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weight and performance calculations for the Douglas DC-4E
Douglas DC-4E
role : commuter airliner
importance : *
first flight : 7 June 1938 Clover field , Santa Monica with Carl Cover at the controls. operational : only one aircraft used operational
country : United States of America
design :
production : 1 prototype
general information :
For production aircraft cabin pressurization was foreseen. Fuselage was designed for
pressure difference. At 20.000ft pressure could be maintained equivalent to 12.000ft.
Fuel : main wing tanks : 1650 US Gallon, auxiliary tanks 400 US Gallon . 2050 us
Gallon = 7759 litre, estimated range with this amount of fuel : 2359 km.
Day capacity 42 and 30 as sleeper transport with sleeping beds.
It had a tail with 3 vertical stabilizers enabling use of existing hangars and to provide
sufficient fin-area to maintain flight on only 2 engines running at one side. Ceiling on
only 2 engines was 2440m.
To complex design, became to expensive and only one example built. It was used by
United Airlines in 1939 for evaluation but due to its complex systems to expensive to
maintain. End of 1939 the only aircraft was sold to Japan, to Imperial Japanese
Airways. The Japanese studied the design and the information was used to develop the
Nakajima G5N bomber.
users : United airlines, Imperial Japanese Airlines
registration : NX18100
crew : 3 passengers : 42
powerplant : 4 Pratt & Whitney R-2180-S1A1-G Twin Hornet air-cooled 14 -cylinder radial engine 1150 [hp](857.6 KW)
normal rating, supercharged engine, low blower, constant power to height : 1830 [m]
and with 1400 [hp](1044.0 KW) available for take-off
dimensions :
wingspan : 42.14 [m], length : 29.74 [m], height : 7.48 [m]
wing area : 200.21 [m^2]
weights :
max.take-off weight : 30164 [kg]
empty weight operational : 19307 [kg] useful load : 4200 [kg]
performance :
maximum speed :394 [km/u] op 2134 [m]
cruise speed :374 [km/u] op 2134 [m]
service ceiling : 7000 [m]
range : 2359 [km]
description :
low-winged monoplane with retractable landing gear with nose wheel
tapered multi-cellular wing with flush-riveted stressed skin
with hydraulically-operated trailing-edge split flaps airfoil : unknown
engines and landing gear attached to the wings, fuel tanks in the wings
construction : all-metal stressed-skin (duraluminium) airplane
airscrew :
four Hamilton Standard hydromatic 3 -bladed tractor airscrews with max. efficiency
:0.74 [ ]
estimated diameter airscrew 4.34 [m]
relative pitch (J) : 1.12 [ ]
power loading prop : 131.73 [KW/m]
theoretical pitch without slip : 5.52 [m]
blade angle prop at max.speed : 29.35 [ ]
tip-speed close to speed of sound (above Mach 0.85) > loose of efficiency
reduction : 0.56 [ ]
airscrew revs : 1322 [r.p.m.]
