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weight and performance calculations for the Avro 691 Lancastrian
Avro 691 Lancastrian C.1
role : medium weight passenger and mail aircraft
importance : ****
first flight : operational : April 1945
country : United-Kingdom
design : Roy Chadwick
production : ca. 91 aircraft, including conversions.
general information :
The Lancastrian was derived from the famous Lancaster bomber. It was a transitional
plane in anticipation of the first post-war airliners. Compared to the Lancaster it was
little changed, only there was a passenger cabin built in and the military equipment
was removed. It was fast with a long range and could carry a heavy load but internal
space was limited so it could carry not to much passengers. Besides the passengers it
took a load of mail.
It entered service in April 1945 with the BOAC, which used it on the route
to Australia and New Zealand flew. Later they also flew to South America. The Lancastrian re-opened the long distance routes in the British Empire after WWII,
giving good prestige but operations with the limited number of passengers was un-
economical. After 1947 they were only used for charter flights. The Lancastrian was
also used in the Berlin Airlift in 1948 to transport petrol. 15 aircraft made over 5000
trips. In 1951 most of them were taken out of service.
fuel capacity : 14429 litre (10375 kg) oil capacity : 681 litre (613 kg)
primary users : BOAC (20), British South American Airways, Trans-Canada Airlines
(12), Alitalia, RAF (65)
flight crew : 4 cabin crew : 0 passengers : 13
flight crew consist of captain, first officer, navigation officer and radio officer
engine : 4 Rolls Royce Merlin 24 liquid-cooled 12 -cylinder V-engine 1175 [hp]
(876.2 KW) normal rating, supercharged engine, high blower, constant power to height
: 5340 [m] and with 1620 [hp](1208.0 KW) available for take-off
dimensions :
wingspan : 31.09 [m], length : 23.42 [m], height : 5.94 [m]
wing area : 120.5 [m^2]
weights :
max.take-off weight : 29484 [kg]
empty weight operational : 16413 [kg] useful load : 3560 [kg]
performance :
maximum continuous speed : 507 [km/u] op 5340 [m]
normal cruise speed : 470 [km/u] op 5334 [m] (86 [%] power)
service ceiling : 7770 [m]
range with max fuel : 4847 [km] and allowance for 419.3 [km] diversion and 30 [min]
hold
description :
shoulder-winged monoplane with retractable landing gear with tail wheel
tapered wing with slotted flaps airfoil : root : NACA 23018 tip : NACA 23012
engines and landing gear attached to the wings, fuel tanks in the wings
construction : all-metal stressed-skin (Alclad-aluminium) airplane
fuselage shape : 0
airscrew :
four Hamilton-Standard constant speed full-feathering 3 -bladed tractor airscrews with
max. efficiency :0.76 [ ]
diameter airscrew 4.00 [m]
relative pitch (J) : 1.76 [ ]
power loading prop : 146.03 [KW/m]
theoretical pitch without slip : 7.86 [m]
blade angle prop at max.speed : 40.84 [ ]
tip-speed close to speed of sound (above Mach 0.85) > loose of efficiency
reduction : 0.42 [ ]
airscrew revs : 1197 [r.p.m.]
aerodynamic pitch at max. continuous speed 7.06 [m]
blade-tip speed at max.continuous speed : 288 [m/s]
propellor noise in flight : 100 [Db]
calculation : *1* (dimensions)
measured wing chord : 3.72 [m] at 50% wingspan
mean wing chord : 3.88 [m]
calculated average wing chord tapered wing with rounded tips: 4.35 [m]
wing aspect ratio : 8.0 []
seize (span*length*height) : 4325 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 42.1 [kg/hr]
fuel consumption (econ. cruise speed) : 903.6 [kg/hr] (1232.7 [litre/hr]) at 86 [%] power
distance flown for 1 kg fuel : 0.52 [km/kg] at 5334 [m] height, sfc : 300.0 [kg/kwh]
estimated total fuel capacity : 14429 [litre] (10576 [kg])
calculation : *3* (weight)
weight engine(s) dry with reduction gear : 2632.0 [kg] = 0.75 [kg/KW]
weight 667.4 litre oil tank : 56.73 [kg]
oil tank filled with 26.3 litre oil : 23.6 [kg]
