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weight and performance calculations for the Convair CV-240

Western Airlines, N6404H CV240-1, 10 passengers windows on the port side

Convair CV-240

role : commuter airliner

importance : ****

first flight : 16 March 1947 N24501 operational : June 1948

country : United States of America

design :

production : 176 civil aircraft and 395 military between 1948 and 1958.

general information :

The series Convair-liners were a resounding success. It was a worthy successor to the DC-3 and for over 20 years it retained this role through constant improvements to its design. The CV110 was the first model, it made the first flight 8 July 1946, but with its seating for 30 passengers it was considered by the airlines to be too small, and only one prototype was built. After this work started at a scaled-up variant for 40 passengers with pressurized cabin, indicated as CV240. On 16 March 1947 the CV-240 flew. Important innovations in this aircraft class were with the CV240 a pressurized cabin, a nosewheel landing gear, an extensive system of flaps and low operating costs. In addition, the comfort for the passengers was superior to that of its closest competitors (Vickers Viking, Martin 2-0-2). A year later, 150 of them had already been sold. American Airlines was the first to take the type into service, receiving the first CV240 in February 1948 and starting operations in June 1948. KLM flew 12 years with the CV240, from 1948 till 1960.

Also many were built for the military, for the training role, indicated as T-29, as R4Y for the US navy and as C-131 Samaritan military transport for the USAF.

Fuel capacity : 1000 US gallon (3785 litres) – 1550 US gallon (5867 litres)

primary users : American Airlines (75), Pan American (20), Western Airlines (10), Continental (5), KLM (12), Swissair (4), FAMA (Argentina, 5), TAA (Australia, 5)

flight crew : 3 cabin crew : 1 passengers : 40

flight crew consist of pilot, co-pilot and radio operator

powerplant : 2 Pratt & Whitney R-2800-CA18 Double Wasp air-cooled 18 -cylinder radial engine 2100 [hp](1566.0 KW)

normal rating, supercharged engine, high blower, constant power to height : 4000 [m]

and with 2400 [hp](1789.7 KW) available for take-off

dimensions :

wingspan : 27.98 [m], length : 22.76 [m], height : 8.22 [m]

wing area : 75.9 [m^2]

weights :

max.take-off weight : 19278 [kg]

empty weight operational : 13381 [kg] useful load : 4400 [kg]

performance :

maximum continuous speed : 508 [km/u] op 4000 [m]

normal cruise speed : 432 [km/u] op 4880 [m] (70 [%] power)

service ceiling : 9150 [m]

range with max fuel : 2618 [km] and allowance for 137.4 [km] diversion and 30 [min]

hold

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 : O

airscrew :

two Hamilton Standard constant speed 3 -bladed tractor airscrews with max. efficiency :0.77 [ ]

estimated diameter airscrew 3.93 [m]

relative pitch (J) : 2.00 [ ]

power loading prop : 265.64 [KW/m]

high power loading prop > more bladed prop needed

theoretical pitch without slip : 8.72 [m]

blade angle prop at max.speed : 44.27 [ ]

reduction : 0.40 [ ]

airscrew revs : 1080 [r.p.m.]

aerodynamic pitch at max. continuous speed 7.84 [m]

blade-tip speed at max.continuous speed : 263 [m/s]

propellor noise in flight : 91 [Db]

calculation : *1* (dimensions)

measured wing chord : 2.58 [m] at 50% wingspan

mean wing chord : 2.71 [m]

calculated average wing chord tapered wing with rounded tips: 2.66 [m]

wing aspect ratio : 10.3 []

seize (span*length*height) : 5235 [m^3]

calculation : *2* (fuel consumption)

oil consumption : 28.2 [kg/hr]

fuel consumption (econ. cruise speed) : 624.8 [kg/hr] (852.4 [litre/hr]) at 70 [%] power

distance flown for 1 kg fuel : 0.69 [km/kg] at 4880 [m] height, sfc : 285.0 [kg/kwh]

estimated total fuel capacity : 5863 [litre] (4298 [kg])

calculation : *3* (weight)

weight engine(s) dry with reduction gear : 2146.0 [kg] = 0.69 [kg/KW]

weight 306.6 litre oil tank : 26.06 [kg]

oil tank filled with 23.5 litre oil : 21.1 [kg]

oil in engine 17.4 litre oil : 15.7 [kg]

fuel in engine 21.4 litre fuel : 15.66 [kg]

weight 362.4 litre gravity patrol tank(s) : 54.4 [kg]

weight jet stacks : 78.3 [kg]

weight NACA cowling 70.2 [kg]

weight variable pitch control : 16.6 [kg]

weight airscrew(s) incl. boss & bolts : 416.0 [kg]

total weight propulsion system : 2843 [kg](14.7 [%])