aerodynamic pitch at max. continuous speed 4.84 [m]
blade-tip speed at max.continuous speed : 319 [m/s]
propellor noise in flight : 110 [Db]
additional sound isolation of the fuselage needed
calculation : *1* (dimensions)
measured wing chord : 4.56 [m] at 50% wingspan
mean wing chord : 4.75 [m]
calculated average wing chord tapered wing with rounded tips: 4.60 [m]
wing aspect ratio : 8.9 []
seize (span*length*height) : 9374 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 44.6 [kg/hr]
fuel consumption(cruise speed) : 795.0 [kg/hr] (1084.5 [litre/hr]) at 71 [%] power
distance flown for 1 kg fuel : 0.47 [km/kg] at 3500 [m] height, sfc : 326.7 [kg/kwh]
estimated total fuel capacity : 7758 [litre] (5687 [kg])
calculation : *3* (weight)
weight engine(s) dry with reduction gear : 2988.0 [kg] = 0.87 [kg/KW]
weight 461.4 litre oil tank : 39.22 [kg]
oil tank filled with 25.7 litre oil : 23.1 [kg]
oil in engine 19.1 litre oil : 17.2 [kg]
fuel in engine 23.4 litre fuel : 17.15 [kg]
weight 461.1 litre gravity patrol tank(s) : 69.2 [kg]
weight Burgess type silencers : 68.6 [kg]
weight NACA cowling 38.4 [kg]
weight variable pitch control : 73.4 [kg]
weight airscrew(s) incl. boss & bolts : 954.0 [kg]
total weight propulsion system : 4215 [kg](14.0 [%])
***************************************************************
fuselage aluminium frame : 3349 [kg]
cabin layout : pitch : 87 [cm] ( 2+2 ) seating in 10 rows
weight two toilets : 16 [kg]
weight 4 fire extinguisher : 12 [kg]
weight pantry : 37.1 [kg]
weight garderobe : 21.0 [kg]
weight 22 windows : 19.8 [kg]
weight door : 5.0 [kg]
passenger cabin max.width : 3.34 [m] cabin length : 11.90 [m] cabin height : 1.90 [m]
weight cabin furbishing : 272.2 [kg]
weight cabin floor : 241.3 [kg]
pressure at cruise height : 0.47 [kg/cm2] cabin pressure : 0.66 [kg/cm2]
fuselage covering ( 228.9 [m2] duraluminium 3.49 [mm]) : 2124.8 [kg]
fuselage (sound proof) isolation : 104.7 [kg]
weight radio transceiver equipment : 7.0 [kg]
weight artificial horizon : 1.1 [kg]
weight instruments. : 8.0 [kg]
weight APU : 50 [kg]
weight lighting : 10.5 [kg]
weight electricity generator : 10.5 [kg]
weight controls : 14.3 [kg]
weight seats : 225.0 [kg]
weight air conditioning : 63 [kg]
weight hot and cold running water system : 36 [kg]
total weight fuselage : 6517 [kg](21.6 [%])
***************************************************************
total weight aluminium ribs (324 ribs) : 1076 [kg]
weight engine mounts : 172 [kg]
weight fuel tanks empty for total 7297 [litre] fuel : 584 [kg]
weight wing covering (painted aluminium 2.14 [mm]) : 2314 [kg]
total weight aluminium spars (multi-cellular wing structure) : 1700 [kg]
weight wings : 5090 [kg]
weight wing/square meter : 25.42 [kg]
cantilever wing without bracing cables
weight rubber de-icing boots : 46.4 [kg]
weight fin & rudder (20.6 [m2]) : 527.1 [kg]
weight stabilizer & elevator (22.5 [m2]): 574.2 [kg]
weight flight control servo actuators: 35.1 [kg]
weight split flap (10.0 [m2]) : 130.3 [kg]
total weight wing surfaces & bracing : 7159 [kg] (23.7 [%])
*******************************************************************
wheel pressure : 15082.0 [kg]
weight 2 Dunlop main wheels (1740 [mm] by 348 [mm]) : 692.4 [kg]
weight nose wheel : 55.8 [kg]
weight Bendix wheel-brakes : 23.5 [kg]
weight pneumatic-hydraulic shock absorbers : 31.3 [kg]
weight undercarriage with axle 412.6 [kg]
total weight landing gear : 1215.6 [kg] (4.0 [%]
*******************************************************************
********************************************************************
calculated empty weight : 19106 [kg](63.3 [%])
weight oil for 7.6 hours flying : 337.3 [kg]
calculated operational weight empty : 19444 [kg] (64.5 [%])
published operational weight empty : 19307 [kg] (64.0 [%])
weight crew : 243 [kg]
weight fuel for 2.0 hours flying : 1590 [kg]
weight catering : 92.6 [kg]
weight water : 74.1 [kg]
********************************************************************
operational weight empty: 21443 [kg](71.1 [%])
weight 42 passengers : 3234 [kg]
weight luggage & freight : 966 [kg]
