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weight and performance calculations for the Fokker F-32
F-21 124M prototype
Fokker F-32
role : multi-engined passenger aircraft
importance : *
first flight : 13 September 1929 Hasbrouck Heights flown by Marshall Boggs. operational : April 1930
first flight : April 1930 operational : only small number built
country : United States of America
design :
production : 10 aircraft, built in Teterboro.
general information :
World biggest land based passenger airplane in 1930. Tandem engines > rear engine overheated quickly. The prototype 124M crashed on 7 November 1929 because of a double engine failure resulting in loss of control at Roosevelt field, Long Island, there were no fatalities only 2 wounded (including pilot Marshall Boggs ) . It crashed on a house in Carle Place
. The F-32 proved underpowered, worsened by the tandem engine configuration with the rear propellor operating in the disturbed air from the front propellor. Installed power 4 x 429 KW should be sufficient, giving power loading of 6.0 kg/KW which is better than the Fokker FVIIb/3m (7.8 kg/kw) and the Ford 5AT Trimotor (6.1 kg/kw). So the under power situation must be caused by the overheated rear engines and low efficiency of the rear propellor. The F-32 was also victim of the downfall of the economy and the need for big passenger aircraft vanished. Western Air Express flew for one year the route San Francisco – Los Angeles with the F-32. Already in mid 1931 the F-32 was taken out of service. Also the airworthiness certification was withdrawn in 1931 by the CAA after a crash with a F.10, giving doubts about the safety of the wooden Fokker wing.
Fuel capacity : 4 x 662 litre = 2648 litre total. Price : 110.000 USD
There was a pantry on board, garderobe and two toilets.
users : Universal Air Lines (5), Western Air Express (5)
registrations : NC334N, NC333N, N130N, NC130M, NC342N, 124M
pilots : Marshall Boggs, Fred Kelly
crew : 2 passengers : 32
engine : 4 Pratt & Whitney R-1860 Hornet B1 air-cooled 9 -cylinder radial engine 575 [hp](428.8 KW)
without supercharger
dimensions :
wingspan : 30.18 [m], length : 21.29 [m], height : 5.03[m]
wing area : 122.0 [m^2]
weights :
max.take-off weight : 10205 [kg]
empty weight operational : 6440 [kg] useful load : 2900 [kg]
performance :
maximum speed :225 [km/hr] at sea-level
cruise speed :202 [km/u] op 100 [m]
service ceiling : 4000 [m]
range : 898 [km]
description :
parasol wing with fixed landing gear and tail strut
two spar tapered wing
engines in tandem underwing, landing gear and fuel attached to the wings, useful load
in the fuselage
airscrew :
two fixed pitch 2 -bladed tractor airscrews and two fixed pitch pusher propellor with max. efficiency :0.53 [ ]
estimated diameter airscrew 3.11 [m]
power loading prop : 137.87 [KW/m]
prop efficiency ratio: 8.21 [1/s]
angle of attack prop : 14.71 [ ]
fine pitch
reduction : 1.00 [ ]
airscrew revs : 1950 [r.p.m.]
