Aircraft investigation >>>>>>> HOME PAGE

weight and performance calculations for the Fokker F.XVIII

Fokker F.XVIII

role : multi-engined passenger aircraft

importance : **

first flight : 30 June 1932 operational : December 1933

country : The Netherlands

design :

production : 5 aircraft

general information :

Designed specially for the long distance route to Indonesia and for this purpose it had a long range. It was developed from the F.XII. For better aerodynamics it had a rounded top fuselage. Used by KLM on its Amsterdam – Batavia route. December 1933 PH-AIP became famous for its Christmas flight to Batavia,( crew : pilot Iwan Smirnoff, co-pilot Piet Soer, radio-operator C.H.van Beukering, mechanic J.Grosfeld) ,making the round-trip in 73 hours 34 minutes. Next year PH-AIS “Snip” made a similar Christmas flight but now to Curacao. It had stronger 550hp Wasp TD1 engines and 8 additional fuel tanks for 3500 litre in the fuselage making total capacity ca. 6000 litre to make the long distance non-stop flights from Casablanca to Porto de Praia, Cape Verde (2650km) and from Porto de Praia to Paramaribo over the South Atlantic ocean (3575 km).additional oil : 180 litre. To fly 3575 km non-stop a total of ca. 5220 litre fuel (3825 kg) was needed. Max. TOW was approved for the flight to be 10.000 kg. It was the first trans-atlantic KLM flight. Crew : Captain Jan Hondong, co-pilot Jan Van Balkom, radio-operator Simon van der Molen, mechanic Leo Stolk. It landed 22 December 1934 in Willemstad, Curacao, the 12200 km distance took 54 hour 27 minutes. The “Snip” stayed in Curacao and flew for the KLM-West-Indisch bedrijf as PJ-AIS later it was accompanied by PH-AIO “Oehoe” which was shipped by boat and given new reg. and name PJ-AIO “Oriol”. They flew to Paramaribo, Venezuela, Cuba, Colombia, Jamaica and Miami. During WW2 Pj_AJO was used as maritime patrol aircraft by the Dutch air force. They were in service till 1946 !

On the route to Batavia the F.XVIII carried only 4 – 6 passengers, against 12 passengers on European flights . It was replaced by the Douglas D.C.2 from October 1936.

The F.XVIII was used intensively and flew average 850 hour a year for the KLM (2.3 hr/day).

PH-AIP “Pelikaan” was sold to Air Tropique and ended in the Spanish civil war

and was subsequently destroyed by a bombing raid at Vilajuiga, Spain on 6 February 1939.

Fuel consumption : 290 litre/hour

users : KLM

registrations : PH-AIO “Oehoe” later PJ-AIO “Oriol”, PH-AIP “Pelikaan”, PH-AIQ

“Kwartel”, OK-AIQ, PH-AIR “Rijstvogel”, PH-AIS “Snip”, PJ-AIS, F-APIP

crew : 3 passengers : 12

engine : 3 Pratt & Whitney R-1340-C1 Wasp air-cooled 9 -cylinder radial engine 420 [hp](313.2 KW)

supercharged engine

dimensions :

wingspan : 24.5 [m], length : 18.5 [m], height : 4.8[m]

wing area : 84.5 [m^2]

weights :

max.take-off weight : 7850 [kg]

empty weight operational : 4620 [kg] useful load : 1200 [kg]

performance :

maximum speed :240 [km/hr] at sea-level

cruise speed :216 [km/u] op 100 [m]

service ceiling : 5600 [m]

range : 1820 [km]

description :

high-winged monoplane with fixed landing gear and tail wheel

two spar tapered wing

2 engines attached to the wings 1 in the fuselage, landing gear attached to the wings,

useful load inside the fuselage, fuel tanks in the wings

construction : steel tube fuselage, wooden wing covered with Bakelite-glued plywood

(water & heat resistant)

airscrew :

ground adjustable 2 -bladed metal Hamilton Standard tractor propeller with max.

efficiency :0.73 [ ]

estimated diameter airscrew 3.10 [m]

power loading prop : 101.03 [KW/m]

prop efficiency ratio: 5.97 [1/s]

angle of attack prop : 15.31 [ ]

reduction : 1.00 [ ]

airscrew revs : 2000 [r.p.m.]

pitch at Max speed 2.00 [m]

blade-tip speed at Vmax and m revs. : 331 [m/s]

