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weight and performance calculations for the Boeing 377 Stratocruiser
Boeing 377 Stratocruiser
importance : ****
first flight : 8 July 1947 operational : April 1949
country : United States of America
design :
production : 56 aircraft
general information :
Loved by its passengers for its speed, comfort and capability to fly above the weather. But had frequent mechanical problems hampering reliable flying service. The engine was giving frequent troubles and also the massive propellors gave structural and pitch control problems. The Stratoliner was more expensive to buy and to operate than the Douglas DC-6 or Lockheed Constellation. It was developed from the military transport C-97 Stratofreighter . On 29 November 1945 Panam signed a contract as launch customer for 20 Boeing 377’s with a total value of 24.500.000 usd = 1.225.000 usd for each aircraft.
The double-bubble fuselage had 187m3 space inside. The cabin width for the upper-lobe was 3.35m.
The 377 flew from San Francisco to Honolulu for Panam. It was used on domestic routes in the USA and it was used for transatlantic flights.
The 377 suffered from propellor over speeding resulting in catastrophic failures of the prop-blades. The engines struggled with thermal problems. It had frequent in-flight emergencies leading to hull-losses and fatal accidents. According below calculations in case of a double power unit failure it could not stay in the air and an emergency landing was the only option. Despite the problems and expensive operating cost it was in service for more then 10 years.
Boeing set the never-exceed speed for operation at 565 km/hr, during testing a speed was reached in a shallow dive of 658 km/hr.
In 1961 the 377 was taken out of service by the American airlines, replaced by the new jetliners.
users : Panam (20) , United Airlines (7), Northwest Orient Airlines (10), BOAC(6+4),
American Overseas Airlines (8),
crew : 6 passengers : 75
powerplant : 4 Pratt & Whitney R-4360B-6 Wasp Major air-cooled 28 -cylinder radial
engine 3500 [hp] (2610.0 KW)
normal rating, supercharged engine, low blower, constant power to height : 2830 [m]
dimensions :
wingspan : 43.05 [m], length : 33.63 [m], height : 11.66 [m]
wing area : 164.3 [m^2]
weights :
max.take-off weight : 67132 [kg]
empty weight operational : 37875 [kg] useful load : 11400 [kg]
performance :
maximum speed :604 [km/u] op 1829 [m]
cruise speed : 547 [km/u] op 7620 [m]
service ceiling : 9800 [m]
range : 6800 [km]
description :
low-winged monoplane with retractable landing gear with nose wheel
tapered multi-cellular wing with flush-riveted stressed skin
with slotted flaps airfoil : Boeing 117
engines and landing gear attached to the wings, fuel tanks in the wings
construction : all-metal stressed-skin (Alclad-aluminium) airplane
fuselage shape : 8 “Double-Bubble”
airscrew :
four Hamilton-Standard constant speed full-feathering 4 -bladed tractor airscrews with max. efficiency :0.70 [ ]
diameter airscrew 5.08 [m]
relative pitch (J) : 1.91 [ ]
power loading prop : 256.88 [KW/m]
high power loading prop > more bladed prop needed
theoretical pitch without slip : 10.78 [m]
blade angle prop at max.speed : 43.01 [ ]
tip-speed close to speed of sound (above Mach 0.85) > loose of efficiency
reduction : 0.38 [ ]
airscrew revs : 1012 [r.p.m.]
aerodynamic pitch at max. continuous speed 9.69 [m]
blade-tip speed at max.continuous speed : 315 [m/s]
propellor noise in flight : 109 [Db]
risk of damage to the human hearing, passengers can endure 83 DB for 4 hrs safely, 86 Db only for 2 hrs. Additional isolation of the fuselage needed
calculation : *1* (dimensions)
measured wing chord : 3.97 [m] at 50% wingspan
mean wing chord : 3.82 [m]
calculated average wing chord tapered wing with rounded tips: 3.66 [m]
Above seating arrangement is for 61 seats on upper deck and 14 in the lower-deck lounge.
Total 75 passengers. Wing span 141 ft 3 in = 43.05 [m] length : 110 ft 4 in = 33.63 [m] height : 38 ft 3 in = 11.66 [m] weight, gross 148.000 pounds = 67132 [kg] Propellors, 4-bladed 16 ft 8 in diam. = 5.08 [m] cargo capacity : 17100 pounds = 7757 [kg]
Cruising speed 340 mph = 547 [km/hr] Max. speed : 400 mph = 644 [km/hr]
Operating range : 4500 miles = 7240 [km] normal operating altitude : 15000-25000 ft = 4572 – 7620 [m] Max. service altitude : 33.000 ft = 10058 [m] rate of climb : 1100 ft/min = 335 [m/min].
