Aircraft investigation >>>>>>> HOME PAGE
weight and performance calculations for the Douglas DC-3
Douglas DC-3
importance : *****
first flight : 17 December 1935 operational : 25 June 1936
country : United States of America
design : design team led by Arthur E. Raymond
production : 607 civil aircraft (including military production 1936-1947 : 10.654 aircraft by Douglas, 485 built under license in Japan and 2000 in Russia as Li-2)
general information :
Designed as Sleeper Transport, a scaled up DC-2 with roomy fuselage for 21
passengers. It was a big success. It was the standard passenger airliner for many
airlines before WWII serving 90% of the market. It could cross the USA eastbound
from Los Angeles to New York in 15 hours, with only 3 stops. Westbound against the
wind it took 17.5 hrs. (4000 km, a stop takes ca. 30 min, without wind actual time in
the air ca. 15 hr > gives average speed of 266 km/hr)
In WWII thousands were built for the military as troop transport and cargo plane,
known as Dakota. The DC-3 and Dakota was used for long time after WWII.
In 2017 about 300 DC-3’s were still being used in a variety of roles !
Fuel Capacity : 3736 litre
users : American Airlines, United Airlines, KLM, and many more
crew : 3 passengers : 21
engine : 2 Wright GR-1820-G102A Cyclone air-cooled 9 -cylinder radial engine 900 [hp](671.1 KW)
supercharged engine, constant power to height : 2134 [m]
dimensions :
wingspan : 28.96 [m], length : 19.7 [m], height : 5.16 [m]
wing area : 91.7 [m^2]
weights :
max.take-off weight : 11415 [kg]
empty weight operational : 7650 [kg] useful load : 2100 [kg]
performance :
maximum speed :313 [km/u] op 2000 [m]
cruise speed :297 [km/u] op 2000 [m]
service ceiling : 6840 [m]
range : 2091 [km]
description :
low-winged monoplane with retractable landing gear with tail wheel
tapered wing with split flap airfoil : root : NACA 2215 tip : NACA 2206
engines and landing gear attached to the wings, fuel tanks in the wings
construction : all-metal stressed-skin (duraluminium) airplane
airscrew :
two Hamilton Standard constant-speed 3 -bladed tractor airscrews with max. efficiency
:0.74 [ ]
estimated diameter airscrew 3.19 [m]
power loading prop : 140.26 [KW/m]
angle of attack prop at max. speed : 25.75 [ ]
reduction : 0.62 [ ]
airscrew revs : 1438 [r.p.m.]
pitch at Max speed 3.62 [m]
blade-tip speed at Vmax and max revs. : 255 [m/s]
calculation : *1* (dimensions)
measured wing chord : 3.10 [m] at 50% wingspan
mean wing chord : 3.17 [m]
calculated average wing chord tapered wing with rounded tips: 3.06 [m]
wing aspect ratio : 9.15 []
seize (span*length*height) : 2944 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 18.8 [kg/hr]
fuel consumption(cruise speed) : 304.6 [kg/hr] (415.6 [litre/hr]) at 75 [%] power
distance flown for 1 kg fuel : 0.97 [km/kg] at 3420 [m] height, sfc : 302.6 [kg/kwh]
total fuel capacity : 3736 [litre] (2739 [kg])
calculation : *3* (weight)
weight engine(s) dry : 1060.0 [kg] = 0.79 [kg/KW]
weight reduction gear : 56.4 [kg]
weight 210.4 litre oil tank : 17.88 [kg]
oil tank filled with 10.1 litre oil : 9.0 [kg]
oil in engine 7.5 litre oil : 6.7 [kg]
fuel in engine 9.2 litre fuel : 6.71 [kg]
weight 176.7 litre gravity patrol tank(s) : 26.5 [kg]
weight starter (E.H.I. - Electric Hand Inertia): 16.4 [kg]
weight NACA cowling 30.1 [kg]
weight variable pitch control : 13.4 [kg]
