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weight and performance calculations for the Lockheed L1011 Tristar 250
Delta Airlines Tristar 250 N1739D c/n 193C-1237 at Frankfurt-Main apt, July 1994
Lockheed L1011 Tristar 250
role : wide-body airliner
importance : **
first flight : operational : June 1978
country : United States of America
design :
production : 6 aircraft
general information :
Upgrade developed for late model L-1011-1 and -100 and -200, with higher MTOW,
more fuel and range and more powerful RB211-524B engines. Only Delta chose finally
to have 6 of there ordered aircraft to be converted to this version.
primary users : Delta Airlines
Accommodation:
flight crew : 3 cabin crew : 9
flight crew consist of pilot, co-pilot and flight engineer
passengers : seating for 256 in two class : 28 business class and 228 economy
class seats ( 32 -in pitch)
exit limit : 400 passengers, high density seating for 384 passengers
engine : 3 Rolls Royce RB211-524B turbofan engines of 222.4 [KN] (49996.7 [lbf])
dimensions :
wingspan : 47.34 [m], length overall: 54.17 [m], length of fuselage : 54.17 [m]
height : 16.87 [m] wing area : 321.1 [m^2] fuselage exterior width : 5.97 [m]
weights :
operating empty weight : 112970 [kg] max. structural payload : 40345 [kg]
Zero Fuel weight (ZFW) : 153315 [kg] max. landing weight (MLW) : 166920 [kg]
max. take-off weight : 224980 [kg] weight fuel : 93992 [kg] (119735 [litres])
performance :
Never-exceed speed : 0.95 [Mach] (1035 [km/hr]) at 9145 [m]
critical Mach speed : 0.88 [Mach]
max. cruising speed : 973 [km/hr] (Mach 0.91 ) at 10670 [m] (33 [%] power)
economic cruising speed : 899 [km/hr] (Mach 0.84 ) at 10670 [m]
service ceiling : 12800 [m]
range with max fuel and MTOW : 10934 [km] (ATA domestic fuel reserves –
370.0 [km] alternate)
description :
cantilever low-wing monoplane with retractable landing gear with nose wheel
Wings : primary two-spar box-type fail-safe wing structure of high-strength aluminium
alloy with Fowler-type double slotted trailing edge flaps with Kruger flaps on the LE
wing root and slotted LE flaps (slats) on outer wing ,with spoilers airfoil : Lockheed
average thickness/chord ratio : 10.0 [%], sweep angle 3/4 chord: 35.0 [°]
2 engines attached to the wings 1 in the tail, landing gear attached to the wings, fuel
tanks in the wings and in the fuselage
Fuselage : Pressurized conventional semi-monocoque fail safe structure of circular
cross-section built mainly of high-strength aluminium alloy
calculation : *1* (dimensions)
wing chord at root : 10.46 [m]
wing chord at tip : 3.12 [m]
taper ratio : 0.298 [ ]
mean wing chord : 6.78 [m]
calculated average wing chord tapered wing with rounded tips: 6.99 [m]
wing aspect ratio : 6.98 []
Oswald factor (e): 0.670 []
seize (span*length*height) : 43262 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 6.0 [kg/hr]
fuel consumption (econ. cruise speed) : 7475.1 [kg/hr] (9522.4 [litre/hr]) at 29 [%] power
distance flown for 1 kg fuel : 0.12 [km/kg] at 10670 [m] height, sfc : 38.3 [kg/KN/h]
total fuel capacity : 119735 [litre] (93992 [kg])
calculation : *3* (weight)
weight engine(s) dry : 15075.0 [kg] = 22.59 [kg/KN]
weight 114.9 litre oil tank : 9.77 [kg]
oil tank filled with 4.2 litre oil : 3.8 [kg]
oil in engine 8.2 litre oil : 7.3 [kg]
fuel in engine 36.4 litre fuel : 26.69 [kg]
weight fuel lines : 188.1 [kg]
weight engine cowling : 1734.7 [kg]
Landing Delta Airlines Tristar 250 at Stuttgart, April 1992, N1738D c/n 193C-1234 note the deployed thrust reverser of the tail engine.
