Dayton-Wright D.H.4 Liberty Plane
role : light bomber
first flight : operational : August 1918
country : United States of America
design :
production : 4846 aircraft
general information :
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 Oktober 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. At the time of its entry into the war, the United States Army Air Service lacked any aircraft suitable for front line combat. It therefore procured various aircraft from the British and French, one being the DH.4. As the DH-4, it was manufactured mostly by Dayton-Wright (3106 aircraft) and Fisher Body (1600 aircraft) for service with the United States from 1918, the first American built DH-4 being delivered to France in May 1918, with combat operations commencing in August 1918.[38][39] The powerplant was a Liberty L-12 of 400 hp (300 kW) and it was fitted with two .30 in (7.62 mm) Marlin (a development of the Colt-Browning) machine guns in the nose and two .30 in (7.62 mm) Lewis guns in the rear and could carry 322 lb (146 kg) of bombs. it could also be equipped with various radios like the SCR-68 for artillery spotting missions. The heavier engine reduced performance compared with the Rolls-Royce powered version, but as the "Liberty Plane" it became the US Army Air Service standard general purpose two-seater, and on the whole was fairly popular with its crews. Aircrew operating the DH-4 were awarded four of the six Medals of Honor awarded to American aviators. First Lieutenant Harold Ernest Goettler and Second Lieutenant Erwin R. Bleckley received posthumous awards after being killed on 12 October 1918 attempting to drop supplies to the Lost Battalion of the 77th Division, cut off by German troops during the Meuse-Argonne Offensive;[38] while Second Lieutenant Ralph Talbot and Gunnery Sergeant Robert G. Robinson of the United States Marine Corps (USMC) were awarded the Medal of Honor for beating off attacks from 12 German fighters during a bombing raid over Belgium on 8 October 1918.[40][41] The type flew with 13 U.S. squadrons by the end of 1918.[42]Following the end of the First World War, America had a large surplus of DH-4s, with the improved DH-4B becoming available, although none had been shipped to France. It was therefore decided that there was no point in returning aircraft across the Atlantic, so those remaining in France, together with other obsolete observation and trainer aircraft, were burned in what became known as the "Billion Dollar Bonfire".[43][39] With limited funds available to develop and purchase replacements, the remaining DH-4s formed a major part of American air strength for several years, used for many roles, with as many as 60 variants produced.
The crew’s clothing had a heating system.
The American DH4’s had a Wimperis bombsight.
The Course Setting Bomb Sight (CSBS) is the canonical vector bombsight, the first practical system for properly accounting for the effects of wind when dropping bombs. It is also widely referred to as the Wimperis sight after its inventor, Harry Wimperis.
users : US Air Force
crew : 2
armament : 2 synchronized 7.62 [mm] (0.300 in) Marlin M1917 machine-guns
and 2 movable 7.70 [mm] (0.303 in) Lewis MK.III machine-guns
engine : 1 Liberty L-12 liquid-cooled 12 -cylinder V-engine 400 [hp](294.2 KW)
dimensions :
wingspan : 12.95 [m], length : 9.29 [m], height : 3.15[m]
wing area : 40.0 [m^2]
weights :
max.take-off weight : 1625 [kg]
empty weight operational : 1085 [kg] bombload : 146 [kg]
performance :
maximum speed : 201 [km/hr] at sea-level
climbing speed : 218 [m/min]
service ceiling : 5944 [m]
endurance : 3.63 [hours]
estimated action radius : 328 [km]
description :
2-bay biplane with fixed landing gear and tail strut
two spar upper and lower wing
engines, landing gear, fuel and bombs in or attached to the fuselage
airscrew :
fixed pitch 4 -bladed tractor airscrew with max. efficiency :0.58 [ ]
estimated diameter airscrew 2.69 [m]
angle of attack prop : 16.81 [ ]
reduction : 1.00 [ ]
airscrew revs : 1750 [r.p.m.]