pitch at Max speed 1.92 [m]
blade-tip speed at Vmax and max revs. : 324 [m/s]
calculation : *1* (dimensions)
measured wing chord : 4.36 [m] at 50% wingspan
mean wing chord : 4.04 [m]
calculated average wing chord tapered wing with rounded tips: 4.04 [m]
wing aspect ratio : 7.47 []
seize (span*length*height) : 3232 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 22.3 [kg/hr]
fuel consumption(cruise speed) : 385.6 [kg/hr] (526.0 [litre/hr]) at 68 [%] power
distance flown for 1 kg fuel : 0.53 [km/kg] at 2000 [m] height, sfc : 329.0 [kg/kwh]
estimated total fuel capacity : 2648 [litre] (1941 [kg])
calculation : *3* (weight)
weight engine(s) dry : 1524.0 [kg] = 0.89 [kg/KW]
weight 175.0 litre oil tank : 14.88 [kg]
oil tank filled with 12.9 litre oil : 11.5 [kg]
oil in engine 9.6 litre oil : 8.6 [kg]
fuel in engine 11.7 litre fuel : 8.58 [kg]
weight 223.6 litre gravity patrol tank(s) : 33.5 [kg]
weight inertia starter : 10.5 [kg]
weight cowling 17.2 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 185.5 [kg]
total weight propulsion system : 1799 [kg](17.6 [%])
***************************************************************
fuselage skeleton (steel tubes) : 8.98 [cm]): 1353 [kg]
cabin layout : pitch : 87 [cm] (2+2) seating in 8.0 rows
weight toilets : 16 [kg]
weight 4 fire extinguisher : 12 [kg]
weight pantry : 22.7 [kg]
weight garderobe : 16.0 [kg]
weight 16.0 windows : 14.40 [kg]
passenger cabin width : 2.71 [m] cabin length : 8.06 [m] cabin height : 1.90 [m]
weight cabin furbishing : 132.10 [kg]
weight cabin floor : 139.80 [kg]
bracing : 218.4 [kg]
fuselage covering ( 85.6 [m2] doped linen fabric) : 26.6 [kg]
weight radio navigation equipment : 7.0 [kg]
weight instruments. : 4.0 [kg]
weight lighting : 8.0 [kg]
weight dual controls + indicators: 34.0 [kg]
weight seats : 170.0 [kg]
weight air conditioning : 48 [kg]
total weight fuselage : 2214 [kg](21.7 [%])
***************************************************************
Typical Fokker promotion in the late twenties. 27 September 1929 the F-32 was presented to the public at Teterboro airport. 18 Girls dancing on top of the wing watched by 25.000 spectators.
weight 2.4 mm plywood wing covering : 187 [kg]
total weight ribs (138 ribs) : 607 [kg]
weight engine mounts : 86 [kg]
weight fuel tanks empty for total 2424 [litre] fuel : 194 [kg]
load on front upper spar (clmax) per running metre : 1401.6 [N]
load on rear upper spar (vmax) per running metre : 782.0 [N]
total weight 4 spars : 535 [kg]
weight wings : 1329 [kg]
weight wing/square meter : 10.90 [kg]
cantilever wing without bracing cables
weight fin & rudder (10.6 [m2]) : 116.8 [kg]
weight stabilizer & elevator (13.7 [m2]): 150.4 [kg]
total weight wing surfaces & bracing : 1876 [kg] (18.4 [%])
*******************************************************************
wheel pressure : 5102.5 [kg]
weight 2 wheels (1290 [mm] by 258 [mm]) : 262.2 [kg]
weight tailskid : 15.7 [kg]
weight undercarriage with axle 185.3 [kg]
total weight landing gear : 463.2 [kg] (4.5 [%]
*******************************************************************
********************************************************************
calculated empty weight : 6353 [kg](62.2 [%])
weight oil for 5.3 hours flying : 118.7 [kg]
calculated operational weight empty : 6471 [kg] (63.4 [%])
published operational weight empty : 6440 [kg] (63.1 [%])
***o***
"
weight crew : 162 [kg]
weight fuel for 1.5 hours flying : 578 [kg]
weight catering : 56.8 [kg]
weight water : 22.7 [kg]
********************************************************************
One F-32 ended up at the Wilshire Blvd., Los Angeles car service station
operational weight empty: 7291 [kg](71.4 [%])
weight 32 passengers : 2464 [kg]
weight luggage & freight : 436 [kg]
operational weight loaded: 10191 [kg](99.9 [%])
fuel reserve : 14.0 [kg] enough for 0.04 [hours] flying