weight thrust reversers : 1000.8 [kg]
total weight propulsion system : 18046 [kg](8.0 [%])
***************************************************************
Accommodation cabin facilities:
typical 2-class cabin layout for 256 passengers : economy : pitch : 81.3 [cm] 32.0 [-in]
( 2+5+2 ) seating in 29.3 rows
weight passenger seats : 1561.0 [kg]
weight cabin crew seats : 45.0 [kg]
weight flight crew seats : 63.0 [kg]
weight 2 jump seats in the cockpit :14.0 [kg]
high density seating passengers : 384 [pax] at mainly 10 -abreast seating in
43.8 rows, pitch 79.2 [cm] 31.2 [-in]
pax density, normal seating : 0.84 [m2/pax], high density seating : 0.56 [m2/pax]
weight 7 lavatories : 215.1 [kg]
weight 3 galleys : 311.0 [kg]
weight elevator galley : 145 [kg]
Interior of Delta Airlines Tristar 250 N740DA c/n 193C-1244
weight overhead stowage for hand luggage : 89.6 [kg]
weight 3 wardrobe closets : 25.6 [kg]
weight 3 movie screens : 63.7 [kg]
weight 61 windows (47x38cm) : 54.6 [kg]
weight 6 (1.93 x 1.07 [m]) Type A main entry doors : 364.6 [kg]
weight 3 (main door size : 1.75 x 1.78 [m]) freight doors (belly) : 259.0 [kg]*
total belly baggage/cargo hold volume : 110.4 [m3]
underfloor belly hold can accommodate : 16 LD3 containers
and : 19.8 [m3] bulk cargo
cabin volume (usable), excluding flight deck : 452 [m3]
passenger compartment volume : 295 [m3]
passenger cabin max width : 5.77 [m] cabin length : 41.44 [m] max cabin height : 2.41
[m]
floor area : 215.4 [m2]
weight cabin facilities : 3211.3 [kg]
safety facilities:
weight 2 type I emergency exits (0.61 x 1.52 [m]): 54.6 [kg]
evacuation time with 384 passengers : 54 [sec]
weight 12 hand fire extinguisher : 36 [kg]
weight cockpit voice recorder (CVR) and flight data recorder (FDR): 20.0 [kg]
weight oxygen masks & oxygen generators : 166.4 [kg]
weight emergency flare installation : 10 [kg]
weight 6 emergency evacuation slides : 347.3 [kg]
weight safety equipment & facilities : 635 [kg]
fuselage construction:
fuselage aluminium frame : 20630 [kg]
floor loading (payload/m2): 187 [kg/m2]
weight rear pressure bulkhead : 445.4 [kg]
fuselage covering ( 806.3 [m2] duraluminium 2.86 [mm]) : 6151.0 [kg]
weight floor beams : 5230.7 [kg]
weight cabin furbishing : 3239.7 [kg]
weight cabin floor : 3046.5 [kg]
weight (sound proof) isolation : 648.3 [kg] TO-noise level : 98.0 [EPNdB]
weight 17504 [litre] main central fuel tanks empty : 980.2 [kg]
weight 12092 [litre] additional central fuel tank (ACT) empty : 677.2 [kg]
Delta Airlines L-1011-250 underfloor galley with elevators
weight empty 260 [litre] potable water tank : 23.0 [kg]
weight empty waste tank : 32.7 [kg]
weight engine mount in tail : 111 [kg]
weight fuselage structure : 41216.3 [kg]
Avionics:
weight VHF radio and Selcal : 9.0 [kg]
weight flight and service attendants intercom : 5.0 [kg]
weight dual cloud-collision radar : 25.0 [kg]
weight monochromatic weather X-band (3.2cm wavelength) radar system : 25.0 [kg]
weight VOR/ILS,RMI,DME,radio altimeter, ASI, time clock : 20.0 [kg]
weight Avionic Flight Control System : 33.0 [kg]
weight CAT IIIA auto-landing system : 10.0 [kg]
weight artificial horizons, compass, alti-meters : 7 [kg]
weight ground proximity warning system (GPWS) : 6 [kg]
weight engine monitoring gauges & control switches : 21 [kg]
weight Performance Management System (PMS) : 12 [kg]
weight reserve ADI, ASI, alti-meter, compass, engine temp. and rpm indicators :
15 [kg]
weight DLC (spoiler) control: 95 [kg]
weight avionics : 258.0 [kg]
Systems:
Air-conditioning and pressurization system maintains sea level conditions up to
