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weight and performance calculations for the Douglas DC-2
PH-AJU “Uiver” flying over Amsterdam (?)
Douglas DC-2
role : multi-engined passenger aircraft
importance : ****
first flight : 11 May 1934 operational : May 1934
country : United States of America
design :
production : 198 aircraft
general information :
TWA wanted to buy the Boeing 247, but first production was for United Airlines, who had exclusive rights, occupying the production line. TWA then turned to Douglas to build a new aircraft. This resulted in the DC-1, first flying 1 July 1933, an even more advanced design with variable pitch propellors, retractable landing gear, split flaps for low landing speed and place for 12 passengers. Only one was built, soon followed by the even better DC-2 with more powerful engines, longer fuselage with place for 14 passengers. TWA was launch customer and ordered 20.
The DC-2 flew on the important Los Angeles -New York route, flying the distance in 18 hours.
KLM entered its first DC-2 PH-AJU “Uiver” in the October 1934 Macrobertson Air Race, also known as the Melbourne race, between London and Melbourne. Out of 20 participants, including an Boeing 247D, it arrived second, only behind the purpose-built De Havilland DH.88 racer.
Vland : 58 knots = 107 km/hr. With it’s high wheel pressure it could only operated from paved runways. During the Melbourne race it made an emergency landing near Albury, Australia, it get stuck in the soft ground !
users : TWA, KLM (18), LOT, Swissair, CLS, LAPE
registrations : PH-AJU “Uiver”, PH-AKS, PH-ALF, PH-AKJ “Jan van Gent”, PH-AKH “Haan”
crew : 3 passengers : 14
engine : 2 Wright SGR-1820-F3 Cyclone air-cooled 9 -cylinder radial engine 710 [hp]
(529.4 KW) supercharged engine, constant power to height : 2134 [m]
dimensions :
wingspan : 25.91 [m], length : 18.89 [m], height : 4.97 [m]
wing area : 87.2 [m^2]
weights :
max.take-off weight : 8419 [kg]
empty weight operational : 5628 [kg] useful load : 1400 [kg]
performance :
maximum speed :340 [km/u] op 2400 [m]
cruise speed :323 [km/u] op 2400 [m]
service ceiling : 6840 [m]
range : 1600 [km]
description :
low-winged monoplane with retractable landing gear with tail wheel
tapered wing with split flap airfoil : root : NACA 2215 tip : NACA 2209
engines and landing gear attached to the wings, fuel tanks in the wings
construction : all-metal stressed-skin (duraluminium) airplane
airscrew :
two Hamilton Standard variable pitch 3 -bladed tractor airscrews with max. efficiency
:0.73 [ ]
estimated diameter airscrew 3.12 [m]
power loading prop : 113.13 [KW/m]
prop efficiency ratio: 9.78 [1/s]
angle of attack prop at max. speed : 30.43 [ ]
reduction : 0.62 [ ]
airscrew revs : 1312 [r.p.m.]
