less than 1% to the historical. Design payload was 1,863 lbs.; the historical value was 18 lbs. lighter. Design aSpeed as 128 mph. Historical values for wing area and loaded weight were used for performance calculations. The forward fixed Vickers MG is synchronized, lowering RoF by 10% (see p. W:MP8). The design purchases a 114-gallon fuel tank; the historical capacity is shown.

 

Variants:

The original DH.9 used a 172-kW engine, giving a top speed of 110 mph. 3,200 were built; many of the surplus craft were scrapped and burned following the war.

The DH-9AJ was a single prototype with a 347-kW engine.

The USD-9A was an American built version with 7.62mm Browning MGs. 9 built.

The USD-9B was a single USD-9A re-engined with a 313-kW Liberty 12A engine.

The DH.9B and -C were civilian conversions for passenger transport following the war. The -B carried two passengers in exposed seats; one in front of and one behind the pilot. The -C carried one passenger in an open seat in front of the cockpit, while two more passengers were seated behind the pilot under a canopy.

 

From the Aerodrome for GURPS

2008 by Jim Antonicic