weight airscrew(s) incl. boss & bolts : 174.7 [kg]
total weight propulsion system : 1443 [kg](12.6 [%])
***************************************************************
fuselage aluminium frame : 1366 [kg]
cabin layout : pitch : 87 [cm] (2+1) seating in 7.0 rows
weight toilet : 8 [kg]
weight 2 fire extinguisher : 6 [kg]
weight pantry : 20.7 [kg]
weight 14 windows : 12.6 [kg]
passenger cabin width : 2.30 [m] cabin length : 6.69 [m] cabin height : 1.90 [m]
weight cabin furbishing : 82.2 [kg]
weight cabin floor : 98.5 [kg]
fuselage covering ( 104.0 [m2] duraluminium 3.94 [mm]) : 1083.0 [kg]
fuselage (sound proof) isolation : 30.5 [kg]
weight radio transceiver equipment : 7.0 [kg]
weight Sperry gyro auto-pilot - course control equipment : 1.5 [kg]
weight instruments. : 6.0 [kg]
weight lighting : 5.2 [kg]
weight electricity generator : 11.0 [kg]
weight controls : 10.0 [kg]
weight seats : 120.0 [kg]
weight air conditioning : 32 [kg]
total weight fuselage : 2856 [kg](25.0 [%])
***************************************************************
total weight aluminium ribs (184 ribs) : 407 [kg]
weight engine mounts : 67 [kg]
weight two 1572 [litre] main fuel tanks empty : 251.5 [kg]
weight wing covering (painted aluminium 1.46 [mm]) : 721 [kg]
total weight aluminium spars (multi-cellular wing structure) : 709 [kg]
weight wings : 1837 [kg]
weight wing/square meter : 20.04 [kg]
cantilever wing without bracing cables
weight rubber de-icing boots : 31.9 [kg]
weight fin & rudder (9.7 [m2]) : 196.5 [kg]
weight stabilizer & elevator (10.3 [m2]): 207.4 [kg]
weight split flap(4.6 [m2]) : 48.9 [kg]
total weight wing surfaces & bracing : 2641 [kg] (23.1 [%])
*******************************************************************
Can only operate from paved runways
wheel pressure : 5707.5 [kg]
weight 2 wheels (1170 [mm] by 234 [mm]) : 272.3 [kg]
weight tailwheel(s) : 5.9 [kg]
weight wheel hydraulic operated retraction system : 44.4 [kg]
weight undercarriage with axle 342.9 [kg]
total weight landing gear : 665.5 [kg] (5.8 [%]
*******************************************************************
********************************************************************
calculated empty weight : 7605 [kg](66.6 [%])
weight oil for 8.4 hours flying : 158.8 [kg]
calculated operational weight empty : 7764 [kg] (68.0 [%])
published operational weight empty : 7650 [kg] (67.0 [%])
___o___
" "
weight crew : 243 [kg]
weight fuel for 2.0 hours flying : 609 [kg]
weight catering : 51.7 [kg]
weight water : 20.7 [kg]
********************************************************************
operational weight empty: 8689 [kg](76.1 [%])
weight 21 passengers : 1617 [kg]
weight luggage & freight : 483 [kg]
operational weight loaded: 10789 [kg](94.5 [%])
fuel reserve : 626.1 [kg] enough for 2.06 [hours] flying
operational weight fully loaded : 11415 [kg] with fuel tank filled for 51 [%]
published maximum take-off weight : 11415 [kg] (100.0 [%])
calculation : * 4 * (engine power)
power loading (Take-off) : 8.50 [kg/kW]
power loading (operational without useful load) : 6.47 [kg/kW]
power loading (Take-off) 1 PUF: 17.01 [kg/kW]
total power : 1342.3 [kW] at 2300 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 4.3 [g] at 1000 [m]
limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 2.2 [g]
design flight time : 4.93 [hours]
design cycles : 5964 sorties, design hours : 29394 [hours]