6400 [m] and gives equivalent of 2440 [m] at 12200 [m]. pressure differential : 0.58
[bar] (kg/cm2)
pressurized fuselage volume : 624 [m3] cabin air refreshment time : 3.1 [min]
weight air-conditioning and pressurization system : 341 [kg]
weight APU / engine starter: 111.2 [kg]
weight lighting : 84.5 [kg]
weight four independent 207 bar hydraulic systems : 182.9 [kg]
weight three engine-driven 90kVA 400 Hertz electricity generators : 64.0 [kg]
weight integrated drive generator (IDG) : 25 [kg]
weight three 24V 25Ah nickel-cadmium batteries : 35.6 [kg]
weight controls : 22.4 [kg]
weight systems : 866.7 [kg]
total weight fuselage : 46187 [kg](20.5 [%])
***************************************************************
total weight aluminium ribs (1516 ribs) : 7178 [kg]
weight engine mounts : 222 [kg]
weight 6 wing fuel tanks empty for total 90139 [litre] fuel : 5048 [kg]
weight wing covering (painted aluminium 3.72 [mm]) : 6448 [kg]
total weight aluminium spars (multi-cellular wing structure) : 8416 [kg]
weight wings : 22042 [kg]
weight wing/square meter : 68.65 [kg]
weight thermal leading-edge anti-icing : 52.1 [kg]
weight active control ailerons (14.86 [m2]) : 567.3 [kg]
weight fin (51.10 [m2]) : 1757.9 [kg]
weight rudder (11.89 [m2]) : 392.5 [kg]
weight variable-incidence tailplane (flying stabilizer) (94.85 [m2]): 3660.8 [kg]
weight elevators (24.19 [m2]): 449.28 [kg]
weight flight control hydraulic servo actuators: 72.1 [kg]
weight trailing-edge double slotted flaps (49.80 [m2]) : 1458.1 [kg]
weight leading edge Krueger flaps and slats (33.45 [m2]) : 680.9 [kg]
weight spoilers (19.9 [m2]) : 334.8 [kg]
total weight wing construction : 36738 [kg] (32.5 [%])
*******************************************************************
tire pressure main wheels : 12.41 [Bar] (nitrogen), ply rating : 23 PR
tire speed limit : 389 [km/hr]
total tyre footprint : 1.16 [m2]
Runway LCN at MTOW (0.76m radius of rigidity) : 50 [ ]
Aircraft Classification Number (ACN), MTOW on rigid runway and medium subgrade strength (B) : 74 [ ]
Can only operate from paved runways subgrade A
wheel pressure : 24747.8 [kg]
weight 8 Dunlop main wheels (1270 [mm] by 508 [mm]) : 1423.2 [kg]
weight 2 nose wheels : 177.9 [kg]
weight hydraulic disc wheel-brakes : 153.3 [kg]
weight Duplex anti-skid units : 9.0 [kg]
weight oleo-pneumatic shock absorbers : 204.4 [kg]
weight wheel hydraulic operated retraction system : 2022.6 [kg]
weight undercarriage struts (four-wheel bogies) with axle 6021.4 [kg]
total weight landing gear : 10011.9 [kg] (4.5 [%]
*******************************************************************
********************************************************************
calculated empty weight : 110983 [kg](49.3 [%])
weight oil for 13.5 hours flying : 90.6 [kg]
weight lifejackets : 115.2 [kg]
weight 5 life rafts : 160.0 [kg]
weight catering : 288.0 [kg]
weight water : 230.4 [kg]
weight crew : 972 [kg]
weight crew luggage, nav. chards, flight doc., miscell. items : 131 [kg]
operational weight empty : 112970 [kg] (50.2 [%])
********************************************************************
weight 256 passengers : 19712 [kg]
weight luggage : 4096 [kg]
weight cargo : 16537 [kg] (cargo + luggage/m3 belly : 178 [kg/m3])
zero fuel weight (ZFW): 153315 [kg](68.1 [%])
weight fuel for landing (1.8 hours flying) : 13605 [kg]
max. landing weight (MLW): 166920 [kg](74.2 [%])
max. fuel weight : 206962 [kg] (92.0 [%])
payload with max fuel : 194 passengers + luggage 18018 [kg]
published maximum take-off weight : 224980 [kg] (100.0 [%])
calculation : * 4 * (engine power)
power loading (Take-off) : 337 [kg/KN]
