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weight and performance calculations for the Douglas DC-6
Douglas DC-6
role : commuter prop 50
importance : ****
first flight : 29 June 1946 operational : March 1947
country : United States of America
design :
production : DC-6 175 aircraft
general information :
Successor of the successful Skymaster. Designed as military transport aircraft for the
USAAF. It was bigger, more powerful and had a pressurized cabin. It made the first
flight as XC-112A on 15 February 1946. With the end of WWII the need for the
military transport version was no longer there and Douglas converted it to a civil
airliner. Making the first flight in June 1946 and entering service with United
Airlines in the spring of 1947 on the trans-continental routes across the USA.
It turned out into a successful airliner. The KLM flew till 1957 with the DC-6.
Cabin width : 3.18m (same as the DC-4) Fuel capacity : 16100 litre or 17870 litre.
Landing weight : 28830 kg Max. Cruise speed : 534 km/hr at 7260m Normal cruising
speed at 60% power : 445 km/hr. landing speed : 140 km/hr
primary users : United Airlines (35), American Airlines (47), KLM (8), SABENA, SAS
flight crew : 3 cabin crew : 3 passengers : 48-68
powerplant : 4 Pratt & Whitney R-2800-CA15 Double Wasp air-cooled 18 -cylinder
radial engine 2100 [hp] (1566.0 KW) normal rating, supercharged engine, high blower,
constant power to height : 4000 [m] and with 2400 [hp](1789.7 KW) available for
take-off
dimensions :
wingspan : 35.81 [m], length : 30.66 [m], height : 8.66 [m]
wing area : 135.9 [m^2]
weights :
max.take-off weight : 44100 [kg]
empty weight operational : 23844 [kg] useful load : 6800 [kg]
performance :
maximum continous speed : 534 [km/u] op 4000 [m]
normal cruise speed : 501 [km/u] op 6000 [m] (72 [%] power)
service ceiling : 6700 [m]
range with max fuel : 5375 [km] and allowance for 475.1 [km] diversion and 30 [min]
hold
description :
low-winged monoplane with retractable landing gear with nose wheel
tapered multi-cellular wing with flush-riveted stressed skin
with Fowler flaps airfoil : NACA
engines and landing gear attached to the wings, fuel tanks in the wings
construction : all-metal aluminium-alloy stressed-skin construction with pressurized
fuselage. fuselage shape : O
airscrew :
four Hamilton-Standard constant speed, reversible pitch 3 -bladed tractor airscrews
max. efficiency :0.82 [ ]
diameter airscrew 4.04 [m]
relative pitch (J) : 2.04 [ ]
power loading prop : 258.41 [KW/m]
theoretical pitch without slip : 9.15 [m]
blade angle prop at max.speed : 44.89 [ ]
reduction : 0.40 [ ]
airscrew revs : 1080 [r.p.m.]
aerodynamic pitch at max. continuous speed 8.24 [m]
blade-tip speed at max.continuous speed : 272 [m/s]
propellor noise in flight : 94 [Db]
calculation : *1* (dimensions)
measured wing chord : 3.77 [m] at 50% wingspan
mean wing chord : 3.80 [m]
calculated average wing chord tapered wing with rounded tips: 3.68 [m]
wing aspect ratio : 9.4 []
seize (span*length*height) : 9508 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 56.4 [kg/hr]
fuel consumption (econ. cruise speed) : 1283.0 [kg/hr] (1750.4 [litre/hr]) at 72 [%]
power
distance flown for 1 kg fuel : 0.39 [km/kg] at 6000 [m] height, sfc : 285.0 [kg/kwh]
estimated total fuel capacity : 17870 [litre] (13080 [kg])
calculation : *3* (weight)
weight engine(s) dry with reduction gear : 4292.0 [kg] = 0.69 [kg/KW]
weight 965.1 litre oil tank : 82.03 [kg]
oil tank filled with 47.0 litre oil : 42.2 [kg]
oil in engine 34.9 litre oil : 31.3 [kg]
fuel in engine 42.7 litre fuel : 31.32 [kg]
weight 744.2 litre gravity patrol tank(s) : 111.6 [kg]
weight jet stacks : 156.6 [kg]
weight NACA cowling 70.2 [kg]
weight variable pitch control : 36.2 [kg]
weight airscrew(s) incl. boss & bolts : 903.8 [kg]
total weight propulsion system : 5721 [kg](13.0 [%])
***************************************************************
fuselage aluminium frame : 4525 [kg]
cabin layout : pitch : 87 [cm] (2+2) seating in 15.0 rows
pax density (normal seating) : 1.06 [m2/pax]
