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weight and performance calculations for the McDonnel Douglas DC-8-71
***** PRELIMINARY FILE ****
Delta DC-8-71 N825E c/n 45944 taking off at Fort Lauderdale, Florida, November 1987
McDonnel Douglas DC-8-71
role : long-range jet airliner
importance : **
first flight : 15 August 1981 operational : begin 1983
country : United States of America
design :
production : 53 aircraft
general information :
At the end of the seventies, people started to think of ways to
DC-8 to be able to keep in service longer. It was decided to equip existing -61,-62 and -63's with the quiet and economical CFM56 engine, so the -71, -72 and -73 were born. The MTOW has remained the same, only the empty weight is slightly higher due to the heavier engines. The Super 70 series was only used for the transport of passengers for a short time, soon they were converted into cargo aircraft. The freight version of UPS can carry 42638kg of cargo.
primary users : Delta Airlines
Accommodation:
flight crew : 4 cabin crew : 7
flight crew consist of pilot, co-pilot, navigator and flight engineer
passengers : seating for 215 in two class : 20 business class and 195 economy class seats ( 32 -in pitch)
high density seating for 259 passengers
engine : 4 GE-Snecma CFM56-2C1 turbofan engines of 97.5 [KN] (21918.5 [lbf])
dimensions :
wingspan : 43.41 [m], length : 57.12 [m], height : 12.92 [m]
wing area : 267.9 [m^2] fuselage exterior width : 3.67 [m]
weights :
operating empty weight : 74299 [kg] max. structural payload : 27307 [kg]
Zero Fuel weight (ZFW) : 101606 [kg] max. landing weight (MLW) : 108864 [kg]
max.take-off weight : 147420 [kg] weight fuel : 70842 [kg] (88552 [liter])
performance :
Max. operating Mach number (Mmo) : 0.89 [Mach] (965 [km/hr]) at 9150 [m]
normal cruise speed : 887 [km/hr] (Mach 0.82 ) at 9449 [m] (33 [%] power)
economic cruise speed : 880 [km/hr] (Mach 0.81 ) at 9449 [m]
service ceiling : 12000 [m]
range with max fuel : 11110 [km] (ATA domestic fuel reserves - 370.0 [km] alternate)
description :
low-wing cantilever monoplane with retractable landing gear with nose wheel
two spar fail-safe wing structure
with Fowler flaps with no leading edge flaps ,with spoilers airfoil : NACA with supercritical cross-section
sweep angle 3/4 chord: 30.0 [°]
engines attached with pylons to the wing, main landing gear attached to the wings, fuel tanks in the wings and fuselage
construction : all-metal aluminium-alloy stressed-skin construction with pressurized fuselage
fuselage shape : 0
calculation : *1* (dimensions)
wing chord : 6.17 [m]
mean wing chord : 6.17 [m]
calculated average wing chord tapered wing with rounded tips: 6.06 [m]
wing aspect ratio : 7.03 []
seize (span*length*height) : 32036 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 11.7 [kg/hr]
fuel consumption (econ. cruise speed) : 5430.4 [kg/hr] (6788.0 [litre/hr]) at 21 [%] power
distance flown for 1 kg fuel : 0.16 [km/kg] at 9449 [m] height, sfc : 64.8 [kg/KN/h]
total fuel capacity : 88552 [litre] (70842 [kg])
calculation : *3* (weight)
weight engine(s) dry : 8400.0 [kg] = 21.54 [kg/KN]
weight 212 litre oil tank : 18.04 [kg]
oil tank filled with 2.5 litre oil : 2.2 [kg]
oil in engine 4.8 litre oil : 4.3 [kg]
fuel in engine 21.3 litre fuel : 15.60 [kg]
weight fuel lines 131.4 [kg]
weight engine cowling 1014.0 [kg]
weight thrust reversers 156.0 [kg]
total weight propulsion system : 9742 [kg](6.6 [%])
***************************************************************
Accommodation cabin facilities:
typical 2-class cabin layout for 215 passengers : economy : pitch : 81.3 [cm] ( 3+3 ) seating in 36.5 rows
Length 187ft 5in = 57.12 [m] = DC-8-71 length
weight seats : 1130.0 [kg]
high density seating passengers : 259 [pax] at 6 -abreast seating in 43.2 rows, pitch 83.8 [cm]
pax density, normal seating : 0.64 [m2/pax], high density seating : 0.53 [m2/pax]
weight 6 lavatories : 92.9 [kg]
weight 4 galleys : 261.7 [kg]
weight overhead stowage for hand luggage : 75.2 [kg]
weight 4 wardrobe closets : 43.0 [kg]
weight 75 windows : 67.5 [kg]
weight 2 1.83x0.86 [m] entrance/exit doors : 143.7 [kg]
weight 2 freight doors (belly) : 114.1 [kg]
cabin volume (usable), excluding flight deck : 371.72 [m3]
passenger cabin max.width : 3.45 [m] cabin length : 44.48 [m] cabin height : 2.19 [m]
