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weight and performance calculations for the Lockheed L-749A Constellation
The L-749A could take a “speed pack” cargo container under its belly
Lockheed L-749A Constellation
role : trans-Atlantic airliner
importance : ****
first flight : 1949 operational : July 1949
country : United States of America
design :
production : 59 aircraft
general information :
The L-749A had a reinforced fuselage and strengthened landing gear, which allowed the maximum take-off weight to be increased up to 48534 kg. It had a Plycor floor and new Curtiss Electric propellers.
KLM ordered 7 pieces of this version, the first of which was delivered in September 1949.
They remained in use with KLM until 1959. TWA operated the L-749A till 1967.
L-749A empty weight : 27780 [kg] MTOW : 48535 [kg]
primary users : South African Airways, TWA(26), KLM(7), Eastern Airlines
flight crew : 4 cabin crew : 3 passengers : 60
flight crew consist of pilot, co-pilot, radio operator and engineer
powerplant : 4 Wright R-3350-C18-BD1 Duplex-Cyclone air-cooled 18 -cylinder radial engine 2100 [hp](1566.0 KW)
normal rating, supercharged engine, high blower, constant power to height : 4260 [m]
and with 2500 [hp](1864.2 KW) available for take-off
dimensions :
wingspan : 37.49 [m], length : 29.67 [m], height : 6.83 [m]
wing area : 153.29 [m^2]
weights :
max.take-off weight : 48535 [kg]
empty weight operational : 27780 [kg] useful load : 8100 [kg]
performance :
maximum continous speed : 550 [km/u] op 4260 [m]
normal cruise speed : 492 [km/u] op 6100 [m] (67 [%] power)
service ceiling : 7300 [m]
range with max fuel : 5890 [km] and allowance for 549.2 [km] diversion and 30 [min] hold
The longer nose of N6021C houses a weather radar ?
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 : 8
airscrew :
four Hamilton-Standard Hydromatic 43E60 constant speed, reversible pitch 3 -bladed
tractor airscrews with max. efficiency :0.82 [ ]
diameter airscrew 4.62 [m]
relative pitch (J) : 1.89 [ ]
power loading prop : 225.44 [KW/m]
theoretical pitch without slip : 9.71 [m]
blade angle prop at max.speed : 42.73 [ ]
reduction : 0.4375 [ ]
airscrew revs : 1050 [r.p.m.]
aerodynamic pitch at max. continuous speed 8.73 [m]
blade-tip speed at max.continuous speed : 296 [m/s]
propellor noise in flight : 102 [Db]
Skyways L-749A at Manchester Ringway apt. 1963
calculation : *1* (dimensions)
measured wing chord : 3.96 [m] at 50% wingspan
mean wing chord : 4.09 [m]
calculated average wing chord tapered wing with rounded tips: 3.99 [m]
wing aspect ratio : 9.2 []
seize (span*length*height) : 7597 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 50.1 [kg/hr]
fuel consumption (econ. cruise speed) : 1198.0 [kg/hr] (1634.4 [litre/hr]) at 67 [%] power
distance flown for 1 kg fuel : 0.41 [km/kg] at 6100 [m] height, sfc : 286.0 [kg/kwh]
estimated total fuel capacity : 22207 [litre] (16278 [kg])
calculation : *3* (weight)
weight engine(s) dry with reduction gear : 4840.0 [kg] = 0.77 [kg/KW]
weight 958.5 litre oil tank : 81.47 [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 694.8 litre gravity patrol tank(s) : 104.2 [kg]
weight jet stacks : 156.6 [kg]
weight NACA cowling 70.2 [kg]
weight variable pitch control : 49.0 [kg]
weight airscrew(s) incl. boss & bolts : 1224.9 [kg]
total weight propulsion system : 6582 [kg](13.6 [%])
***************************************************************
fuselage aluminium frame : 5601 [kg]