operational wing loading : 929 [N/m^2]
wing stress (3 g) during operation : 139 [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 : 0.96 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° : 0.16 [ ]
lift coefficient at max. angle of attack : 1.31 [ ]
max.lift coefficient full flaps : 1.41 [ ]
lift coefficient at max. speed : 0.24 [ ]
induced drag coefficient at max. speed : 0.0028 [ ]
drag coefficient at max. speed : 0.0326 [ ]
drag coefficient (zero lift) : 0.0299 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW loaded : 11110 [kg]): 138 [km/u]
stalling speed at sea-level with full flaps (normal landing weight): 119 [km/u]
landing speed at sea-level (normal landing weight : 8913 [kg]): 137 [km/hr]
max. endurance speed : 138 [km/u] min. brpu : 143 [kg/hr] at cruise height : 100 [m]
max. rate of climb speed : 141.9 [km/hr] at sea-level
max. range speed : 193 [km/u] min.fuel cons.: 0.920 [kg/km] at cruise height : 1710 [m]
The DST had an additional row of windows, for the upper bunk beds, here visible above the United Air Lines titles.
cruising speed : 297 [km/hr] at 3420 [m] (power:85 [%])
maximum speed : 313 [km/hr] at 2000 [m] (power:105 [%])
climbing speed at sea-level (loaded) : 368 [m/min]
climbing speed at 1000 [m] with 1 engine out (PUF / MTOW) : 88 [m/min]
calculation : *9* (regarding various performances)
take-off speed : 168.3 [km/u]
emergency/TO power : 1000 [hp] at 2424 [rpm]
static prop wash : 160 [km/u]
high wheel pressure, can only take off from paved runways
take-off distance at sea-level : 562 [m]
lift/drag ratio : 13.43 [ ]
climb to 1000m with max payload : 3.09 [min]
climb to 2000m with max payload : 6.28 [min]
climb to 3000m with max payload : 10.39 [min]
practical ceiling (operational weight 8689 [kg] ) : 7500 [m]
practical ceiling fully loaded (mtow- 30 min.fuel:11263 [kg] ) : 6000 [m]
calculation *10* (action radius & endurance)
published range : 2091 [km] with 3 crew and 1263.2 [kg] useful load and 88.1 [%] fuel
range : 1275 [km] with 3 crew and 2100.0 [kg] useful load and 53.7 [%] fuel
range : 1541 [km] with 21.0 passengers with each 10 [kg] luggage and 64.9 [%] fuel
Available Seat Kilometres (ASK) : 32366 [paskm]
max range theoretically with additional fuel tanks total 4870.1 [litre] fuel : 3882 [km]
useful load with range 500km : 3057 [kg]
useful load with range 500km : 21 passengers
production (useful load): 908 [tonkm/hour]
production (passengers): 6237 [paskm/hour]
oil and fuel consumption per tonkm : 0.36 [kg]
fuel cost per paskm : 0.036 [eur]
crew cost per paskm : 0.033 [eur]
Measured chord at root : 4.52 [m]
economic hours : 12775 [hours] is less then design hours
time between engine failure : 58 [hr]
can continue fly on 1 engine, low risk for emergency landing for PUF
writing off per paskm : 0.055 [eur]
insurance per paskm : 0.026 [eur]
maintenance cost per paskm : 0.128 [eur]
direct operating cost per paskm : 0.277 [eur]
direct operating cost per tonkm : 2.773 [eur]
2+1 layout, 7 rows > 21 passengers was the normal layout in the 1930’s.
Literature :
Piston-engined airliners page 34, 35
Praktisch handboek vliegtuigen deel 2 page262,263
Split flaps applied for slow approach
The stewardess was introduced in the 1930’s
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 October 2021 contact : info.aircraftinvestigation@gmail.com python 3.7.4