Airco D.H.4 (360 hp)
role : light bomber
first flight : operational : April 1918
country : United-Kingdom
design :
production : all D.H.4 versions : 6295 aircraft (4846 built in the USA DH-4A “Liberty
plane”, 1449 in the UK)
general information :
The 250 hp D.H.4 had excellent performance, this was again boasted by the installation of a 360 hp RR Eagle VIII engine. The high speed and high altitude made it difficult to intercept. The higher weight of the engine (dry weight 379 kg) did however limit the bombload. Maybe for this reason the high power D.H.4 was more used as high speed, high altitude reconnaissance plane and as fighter plane and not so much as bomber. It performance was so good, even better then most enemy fighters, it could operate without fighter escort.
Frankfurt-am-Main was for the first time raided by DH4 in the summer of 1918. (operating from Ochey, France it is a distance of 265 km, with 360 hp engine this distance is only possible with a bombload of 130 kgs) The raid was done by 12 DH4’s of 55sq bombing the city from 4250m height. The day bombers were attacked on the way back by 25 German fighters near Mannheim but no D.H.4 was shot down. 2 Albatros-fighters were shot down.
Chord : 1.67m span tail : 4.26m
Surface tail planes : 7.49m^2
Elevators each : 1.11m^2
rudder : 1.27m^2
ailerons each : 1.89m^2
airscrew : diam. : 2.66m pitch : 2.49m 1355 r.p.m.
fuel capacity : 66 gallon = 300 litre.
Time to height (176 KW/375 hp engine )
5.15 min. naar 1976m
9.00 min. naar 3040m
16.30 min. naar 4560m
In July 1917 a D.H.4 was sent to the USA for evaluation. The Americans fitted the aircraft with a 400 hp Liberty 12 engine. It made its first flight 29 October 1917 and was put in large scale production. It was designated D.H.4 “Liberty Plane” and 4846 were built. It entered service in August 1918 with the US troops in Europe.> see Dayton-Wright D.H.4 Liberty plane.
After the war the D.H.4 served for a long time on with different Air Forces and also with private companies till the 1930’s.
users : UK, USA, Belgium, Canada, New-Zeeland, South-Africa, Spain, Chile, Greece
crew : 2
armament : 1 synchronized 7.70 [mm] (0.303 in) Vickers machine-gun
and 1 movable 7.70 [mm] (0.303 in) Lewis MK.III machine-gun for the observer
engine : 1 Rolls Royce Eagle VIII liquid-cooled 12 -cylinder V-engine 360 [hp](264.8 KW) 375 [hp] max. rating
dimensions :
wingspan : 13.21 [m], length : 9.34 [m], height : 3.55[m]
wing area : 40.32 [m^2]
weights :
max.take-off weight : 1575 [kg]
empty weight operational : 1085 [kg] bombload : 210 [kg]
performance :
maximum speed : 220 [km/hr] at sea-level
climbing speed : 305 [m/min]
service ceiling : 6700 [m]
endurance : 4.72 [hours]
estimated action radius : 467 [km]
description :
2-bay biplane with fixed landing gear and tail strut
two spar upper and lower wing
engine, landing gear and fuel in or attached to fuselage, bombs attached to the wing
airscrew :
fixed pitch 4 -bladed tractor airscrew with max. efficiency :0.60 [ ]
estimated diameter airscrew 2.69 [m]
angle of attack prop : 26.91 [ ]
coarse pitch
reduction : 0.60 [ ]
airscrew revs : 1140 [r.p.m.]
