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weight and performance calculations for the Boeing 720B
***** PRELIMINARY FILE ****
Boeing 720-023(B) G-BCBA c/n 18014 of Monarch Airlines. This aircraft was delivered to American Airlines in July 1960 as a 720 and was later converted to 720B.
Boeing 720B
role : jet airliner
importance : ****
first flight : 6 October 1960 operational : April 1961 (American Airlines)
country : United States of America
design :
production : 99 720B aircraft
general information :
This version is equipped with the more efficient and quieter turbofan engines instead of the turbojets in the 720. The turbofans are 15% more economical. The 720B was the most versatile of the 707 family, it was economical, had high performance and its range matched that of the 707-320C.
primary users : American Airlines (8), Lufthansa (8), Northwest Orient Airlines (6), Ethiopian
Airlines, Pakistan Int’l, El Al (2), Saudi Arabian Airlines, Panam (3) Continental (6),
Western Airlines (17)
Accommodation:
flight crew : 3 cabin crew : 5
flight crew consist of pilot, co-pilot and flight engineer
passengers : seating for 136 in two class : 12 business class and 124 coach class seats ( 34 -in pitch)
high density seating for 165 passengers
engine : 4 Pratt & Whitney JT3D-1 turbofan engines of 75.62 [KN](16999.8 [lbf])
dimensions :
wingspan : 39.83 [m], length : 41.72 [m], height : 12.47 [m]
wing area : 226.04 [m^2] fuselage exterior width : 3.76 [m]
weights :
empty weight : 49705 [kg]
operating empty weight : 52390 [kg] max. structural payload : 18370 [kg]
Zero Fuel weight (ZFW) : 70760 [kg] max. landing weight (MLW) : 79380 [kg]
max.take-off weight : 106140 [kg] weight fuel : 49040 [kg] (61300 [litre])
performance :
Max. operating Mach number (Mmo) : 0.89 [Mach] (995 [km/hr]) at 7620 [m]
normal cruise speed : 866 [km/hr] (Mach 0.82 ) at 11430 [m] (31 [%] power)
service ceiling : 12192 [m]
range with max fuel : 5043 [km] and allowance for 560.5 [km] diversion and 30 [min] hold
description :
low-wing cantilever monoplane with retractable landing gear with nose wheel
tapered multi-cellular wing with flush-riveted stressed skin
with Fowler flaps airfoil : NACA
sweep angle 3/4 chord: 34.0 [°]
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)
measured wing chord : 5.74 [m] at 50% wingspan
mean wing chord : 5.68 [m]
calculated average wing chord tapered wing with rounded tips: 5.62 [m]
wing aspect ratio : 7.02 []
seize (span*length*height) : 20721 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 30.2 [kg/hr]
fuel consumption (econ. cruise speed) : 7419.4 [kg/hr] (9274.2 [litre/hr]) at 31 [%] power
distance flown for 1 kg fuel : 0.12 [km/kg] at 11430 [m] height, sfc : 79.2 [kg/KN/h]
total fuel capacity : 61300 [litre] (49040 [kg])
calculation : *3* (weight)
weight engine(s) dry : 7420.0 [kg] = 24.53 [kg/KN]
weight 241.8 litre oil tank : 20.55 [kg]
oil tank filled with 1.9 litre oil : 1.7 [kg]
oil in engine 50.5 litre oil : 45.4 [kg]
fuel in engine 37.1 litre fuel : 27.22 [kg]
weight fuel lines 61.3 [kg]
weight engine cowling 907.4 [kg]
total weight propulsion system : 8484 [kg](8.0 [%])
***************************************************************
fuselage aluminium frame : 12680 [kg]
floor loading : 192 [kg/m2]
typical cabin layout for 136 passengers : economy : pitch : 86 [cm] ( 3+3 ) seating in 23.1 rows
Northwest airlines interior
pax density (normal seating) : 0.70 [m2/pax]
high density seating passengers : 167 at 6 -abreast seating in 27.8 rows, pitch 83.8 [cm]