high density seating passengers : 107 at 5 -abreast seating in 21.4 rows
weight 3 toilets : 25.8 [kg]
weight 6 fire extinguisher : 18 [kg]
weight pantry : 90.1 [kg]
weight 32 windows : 28.8 [kg]
weight 4 emergency exits : 12.0 [kg]
weight 8 life rafts : 90.0 [kg]
weight oxygen masks & oxygen generators : 39.0 [kg]
weight 2 entrance/exit doors : 24.0 [kg]
weight 2 freight doors (belly) : 8.0 [kg]
weight ladies" powder room : 16 [kg]
weight men’s dressing room : 12 [kg]
weight diplomatic mail locker : 2 [kg]
At first the DC-6 also had sleeper facilities
extra main deck space for freight/mail/luggage etc. : 7.74 [m3]
cabin volume (usable), excluding flight deck : 134.26 [m3]
passenger cabin max.width : 3.01 [m] cabin length : 21.12 [m] cabin height : 2.36 [m]
pressure at cruise height 6100.00 [m] : 0.47 [kg/cm2] cabin pressure : 0.77 [kg/cm2]
weight rear pressure bulkhead : 115.4 [kg]
weight air pressurization system : 37.5 [kg]
fuselage covering ( 220.7 [m2] duraluminium 2.73 [mm]) : 1587.5 [kg]
weight floor beams : 115.1 [kg]
weight cabin furbishing : 385.9 [kg]
weight cabin floor : 330.9 [kg]
fuselage (sound proof) isolation : 76.2 [kg]
weight radio transceiver equipment : 7.0 [kg]
weight radio direction finding (RDF) equipment : 5.0 [kg]
weight artificial horizon : 1.1 [kg]
weight instruments. : 13.0 [kg]
weight APU / engine starter: 78.3 [kg]
weight lighting : 15.0 [kg]
weight electricity generator : 15.0 [kg]
weight controls : 13.7 [kg]
weight seats : 330.0 [kg]
weight air conditioning : 90 [kg]
total weight fuselage : 7984 [kg](18.1 [%])
***************************************************************
total weight aluminium ribs (594 ribs) : 1573 [kg]
weight engine mounts : 313 [kg]
weight fuel tanks empty for total 20570 [litre] fuel : 1646 [kg]
weight wing covering (painted aluminium 2.13 [mm]) : 1564 [kg]
The DC-6 had 2+2 seating and overhead sleeper beds.
total weight aluminium spars (multi-cellular wing structure) : 1647 [kg]
weight wings : 4784 [kg]
weight wing/square meter : 35.20 [kg]
cantilever wing without bracing cables
weight rubber de-icing boots : 39.4 [kg]
weight fin & rudder (14.9 [m2]) : 526.1 [kg]
weight stabilizer & elevator (15.3 [m2]): 539.2 [kg]
weight flight control hydraulic servo actuators: 35.1 [kg]
total weight wing surfaces & bracing : 7882 [kg] (17.9 [%])
*******************************************************************
Can only operate from paved runways
wheel pressure : 11025.0 [kg]
weight 4 Dunlop main wheels (1330 [mm] by 266 [mm]) : 504.9 [kg]
weight nose wheel : 63.1 [kg]
weight hydraulic wheel-brakes : 30.6 [kg]
weight pneumatic-hydraulic shock absorbers : 40.9 [kg]
weight wheel hydraulic operated retraction system : 115.5 [kg]
weight undercarriage struts with axle 979.3 [kg]
total weight landing gear : 1732.0 [kg] (3.9 [%]
*******************************************************************
********************************************************************
calculated empty weight : 23320 [kg](52.9 [%])
weight oil for 12.9 hours flying : 725.8 [kg]
calculated operational weight empty : 24045 [kg] (54.5 [%])
published operational weight empty : 23844 [kg] (54.1 [%])
weight crew : 486 [kg]
weight fuel for 2.0 hours flying : 2566 [kg]
weight catering : 225.3 [kg]
weight water : 180.2 [kg]
********************************************************************
operational weight empty: 27503 [kg](62.4 [%])
weight 60 passengers : 4620 [kg]
weight luggage : 732 [kg]
weight cargo : 1448 [kg]
operational weight loaded: 34303 [kg](77.8 [%])
fuel reserve : 9797.1 [kg] enough for 7.64 [hours] flying
operational weight fully loaded : 44100 [kg] with fuel tank filled for 79 [%]
published maximum take-off weight : 44100 [kg] (100.0 [%])
calculation : * 4 * (engine power)
power loading (Take-off) : 7.04 [kg/kW]
power loading (operational without useful load) : 4.39 [kg/kW]
power loading (Take-off) 1 PUF: 9.39 [kg/kW]
total power : 6263.9 [kW] at 2700 [r.p.m]
The DC-6 had square windows, while the DC-4 had round windows.