pilot Major Edgar Cadbury and gunner Captain Robert Leckie shot down Zeppelin L 70 over the North Sea 6 Aug. 1918. Remarkable a light bomber was used for the interception of a Zeppelin but gives good indication of the good performance of the D.H.4
pitch at Max speed 3.22 [m]
blade-tip speed at Vmax and max revs. : 172 [m/s]
calculation : *1* (dimensions)
mean wing chord : 1.53 [m]
calculated wing chord (rounded tips): 1.67 [m]
wing aspect ratio : 8.66 []
estimated gap : 1.78 [m]
gap/chord : 1.17 [ ]
seize (span*length*height) : 438 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 4.0 [kg/hr]
fuel consumption(cruise speed) : 41.1 [kg/hr] (56.0 [litre/hr]) at 47 [%] power
distance flown for 1 kg fuel : 4.82 [km/kg]
estimated total fuel capacity : 300 [litre] (220 [kg])
calculation : *3* (weight)
weight engine(s) dry : 379.0 [kg] = 1.43 [kg/KW]
weight reduction gear : 29.1 [kg]
weight 32 litre oil tank : 2.7 [kg]
oil tank filled with 2.0 litre oil : 1.8 [kg]
oil in engine 15 litre oil : 13.2 [kg]
fuel in engine 2 litre fuel : 1.3 [kg]
weight 24 litre gravity patrol tank(s) : 3.6 [kg]
weight radiator : 42.4 [kg]
weight exhaust pipes & fuel lines 31.7 [kg]
weight self-starter : 6.5 [kg]
weight cowling 10.6 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 50.3 [kg]
total weight propulsion system : 599 [kg](38.0 [%])
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fuselage skeleton (wood gauge : 5.35 [cm]): 69 [kg]
bracing : 4.5 [kg]
fuselage covering ( 16.5 [m2] doped linen fabric) : 5.3 [kg]
weight controls + indicators: 6.7 [kg]
weight seats : 6.0 [kg]
weight other details, lighting set, etc. : 5.1 [kg]
weight bomb storage : 14.7 [kg]
weight 276 [litre] main fuel tank empty : 22.1 [kg]
weight oxygen/compressed air flasks for high altitude : 10.2 [kg]
weight engine mounts & firewalls : 13 [kg]
total weight fuselage : 156 [kg](9.9 [%])
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weight wing covering (doped linen fabric) : 26 [kg]
total weight ribs (84 ribs) : 94 [kg]
load on front upper spar (clmax) per running metre : 422.7 [N]
load on rear upper spar (vmax) per running metre : 339.1 [N]
total weight 8 spars : 34 [kg]
weight wings : 153 [kg]
weight wing/square meter : 3.80 [kg]
weight 8 interplane struts & cabane : 20.9 [kg]
weight cables (77 [m]) : 4.7 [kg] (= 62 [gram] per metre)
diameter cable : 3.2 [mm]
weight fin & rudder (2.0 [m2]) : 8.0 [kg]
weight stabilizer & elevator (4.5 [m2]): 17.6 [kg]
total weight wing surfaces & bracing : 205 [kg] (13.0 [%])
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weight machine-gun(s) : 28.9 [kg]
weight Scarff ring mounting mg :5.0 [kg]
weight ammunition magazine(s) :2.0 [kg]
weight synchronizing system : 1.0 [kg]
weight Aldis gunsight : 0.8 [kg]
weight armament : 38 [kg]
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wheel pressure : 787.5 [kg]
weight 2 wheels (750 [mm] by 94 [mm]) : 28.4 [kg]
weight tailskid : 3.1 [kg]
weight undercarriage with axle 22.8 [kg]
total weight landing gear : 54.4 [kg] (3.5 [%]
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calculated empty weight : 1052 [kg](66.8 [%])
weight oil for 5.7 hours flying : 22.5 [kg]
weight cooling fluids : 57.2 [kg]
weight 6 drums empty : 2.5 [kg]
weight ammunition (1164 rounds) : 42.1 [kg]
weight Very pistol with cartridges : 3.6 [kg]
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calculated operational weight empty : 1177 [kg] (74.7 [%])
published operational weight empty : 1085 [kg] (68.9 [%])
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weight crew : 162 [kg]
weight (electrical heated) clothing for high altitude : 12.0 [kg]
weight fuel for 2.0 hours flying : 82 [kg]