oil in engine 195.2 litre oil : 175.2 [kg]
fuel in engine 23.9 litre fuel : 17.52 [kg]
weight 524.1 litre gravity patrol tank(s) : 78.6 [kg]
weight radiator : 560.8 [kg]
weight exhaust pipes & fuel lines 152.6 [kg]
weight Burgess type silencers : 70.1 [kg]
weight cowling 35.0 [kg]
weight variable pitch control : 27.6 [kg]
weight airscrew(s) incl. boss & bolts : 690.8 [kg]
total weight propulsion system : 4493 [kg](15.2 [%])
***************************************************************
fuselage aluminium frame : 2499 [kg]
cabin layout : pitch : 87 [cm] (1+1) seating in 6 rows
pax density (normal seating) : 2.05 [m2/pax]
high density seating passengers : 32 at 2 -abreast seating in 16.2 rows
weight 1 toilets : 8.0 [kg]
weight 2 hand fire extinguisher : 6 [kg]
weight 15 windows : 13.5 [kg]
weight 1 life rafts : 16.2 [kg]
weight 1 entrance/exit doors : 5.0 [kg]
extra main deck space for freight/mail/luggage etc. : 9.98 [m3]
cabin volume (usable), excluding flight deck : 31.15 [m3]
passenger cabin max.width : 1.67 [m] cabin length : 15.98 [m] cabin height : 1.90 [m]
fuselage covering ( 93.5 [m2] duraluminium 6.60 [mm]) : 1621.7 [kg]
weight floor beams : 7.1 [kg]
weight cabin furbishing : 46.1 [kg]
weight cabin floor : 51.7 [kg]
fuselage (sound proof) isolation : 31.4 [kg]
weight radio transceiver equipment : 7.0 [kg]
weight artificial horizon : 1.1 [kg]
weight instruments. : 8.0 [kg]
weight lighting : 3.2 [kg]
weight electricity generator : 18.0 [kg]
weight controls : 11.2 [kg]
weight seats : 85.0 [kg]
weight air conditioning : 20 [kg]
total weight fuselage : 4410 [kg](15.0 [%])
***************************************************************
total weight aluminium ribs (389 ribs) : 1051 [kg]
weight engine mounts : 175 [kg]
weight fuel tanks empty for total 13905 [litre] fuel : 1112 [kg]
weight wing covering (painted aluminium 1.73 [mm]) : 1124 [kg]
total weight aluminium spars (multi-cellular wing structure) : 985 [kg]
weight wings : 3160 [kg]
weight wing/square meter : 26.22 [kg]
cantilever wing without bracing cables
weight rubber de-icing boots : 34.2 [kg]
weight fin & rudder (11.2 [m2]) : 295.9 [kg]
weight stabilizer & elevator (13.6 [m2]): 356.4 [kg]
weight slotted flaps (10.0 [m2]) : 137.7 [kg]
total weight wing surfaces & bracing : 5272 [kg] (17.9 [%])
*******************************************************************
wheel pressure : 14742.0 [kg]
weight 2 Dunlop main wheels (1630 [mm] by 326 [mm]) : 518.1 [kg]
weight tailwheel(s) : 5.9 [kg]
weight hydraulic wheel-brakes : 18.0 [kg]
weight Dowty shock absorbers : 24.1 [kg]
weight wheel hydraulic operated retraction system : 88.6 [kg]
weight undercarriage struts with axle 673.8 [kg]
total weight landing gear : 1328.5 [kg] (4.5 [%]
*******************************************************************
********************************************************************
calculated empty weight : 15503 [kg](52.6 [%])
weight oil for 12.4 hours flying : 520.5 [kg]
weight ethylene glycol cooling fluids : 567.8 [kg]
calculated operational weight empty : 16591 [kg] (56.3 [%])
published operational weight empty : 16413 [kg] (55.7 [%])
weight crew : 324 [kg]
weight fuel for 2.0 hours flying : 1807 [kg]
weight catering : 46.9 [kg]
weight water : 18.8 [kg]
********************************************************************
operational weight empty: 18788 [kg](63.7 [%])
weight 13 passengers : 1001 [kg]
weight luggage : 159 [kg]
weight cargo : 474 [kg]
operational weight loaded: 20422 [kg](69.3 [%])
fuel reserve : 8769.3 [kg] enough for 9.71 [hours] flying
possible additional useful load : 292 [kg]
operational weight fully loaded : 29484 [kg] with fuel tank filled for 100 [%]
published maximum take-off weight : 29484 [kg] (100.0 [%])
calculation : * 4 * (engine power)
power loading (Take-off) : 6.10 [kg/kW]
power loading (operational without useful load) : 5.36 [kg/kW]
power loading (Take-off) 1 PUF: 8.14 [kg/kW]