wing aspect ratio : 11.3 []
seize (span*length*height) : 16881 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 83.5 [kg/hr]
fuel consumption(cruise speed) : 2039.6 [kg/hr] (2782.5 [litre/hr]) at 66 [%] power
distance flown for 1 kg fuel : 0.28 [km/kg] at 4900 [m] height, sfc : 295.0 [kg/kwh]
estimated total fuel capacity : 37426 [litre] (27433 [kg])
calculation : *3* (weight)
weight engine(s) dry with reduction gear : 6544.0 [kg] = 0.63 [kg/KW]
weight 1584.0 litre oil tank : 134.64 [kg]
oil tank filled with 78.3 litre oil : 70.3 [kg]
oil in engine 58.1 litre oil : 52.2 [kg]
fuel in engine 71.2 litre fuel : 52.20 [kg]
weight 1182.9 litre gravity patrol tank(s) : 177.4 [kg]
The lower-deck Hawaiian lounge and cocktail bar was loved by the passengers.
weight Burgess type silencers : 208.8 [kg]
weight NACA cowling 116.9 [kg]
weight variable pitch control : 89.8 [kg]
weight airscrew(s) incl. boss & bolts : 2533.6 [kg]
total weight propulsion system : 9890 [kg](14.7 [%])
***************************************************************
fuselage aluminium frame : 6254 [kg]
cabin layout : pitch : 81 [cm] ( 2+2 ) seating in 19.0 rows
pax density : 1.01 [m2/pax]
weight 5 toilets : 40.8 [kg]
weight 8 fire extinguisher : 22.5 [kg]
weight pantry : 124.4 [kg]
weight staircase : 110 [kg]
weight 40 windows : 36.0 [kg]
weight 4 emergency exits : 12.0 [kg]
weight 9 life rafts : 112.5 [kg]
weight oxygen masks & oxygen generators : 48.8 [kg]
weight door : 5.0 [kg]
passenger cabin max.width : 3.35 [m] cabin length : 19.11 [m] cabin height : 1.90 [m]
pressure at cruise height : 0.44 [kg/cm2] cabin pressure : 0.77 [kg/cm2]
weight rear pressure bulkhead : 158.9 [kg]
weight air pressurization system : 36.1 [kg]
fuselage covering ( 270.6 [m2] duraluminium 3.10 [mm]) : 2208.3 [kg]
weight floor beams : 156.9 [kg]
weight cabin furbishing : 438.2 [kg]
weight cabin floor : 498.7 [kg]
fuselage (sound proof) isolation : 118.6 [kg]
weight radio transceiver equipment : 7.0 [kg]
Double main and nosewheels
weight radio direction finding (RDF) equipment : 5.0 [kg]
weight artificial horizon : 1.1 [kg]
weight instruments. : 13.0 [kg]
weight APU / engine starter: 130.5 [kg]
weight lighting : 18.8 [kg]
weight electricity generator : 18.8 [kg]
weight controls : 15.4 [kg]
weight seats : 405.0 [kg]
weight air conditioning : 112 [kg]
weight hot and cold running water system : 64 [kg]
total weight fuselage : 11035 [kg](16.4 [%])
***************************************************************
total weight aluminium ribs (898 ribs) : 2394 [kg]
weight engine mounts : 522 [kg]
weight fuel tanks empty for total 36243 [litre] fuel : 2899 [kg]
weight wing covering (painted aluminium 4.46 [mm]) : 3953 [kg]
total weight aluminium spars (multi-cellular wing structure) : 2210 [kg]
weight wings : 8557 [kg]
weight wing/square meter : 52.08 [kg]
cantilever wing without bracing cables
weight rubber de-icing boots : 47.4 [kg]
weight fin & rudder (21.5 [m2]) : 1123.6 [kg]
weight stabilizer & elevator (18.5 [m2]): 963.9 [kg]
weight flight control servo actuators: 74.9 [kg]
total weight wing surfaces & bracing : 14188 [kg] (21.1 [%])
*******************************************************************
Can only operate from paved runways
wheel pressure : 16783.0 [kg]
weight 4 Dunlop main wheels (1730 [mm] by 346 [mm]) : 830.1 [kg]
weight 2 Dunlop nose wheels : 207.5 [kg]
weight hydraulic wheel-brakes : 49.3 [kg]
weight pneumatic-hydraulic shock absorbers : 65.7 [kg]
weight wheel hydraulic operated retraction system : 143.6 [kg]
weight undercarriage with axle 988.3 [kg]
total weight landing gear : 2153.7 [kg] (3.2 [%]
*******************************************************************
********************************************************************
calculated empty weight : 37267 [kg](55.5 [%])
weight oil for 14.2 hours flying : 1187.7 [kg]
calculated operational weight empty : 38455 [kg] (57.3 [%])
published operational weight empty : 37875 [kg] (56.4 [%])
weight crew : 486 [kg]
weight fuel for 2.0 hours flying : 4079 [kg]
weight catering : 311.1 [kg]
weight water : 248.9 [kg]
********************************************************************
operational weight empty: 43580 [kg](64.9 [%])
weight 75 passengers : 5775 [kg]