***************************************************************

fuselage aluminium frame : 2624 [kg]

typical cabin layout for 40 passengers : pitch : 81 [cm] ( 2+2 ) seating in 10.0 rows

pax density (normal seating) : 0.89 [m2/pax]

high density seating passengers : 51 at 4 -abreast seating in 12.8 rows

weight 1 toilets : 6.3 [kg]

weight 3 hand fire extinguisher : 9 [kg]

weight pantry : 33.9 [kg]

weight 22 windows : 19.8 [kg]

weight 4 emergency exits : 12.0 [kg]

weight oxygen masks & oxygen generators : 26.0 [kg]

weight 2 entrance/exit doors : 24.0 [kg]

extra main deck space for freight/mail/luggage etc. : 7.75 [m3]

cabin volume (usable), excluding flight deck : 69.70 [m3]

passenger cabin max.width : 2.80 [m] cabin length : 12.67 [m] cabin height : 1.90 [m]

pressure at cruise height 6100.00 [m] : 0.47 [kg/cm2] cabin pressure : 0.77 [kg/cm2]

weight rear pressure bulkhead : 94.4 [kg]

weight air pressurization system : 16.8 [kg]

fuselage covering ( 135.4 [m2] duraluminium 2.58 [mm]) : 917.7 [kg]

weight floor beams : 67.6 [kg]

weight cabin furbishing : 158.6 [kg]

weight cabin floor : 181.4 [kg]

fuselage (sound proof) isolation : 42.3 [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. : 11.0 [kg]

weight APU / engine starter: 78.3 [kg]

weight lighting : 10.0 [kg]

weight electricity generator : 10.0 [kg]

weight controls : 10.7 [kg]

weight seats : 220.0 [kg]

weight air conditioning : 60 [kg]

total weight fuselage : 4590 [kg](23.8 [%])

***************************************************************

total weight aluminium ribs (363 ribs) : 687 [kg]

weight engine mounts : 157 [kg]

weight two 2750 [litre] main fuel tanks empty : 440.0 [kg]

weight wing covering (painted aluminium 3.00 [mm]) : 1229 [kg]

total weight aluminium spars (multi-cellular wing structure) : 1133 [kg]

weight wings : 3049 [kg]

weight wing/square meter : 40.17 [kg]

cantilever wing without bracing cables

weight rubber de-icing boots : 30.8 [kg]

weight fin & rudder (9.1 [m2]) : 366.4 [kg]

weight stabilizer & elevator (8.5 [m2]): 343.6 [kg]

weight fowler flaps (6.3 [m2]) : 133.1 [kg]

total weight wing surfaces & bracing : 4520 [kg] (23.4 [%])

*******************************************************************

wheel pressure : 4241.2 [kg]

weight 4 Dunlop main wheels (1010 [mm] by 202 [mm]) : 361.0 [kg]

weight 2 Dunlop nose wheels : 90.2 [kg]

weight hydraulic wheel-brakes : 17.8 [kg]

weight pneumatic-hydraulic shock absorbers : 23.7 [kg]

weight wheel hydraulic operated retraction system : 263.5 [kg]

weight undercarriage struts with axle 548.2 [kg]

total weight landing gear : 1304.5 [kg] (6.8 [%]

*******************************************************************

********************************************************************

calculated empty weight : 13258 [kg](68.8 [%])

weight oil for 7.3 hours flying : 205.0 [kg]

calculated operational weight empty : 13463 [kg] (69.8 [%])

published operational weight empty : 13381 [kg] (69.4 [%])

weight crew : 324 [kg]

weight fuel for 1.5 hours flying : 937 [kg]

weight catering : 84.8 [kg]

weight water : 67.9 [kg]

********************************************************************

operational weight empty: 14876 [kg](77.2 [%])

weight 40 passengers : 3080 [kg]

weight luggage : 488 [kg]

weight cargo : 832 [kg]

operational weight loaded: 19276 [kg](100.0 [%])

fuel reserve : 1.5 [kg] enough for 0.00 [hours] flying

operational weight fully loaded : 19278 [kg] with fuel tank filled for 22 [%]

published maximum take-off weight : 19278 [kg] (100.0 [%])

calculation : * 4 * (engine power)

power loading (Take-off) : 5.39 [kg/kW]

power loading (operational without useful load) : 4.75 [kg/kW]

power loading (Take-off) 1 PUF: 10.77 [kg/kW]

max.total take-off power : 3579.4 [kW]

calculation : *5* (loads)

manoeuvre load : 4.2 [g] at 1000 [m]

limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 2.2 [g]

design flight time : 4.24 [hours]

design cycles : 9422 sorties, design hours : 39968 [hours]

operational wing loading : 2465 [N/m^2]

