il2_specs

Airco D.H.4

Description

Designed by Geoffrey de Havilland to be a two-seat light bomber powered by a BHP engine. First prototype flew in August 1916, but as the BHP engine proved to be weak it required a major redesign and DH.4 was adapted to be equipped with a Rolls Royce Eagle engine. First order for 50 planes powered by Eagle III engine (250hp) was placed at the end of 1916.

Basically an all-wooden construction tractor biplane, Airplane armament consisted of one forward-firing Vickers synchronized machine gun and one or two Lewis guns on the Scarff ring mount at the observer position. It could carry up to 460 pounds of bombs on external racks on wings or central position.

Due to shortages of Rolls Royce engines the production airplanes were also fitted with BHP (230hp), RAF3A (200hp), the Siddeley Puma (230hp) and the 260hp Fiat, yet none of the alternative powered DH.4\s could match the Rolls Royce powered machines. First DH.4 in frontline service were supplied to No.55 squadron on March 1917; it was the first RFC squadron fully equipped with this type. Till the end of 1917, a total of 6 squadrons were equipped with DH.4\s. It also was used by RNAS squadrons for naval operations for recon and anti-submarine use.

Reported to be pleasant to fly and easy to operate, the crews loved it because of its speed and maneuverability (the only “flaw” noted by its crews was the fuel tank placed between pilot and observer cockpits which caused communication problems between them). Due to its abilities, it was often used without fighter cover as its speed and good altitude performance allowed it to survive. Mostly used as a light day-bomber, it also could carry radio equipment for artillery observation duties and camera equipment for photo-reconnaissance missions.

Produced by Airco, F.W. Berwick and Co, Glendower Aircraft Company, Palladium Autocars, Vulcan Motor and Engineering, and the Westland Aircraft Works in the UK, a total of 1,449 aircraft were built in the UK for the RFC and RNAS through the end of the war.

Moteur: V-type 12 cyl. Rolls Royce Eagle VII
Puissance: 275 cv. (320hp at 1800 RPM)

Dimensions:
Hauteur: 3100 mm
Longueur: 9200 mm
Envergure: 12916 mm
Surface alaire : 40 m²

Masses:
A vide: 1088 kg
Capacite reservoirs de carburant: 249 liters
Capacite reservoirs d\huile: 27,3 liters
Au decollage sans emport de bombes: 1588 kg

Vitesse (VI), sans bombes:
Niveau de la mer - 200 km/h
1000 - 189 km/h
2000 - 178 km/h
3000 - 166 km/h
4000 - 154 km/h
5000 - 140 km/h

Temps de montee, Reservoirs pleins, sans bombes:
1000 m - 3 min. 23 sec.
2000 m - 7 min. 7 sec.
3000 m - 11 min. 47 sec.
4000 m - 17 min. 52 sec.
5000 m - 27 sec.

Plafond opérationnel: 6800 m

Autonomie: 3 h.

Armement:
Armes fixees: 1 x Vickers Mk.I 7,69 mm, 500 cartouches par baril.
Poste de tir arriere: 1 x Lewis 7,69 mm, 8 chargeurs de 97 coups

Configurations possibles d\emport offensif:
12 x 20lb (109 kg)
8 x 20lb + 2 x 112lb (175 kg)
4 x 112lb (203,4 kg)
2 x 112lb (101,7 kg)
2 x 230lb (208,8 kg)
Masse de bombe maximale: 208,8 kg

References
1) Air Board Data Charts, 1917.
2) Notes on the prediction and analysis of airplane performance, reports and memoranda no.474, may 1918, tables no. 10 and 11.
3) Windsock Datafile Special - Airco DH.4 Vol.1, by J.M. Bruce.
4) Rolls Royce engine charts, 1917.
5) WWI Aeroplanes data, by J.M. Bruce.
6) Various NACA reports.

Modifications



Aldis

Collimateur à réfraction Aldis
Masse supplémentaire : 2 kg


Cooper / H.E.R.L. / H.E.R.F.C. bombes

12 x bombes d’emploi général 24 lb Cooper (11 kg)
Masse supplémentaire : 167 kg
Masse des munitions : 131 kg
Masse des pylones : 36 kg
Perte estimée de vitesse avant le largage : 7 km/h
Perte estimée de vitesse après le largage : 3 km/h

4 x bombes d’emploi général 112 lb H.E.R.L. (51 kg)
Masse supplémentaire : 227 kg
Masse des munitions : 204 kg
Masse des pylones : 24 kg
Perte estimée de vitesse avant le largage : 8 km/h
Perte estimée de vitesse après le largage : 4 km/h

2 x bombes d’emploi général 230 lb H.E.R.F.C. (104 kg)
Masse supplémentaire : 224 kg
Masse des munitions : 208 kg
Masse des pylones : 16 kg
Perte estimée de vitesse avant le largage : 5 km/h
Perte estimée de vitesse après le largage : 3 km/h 

Lumière de cockpit

Lumière à ampoule pour les sorties de nuit
Masse supplémentaire : 1 kg


Jauge d\essence,

Jauge de niveau de carburant à aiguille (0-30 Gallons)
Masse supplémentaire : 1 kg


Camera

Camera for taking aerial photographs
Additional mass: 10 kg


Radio

Radio transmitter
Additional mass: 10 kg 

Twin Lewis Overwing

Two overwing mounted additional fixed Lewis machineguns.
Ammo: 194 of 7.69mm rounds (2 drums with 97 rounds in each)
Projectile weight: 11 g
Muzzle velocity: 745 m/s
Rate of fire: 550 rpm
Guns weight: 15 kg (w/o ammo drums)
Mounts weight: 6 kg
Ammo weight: 10 kg
Total weight: 31 kg
Estimated speed loss: 5 km/h 

Twin Lewis MG turret

Scarff ring turret with twin Lewis MG
Ammo: 776 of 7.69mm rounds (8 drums with 97 rounds in each)
Projectile weight: 11 g
Muzzle velocity: 745 m/s
Rate of fire: 550 rpm
Guns weight: 15 kg (w/o ammo drums)
Mount weight: 12 kg
Ammo weight: 32 kg
Total weight: 59 kg
Estimated speed loss: 2 km/h 

Twin forward Vickers

Twin fixed forward firing Vickers guns.
Ammo: 1000 of 7.69mm rounds (500 rounds for each gun)
Projectile weight: 11 g
Muzzle velocity: 745 m/s
Rate of fire: 750 rpm
Guns weight: 13 kg (w/o ammo drums)
Mounts weight: 4 kg
Ammo weight: 21 kg
Total weight: 38 kg