Kenya Airways Douglas DC-8-71 EI-BZU c/n 45994 parked at Nairobi, Kenia, May 1991
floor area : 138.3 [m2]
weight cabin facilities : 1928.1 [kg]
safety facilities:
weight 2 over wing emergency exits : 68.5 [kg]
weight 10 hand fire extinguisher : 31 [kg]
weight lifejackets : 96.8 [kg]
weight cockpit voice recorder (CVR) and flight data recorder (FDR): 20.0 [kg]
weight oxygen masks & oxygen generators : 139.8 [kg]
weight emergency flare installation : 10 [kg]
weight 2 emergency evacuation slides : 98.6 [kg]
weight safety equipment & facilities : 465 [kg]
fuselage construction:
fuselage aluminium frame : 22408 [kg]
floor loading (payload/m2): 198 [kg/m2]
weight rear pressure bulkhead : 214.3 [kg]
fuselage covering ( 491.0 [m2] duraluminium 3.85 [mm]) : 4980.7 [kg]
weight floor beams : 839.9 [kg]
weight cabin furbishing : 1188.1 [kg]
weight cabin floor : 1989.4 [kg]
fuselage (sound proof) isolation : 355.3 [kg]
weight 11182 [litre] main central fuel tanks empty : 626.2 [kg]
weight fuselage structure : 32602.3 [kg]
Avionics:
weight HF and UHF radio : 7.0 [kg]
weight dual cloud-collision radar : 25.0 [kg]
weight VOR/ILS,RMI,Doppler,radio altimeter : 12.0 [kg]
weight Integrated Flight System / auto-pilot : 23.0 [kg]
weight artificial horizons, compass, alti-meters : 7 [kg]
weight engine monitoring gauches & control switches : 12 [kg]
weight avionics : 86.0 [kg]
BAX global DC-8-7(F) cockpit, N829BX
Systems:
Air-conditioning and pressurisation system maintains sea level conditions up to 6550 [m]
and gives equivalent of 2000 [m] at 11200 [m]. pressure differential : 0.59 [bars] (kg/cm2)
weight air-conditioning and pressurisation system : 318 [kg]
weight APU / engine starter: 48.8 [kg]
weight lighting : 71.0 [kg]
weight engine-driven 40kVA electricity generators : 53.8 [kg]
weight controls : 22.7 [kg]
weight systems : 514.3 [kg]
total weight fuselage : 35595 [kg](24.1 [%])
***************************************************************
total weight aluminium ribs (1220 ribs) : 5257 [kg]
weight engine mounts : 195 [kg]
weight 6 fuel tanks empty for total 77370 [litre] fuel : 4333 [kg]
weight wing covering (painted aluminium 2.68 [mm]) : 3879 [kg]
total weight aluminium spars (multi-cellular wing structure) : 3221 [kg]
weight wings : 12358 [kg]
weight wing/square meter : 46.13 [kg]
weight thermal leading-edge anti-icing : 47.8 [kg]
weight fin & rudder (21.9 [m2]) : 1012.2 [kg]
weight stabilizer & elevator (30.1 [m2]): 1392.2 [kg]
weight flight control hydraulic servo actuators: 67.5 [kg]
weight Fowler flaps (43.4 [m2]) : 654.0 [kg]
weight spoilers (9.5 [m2]) : 38.3 [kg]
total weight wing surfaces & bracing : 20097 [kg] (13.6 [%])
*******************************************************************
tyre pressure main wheels : 13.20 [Bar] (nitrogen), ply rating : 23 PR
Can only operate from paved runways
wheel pressure : 16216.2 [kg]
weight 8 Dunlop main wheels (1120 [mm] by 390 [mm]) : 1368.0 [kg]
weight 2 nose wheels : 171.0 [kg]
weight mult-disc wheel-brakes : 101.6 [kg]
weight flywheel detector type anti-skid units : 9.0 [kg]
weight oleo-pneumatic shock absorbers : 135.5 [kg]
weight wheel hydraulic operated retraction system : 1317.0 [kg]
weight undercarriage struts (four-wheel bogies) with axle 3416.9 [kg]
total weight landing gear : 6519.0 [kg] (4.4 [%]
*******************************************************************
United N8087U c/n 45977 at Chicago O’hare airport. May 1987
********************************************************************
calculated empty weight : 71953 [kg](48.8 [%])
weight oil for 15.0 hours flying : 183.2 [kg]
weight catering : 436.1 [kg]
weight water : 697.8 [kg]
weight crew : 891 [kg]
weight crew lugage,nav.chards,flight doc.,miscell.items : 138 [kg]
operational weight empty : 74299 [kg] (50.4 [%])
********************************************************************
weight 215 passengers : 16555 [kg]
weight luggage : 3440 [kg]
weight cargo : 7312 [kg]
zero fuel weight (ZFW): 101606 [kg](68.9 [%])
weight fuel for landing (1.3 hours flying) : 7258 [kg]
max. landing weight (MLW): 108864 [kg](73.8 [%])
max. fuel weight : 145141 [kg] (98.5 [%])
payload with max fuel : 25 passengers+luggage 2279 [kg]
published maximum take-off weight : 147420 [kg] (100.0 [%])
calculation : * 4 * (engine power)
power loading (Take-off) : 378 [kg/KN]
power loading (Take-off) 1 PUF: 504 [kg/KN]