cabin layout : pitch : 81 [cm] ( 3+2 ) seating in 12.0 rows
pax density (normal seating) : 0.95 [m2/pax]
high density seating passengers : 87 at 5 -abreast seating in 17.4 rows
weight 4 toilets : 28.3 [kg]
weight 6 fire extinguisher : 18 [kg]
weight pantry : 100.6 [kg]
weight 26 windows : 23.4 [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]
extra main deck space for freight/mail/luggage etc. : 6.06 [m3]
cabin volume (usable), excluding flight deck : 131.26 [m3]
passenger cabin max.width : 3.30 [m] cabin length : 17.20 [m] cabin height : 2.36 [m]
pressure at cruise height 6100.00 [m] : 0.47 [kg/cm2] cabine pressure : 0.77 [kg/cm2]
weight rear pressure bulkhead : 180.2 [kg]
weight air pressurization system : 33.5 [kg]
fuselage covering ( 210.1 [m2] duraluminium 3.55 [mm]) : 1972.5 [kg]
weight floor beams : 177.2 [kg]
weight cabin furbishing : 362.7 [kg]
weight cabin floor : 287.7 [kg]
fuselage (sound proof) isolation : 73.5 [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 : 335.0 [kg]
weight air conditioning : 90 [kg]
total weight fuselage : 9514 [kg](19.6 [%])
***************************************************************
total weight aluminium ribs (606 ribs) : 1731 [kg]
weight engine mounts : 313 [kg]
weight fuel tanks empty for total 21512 [litre] fuel : 1721 [kg]
weight wing covering (painted aluminium 2.41 [mm]) : 1993 [kg]
total weight aluminium spars (multi-cellular wing structure) : 2219 [kg]
weight wings : 5943 [kg]
weight wing/square meter : 38.77 [kg]
cantilever wing without bracing cables
weight rubber de-icing boots : 41.2 [kg]
weight fin & rudder (16.3 [m2]) : 635.0 [kg]
weight stabilizer & elevator (17.2 [m2]): 669.8 [kg]
weight flight control hydraulic servo actuators: 42.3 [kg]
total weight wing surfaces & bracing : 9366 [kg] (19.3 [%])
*******************************************************************
Can only operate from paved runways
wheel pressure : 12133.8 [kg]
weight 4 Dunlop main wheels (1330 [mm] by 266 [mm]) : 628.3 [kg]
weight nose wheel : 78.5 [kg]
weight hydraulic wheel-brakes : 35.9 [kg]
weight pneumatic-hydraulic shock absorbers : 47.8 [kg]
weight wheel hydraulic operated retraction system : 135.1 [kg]
weight undercarriage struts with axle 1102.0 [kg]
total weight landing gear : 2027.0 [kg] (4.2 [%]
*******************************************************************
********************************************************************
calculated empty weight : 27489 [kg](56.6 [%])
weight oil for 14.4 hours flying : 719.9 [kg]
calculated operational weight empty : 28209 [kg] (58.1 [%])
published operational weight empty : 27780 [kg] (57.2 [%])
weight crew : 567 [kg]
weight fuel for 2.0 hours flying : 2396 [kg]
weight catering : 251.4 [kg]
weight water : 201.1 [kg]
********************************************************************
operational weight empty: 31625 [kg](65.2 [%])
weight 60 passengers : 4620 [kg]
weight luggage : 732 [kg]
weight cargo : 2748 [kg]
operational weight loaded: 39725 [kg](81.8 [%])
fuel reserve : 8810.4 [kg] enough for 7.35 [hours] flying
operational weight fully loaded : 48535 [kg] with fuel tank filled for 69 [%]
published maximum take-off weight : 48535 [kg] (100.0 [%])
On 5 February 1949 an Eastern Airlines L-749A reg. N115A flew from Los Angeles to New York (LaGuardia apt)in 6 hours 17 minutes, a new west to east speed record for airliners. Distance : 3950 km gives average ground speed of 629 km/hr !