operational weight loaded: 25643 [kg](85.0 [%])
fuel reserve : 4096.6 [kg] enough for 5.15 [hours] flying
possible additional useful load : 424 [kg]
operational weight fully loaded : 30164 [kg] with fuel tank filled for 100 [%]
published maximum take-off weight : 30164 [kg] (100.0 [%])
calculation : * 4 * (engine power)
power loading (Take-off) : 8.79 [kg/kW]
power loading (operational without useful load) : 6.25 [kg/kW]
power loading (Take-off) 1 PUF: 11.72 [kg/kW]
total power : 3430.2 [kW] at 2350 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 6.1 [g] at 1000 [m]
limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 1.3 [g]
design flight time : 4.41 [hours]
design cycles : 2585 sorties, design hours : 11405 [hours]
operational wing loading : 1050 [N/m^2]
wing stress (3 g) during operation : 124 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.81 ["]
max. angle of attack (stalling angle) : 13.07 ["]
angle of attack at max. speed : 0.19 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° : 0.16 [ ]
lift coefficient at max. speed : 0.18 [ ]
lift coefficient at max. angle of attack : 1.31 [ ]
max.lift coefficient full flaps : 1.41 [ ]
induced drag coefficient at max.speed : 0.0014 [ ]
drag coefficient at max. speed : 0.0201 [ ]
drag coefficient (zero lift) : 0.0186 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW loaded : 29369 [kg]): 152 [km/u]
stalling speed at sea-level with full flaps (normal landing weight): 126 [km/u]
landing speed at sea-level (normal landing weight : 21599 [kg]): 145 [km/hr]
max. rate of climb speed : 156 [km/hr] at sea-level
max. endurance speed : 171 [km/u] min.fuel/hr : 408 [kg/hr] at height : 610 [m]
max. range speed : 272 [km/u] at cruise height : 4267 [m]
cruising speed : 374 [km/hr] at 3500 [m] (power:88 [%])
max. continuous speed : 384.15 [km/hr]
maximum speed : 394 [km/hr] at 2134 [m] (power:109 [%])
climbing speed at sea-level (loaded) : 431 [m/min]
climbing speed at 1000 [m] with 1 engine out (PUF / MTOW) : 261 [m/min]
climbing speed at 1000 [m] with 2 engines out (2xPUF / MTOW) : 94 [m/min]
calculation : *9* (regarding various performances)
take-off speed : 185.1 [km/u]
emergency/TO power : 1400 [hp] at 2593 [rpm]
static prop wash : 210 [km/u]
take-off distance at sea-level gras field : 331 [m]
take-off distance at sea-level over 15 [m] height : 421 [m]
landing run : 269 [m]
lift/drag ratio : 17.03 [ ]
climb to 1000m with max payload : 3.17 [min]
climb to 2000m with max payload : 6.56 [min]
climb to 3000m with max payload : 11.14 [min]
practical ceiling (operational weight empty 21443 [kg] ) : 7700 [m]
practical ceiling fully loaded (mtow- 30 min.fuel:29767 [kg] ) : 5800 [m]
calculation *10* (action radius & endurance)
published range : 2359 [km] with 3 crew and 5467.3 [kg] useful load and 88.1 [%] fuel
range : 2956 [km] with 3 crew and 4200.0 [kg] useful load and 110.4 [%] fuel
range : 3213 [km] with 42.0 passengers with each 10 [kg] luggage and 120.0 [%] fuel
Available Seat Kilometres (ASK) : 134937 [paskm]
max range theoretically with additional fuel tanks total 14515.0 [litre] fuel : 5168 [km]
useful load with range 500km : 9578 [kg]
useful load with range 500km : 42 passengers
production (useful load): 3585 [tonkm/hour]
production (passengers): 15721 [paskm/hour]
combi aircraft mail/freight/passengers
oil and fuel consumption per tonkm : 0.23 [kg]
fuel cost per paskm : 0.023 [eur]
crew cost per paskm : 0.008 [eur]
time between engine failure : 470 [hr]
can continue fly on 3 engines, low risk for emergency landing for PUF
writing off per paskm : 0.039 [eur]
insurance per paskm : 0.001 [eur]
maintenance cost per paskm : 0.087 [eur]
direct operating cost per paskm : 0.159 [eur]
direct operating cost per tonkm : 1.590 [eur]
Literature :
Piston-engined airliners page 43,44
Jane’s all the world aircraft 1938 page 265c
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. For copyright on drawings/photographs/
content please mail to below mail address
(c) B van der Zalm 22 January 2022 contact : info.aircraftinvestigation@gmail.com python 3.7.4