pitch at Max speed 1.91 [m]
blade-tip speed at Vmax and max revs. : 253 [m/s]
calculation : *1* (dimensions)
mean wing chord : 1.54 [m]
calculated wing chord (rounded tips): 1.70 [m]
wing aspect ratio : 8.39 []
estimated gap : 1.78 [m]
gap/chord : 1.15 [ ]
seize (span*length*height) : 379 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 4.1 [kg/hr]
fuel consumption(cruise speed) : 60.4 [kg/hr] (82.4 [litre/hr]) at 58 [%] power
distance flown for 1 kg fuel : 3.00 [km/kg]
estimated total fuel capacity : 339 [litre] (249 [kg])
calculation : *3* (weight)
weight engine(s) dry : 383.0 [kg] = 1.30 [kg/KW]
weight 27 litre oil tank : 2.3 [kg]
oil tank filled with 2.2 litre oil : 2.0 [kg]
oil in engine 16 litre oil : 14.7 [kg]
fuel in engine 2 litre fuel : 1.5 [kg]
weight 35 litre gravity patrol tank(s) : 5.3 [kg]
weight radiator : 42.2 [kg]
weight exhaust pipes & fuel lines 34.5 [kg]
weight self-starter : 7.2 [kg]
weight cowling 11.8 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 55.9 [kg]
total weight propulsion system : 558 [kg](34.3 [%])
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fuselage skeleton (wood gauge : 6.04 [cm]): 87 [kg]
bracing : 5.7 [kg]
fuselage covering ( 16.3 [m2] doped linen fabric) : 5.2 [kg]
weight controls + indicators: 6.7 [kg]
weight seats : 6.0 [kg]
weight other details, lighting set, etc. : 5.1 [kg]
weight bomb storage : 10.2 [kg]
weight 304 [litre] main fuel tank empty : 24.4 [kg]
weight oxygen/compressed air flasks for high altitude : 7.9 [kg]
weight engine mounts & firewalls : 15 [kg]
total weight fuselage : 173 [kg](10.6 [%])
***************************************************************
weight wing covering (doped linen fabric) : 26 [kg]
total weight ribs (86 ribs) : 97 [kg]
load on front upper spar (clmax) per running metre : 550.5 [N]
load on rear upper spar (vmax) per running metre : 357.2 [N]
total weight 8 spars : 53 [kg]
weight wings : 175 [kg]
weight wing/square meter : 4.38 [kg]
weight 8 interplane struts & cabane : 23.6 [kg]
weight cables (76 [m]) : 6.3 [kg] (= 83 [gram] per metre)
diameter cable : 3.7 [mm]
weight fin & rudder (1.9 [m2]) : 8.8 [kg]
weight stabilizer & elevator (4.5 [m2]): 20.0 [kg]
total weight wing surfaces & bracing : 234 [kg] (14.4 [%])
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weight machine-gun(s) : 48.6 [kg]
weight pivot mounting mg :6.0 [kg]
weight ammunition magazine(s) :3.4 [kg]
weight synchronizing system : 2.0 [kg]
weight armament : 60 [kg]
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wheel pressure : 812.5 [kg]
weight 2 wheels (760 [mm] by 95 [mm]) : 31.4 [kg]
weight tailskid : 2.2 [kg]
weight undercarriage with axle 23.7 [kg]
total weight landing gear : 57.3 [kg] (3.5 [%]
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calculated empty weight : 1082 [kg](66.6 [%])
weight oil for 4.4 hours flying : 17.9 [kg]
weight cooling fluids : 63.5 [kg]
weight 5 drums empty : 2.1 [kg]
weight ammunition (1485 rounds) : 52.3 [kg]
weight signal pistol with cartridges : 3.6 [kg]
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calculated operational weight empty : 1219 [kg] (75.0 [%])
published operational weight empty : 1085 [kg] (66.8 [%])
calculated empty weight higher then actual OWE, pls check
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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 : 121 [kg]
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operational weight : 1514 [kg](93.2 [%])
bombload could not be carried with fuel for 2 hours flying time
fuel reserve : 111 [kg] enough for 1.84 [hours] flying
operational weight fully loaded : 1625 [kg] with fuel tank filled for 93 [%]
published maximum take-off weight : 1625 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (operational without bombload) : 5.15 [kg/kW]
total power : 294.2 [kW] at 1750 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 3.4 [g] at 1000 [m]
limit load : 3.75 [g] ultimate load : 5.6 [g] load factor : 1.2 [g]
design flight time : 2.90 [hours]
design cycles : 95 sorties, design hours : 275 [hours]
operational wing loading : 371 [N/m^2]
wing stress (3 g) during operation : 254 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.15 ["]
max. angle of attack (stalling angle) : 12.07 ["]
angle of attack at max. speed : 1.11 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° :0.10 [ ]
lift coefficient at max. angle of attack : 1.15 [ ]
lift coefficient at max. speed : 0.20 [ ]
induced drag coefficient at max. speed : 0.0026 [ ]
drag coefficient at max. speed : 0.0394 [ ]
drag coefficient (zero lift) : 0.0369 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 83 [km/u]
landing speed at sea-level (OW without bombload): 99 [km/hr]
min. drag speed (max endurance) : 119 [km/hr] at 2972 [m](power :34 [%])
min. power speed (max range) : 131 [km/hr] at 2972 [m] (power:36 [%])
max. rate of climb speed : 119.0 [km/hr] at sea-level
cruising speed : 181 [km/hr] op 2972 [m] (power:60 [%])
design speed prop : 191 [km/hr]
maximum speed : 201 [km/hr] op 100 [m] (power:99 [%])
climbing speed at sea-level (without bombload) : 381 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 103 [m]
lift/drag ratio : 10.03 [ ]
max. practical ceiling : 6325 [m] with flying weight :1275 [kg]
practical ceiling (operational weight): 5525 [m] with flying weight :1514 [kg]
practical ceiling fully loaded (mtow- 1 hour fuel) : 5350 [m] with flying weight :1565 [kg]
published ceiling (5944 [m]
climb to 1500m (without bombload) : 4.37 [min]
climb to 3000m (without bombload) : 10.62 [min]
max. dive speed : 419.9 [km/hr] at 4350 [m] height
load factor at max. angle turn 2.41 ["g"]
turn radius at 500m: 62 [m]
time needed for 360* turn 10.7 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 1.62 [hours] with 2 crew and 146 [kg] bombload and 39.3 [%] fuel
published endurance : 3.63 [hours] with 2 crew and possible useful (bomb) load : 25 [kg] and 88.1 [%] fuel
action radius : 335 [km] with 2 crew and 20[kg] photo camera/radio transmitter or bombload
max range theoretically with additional fuel tanks for total 537 [litre] fuel : 1179 [km]
useful load with action-radius 250km : 227 [kg]
production : 41.02 [tonkm/hour]
oil and fuel consumption per tonkm : 1.57 [kg]
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Literature : Jane’s fighting aircraft WWI page 238
Bombers1914-19 page 141
Armament of British Aircraft 1909-1939 page 128
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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