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weight and performance calculations for the Fokker Model 4 Universal
Fokker Model 4 Universal
role : medium weight passenger aircraft
importance : ***
first flight : autumn 1925 operational : March 1926
country : United States of America
design : R.B.C. “Bob” Noorduyn, A. Francis Archer
production : 44 aircraft
general information :
Popular utility / bush plane. High theoretical max. range, but the Model 4 was refused to Charles Lindbergh for his cross Atlantic flight. The manufacturer Atlantic Aircraft Corporation found it to risky and was afraid for its own reputation. The Universal was designed and built entirely in the US. From the start it was also designed as cargo/mail aircraft so not exclusively for passenger transport, making it a versatile aircraft.
users : Ansett, Colonial Air transport, Pacific Air Transport,
Western Canada Airways (8)
registrations : G-CAHI, VH-UTO, N-AABA, X181H, C1547, 696, G-CAGE, G-CAGD,
G-EBUT, NC3199, VP-KAB, VH-UJT, NC761Y, G-CAFU,
pilots : William Dunning, Jack Frye, Punch Dickins, Walter Gilbert, S.F.Timber Woods,
John Carberry
crew : 1 passengers : 4
engine : 1 Wright R-790 J-5C Whirlwind air-cooled 9 -cylinder radial engine 220 [hp]
(164.1 KW) without supercharger
dimensions :
wingspan : 14.56 [m], length : 10.13 [m], height : 2.7[m]
wing area : 31.68 [m^2]
weights :
max.take-off weight : 1818 [kg]
empty weight operational : 996 [kg] useful load : 427 [kg]
performance :
maximum speed :189 [km/hr] at sea-level
cruise speed :170 [km/u] op 100 [m]
service ceiling : 3658 [m]
range : 805 [km]
description :
parasol wing with fixed landing gear and tail strut
two spar tapered wing
engine, fuel and useful load in or attached to fuselage, landing gear attached to the wing
airscrew :
ground adjustable 2 -bladed metal Hamilton Standard tractor propeller with max. efficiency :0.70 [ ]
estimated diameter airscrew 2.50 [m]
power loading prop : 65.62 [KW/m]
prop efficiency ratio: 8.89 [1/s]
angle of attack prop : 14.97 [ ]
fine pitch
reduction : 1.00 [ ]
airscrew revs : 2000 [r.p.m.]
pitch at Max speed 1.57 [m]
blade-tip speed at Vmax and max revs. : 267 [m/s]
calculation : *1* (dimensions)
measured wing chord : 2.50 [m] at 50% wingspan
mean wing chord : 2.18 [m]
calculated average wing chord tapered wing with rounded tips: 2.18 [m]
wing aspect ratio : 6.69 []
seize (span*length*height) : 398 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 3.0 [kg/hr]
fuel consumption(cruise speed) : 37.2 [kg/hr] (50.7 [litre/hr]) at 70 [%] power
distance flown for 1 kg fuel : 4.57 [km/kg] at 1829 [m] height, sfc : 323.7 [kg/kwh]
estimated total fuel capacity : 273 [litre] (200 [kg])
calculation : *3* (weight)
weight engine(s) dry : 236.0 [kg] = 1.44 [kg/KW]
weight 22.8 litre oil tank : 1.94 [kg]
oil tank filled with 1.2 litre oil : 1.1 [kg]
oil in engine 0.9 litre oil : 0.8 [kg]
fuel in engine 1.1 litre fuel : 0.82 [kg]
weight 21.6 litre gravity patrol tank(s) : 3.2 [kg]
weight inertia starter : 4.0 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 15.1 [kg]
total weight propulsion system : 261 [kg](14.4 [%])
***************************************************************
fuselage skeleton (steel tubes) : 5.02 [cm]): 201 [kg]
cabin layout : pitch : 87 [cm] (1+1) seating in 2.0 rows
weight 4.0 windows : 3.60 [kg]
passenger cabin width : 1.22 [m] cabin length : 1.74 [m] cabin height : 1.80 [m]
weight cabin furbishing : 7.69 [kg]
weight cabin floor : 13.58 [kg]
bracing : 14.4 [kg]
fuselage covering ( 19.4 [m2] doped linen fabric) : 6.0 [kg]
weight instruments. : 2.5 [kg]
weight lighting : 1.1 [kg]
weight controls : 5.6 [kg]
weight seats : 25.0 [kg]
weight 251 [litre] main fuel tank empty : 20.1 [kg]
weight air conditioning : 6 [kg]
weight engine mounts & firewalls : 8 [kg]
total weight fuselage : 315 [kg](17.3 [%])
***************************************************************
weight 2.4 mm plywood wing covering : 49 [kg]
total weight ribs (46 ribs) : 108 [kg]
load on front upper spar (clmax) per running metre : 1027.4 [N]
load on rear upper spar (vmax) per running metre : 351.6 [N]
total weight 4 spars : 105 [kg]
weight wings : 262 [kg]
weight wing/square meter : 8.27 [kg]
cantilever wing without bracing cables
weight fin & rudder (2.5 [m2]) : 20.7 [kg]
weight stabilizer & elevator (3.6 [m2]): 29.7 [kg]
total weight wing surfaces & bracing : 312 [kg] (17.2 [%])
*******************************************************************
wheel pressure : 909.0 [kg]
weight 2 wheels (910 [mm] by 140 [mm]) : 37.8 [kg]
weight tailskid : 4.6 [kg]
weight undercarriage with axle 54.6 [kg]