calculation : *5* (loads)
manoeuvre load : 5.9 [g] at 1000 [m]
limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 1.2 [g]
design flight time : 7.51 [hours]
design cycles : 2155 sorties, design hours : 16183 [hours]
operational wing loading : 1985 [N/m^2]
wing stress (3 g) during operation : 169 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.79 ["]
max. angle of attack (stalling angle, clean) : 12.84 ["]
max. angle of attack (full flaps) : 11.95 ["]
angle of attack at max. speed : 0.67 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° : 0.16 [ ]
lift coefficient at max. speed : 0.22 [ ]
lift coefficient at max. angle of attack : 1.31 [ ]
max.lift coefficient full flaps : 1.67 [ ]
induced drag coefficient at max.speed : 0.0021 [ ]
drag coefficient at max. speed : 0.0272 [ ]
drag coefficient (zero lift) : 0.0251 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW loaded : 42817 [kg]): 224 [km/u]
stalling speed at sea-level with full flaps (normal landing weight): 149 [km/u]
landing speed at sea-level (normal landing weight : 32795 [kg]): 172 [km/hr]
max. rate of climb speed : 227 [km/hr] at sea-level
max. endurance speed : 234 [km/u] min.fuel/hr : 716 [kg/hr] at height : 610 [m]
max. range speed : 389 [km/u] min. fuel consumption : 2.698 [kg/km] at cruise height :
5486 [m]
cruising speed : 501 [km/hr] at 6000 [m] (power:74 [%])
max. continuous speed* : 534.00 [km/hr] at 4000 [m] (power:100 [%])
Passengers disembarking from an SAS DC-6: Note the upper row of windows, indicating this was built as the optional sleeper variant of the original-length DC-6
climbing speed at sea-level (loaded) : 650 [m/min]
climbing speed at 1000 [m] with 1 engine out (PUF / MTOW) : 290 [m/min]
climbing speed at 1000 [m] with 2 engines out (2xPUF / MTOW) : 72 [m/min]
calculation : *9* (regarding various performances)
take-off speed : 272.3 [km/u]
emergency/TO power : 2400 [hp] at 2886 [rpm]
static prop wash : 155 [km/u]
high wheel pressure, can only take off from paved runways
take-off distance at sea-level concrete runway : 1406 [m]
take-off distance at sea-level over 15 [m] height : 1493 [m]
landing run : 367 [m]
lift/drag ratio : 15.10 [ ]
climb to 1000m with max payload : 2.46 [min]
climb to 2000m with max payload : 5.02 [min]
climb to 3000m with max payload : 7.68 [min]
climb to cruise height 6000 [m] with max payload : 30.38 [min]
practical ceiling (operational weight empty 27503 [kg] ) : 9700 [m]
practical ceiling fully loaded (mtow- 30 min.fuel:43458 [kg] ) : 7100 [m]
calculation *10* (action radius & endurance)
published range : 4500 [km] with 6 crew and 8182.3 [kg] useful load and 88.1 [%]
fuel (no reserves)
range : 5040 [km] with 6 crew and 6800.0 [kg] useful load and 98.7 [%] fuel
range : 5605 [km] with 60.0 passengers with each 12.2 [kg] luggage and 109.7 [%]
fuel
Available Seat Kilometres (ASK) : 336310 [paskm]
max range theoretically with additional fuel tanks total 27437.2 [litre] fuel : 7448 [km]
useful load with range 500km : 18831 [kg]
useful load with range 500km : 60 passengers
production (theor.max load): 9434 [tonkm/hour]
production (useful load): 3407 [tonkm/hour]
production (passengers): 30060 [paskm/hour]
combi aircraft mail/freight/passengers
oil and fuel consumption per tonkm : 0.14 [kg]
fuel cost per paskm : 0.045 [eur]
crew cost per paskm : 0.025 [eur]
time between engine failure : 504 [hr]
can continue fly on 3 engines, low risk for emergency landing for PUF
writing off per paskm : 0.043 [eur]
insurance per paskm : 0.001 [eur]
maintenance cost per paskm : 0.176 [eur]
direct operating cost per paskm : 0.289 [eur]
direct operating cost per tonkm (max. load): 0.920 [eur]
direct operating cost per tonkm (normal useful load): 2.547 [eur]
literature :
Jane’s commercial transport aircraft page 117
Praktisch handboek vliegtuigen deel 5 page 52,53
Jane’s fighting aircraft WWII page 25
Amerikaanse vliegtuigbouwers page 64
Piston engined airliners page 57,58,60
Encyclopedie van de luchtvaart 1945-2005 page 50
Verkeersvliegtuigen nu en straks page 33
Approaching SABENA DC-6 with extended Fowler flaps
* max.continous speed : max.level speed maintainable for minimal 30 min.
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