weight 3 toilets : 44.0 [kg]
weight 7 hand fire extinguisher : 20 [kg]
weight 1 galleys : 110.9 [kg]
weight overhead stowage for hand luggage : 47.6 [kg]
weight 3 closets : 27.2 [kg]
weight 48 windows : 43.3 [kg]
weight 4 over wing emergency exits : 106.1 [kg]
weight lifejackets : 61.2 [kg]
weight oxygen masks & oxygen generators : 88.4 [kg]
weight emergency flare installation : 10 [kg]
weight 4 emergency evacuation slides : 63.9 [kg]
weight 4 entrance/exit doors : 247.7 [kg]
weight 2 freight doors (belly) : 88.4 [kg]
weight ladies’ powder room : 16 [kg]
weight men’s dressing room : 12 [kg]
weight diplomatic mail locker : 2 [kg]
cabin volume (usable), excluding flight deck : 263.44 [m3]
passenger cabin max.width : 3.54 [m] cabin length : 29.94 [m] cabin height : 2.19 [m]
floor area : 95.5 [m2]
pressure difference :0.62 [kg/cm2]
weight rear pressure bulkhead : 173.5 [kg]
weight air pressurization system : 58.0 [kg]
fuselage covering ( 358.4 [m2] duraluminium 2.96 [mm]) : 2804.5 [kg]
weight floor beams : 534.2 [kg]
weight cabin furbishing : 838.9 [kg]
weight cabin floor : 1451.3 [kg]
fuselage (sound proof) isolation : 260.2 [kg]
weight radio transceiver equipment : 7.0 [kg]
weight dual cloud-collision radar : 25.0 [kg]
weight radio direction finding (RDF) equipment : 5.0 [kg]
weight Sperry Integrated Flight System : 11.0 [kg]
weight artificial horizon : 1.1 [kg]
weight instruments. : 38.0 [kg]
weight APU / engine starter: 37.8 [kg]
weight lighting : 34.0 [kg]
weight electricity generator : 34.0 [kg]
Northwest Airlines 720B N721US cockpit
weight controls : 17.1 [kg]
weight seats : 720.0 [kg]
weight 30650 [litre] main central fuel tanks empty : 1716.4 [kg]
weight air conditioning : 204 [kg]
total weight fuselage : 22278 [kg](21.0 [%])
***************************************************************
total weight aluminium ribs (955 ribs) : 3785 [kg]
weight engine mounts : 151 [kg]
weight fuel tanks empty for total 30650 [litre] fuel : 1716 [kg]
weight wing covering (painted aluminium 2.41 [mm]) : 2942 [kg]
total weight aluminium spars (multi-cellular wing structure) : 4202 [kg]
weight wings : 10930 [kg]
weight wing/square meter : 48.35 [kg]
weight rubber de-icing boots : 43.8 [kg]
weight fin & rudder (18.4 [m2]) : 893.1 [kg]
weight stabilizer & elevator (25.4 [m2]): 1231.3 [kg]
weight flight control hydraulic servo actuators: 59.5 [kg]
weight fowler flaps (14.1 [m2]) : 345.9 [kg]
total weight wing surfaces & bracing : 15371 [kg] (14.5 [%])
*******************************************************************
wielen naar verhouding erg licht
wheel pressure : 11675.4 [kg]
weight 8 Dunlop main wheels (1130 [mm] by 226 [mm]) : 991.5 [kg]
weight 2 Dunlop nose wheels : 123.9 [kg]
weight hydraulic wheel-brakes : 70.8 [kg]
weight pneumatic-hydraulic shock absorbers : 94.3 [kg]
weight wheel hydraulic operated retraction system : 973.1 [kg]
weight undercarriage struts with axle 2563.3 [kg]
total weight landing gear : 4817.0 [kg] (4.5 [%]
*******************************************************************
********************************************************************
calculated empty weight : 50950 [kg](48.0 [%])
weight oil for 7.0 hours flying : 211.4 [kg]
weight catering : 277.2 [kg]
weight water : 221.8 [kg]
weight crew : 648 [kg]
weight crew lugage,nav.chards,flight doc.,miscell.items : 82 [kg]
operational weight empty : 52390 [kg] (49.4 [%])
********************************************************************
Seat 5 + 9x6 = 54 + 10x4 = 40 + 7x first class = 106 passengers
weight 136 passengers : 10472 [kg]