calculation : * 4 * (engine power)
power loading (Take-off) : 7.75 [kg/kW]
power loading (operational without useful load) : 5.05 [kg/kW]
power loading (Take-off) 1 PUF: 10.33 [kg/kW]
total power : 6263.9 [kW] at 2525 [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 : 1.4 [g]
design flight time : 8.38 [hours]
design cycles : 2918 sorties, design hours : 24457 [hours]
operational wing loading : 2023 [N/m^2]
wing stress (3 g) during operation : 157 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.80 ["]
max. angle of attack (stalling angle, clean) : 12.97 ["]
max. angle of attack (full flaps) : 12.08 ["]
angle of attack at max. speed : 0.65 ["]
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 : 0.0229 [ ]
drag coefficient (zero lift) : 0.0207 [ ]
calculation : *8* (speeds
KLM L-749A PH-TFG “Friesland”
stalling speed at sea-level (OW loaded : 47337 [kg]): 221 [km/u]
stalling speed at sea-level with full flaps (normal landing weight): 152 [km/u]
landing speed at sea-level (normal landing weight : 38275 [kg]): 174 [km/hr]
max. rate of climb speed : 225 [km/hr] at sea-level
max. endurance speed : 241 [km/u] min.fuel/hr : 763 [kg/hr] at height : 610 [m]
max. range speed : 421 [km/u] min. fuel consumption : 2.745 [kg/km] at cruise height :
6096 [m]
cruising speed : 492 [km/hr] at 6100 [m] (power:68 [%])
max. continuous speed* : 550.00 [km/hr] at 4260 [m] (power:100 [%])
climbing speed at sea-level (loaded) : 540 [m/min]
climbing speed at 1000 [m] with 1 engine out (PUF / MTOW) : 272 [m/min]
climbing speed at 1000 [m] with 2 engines out (2xPUF / MTOW) : 65 [m/min]
calculation : *9* (regarding various performances)
take-off speed : 268.6 [km/u]
emergency/TO power : 2500 [hp] at 2755 [rpm]
static prop wash : 157 [km/u]
high wheel pressure, can only take off from paved runways
take-off distance at sea-level concrete runway : 1244 [m]
take-off distance at sea-level over 15 [m] height : 1348 [m]
landing run : 379 [m]
lift/drag ratio : 16.35 [ ]
climb to 1000m with max payload : 2.80 [min]
climb to 2000m with max payload : 5.72 [min]
climb to 3000m with max payload : 8.78 [min]
climb to cruise height 6100 [m] with max payload : 36.74 [min]
practical ceiling (operational weight empty 31625 [kg] ) : 9400 [m]
practical ceiling fully loaded (mtow- 30 min.fuel:47936 [kg] ) : 7000 [m]
calculation *10* (action radius & endurance)
published range : 5890 [km] with 7 crew and 5417.1 [kg] useful load and 88.1 [%] fuel (no reserves)
range : 4788 [km] with 7 crew and 8100.0 [kg] useful load and 71.6 [%] fuel
range : 5917 [km] with 60.0 passengers with each 12.2 [kg] luggage and 88.5 [%] fuel
Available Seat Kilometres (ASK) : 355005 [paskm]
max range theoretically with additional fuel tanks total 27619.3 [litre] fuel : 7376 [km]
useful load with range 500km : 19027 [kg]
useful load with range 500km : 60 passengers
KLM PH-LDD on Entebbe airfield
production (theor.max load): 9362 [tonkm/hour]
production (useful load): 3985 [tonkm/hour]
production (passengers): 29520 [paskm/hour]
combi aircraft mail/freight/passengers
oil and fuel consumption per tonkm : 0.13 [kg]
fuel cost per paskm : 0.042 [eur]
crew cost per paskm : 0.030 [eur]
economic hours : 18250 [hours] is less then design hours
time between engine failure : 3559 [hr]
can continue fly on 3 engines, low risk for emergency landing for PUF
writing off per paskm : 0.042 [eur]
insurance per paskm : 0.000 [eur]
maintenance cost per paskm : 0.158 [eur]
direct operating cost per paskm : 0.274 [eur]
direct operating cost per tonkm (max. load): 0.863 [eur]
direct operating cost per tonkm (normal useful load): 2.027 [eur]
Literature :
piston engined airliners blz.58
luchtvaart dec'86 blz.354
prakt. handb. vliegt. deel 5 blz.47
Lockheed L-749A Constellation Archives - This Day in Aviation
* 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