weight luggage : 915 [kg]
weight cargo : 4710 [kg]
operational weight loaded: 54980 [kg](81.9 [%])
fuel reserve : 12152.0 [kg] enough for 5.96 [hours] flying
operational weight fully loaded : 67132 [kg] with fuel tank filled for 59 [%]
published maximum take-off weight : 67132 [kg] (100.0 [%])
calculation : * 4 * (engine power)
power loading (Take-off) : 6.43 [kg/kW]
power loading (operational without useful load) : 4.17 [kg/kW]
power loading (Take-off) 1 PUF: 8.57 [kg/kW]
total power : 10439.8 [kW] at 2700 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 5.4 [g] at 1000 [m]
limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 1.0 [g]
design flight time : 8.30 [hours]
design cycles : 1487 sorties, design hours : 12332 [hours]
operational wing loading : 2601 [N/m^2]
wing stress (3 g) during operation : 150 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.19 ["]
max. angle of attack (stalling angle, clean) : 12.51 ["]
max. angle of attack (full flaps) : 14.51 ["]
angle of attack at max. speed : 0.76 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° : 0.11 [ ]
lift coefficient at max. speed : 0.18 [ ]
lift coefficient at max. angle of attack : 1.27 [ ]
max.lift coefficient full flaps : 1.49 [ ]
induced drag coefficient at max.speed : 0.0012 [ ]
drag coefficient at max. speed : 0.0197 [ ]
drag coefficient (zero lift) : 0.0185 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW loaded : 65092 [kg]): 255 [km/u]
stalling speed at sea-level with full flaps (normal landing weight): 200 [km/u]
landing speed at sea-level (normal landing weight : 46931 [kg]): 229 [km/hr]
max. rate of climb speed : 258 [km/hr] at sea-level
max. endurance speed : 266 [km/u] min.fuel/hr : 1185 [kg/hr] at height : 610 [m]
max. range speed : 524 [km/u] min. fuel consumption : 3.870 [kg/km] at cruise height : 8230 [m]
cruising speed : 565 [km/hr] at 4900 [m] (power:84 [%])
max. continuous speed : 565 [km/hr]
maximum speed : 604 [km/hr] at 1829 [m] (power:115 [%])
climbing speed at sea-level (loaded) : 573 [m/min]
climbing speed at 1000 [m] with 1 engine out (PUF / MTOW) : 212 [m/min]
climbing speed at 1000 [m] with 2 engines out (2xPUF / MTOW) : 0 [m/min]
calculation : *9* (regarding various performances)
take-off speed : 310.2 [km/u]
static prop wash : 182 [km/u]
high wheel pressure, can only take off from paved runways
take-off distance at sea-level concrete runway : 1676 [m]
take-off distance at sea-level over 15 [m] height : 1788 [m]
landing run : 684 [m]
lift/drag ratio : 19.37 [ ]
climb to 1000m with max payload : 2.56 [min]
climb to 2000m with max payload : 5.20 [min]
climb to 3000m with max payload : 8.06 [min]
practical ceiling (operational weight empty 43580 [kg] ) : 8800 [m]
practical ceiling fully loaded (mtow- 30 min.fuel:66112 [kg] ) : 6400 [m]
calculation *10* (action radius & endurance)
published range : 6800 [km] with 6 crew and 4020.7 [kg] useful load and 88.1 [%] fuel
range : 4724 [km] with 6 crew and 11400.0 [kg] useful load and 61.2 [%] fuel
range : 6049 [km] with 75.0 passengers with each 12.2 [kg] luggage and 78.4 [%] fuel
Available Seat Kilometres (ASK) : 453676 [paskm]
max range theoretically with additional fuel tanks total 39012.4 [litre] fuel : 7389 [km]
useful load with range 500km : 26819 [kg]
useful load with range 500km : 75 passengers
production (theor.max load): 15389 [tonkm/hour]
production (useful load): 6541 [tonkm/hour]
production (passengers): 43035 [paskm/hour]
combi aircraft mail/freight/passengers
oil and fuel consumption per tonkm : 0.14 [kg]
fuel cost per paskm : 0.049 [eur]
crew cost per paskm : 0.007 [eur]
time between engine failure : 565 [hr]
can continue fly on 3 engines, low risk for emergency landing for PUF
writing off per paskm : 0.058 [eur]
insurance per paskm : 0.001 [eur]
maintenance cost per paskm : 0.128 [eur]
direct operating cost per paskm : 0.244 [eur]
direct operating cost per tonkm (max. load): 0.681 [eur]
direct operating cost per tonkm (normal useful load): 1.603 [eur]
Literature :
Piston-engined airliners page 52,53
Praktisch handboek vliegtuigen deel 5 page 44,45
Boeing 377 Stratocruiser - Wikipedia
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 January 2022 contact : info.aircraftinvestigation@gmail.com python 3.7.4