weight luggage : 2176 [kg]
weight cargo : 5722 [kg]
zero fuel weight (ZFW): 70760 [kg](66.7 [%])
weight fuel for landing (1.2 hours flying) : 8620 [kg]
max. landing weight (MLW): 79380 [kg](74.8 [%])
max. fuel weight : 101430 [kg] (95.6 [%])
payload with max fuel : 51 passengers+luggage 4710 [kg]
published maximum take-off weight : 106140 [kg] (100.0 [%])
calculation : * 4 * (engine power)
power loading (Take-off) : 351 [kg/KN]
power loading (operational without useful load) : 307 [kg/kN]
power loading (Take-off) 1 PUF: 468 [kg/KN]
max. total take-off power : 302.5 [KN]
calculation : *5* (loads)
manoeuvre load : 10.1 [g] at 1000 [m]
limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 1.0 [g]
design flight time : 4.08 [hours]
design cycles : 2607 sorties, design hours : 10628 [hours]
operational wing loading : 4019 [N/m^2]
wing stress (3 g) during operation : 249 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.81 ["]
max. angle of attack (stalling angle, clean) : 14.00 ["]
On February 12, 1963, the 720-051B N724US c/n 18354 of Northwest Orient Airlines crashed. It was as flight 705 departed from RW27L from Miami (MIA) to Chicago (ORD) with 35 passengers and 8 crew members. However, it ends up in heavy turbulence and breaks into pieces in the air. The wreckage ends up in the remote swamp of Everglades National Park, 37 miles WZW from Miami International Airport. There are no survivors. The aircraft had made its first flight in 1961 and had 4685 flight hours on the clocks.
Location : +- 3km 25°34'N 80°54'W
angle of attack at max. speed : 0.51 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° : 0.15 [ ]
lift coefficient at max. speed : 0.19 [ ]
lift coefficient at max. angle of attack : 1.31 [ ]
max. lift coefficient full flaps : 1.58 [ ]
induced drag coefficient at max.speed : 0.0022 [ ]
drag coefficient at max. speed : 0.0264 [ ]
drag coefficient (zero lift) : 0.0241 [ ]
lift/drag ratio at max. speed : 7.28 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW loaded : 98721 [kg]): 263 [km/u]
stalling speed at sea-level with full flaps (normal landing weight): 214 [km/u]
landing speed at sea-level (normal landing weight : 79131 [kg]): 246 [km/hr]
max. rate of climb speed : 637 [km/hr] at sea-level
max. endurance speed : 562 [km/u] min. fuel/hr : 4823 [kg/hr] at height : 9144 [m]
max. range speed : 796 [km/u] min. fuel consumption : 6.989 [kg/km] at cruise height : 10363 [m]
cruising speed : 866 [km/hr] at 11430 [m] (power:21 [%])
max. operational speed (Mmo) : 995.00 [km/hr] (Mach 0.89 ) at 7620 [m] (power:40.8 [%])
airflow : 474.3 [kg/s]
speed of thrust jet : 1577 [km/hr]
climbing speed at sea-level (loaded) : 2175 [m/min]
climbing speed at 1000 [m] with 1 engine out (PUF / MTOW) : 1894 [m/min]
climbing speed at 1000 [m] with 2 engines out (2xPUF / MTOW) : 1835 [m/min]
calculation : *9* (regarding various performances)
take-off speed : 327.0 [km/u]
high wheel pressure, can only take off from paved runways
take-off distance at sea-level concrete runway : 1396 [m]
take-off distance at sea-level over 15 [m] height : 1469 [m]
On May 20, 1965, Boeing 720-040B AP-AMH c/n 18379 of Pakistan International Airlines (PIA) crashed shortly before landing at Cairo. It operated Flight 705 between Dhahran(DHA) and Cairo(CAI) with 114 passengers and 13 crew members. The aircraft descends too far, for unknown reasons, during the approach of RW34 and flies to the ground. There are 121 dead and 6 seriously injured. The aircraft had made its first flight in 1962 and was equipped with JT3D-3B engines. Location +-100m 30°01'37.06"N 31°27'03.76"E