power loading (Take-off) 1 PUF: 506 [kg/KN]
max. total take-off power : 667.2 [KN]
calculation : *5* (loads)
manoeuvre load : 1.6 [g] at 9000 [m]
limit load : 2.5 [g] ultimate load : 3.8 [g] load factor : 1.0 [g]
design flight time : 2.25 [hours]
design cycles : 14225 sorties, design hours : 32006 [hours]
max. wing loading (MTOW & flaps retracted) : 701 [kg/m2]
wing stress (2 g) during operation : 174 [N/kg] at 2g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -2.06 ["]
max. angle of attack (stalling angle, clean) : 15.39 ["]
max. angle of attack (full flaps) : 19.49 ["]
angle of attack at max. speed : 1.77 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° : 0.17 [ ]
lift coefficient at max. speed : 0.32 [ ]
lift coefficient at max. angle of attack (clean): 1.44 [ ]
max. lift coefficient full flaps : 2.19 [ ]
drag coefficient at max. speed : 0.0521 [ ]
drag coefficient at econ. cruise speed : 0.0513 [ ]
induced drag coefficient at econ. cruise speed : 0.0144 [ ]
drag coefficient (zero lift) : 0.0370 [ ]
lift/drag ratio at econ. speed : 6.06 [ ]
calculation : *8* (speeds
take-off decision speed (V1) : 270 [km/u] (146 [kt])
lift-off speed (VLOF) : 296 [km/u] (160 [kt])
take-off safety speed (V2) : 313 [km/u] (169 [kt])
steady initial climb speed (V4) : 339 [km/u] (183 [kt])
flap retraction speed (V3) at 500m (OW loaded : 217505 [kg]): 335 [km/u] (181 [kt])
climb speed (to FL150 with 58 [%] power) : 515 [km/hr] (278 [kt])
max. endurance speed (Vbe): 482 [km/u] min. fuel/hr : 6712 [kg/hr] at height : 3962 [m]
max. range speed (Vbr): 919 [km/u] (0.87 [mach]) min. fuel consumption : 8.02 [kg/km] at cruise height : 11278 [m]
max. cruising speed : 973 [km/hr] (525 [kt]) at 10670 [m] (power:35 [%])
max. operational speed (Mmo) : 1035 [km/hr] (Mach 0.95 ) at 9145 [m] (power:46 [%])
airflow at cruise speed per engine : 386.4 [kg/s]
speed of thrust jet : 1694 [km/hr]
initial descent speed 10000 - 7315 [m]: Mach 0.72
descent speed 7315 - 3048 [m]: 519 [km/u] (280 [kt])
approach speed 3048 - 500 [m] (clean): 389 [km/u] (210 [kt])
minimum control speed (MCS) Vmca (clean): 322 [km/u] (174 [kt])
stalling speed clean at 500 [m] height at Max.Landing Weight : 166920 [kg]):
280 [km/u] (151 [kt])
final approach speed (landing speed) at sea-level with full flaps VREF (max.
landing weight): 263 [km/u] (142 [kt])
ICAO Aircraft Approach Category (APC) : D
stalling speed at sea-level with full flaps VSO (max. landing weight): 202 [km/u]
rate of climb at sea-level ROC (loaded, 58 % power) : 773 [m/min]
rate of climb at sea-level ROC (loaded, 75% power) : 1321 [m/min]
rate of climb at 1000 [m] with 1 engine out (PUF/MTOW, 100 % power on remaining engines) : 2017 [m/min]
rate of descent from FL240 to FL100 (7315m > 3048m): 1067 [m/min] (3501 [ft/min])
rate of descent during approach with landing gear extended, with use of spoilers:
457 [m/min] (1499 [ft/min])
calculation : *9* (regarding various performances)
high wheel pressure, can only take off from paved runways
take-off distance at sea-level concrete runway : 2304 [m]
ICAO Aerodrome Reference Code : 4D
take-off distance at sea-level over 15 [m] height : 2471 [m]
FAR TO runway length requirement at MTOW, standard day at SL (ASDA): 2836 [m]
landing run (MLW) : 879 [m]
landing distance (C.A.R.) from 15 [m] at SL, dry runway : 1846 [m]
landing distance (C.A.R.) from 15 [m] at SL, wet runway : 2146 [m]
FAR landing runway length requirements at SL : 1757 [m]
max. lift/drag ratio : 9.97 [ ]
climb to 5000 [m] with max payload : 5.98 [min]
climb to 10000 [m] with max payload : 18.41 [min]