total weight landing gear : 97.0 [kg] (5.3 [%]
*******************************************************************
********************************************************************
calculated empty weight : 985 [kg](54.2 [%])
weight oil for 5.7 hours flying : 16.8 [kg]
calculated operational weight empty : 1002 [kg] (55.1 [%])
published operational weight empty : 996 [kg] (54.8 [%])
***o***
"
weight crew : 81 [kg]
weight fuel for 2.0 hours flying : 74 [kg]
********************************************************************
operational weight empty: 1157 [kg](63.7 [%])
weight 4 passengers : 308 [kg]
weight luggage & freight : 119 [kg]
operational weight loaded: 1584 [kg](87.1 [%])
fuel reserve : 125.4 [kg] enough for 3.37 [hours] flying
possible additional useful load : 108 [kg]
operational weight fully loaded : 1818 [kg] with fuel tank filled for 100 [%]
published maximum take-off weight : 1818 [kg] (100.0 [%])
calculation : * 4 * (engine power)
power loading (Take-off) : 11.08 [kg/kW]
power loading (operational without useful load) : 7.05 [kg/kW]
total power : 164.1 [kW] at 2000 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 3.1 [g] at 1000 [m]
limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 2.2 [g]
design flight time : 3.31 [hours]
design cycles : 4187 sorties, design hours : 13870 [hours]
operational wing loading : 358 [N/m^2]
wing stress (3 g) during operation : 130 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.22 ["]
max. angle of attack (stalling angle) : 12.76 ["]
angle of attack at max. speed : 1.40 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° :0.10 [ ]
lift coefficient at max. angle of attack : 1.14 [ ]
lift coefficient at max. speed : 0.21 [ ]
induced drag coefficient at max. speed : 0.0029 [ ]
drag coefficient at max. speed : 0.0407 [ ]
drag coefficient (zero lift) : 0.0378 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW loaded : 1781 [kg]): 101 [km/u]
landing speed at sea-level: 119 [km/hr]
min. drag speed (max endurance) : 134 [km/hr] at 1829 [m](power :56 [%])
min. power speed (max range) : 134 [km/hr] at 1829 [m] (power:56 [%])
max. rate of climb speed : 112.6 [km/hr] at sea-level
cruising speed : 170 [km/hr] op 1829 [m] (power:78 [%])
design speed prop : 180 [km/hr]
maximum speed : 189 [km/hr] op 100 [m] (power:108 [%])
climbing speed at sea-level : 334 [m/min]
calculation : *9* (regarding various performances)
take-off speed : 122.5 [km/u]
emergency/TO power : 237 [hp] at 2200 [rpm]
static prop wash : 157 [km/u]
take-off distance at sea-level : 216 [m]
lift/drag ratio : 10.21 [ ]
climb to 1000m with max payload : 8.58 [min]
climb to 2000m with max payload : 22.91 [min]
climb to 3000m with max payload : 47.80 [min]
practical ceiling (operational weight 1157 [kg] ) : 5973 [m]
practical ceiling fully loaded (mtow- 30 min.fuel:1799 [kg] ) : 3368 [m]
max. dive speed : 407.9 [km/hr] at 2368 [m] height
turning speed at CLmax : 128.2 [km/u] at 50 [m] height
turn radius at 50m: 57 [m]
time needed for 360* turn 10.1 [seconds] at 50m
load factor at max. angle turn 2.46 ["g"]
calculation *10* (action radius & endurance)
published range : 805 [km] with 1 crew and 559.0 [kg] useful load and 88.1 [%] fuel
range : 1409 [km] with 1 crew and 427.0 [kg] useful load and 154.2 [%] fuel
range : 1770 [km] with 4.0 passengers with each 10 [kg] luggage and 193.7 [%] fuel
Available Seat Kilometers (ASK) : 7080 [paskm]
max range theoretically with additional fuel tanks total 1002.8 [litre] fuel : 3361 [km]
useful load with range 500km : 626 [kg]
useful load with range 500km : 4 passengers
production (useful load): 106.44 [tonkm/hour]
production (passengers): 680.40 [paskm/hour]
oil and fuel consumption per tonkm : 0.38 [kg]
oil and fuel consumption per paskm : 0.06 [kg]
fuel cost per paskm : 0.06 [eur]
crew cost per paskm : 0.22 [eur]
economic hours : 12775 [hours] is less then design hours
time between engine failure : 330 [hr]
in case of engine failure only option is emergency landing
writing off per paskm : 0.08 [eur]
insurance per paskm : 0.04 [eur]
maintenance cost per paskm : 0.29 [eur]
direct operating cost per paskm : 0.70 [eur]
Literature :
Fokker verkeersvliegtuigen page 108 – 111
Fokker verkeersvliegtuigen 1920-1940 page 65
Fokker – bouwer aan de wereldluchtvaart page 64
Alles over de Fokker Friendship page 55,56,124,125, 126
Piston-engined airliners page 18,19
Geiillustreerde encyclopedie van de luchtvaart 1848-1939 page198,199
Fokker roaring twenties page 17,19,20,21
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 10 May 2021 contact : info.aircraftinvestigation@gmail.com python 3.7.4