landing run : 1178 [m]
landing run from 15 [m] : 2049 [m]
lift/drag ratio : 13.14 [ ]
max. theoretical ceiling : 18600 [m] with flying weight :98721 [kg] line 3359
climb to 1000m with max payload : 0.51 [min]
climb to 2000m with max payload : 1.00 [min]
climb to 3000m with max payload : 1.46 [min]
climb to 5000 [m] with max payload : 2.29 [min]
minimum flying speed at 12192 [m] : 599 [km/hr]
theoretical ceiling fully loaded (mtow- 60 min. fuel:98721 [kg] ) : 18600 [m]
calculation *10* (action radius & endurance)
published range : 5043 [km] with 8 crew and 10545 [kg] useful load and 88.1 [%] fuel
range : 4130 [km] with 18370.0 [kg] max. useful load (72.1 [%] fuel)
range : 4797 [km] with 136.0 passengers with each 16 [kg] luggage and 83.8 [%] fuel
range max. fuel : 5724 [km] with 4710.0 [kg] useful load and 100.0 [%] fuel
Available Seat Kilometres (ASK) : 652458 [paskm]
max range theoretically with additional fuel tanks total 67187.5 [litre] fuel : 7690 [km]
useful load with range 500km : 49466 [kg]
useful load with range 500km : 136 passengers
production (theor.max load): 42838 [tonkm/hour]
production (useful load): 15908 [tonkm/hour]
production (passengers): 117776 [paskm/hour]
combi aircraft mail/freight/passengers
oil and fuel consumption per tonkm : 0.174 [kg]
fuel cost per paskm : 0.063 [eur]
crew cost per paskm : 0.009 [eur]
time between engine failure : 481 [hr]
can continue fly on 3 engines, low risk for emergency landing for PUF
writing off per paskm : 0.034 [eur]
On January 01, 1976, a bomb exploded in the front hold of the 707-023(B) OD-AFT c/n 18020 of Middle East Airlines that was en route with 66 passengers and 15 crew members as Flight 438 from Beirut (BEY) to Dubai (DXB). The aircraft crashes out of control in the desert 37km NW of Al Qaysumah in Saudi Arabia, killing all. The aircraft had made its first flight on September 23, 1960 and was delivered to American Airlines on October 10, 1960 as N7534A. The aircraft was sold to MEA in March 1972. Engines : JT3D-1-MC7. The aircraft was delivered as 720 with JT3C-7 turbojets and was later converted to 720B. Location +-2km 28°37'N 45°53'E
insurance per paskm : 0.0008 [eur]
maintenance cost per paskm : 0.026 [eur]
direct operating cost per paskm : 0.133 [eur]
direct operating cost per tonkm (max. load): 0.366 [eur]
direct operating cost per tonkm (normal useful load): 0.987 [eur]
Literature :
Aircraft – Boeing 720B – Northwest Airlines History Center
https://www.boeing.com/search/results.html?q=airplane+characteristics
Jane’s commercial transport aircraft page 51
Wat is dat voor een vliegtuig ? page 38
Straalverkeersvliegtuigen page 101
Praktisch handboek vliegtuigen deel 5 page 70,71
Jane’s all the world aircraft 1964-1965 page 189
Verkeersvliegtuigen (Moussault) page 83,152
Verkehrsflugzeuge page 37
www.rzjets.net (productionlist)
Pan American Boeing 720-023B N708PA c/n 18033 “jet clipper carib”, the engines are JT3D-1 turbofans, not the JT3C-7 as indicated above.
![Olympic Airways B 720-051 (Nestos River) [SX-DBN] | Olympic airlines, Olympics, Boeing 707](images/720Bpre/image12.png)
Boeing 720-051B SX-BDN “Nestos”
Cypres Airways Boeing 720-23(B) G-BCBB c/n 18013 approaching. It flew also with Air Ceylon under registration 4X-JYG
Air Malta Boeing 720-040B AP-AMG c/n 18378 coming in, note the extended leading edge slats.
Lufthansa Boeing 720-030B D-ABOH
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 27 June 2022 contact : info.aircraftinvestigation@gmail.com python 3.7.4