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operational weight : 1433 [kg](91.0 [%])
bombload could not be carried with fuel for 2 hours flying time
fuel reserve : 138 [kg] enough for 3.36 [hours] flying
possible additional useful load : 4 [kg]
operational weight fully loaded : 1575 [kg] with fuel tank filled for 100 [%]
published maximum take-off weight : 1575 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (Take-off) : 5.95 [kg/kW]
total power : 264.8 [kW] at 1900 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 3.9 [g] at 1000 [m]
limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 0.9 [g]
design flight time : 3.30 [hours]
design cycles : 91 sorties, design hours : 300 [hours]
wing loading (MTOW) : 383 [N/m^2]
wing stress (3 g) during operation : 302 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.38 ["]
max. angle of attack (stalling angle) : 11.73 ["]
angle of attack at max. speed : 0.39 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° :0.12 [ ]
lift coefficient at max. angle of attack : 1.14 [ ]
lift coefficient at max. speed : 0.15 [ ]
induced drag coefficient at max. speed : 0.0015 [ ]
drag coefficient at max. speed : 0.0281 [ ]
drag coefficient (zero lift) : 0.0266 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 80 [km/u]
landing speed at sea-level (OW without bombload): 96 [km/hr]
min. drag speed (max endurance) : 127 [km/hr] at 3350 [m](power :31 [%])
min. power speed (max range) : 136 [km/hr] at 3350 [m] (power:32 [%])
max. rate of climb speed : 128.9 [km/hr] at sea-level
cruising speed : 198 [km/hr] op 3350 [m] (power:57 [%])
design speed prop : 209 [km/hr]
maximum speed : 220 [km/hr] op 100 [m] (power:98 [%])
climbing speed at sea-level (without bombload) : 392 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 168 [m]
lift/drag ratio : 11.99 [ ]
max. practical ceiling : 5225 [m] with flying weight :1233 [kg]
practical ceiling (operational weight): 4725 [m] with flying weight :1433 [kg]
practical ceiling fully loaded (mtow- 1 hour fuel) : 4500 [m] with flying weight :1534 [kg]
published ceiling (6700 [m]
climb to 1500m (without bombload) : 4.34 [min]
climb to 3000m (without bombload) : 11.08 [min]
max. dive speed : 496.9 [km/hr] at 3500 [m] height
load factor at max. angle turn 2.31 ["g"]
turn radius at 500m: 65 [m]
time needed for 360* turn 11.2 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 0.66 [hours] with 2 crew and 209 [kg] bombload and 12.3 [%] fuel
published endurance : 4.72 [hours] with 2 crew and possible useful (bomb) load : 42 [kg] and 88.1 [%] fuel
action radius : 521 [km] with 2 crew and 20[kg] photo camera/radio transmitter or bombload
max range theoretically with additional fuel tanks for total 495 [litre] fuel : 1749 [km]
useful load with action-radius 250km : 132 [kg]
production : 26.19 [tonkm/hour]
oil and fuel consumption per tonkm : 1.72 [kg]
_
I_°°=/
°
The 360 hp RR engine had a different exhaust pipes as on the 250 hp engine
Literature :
praktisch handboek vliegtuigen deel 1 page 201
Wikipedia
Jane’s fawoi page 40,41, 238
Warplanes world war one page 136
Bomber page 45, 140
DISCLAIMER Above calculations are based on published data, they must be
regarded as indication not as facts.
Calculated performance and weight may not correspond with actual weights
and performances and are assumptions for which no responsibility can be taken.
Calculations are as accurate as possible, they can be fine-tuned when more data
is available, you are welcome to give suggestions and additional information
so we can improve our program.
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(c) B van der Zalm 16 August 2019 contact : info.aircraftinvestigation@gmail.com python 3.7.4