descent time from 10000 [m] to 250 [m] : 24.33 [min]
ceiling limited by max. pressure differential 14125 [m]
theoretical ceiling fully loaded (mtow- 60 min.fuel: 217505 [kg] ) : 16500 [m]
calculation *10* (action radius & endurance)
range with max. payload: 8318 [km] with 40345.0 [kg] max. useful load (76.2 [%] fuel)*
range with high density pax: 8918 [km] with 384 passengers (81.1 [%] fuel)*
range with typical two-class pax: 10511 [km] with 256 passengers (93.8 [%] fuel)*
range with max.fuel : 11304 [km] with 12 crew and 194 passengers and
100.0 [%] fuel*
ferry range : 11991 [km] with 3 crew and zero payload (100.0 [%] fuel)*
max range theoretically with additional fuel tanks total 144277 [litre] fuel :
14035 [km]*
* calculated ranges without fuel reserves
Available Seat Kilometres (ASK) : 3087119 [paskm]
useful load with range 1000km : 40345 [kg]
useful load with range 1000km : 384 passengers
production (theor.max load): 39256 [tonkm/hour]
production (useful load): 39256 [tonkm/hour]
production (passengers): 303768 [paskm/hour]
oil and fuel consumption per tonkm : 0.191 [kg]
calculation *11* (operating cost)
fuel cost per hour (9522 [litre]):5713 [eur] (32 [pax-km/litre fuel])
fuel cost per seat 1000km flight (312 [pax] 2-class seating): 18.81 [eur/1000PK]
oil cost per hour: 25 [eur]
crew cost per hour : 1650 [eur]
list price 2023 : 294 [mln USD]
average flying hours in 1 year : 2460 [hours] technical life : 13 [year]
real average service life : 15 [years]
depreciation - 16 [years] to 10% residual value
economic hours (expected total flying hours) : 39360 [hours]
financing interest per flying hour : 2690 [EUR]
write off per flying hour : 4683 [EUR]
time between engine failure : 17225 [hr]
can continue fly on 2 engines, low risk for emergency landing for PUF
workhours per day : 8.99 [hr]
no fatalities during service life > 100%% safe
average flight hours till crash : 0.22 [mln hr] (90 service years)
safe flight hours till fatality : 221400 [hr] (90.0 service years)
reservation pax liability/flying hour : 0.58 [SDR*] (0.73 [eur])
insurance cost per hour : 6118 [eur] insurance rate : 13.8 [%]
engine maintenance cost per hour : 767.5 [eur]
wing maintenance cost per hour : 314.0 [eur]
fuselage maintenance cost per hour : 318.52 [eur]
tire life (time till worn out) : 100 [cycles]
maintenance cost per hour (excluding engines): 4311 [eur]
direct operating cost per hour: 25958 [eur], DOC per km : 28.87 [eur]
DOC per seat 1000km flight (312 [pax] 2-class seating): 85.45 [eur/1000PK]
DOC per seat 1000km flight (high density seating): 69.42 [eur/1000PK]
DOC per kg cargo for a 1000km flight : 0.66 [eur/kg] (= DOC/tonkm)
passenger service charge (depart at Schiphol): 11.34 [eur]
security service charge (depart at Schiphol): 10.08 [eur]
airport take-off fee / passenger : 4.30 [eur/pax]
airport landing fee / passenger : 4.30 [eur/pax]
retour ticket price 1000km trip : 254.05 [eur/pax]
price retour ticket Schiphol-Barcelona : 301.05 [eur/pax]
Delta Airlines L-1011-250 N736DY c/n 193C-1227 on its nose at Stuttgart airport, Germany. The nose gear collapsed on take-off, 12 April 1993
accidents with fatalities > no fatal accidents happened with a Tristar 250
Literature :
Lockheed L-1011 TriStar - Wikipedia
Jane’s all the world aircraft 1979-80 page 373
Advanced airliners page 9
confidence rating regarding source data : medium - all information is only available from news, social media or unofficial sources
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 18 November 2023 contact : info.aircraftinvestigation@gmail.com ac jetpax 2020.py python 3.7.4