The propellor tips nearly reach the speed of sound at max.speed and max. rpm 2000 !

calculation : *1* (dimensions)

measured wing chord : 3.68 [m] at 50% wingspan

mean wing chord : 3.45 [m]

calculated average wing chord tapered wing with rounded tips: 3.45 [m]

wing aspect ratio : 7.10 []

seize (span*length*height) : 2176 [m^3]

calculation : *2* (fuel consumption)

oil consumption : 15.0 [kg/hr]

fuel consumption(cruise speed) : 198.5 [kg/hr] (270.8 [litre/hr]) at 65 [%] power

distance flown for 1 kg fuel : 1.09 [km/kg] at 2800 [m] height, sfc : 324.6 [kg/kwh]

estimated total fuel capacity : 2590 [litre] (1899 [kg])

calculation : *3* (weight)

weight engine(s) dry : 1020.0 [kg] = 1.09 [kg/KW]

weight 192.8 litre oil tank : 16.39 [kg]

oil tank filled with 7.0 litre oil : 6.3 [kg]

oil in engine 5.2 litre oil : 4.7 [kg]

fuel in engine 6.4 litre fuel : 4.70 [kg]

weight 115.1 litre gravity patrol tank(s) : 17.3 [kg]

weight gas starter : 7.7 [kg]

weight cowling (Townend ring) 12.5 [kg]

weight airscrew(s) (wood) incl. boss & bolts : 131.2 [kg]

total weight propulsion system : 1204 [kg](15.3 [%])

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

fuselage skeleton (steel tubes) : 8.61 [cm]): 1080 [kg]

cabin layout : pitch : 87 [cm] (1+1) seating in 6.0 rows

weight toilet : 8 [kg]

weight 2 fire extinguisher : 6 [kg]

weight 12.0 windows : 10.80 [kg]

passenger cabin width : 1.54 [m] cabin length : 5.82 [m] cabin height : 1.90 [m]

weight cabin furbishing : 37.75 [kg]

weight cabin floor : 57.51 [kg]

bracing : 151.4 [kg]

fuselage covering ( 64.6 [m2] doped linen fabric) : 20.1 [kg]

weight radio navigation equipment : 7.0 [kg]

weight instruments. : 4.0 [kg]

weight lighting : 3.0 [kg]

weight controls : 9.1 [kg]

weight seats : 75.0 [kg]

weight air conditioning : 18 [kg]

weight engine mount and firewall : 16 [kg]

total weight fuselage : 1503 [kg](19.1 [%])

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

weight 2.4 mm bakelite-glued plywood wing covering : 130 [kg]

total weight wooden ribs (124 ribs) : 467 [kg]

weight engine mounts : 31 [kg]

weight fuel tanks empty for total 2475 [litre] fuel : 198 [kg]

load on front upper spar (clmax) per running metre : 1743.2 [N]

load on rear upper spar (vmax) per running metre : 814.7 [N]

total weight 4 wooden spars : 376 [kg]

weight wings : 973 [kg]

weight wing/square meter : 11.51 [kg]

cantilever wing without bracing cables

weight fin & rudder (7.0 [m2]) : 81.2 [kg]

weight stabilizer & elevator (9.5 [m2]): 110.0 [kg]

total weight wing surfaces & bracing : 1393 [kg] (17.7 [%])

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

wheel pressure : 3925.0 [kg]

weight 2 wheels (1410 [mm] by 282 [mm]) : 266.9 [kg]

weight tailskid : 14.5 [kg]

weight undercarriage with axle 120.5 [kg]

total weight landing gear : 401.9 [kg] (5.1 [%]

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

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

calculated empty weight : 4502 [kg](57.4 [%])

weight oil for 10.1 hours flying : 152.0 [kg]

calculated operational weight empty : 4654 [kg] (59.3 [%])

published operational weight empty : 4620 [kg] (58.9 [%])

***o***

"

weight crew : 243 [kg]

weight fuel for 2.0 hours flying : 397 [kg]

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

operational weight empty: 5294 [kg](67.4 [%])

weight 12 passengers : 924 [kg]

weight luggage & freight : 276 [kg]

operational weight loaded: 6494 [kg](82.7 [%])

fuel reserve : 1355.6 [kg] enough for 6.83 [hours] flying

operational weight fully loaded : 7850 [kg] with fuel tank filled for 92 [%]

published maximum take-off weight : 7850 [kg] (100.0 [%])