operational weight fully loaded : 10205 [kg] with fuel tank filled for 31 [%]
published maximum take-off weight : 10205 [kg] (100.0 [%])
calculation : * 4 * (engine power)
power loading (Take-off) : 5.95 [kg/kW]
power loading (operational without useful load) : 4.25 [kg/kW]
power loading (Take-off) 1 PUF: 7.93 [kg/kW]
total power : 1715.1 [kW] at 1950 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 2.7 [g] at 1000 [m]
limit load : 2.5 [g] ultimate load : 3.8 [g] load factor : 1.3 [g]
design flight time : 3.55 [hours]
design cycles : 2848 sorties, design hours : 10102 [hours]
operational wing loading : 586 [N/m^2]
wing stress (3 g) during operation : 161 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.19 ["]
max. angle of attack (stalling angle) : 12.45 ["]
angle of attack at max. speed : 1.75 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° :0.10 [ ]
lift coefficient at max. angle of attack : 1.15 [ ]
lift coefficient at max. speed : 0.25 [ ]
induced drag coefficient at max. speed : 0.0035 [ ]
drag coefficient at max. speed : 0.0496 [ ]
drag coefficient (zero lift) : 0.0461 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW loaded : 9819 [kg]): 121 [km/u]
landing speed at sea-level: 142 [km/hr]
min. drag speed (max endurance) : 150 [km/hr] at 2000 [m](power :45 [%])
min. power speed (max range) : 150 [km/hr] at 2000 [m] (power:45 [%])
max. rate of climb speed : 133.9 [km/hr] at sea-level
cruising speed : 202 [km/hr] op 2000 [m] (power:73 [%])
design speed prop : 214 [km/hr]
maximum speed : 225 [km/hr] op 100 [m] (power:104 [%])
climbing speed at sea-level : 421 [m/min]
calculation : *9* (regarding various performances)
take-off speed : 147.6 [km/u]
static prop wash : 172 [km/u]
take-off distance at sea-level : 235 [m]
lift/drag ratio : 9.76 [ ]
climb to 1000m with max payload : 5.00 [min]
climb to 2000m with max payload : 12.27 [min]
climb to 3000m with max payload : 22.55 [min]
practical ceiling (operational weight 7291 [kg] ) : 6038 [m]
practical ceiling fully loaded (mtow- 30 min.fuel:10012 [kg] ) : 4248 [m]
max. dive speed : 562.2 [km/hr] at 3248 [m] height
turning speed at CLmax : 164.4 [km/u] at 50 [m] height
turn radius at 50m: 93 [m]
time needed for 360* turn 12.8 [seconds] at 50m
load factor at max. angle turn 2.49 ["g"]
calculation *10* (action radius & endurance)
published range : 898 [km] with 2 crew and 1862.0 [kg] useful load and 88.1 [%] fuel
dit bereik is niet mogelijk met alle pax > nakijken, evt bereik verlagen
range : 353 [km] with 2 crew and 2900.0 [kg] useful load and 34.6 [%] fuel
range : 414 [km] with 32.0 passengers with each 10 [kg] luggage and 40.6 [%] fuel
Available Seat Kilometers (ASK) : 13241 [paskm]
max range theoretically with additional fuel tanks total 4983.4 [litre] fuel : 1918 [km]
useful load with range 500km : 2701 [kg]
useful load with range 500km : 27 passengers
production (useful load): 546.92 [tonkm/hour]
production (passengers): 6480.00 [paskm/hour]
short range airliner line 3734!!
oil and fuel consumption per tonkm : 0.75 [kg]
oil and fuel consumption per paskm : 0.06 [kg]
fuel cost per paskm : 0.06 [eur]
crew cost per paskm : 0.05 [eur]
time between engine failure : 54 [hr]
risk of overheating rear engine > higher risk on double engine failure
can not fly on 2 engines at one side, risk for LOC/emergency landing at double PUF
writing off per paskm : 0.07 [eur]
insurance per paskm : 0.03 [eur]
maintenance cost per paskm : 0.31 [eur]
direct operating cost per paskm : 0.52 [eur]
Literature :
Literature :
Piston engine airliners page 18,19
Praktisch handboek vliegtuigen deel 2 page 236,237
Fokker verkeersvliegtuigen page 132,133
Alles over de Fokker Friendship page 66,67,68,131
Fokker – Bouwer aan de wereldluchtvaart page 82,83
Fokkers roaring twenties page 42, 44
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
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