max.total take-off power : 4832.1 [kW]
calculation : *5* (loads)
manoeuvre load : 4.0 [g] at 1000 [m]
limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 1.3 [g]
design flight time : 7.22 [hours]
design cycles : 2422 sorties, design hours : 17483 [hours]
operational wing loading : 1993 [N/m^2]
wing stress (3 g) during operation : 228 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.44 ["]
max. angle of attack (stalling angle, clean) : 12.34 ["]
max. angle of attack (full flaps) : 11.45 ["]
angle of attack at max. speed : 1.17 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° : 0.12 [ ]
lift coefficient at max. speed : 0.22 [ ]
lift coefficient at max. angle of attack : 1.15 [ ]
max.lift coefficient full flaps : 1.40 [ ]
induced drag coefficient at max.speed : 0.0028 [ ]
drag coefficient at max. speed : 0.0221 [ ]
drag coefficient (zero lift) : 0.0193 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW loaded : 28580 [kg]): 207 [km/u]
stalling speed at sea-level with full flaps (normal landing weight): 155 [km/u]
landing speed at sea-level (normal landing weight : 19491 [kg]): 178 [km/hr]
max. rate of climb speed : 211 [km/hr] at sea-level
max. endurance speed : 212 [km/u] min.fuel/hr : 428 [kg/hr] at height : 610 [m]
max. range speed : 330 [km/u] min. fuel consumption : 1.751 [kg/km] at cruise height : 3962 [m]
cruising speed : 470 [km/hr] at 5334 [m] (power:84 [%])
max. continuous speed* : 507.00 [km/hr] at 5340 [m] (power:100 [%])
climbing speed at sea-level (loaded) : 551 [m/min]
climbing speed at 1000 [m] with 1 engine out (PUF / MTOW) : 249 [m/min]
climbing speed at 1000 [m] with 2 engines out (2xPUF / MTOW) : 42 [m/min]
calculation : *9* (regarding various performances)
take-off speed : 252.5 [km/u]
emergency/TO power : 1620 [hp] at 3000 [rpm]
static prop wash : 167 [km/u]
high wheel pressure, can only take off from paved runways
take-off distance at sea-level concrete runway : 857 [m]
take-off distance at sea-level over 15 [m] height : 952 [m]
landing run : 691 [m]
landing run from 15 [m] : 1399 [m]
lift/drag ratio : 14.79 [ ]
climb to 1000m with max payload : 4.08 [min]
climb to 2000m with max payload : 8.40 [min]
climb to 3000m with max payload : 13.04 [min]
climb to 5000 [m] with max payload : 24.19 [min]
practical ceiling (operational weight empty 18788 [kg] ) : 9500 [m]
practical ceiling fully loaded (mtow- 30 min.fuel:29032 [kg] ) : 6900 [m]
calculation *10* (action radius & endurance)
published range : 4847 [km] with 4 crew and 3250.2 [kg] useful load and 88.1 [%]
fuel (no reserves)
range : 4708 [km] with 4 crew and 3560 [kg] useful load and 85.6 [%] fuel
range : 5957 [km] with 13.0 passengers with each 12.2 [kg] luggage and 107.9 [%]
fuel
Available Seat Kilometres (ASK) : 77148 [paskm]
max range theoretically with additional fuel tanks total 17478.2 [litre] fuel : 7338 [km]
useful load with range 500km : 11850 [kg]
useful load with range 500km : 13 passengers
production (theor.max load): 5570 [tonkm/hour]
production (useful load): 768 [tonkm/hour]
production (passengers): 6110 [paskm/hour]
combi aircraft mail/freight/passengers
oil and fuel consumption per tonkm : 0.170 [kg]
fuel cost per paskm : 0.155 [eur]
crew cost per paskm : 0.049 [eur]
time between engine failure : 261 [hr]
can continue fly on 3 engines, low risk for emergency landing for PUF
writing off per paskm : 0.121 [eur]
insurance per paskm : 0.0047 [eur]
maintenance cost per paskm : 0.186 [eur]
direct operating cost per paskm : 0.515 [eur]
direct operating cost per tonkm (max. load): 0.565 [eur]
direct operating cost per tonkm (normal useful load): 4.096 [eur]
Literature :
praktisch handboek vliegtuigen deel 5 page 100,101,102
piston-engined airliners page 61
verkeersvliegtuigen Moussault page 32,109,110
Jane’s fighting aircraft WWII page 104,105
* max. continuous 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 03 April 2022 contact : info.aircraftinvestigation@gmail.com python 3.7.4