I||

I=||==|

I||

calculation : * 4 * (engine power)

power loading (Take-off) : 8.35 [kg/kW]

power loading (operational without useful load) : 5.63 [kg/kW]

power loading (Take-off) 1 PUF: 12.53 [kg/kW]

total power : 939.6 [kW] at 2000 [r.p.m]

calculation : *5* (loads)

manoeuvre load : 2.9 [g] at 1000 [m]

limit load : 2.5 [g] ultimate load : 3.8 [g] load factor : 1.6 [g]

design flight time : 5.90 [hours]

design cycles : 3705 sorties, design hours : 21850 [hours]

operational wing loading : 614 [N/m^2]

wing stress (3 g) during operation : 160 [N/kg] at 3g emergency manoeuvre

calculation : *6* (angles of attack)

angle of attack zero lift : -2.05 ["]

max. angle of attack (stalling angle) : 11.76 ["]

angle of attack at max. speed : 0.70 ["]

calculation : *7* (lift & drag ratios

lift coefficient at angle of attack 0° :0.17 [ ]

lift coefficient at max. angle of attack : 1.15 [ ]

lift coefficient at max. speed : 0.23 [ ]

induced drag coefficient at max. speed : 0.0031 [ ]

drag coefficient at max. speed : 0.0431 [ ]

drag coefficient (zero lift) : 0.0400 [ ]

calculation : *8* (speeds

stalling speed at sea-level (OW loaded : 7651 [kg]): 128 [km/u]

landing speed at sea-level: 150 [km/hr]

min. drag speed (max endurance) : 174 [km/hr] at 2800 [m](power :52 [%])

min. power speed (max range) : 174 [km/hr] at 2800 [m] (power:52 [%])

max. rate of climb speed : 143.7 [km/hr] at sea-level

cruising speed : 216 [km/hr] op 2800 [m] (power:71 [%])

design speed prop : 228 [km/hr]

maximum speed : 240 [km/hr] op 100 [m] (power:104 [%])

climbing speed at sea-level : 437 [m/min]

calculation : *9* (regarding various performances)

take-off speed : 155.6 [km/u]

static prop wash : 183 [km/u]

take-off distance at sea-level : 233 [m]

lift/drag ratio : 10.22 [ ]

climb to 1000m with max payload : 4.82 [min]

climb to 2000m with max payload : 11.66 [min]

climb to 3000m with max payload : 21.29 [min]

practical ceiling (operational weight 5294 [kg] ) : 6458 [m]

practical ceiling fully loaded (mtow- 30 min.fuel:7751 [kg] ) : 4278 [m]

calculation *10* (action radius & endurance)

published range : 1820 [km] with 3 crew and 1279.9 [kg] useful load and 88.1 [%] fuel

range : 1907 [km] with 3 crew and 1200.0 [kg] useful load and 92.3 [%] fuel

range : 2077 [km] with 12.0 passengers with each 10 [kg] luggage and 100.5 [%] fuel

Available Seat Kilometers (ASK) : 24920 [paskm]

max range theoretically with additional fuel tanks total 4249.2 [litre] fuel : 3389 [km]

useful load with range 500km : 2655 [kg]

useful load with range 500km : 12 passengers

production (useful load): 573.51 [tonkm/hour]

production (passengers): 2592.00 [paskm/hour]

combi aircraft mail/freight/passengers

oil and fuel consumption per tonkm : 0.37 [kg]

oil and fuel consumption per paskm : 0.04 [kg]

fuel cost per paskm : 0.04 [eur]

crew cost per paskm : 0.03 [eur]

__

I=I°_°°°°°°/

°

economic hours : 12775 [hours] is less then design hours

time between engine failure : 65 [hr]

writing off per paskm : 0.05 [eur]

insurance per paskm : 0.01 [eur]

maintenance cost per paskm : 0.22 [eur]

direct operating cost per paskm : 0.34 [eur]

direct operating cost per tonkm : 3.40 [eur]

Literature :

Piston engined airliners page :

Fokker verkeersvliegtuigen page 86 -91

Fokker – bouwer aan de wereldluchtvaart page 72,94,95,99

Fokker verkeersvliegtuigen1920-1940 page 49,50,51

Alles over de Fokker Friendship page 62,63, 130,131

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 18 September 2021 contact : info.aircraftinvestigation@gmail.com python 3.7.4