wing stress (3 g) during operation : 184 [N/kg] at 3g emergency manoeuvre

calculation : *6* (angles of attack)

angle of attack zero lift : -1.76 ["]

max. angle of attack (stalling angle, clean) : 12.51 ["]

max. angle of attack (full flaps) : 11.62 ["]

angle of attack at max. speed : 0.83 ["]

calculation : *7* (lift & drag ratios

lift coefficient at angle of attack 0° : 0.16 [ ]

lift coefficient at max. speed : 0.24 [ ]

lift coefficient at max. angle of attack : 1.30 [ ]

max.lift coefficient full flaps : 1.73 [ ]

induced drag coefficient at max.speed : 0.0022 [ ]

drag coefficient at max. speed : 0.0265 [ ]

drag coefficient (zero lift) : 0.0242 [ ]

calculation : *8* (speeds

stalling speed at sea-level (OW loaded : 18653 [kg]): 198 [km/u]

stalling speed at sea-level with full flaps (normal landing weight): 145 [km/u]

V : 199.44 te laag, Cl > Clmax berekening PR nodig klopt niet meer cl : 1.33 line 216

landing speed at sea-level (normal landing weight : 18879 [kg]): 166 [km/hr]

max. rate of climb speed : 202 [km/hr] at sea-level

max. endurance speed : 199 [km/u] min.fuel/hr : 240 [kg/hr] at height : 610 [m]

max. range speed : 368 [km/u] min. fuel consumption : 1.076 [kg/km] at cruise height : 7620 [m]

cruising speed : 432 [km/hr] at 4880 [m] (power:65 [%])

max. continuous speed* : 508.24 [km/hr] at 4000 [m] (power:100 [%])

climbing speed at sea-level (loaded) : 529 [m/min]

climbing speed at 1000 [m] with 1 engine out (PUF / MTOW) : 163 [m/min]

calculation : *9* (regarding various performances)

take-off speed : 223.1 [km/u]

emergency/TO power : 2400 [hp] at 2800 [rpm]

static prop wash : 146 [km/u]

high wheel pressure, can only take off from paved runways

take-off distance at sea-level concrete runway : 790 [m]

take-off distance at sea-level over 15 [m] height : 885 [m]

landing run : 539 [m]

landing run from 15 [m] : 1127 [m]

lift/drag ratio : 15.99 [ ]

climb to 1000m with max payload : 1.93 [min]

climb to 2000m with max payload : 3.91 [min]

climb to 3000m with max payload : 5.94 [min]

climb to 5000 [m] with max payload : 11.53 [min]

practical ceiling (operational weight empty 14876 [kg] ) : 9500 [m]

practical ceiling fully loaded (mtow- 30 min.fuel:18966 [kg] ) : 8200 [m]

calculation *10* (action radius & endurance)

published range : 2618 [km] with 4 crew and 1704.9 [kg] useful load and 88.1 [%] fuel (no reserves)

range : 755 [km] with 4 crew and 4400.0 [kg] useful load and 25.4 [%] fuel

range : 1330 [km] with 40.0 passengers with each 12.2 [kg] luggage and 44.8 [%] fuel

Available Seat Kilometres (ASK) : 53196 [paskm]

max range theoretically with additional fuel tanks total 7823.3 [litre] fuel : 5327 [km]

useful load with range 500km : 5011 [kg]

useful load with range 500km : 40 passengers

production (theor.max load): 2165 [tonkm/hour]

production (useful load): 1901 [tonkm/hour]

production (passengers): 17280 [paskm/hour]

oil and fuel consumption per tonkm : 0.302 [kg]

fuel cost per paskm : 0.038 [eur]

crew cost per paskm : 0.026 [eur]

economic hours : 18250 [hours] is less then design hours

time between engine failure : 2210 [hr]

can continue fly on 1 engine, low risk for emergency landing for PUF

writing off per paskm : 0.035 [eur]

insurance per paskm : 0.0007 [eur]

maintenance cost per paskm : 0.075 [eur]

direct operating cost per paskm : 0.174 [eur]

direct operating cost per tonkm (max. load): 1.390 [eur]

direct operating cost per tonkm (normal useful load): 1.583 [eur]

KLM CV240 PH-TEI “Paulus Potter” started to loose height on take-off from Schiphol. The pilot made a belly landing and ended past the threshold. Two girls on the ground were killed.

Literature :

Verkeersvliegtuigen nu en straks page 21

Verkeersvliegtuigen – B.van der Klaauw page 25,26

Airliners.net

Convair C-131 Samaritan (michaelprophet.com)

praktisch handboek vliegtuigen deel 5 page 49,50

piston-engined airliners page 62,63

verkeersvliegtuigen Moussault page 19,98,99

* 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