pitch at Max speed 4.32 [m]
blade-tip speed at Vmax and max revs. : 234 [m/s]
calculation : *1* (dimensions)
measured wing chord : 3.60 [m] at 50% wingspan
mean wing chord : 3.37 [m]
calculated average wing chord tapered wing with rounded tips: 3.24 [m]
wing aspect ratio : 7.70 []
seize (span*length*height) : 2433 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 14.8 [kg/hr]
fuel consumption(cruise speed) : 256.2 [kg/hr] (349.5 [litre/hr]) at 75 [%] power
distance flown for 1 kg fuel : 1.26 [km/kg] at 3420 [m] height, sfc : 322.6 [kg/kwh]
estimated total fuel capacity : 1965 [litre] (1440 [kg])
calculation : *3* (weight)
weight engine(s) dry : 820.0 [kg] = 0.77 [kg/KW]
weight reduction gear : 44.5 [kg]
weight 124.6 litre oil tank : 10.59 [kg]
oil tank filled with 7.9 litre oil : 7.1 [kg]
oil in engine 5.9 litre oil : 5.3 [kg]
fuel in engine 7.2 litre fuel : 5.29 [kg]
weight 148.6 litre gravity patrol tank(s) : 22.3 [kg]
weight starter (E.H.I. - Electric Hand Inertia): 13.0 [kg]
weight NACA cowling 23.7 [kg]
weight variable pitch control : 10.7 [kg]
weight airscrew(s) incl. boss & bolts : 138.8 [kg]
total weight propulsion system : 1124 [kg](13.4 [%])
***************************************************************
fuselage aluminium frame : 1054 [kg]
cabin layout : pitch : 87 [cm] (1+1) seating in 7.0 rows
weight toilet : 8 [kg]
weight 2 fire extinguisher : 6 [kg]
weight 14 windows : 12.6 [kg]
passenger cabin width : 1.67 [m] cabin length : 6.69 [m] cabin height : 1.90 [m]
weight cabin furbishing : 48.9 [kg]
weight cabin floor : 71.6 [kg]
fuselage covering ( 80.2 [m2] duraluminium 3.05 [mm]) : 640.9 [kg]
fuselage (sound proof) isolation : 23.4 [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 : 3.5 [kg]
weight electricity generator : 7.7 [kg]
weight controls : 9.4 [kg]
weight seats : 85.0 [kg]
weight air conditioning : 21 [kg]
total weight fuselage : 1974 [kg](23.5 [%])
***************************************************************
total weight aluminium ribs (128 ribs) : 300 [kg]
weight engine mounts : 53 [kg]
weight two 908 [litre] main fuel tanks empty : 145.3 [kg]
weight wing covering (painted aluminium 1.22 [mm]) : 573 [kg]
total weight aluminium spars (multi-cellular wing structure) : 519 [kg]
weight wings : 1392 [kg]
weight wing/square meter : 15.96 [kg]
cantilever wing without bracing cables
weight fin & rudder (7.8 [m2]) : 125.6 [kg]
weight stabilizer & elevator (9.8 [m2]): 157.3 [kg]
weight split flap(4.4 [m2]) : 37.8 [kg]
total weight wing surfaces & bracing : 1939 [kg] (23.0 [%])
*******************************************************************
wheel pressure : 4209.5 [kg]
weight 2 wheels (1040 [mm] by 208 [mm]) : 180.7 [kg]
weight tailwheel(s) : 5.9 [kg]
weight wheel hydraulic operated retraction system : 35.7 [kg]
weight undercarriage with axle 313.6 [kg]
total weight landing gear : 535.9 [kg] (6.4 [%]
*******************************************************************
********************************************************************
calculated empty weight : 5574 [kg](66.2 [%])
weight oil for 5.9 hours flying : 88.1 [kg]
calculated operational weight empty : 5662 [kg] (67.3 [%])
published operational weight empty : 5628 [kg] (66.8 [%])
___o___
" “
weight crew : 243 [kg]
weight fuel for 2.0 hours flying : 512 [kg]
weight catering : 24.3 [kg]
weight water : 9.7 [kg]
********************************************************************
operational weight empty: 6452 [kg](76.6 [%])
weight 14 passengers : 1078 [kg]
weight luggage & freight : 322 [kg]
operational weight loaded: 7852 [kg](93.3 [%])
fuel reserve : 567.4 [kg] enough for 2.21 [hours] flying
operational weight fully loaded : 8419 [kg] with fuel tank filled for 75 [%]
published maximum take-off weight : 8419 [kg] (100.0 [%])