max. total take-off power : 390.0 [KN]
calculation : *5* (loads)
manoeuvre load : 6.2 [g] at 1000 [m]
limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 0.9 [g]
design flight time : 4.06 [hours]
design cycles : 11273 sorties, design hours : 45735 [hours]
max. wing loading (MTOW & flaps retracted) : 550 [kg/m2]
wing stress (2 g) during operation : 203 [N/kg] at 2g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.80 ["]
max. angle of attack (stalling angle, clean) : 11.98 ["]
max. angle of attack (full flaps) : 11.18 ["]
angle of attack at max. speed : 1.62 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° : 0.15 [ ]
lift coefficient at max. speed : 0.29 [ ]
lift coefficient at max. angle of attack : 1.15 [ ]
max. lift coefficient full flaps : 1.68 [ ]
drag coefficient at max. speed : 0.0228 [ ]
drag coefficient at econ. cruise speed : 0.0237 [ ]
induced drag coefficient at econ. cruise speed : 0.0057 [ ]
drag coefficient (zero lift) : 0.0180 [ ]
lift/drag ratio at max. speed : 12.50 [ ]
calculation : *8* (speeds
stalling speed clean at sea-level (OW loaded : 141990 [kg]): 310 [km/u]
stalling speed at sea-level with full flaps (normal landing weight): 207 [km/u]
landing speed at sea-level (normal landing weight : 108297 [kg]): 238 [km/hr]
approach speed at sea-level with full flaps (normal landing weight): 269 [km/u]
max. rate of climb speed : 712 [km/hr] at sea-level
max. endurance speed : 673 [km/u] min. fuel/hr : 4647 [kg/hr] at height : 9754 [m]
max. range speed : 964 [km/u] min. fuel consumption : 5.503 [kg/km] at cruise height : 11278 [m]
cruising speed : 887 [km/hr] at 9449 [m] (power:22 [%])
max. operational speed (Mmo) : 965.00 [km/hr] (Mach 0.89 ) at 9150 [m] (power:24.5 [%])
airflow at cruise speed per engine : 255.8 [kg/s]
speed of thrust jet : 1184 [km/hr]
climbing speed at sea-level (loaded) : 1903 [m/min]
climbing speed at 1000 [m] with 1 engine out (PUF / MTOW) : 1316 [m/min]
climbing speed at 1000 [m] with 2 engines out (2xPUF / MTOW) : 557 [m/min]
calculation : *9* (regarding various performances)
take-off speed : 331.2 [km/u]
high wheel pressure, can only take off from paved runways
take-off distance at sea-level concrete runway : 2633 [m]
take-off distance at sea-level over 15 [m] height : 2727 [m]
landing run : 1214 [m]
landing run (C.A.R.) from 15 [m] at SL, dry runway : 1945 [m]
landing run (C.A.R.) from 15 [m] at SL, wet runway : 2245 [m]
lift/drag ratio : 15.31 [ ]
climb to 5000 [m] with max payload : 2.64 [min]
climb to 10000 [m] with max payload : 4.44 [min]
theoretical ceiling fully loaded (mtow- 60 min. fuel:141990 [kg] ) : 15800 [m]
calculation *10* (action radius & endurance)
range with max. payload: 7024 [km] with 27307.0 [kg] max. useful load (64.7 [%] fuel)
range with high density pax: 7574 [km] with 259 passengers (69.2 [%] fuel)
range with typical two-class pax: 8281 [km] with 215 passengers (75.0 [%] fuel)
range with max.fuel : 11480 [km] with 11 crew and 25 passengers and 100.0 [%] fuel
ferry range : 11677 [km] with 4 crew and zero payload (100.0 [%] fuel)
max range theoretically with additional fuel tanks total 93527.5 [litre] fuel : 12229 [km]
Available Seat Kilometres (ASK) : 1780315 [paskm]
useful load with range 1000km : 27307 [kg]
useful load with range 1000km : 259 passengers
production (theor.max load): 24221 [tonkm/hour]
production (useful load): 24221 [tonkm/hour]
production (passengers): 190705 [paskm/hour]
oil and fuel consumption per tonkm : 0.225 [kg]
fuel cost per paskm : 0.029 [eur]
crew cost per paskm : 0.008 [eur]
economic hours : 22300 [hours] is less then design hours
time between engine failure : 432 [hr]
can continue fly on 3 engines, low risk for emergency landing for PUF
writing off per paskm : 0.014 [eur]
insurance per paskm : 0.0008 [eur]
maintenance cost per paskm : 0.044 [eur]
direct operating cost per paskm : 0.095 [eur]
direct operating cost per tonkm (max. load): 0.752 [eur]
direct operating cost per tonkm (normal useful load): 0.752 [eur]
Literature :
https://contentzone.eurocontrol.int/aircraftperformance/default.aspx ?
Air International feb’99 page 120
Observers Airliners page 135
https://www.boeing.com/search/results.html?q=airplane+characteristics
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 October 2022 contact : info.aircraftinvestigation@gmail.com python 3.7.4