calculation : * 4 * (engine power)
power loading (Take-off) : 7.95 [kg/kW]
power loading (operational without useful load) : 6.09 [kg/kW]
power loading (Take-off) 1 PUF: 15.90 [kg/kW]
total power : 1058.9 [kW] at 2100 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 6.6 [g] at 1000 [m]
limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 2.4 [g]
design flight time : 3.47 [hours]
design cycles : 7750 sorties, design hours : 26872 [hours]
operational wing loading : 726 [N/m^2]
wing stress (3 g) during operation : 136 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.89 ["]
max. angle of attack (stalling angle) : 13.65 ["]
angle of attack at max. speed : 0.10 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° : 0.16 [ ]
lift coefficient at max. angle of attack : 1.32 [ ]
max.lift coefficient full flaps : 1.42 [ ]
lift coefficient at max. speed : 0.17 [ ]
induced drag coefficient at max. speed : 0.0016 [ ]
drag coefficient at max. speed : 0.0209 [ ]
drag coefficient (zero lift) : 0.0194 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW empty + crew + 2 hrs fuel) : 6452 [kg]): 108 [km/u]
landing speed at sea-level (normal landing weight : 6580 [kg]): 121 [km/hr]
max. endurance speed : 138 [km/u] min. brpu : 101 [kg/hr] at cruise height : 100 [m]
max. rate of climb speed : 134.8 [km/hr] at sea-level
max. range speed : 197 [km/u] min.fuel cons.: 0.639 [kg/km] at cruise height : 1710 [m]
cruising speed : 323 [km/hr] at 3420 [m] (power:54 [%])
design speed prop : 340 [km/hr]
maximum speed : 340 [km/hr] at 2400 [m] (power:66 [%])
climbing speed at sea-level (loaded) : 431 [m/min]
climbing speed at 1000 [m] with 1 engine out (PUF / MTOW) : 112 [m/min]
calculation : *9* (regarding various performances)
take-off speed : 148.0 [km/u]
emergency/TO power : 750 [hp] at 2158 [rpm]
static prop wash : 140 [km/u]
take-off distance at sea-level : 391 [m]
lift/drag ratio : 15.29 [ ]
climb to 1000m with max payload : 1.48 [min]
climb to 2000m with max payload : 2.98 [min]
climb to 3000m with max payload : 4.60 [min]
practical ceiling (operational weight 6452 [kg] ) : 9653 [m]
practical ceiling fully loaded (mtow- 30 min.fuel:8291 [kg] ) : 8533 [m]
calculation *10* (action radius & endurance)
published range : 1600 [km] with 3 crew and 1244.7 [kg] useful load and 88.1 [%] fuel
range : 1404 [km] with 3 crew and 1400.0 [kg] useful load and 77.3 [%] fuel
range : 1634 [km] with 14.0 passengers with each 10 [kg] luggage and 90.0 [%] fuel
Available Seat Kilometres (ASK) : 22871 [paskm]
max range theoretically with additional fuel tanks total 3650.4 [litre] fuel : 4190 [km]
useful load with range 500km : 2279 [kg]
useful load with range 500km : 14 passengers
production (useful load): 736 [tonkm/hour]
production (passengers): 4522 [paskm/hour]
oil and fuel consumption per tonkm : 0.37 [kg]
fuel cost per paskm : 0.037 [eur]
crew cost per paskm : 0.041 [eur]
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 : 0.049 [eur]
insurance per paskm : 0.033 [eur]
maintenance cost per paskm : 0.142 [eur]
direct operating cost per paskm : 0.302 [eur]
direct operating cost per tonkm : 3.019 [eur]
The Uiver at Darwin
“Uiver” stuck in the mud at Albury, Australia. It had made an emergency landing on the race track forced by a severe thunderstorm on 23 October 1934. Cars of the villagers had lighted the track to guide the DC-2 to a save landing.
Literature :
Piston-engined airliners page 33
Praktisch handboek deel 2 page 261,262
“Wij” in de melbourne-race
https://www.klm-va.nl/php/sites/event_historical/aircrafttypes_douglas.php?aircrafttype=DC2
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/
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(c) B van der Zalm 22 October 2021 contact : info.aircraftinvestigation@gmail.com python 3.7.4