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weight and performance calculations for the Junkers Ju-90B
Prototype D-AALU “Der grosse Dessauer” with 1100 hp Daimler Benz DB600C engines
Junkers Ju-90B
role : commuter airliner
importance : **
first flight : 28 August 1937 flown by Hesselbach operational : May 1938
country : Germany
design : Ernst Zindel
production : 18 aircraft
general information :
Prototype had Daimler Benz DB600C engines. But further development was with less powerful BMW 132 engines, leaving the aircraft underpowered. The DB600C engines were reserved for other military projects.
D-AALU prototype was tested for 8 months by Lufthansa but then during a high-speed test it broke up and was lost on 6 February 1938.
The second prototype V2 , registration D-AIVI and named “Preussen” was delivered to Lufthansa in May 1938 but crashed on take-off at Bathurst (now Banjul ) Gambia during a tropical flight test caused by a double engine failure. 12 of the 15 people on board died in the crash.
Despite those problems Lufthansa ordered eight A-1 production aircraft. Only 7 were delivered`, the last one went directly to the Luftwaffe in April 1940.
Fuel capacity 3300 litre. Passenger cabin internal width : 2.83 [m]
With BMW 132H engines the Ju.90 could not stay in the air with 2 engines out.
users : Lufthansa (8)
registrations : D-AALU, D-AIVI “Preussen”, D-AVMF “Brandenburg”, D-AURE
“Bayern”, D-AFHG, D-ABDG
crew : 4 passengers : 40
powerplant : 4 BMW 132H air-cooled 9 -cylinder radial engine 750 [hp](559.3 KW)
normal rating, supercharged engine, low blower, constant power to height : 2600 [m]
and with 830 [hp](618.9 KW) available for take-off
dimensions :
wingspan : 35.02 [m], length : 26.3 [m], height : 7.5 [m]
wing area : 184.0 [m^2]
weights :
max.take-off weight : 23000 [kg]
empty weight operational : 16000 [kg] useful load : 4475 [kg]
performance :
maximum speed :350 [km/u] op 2500 [m]
cruise speed :332 [km/u] op 2500 [m]
service ceiling : 5750 [m]
range : 1179 [km]
description :
low-winged monoplane with retractable landing gear with tail wheel
tapered wing with Junkers-flaps airfoil : Junkers type
engines and landing gear attached to the wings, fuel tanks in the wings
construction : all-metal stressed-skin (duraluminium) airplane
airscrew :
four Hamilton-Standard constant speed full-feathering 3 -bladed tractor airscrews with
max. efficiency :0.74 [ ]
diameter airscrew 3.27 [m]
relative pitch (J) : 1.19 [ ]
power loading prop : 114.02 [KW/m]
theoretical pitch without slip : 4.41 [m]
blade angle prop at max.speed : 30.79 [ ]
reduction : 0.62 [ ]
airscrew revs : 1462 [r.p.m.]
aerodynamic pitch at max. continuous speed 3.89 [m]
blade-tip speed at max.continuous speed : 268 [m/s]
propellor noise in flight : 93 [Db]
calculation : *1* (dimensions)
measured wing chord : 5.23 [m] at 50% wingspan
mean wing chord : 5.25 [m]
calculated average wing chord tapered wing with rounded tips: 5.20 [m]
wing aspect ratio : 6.7 []
seize (span*length*height) : 6908 [m^3]
D-AURE “Bayern” the third prototype, V3 entering service with Lufthansa on the Berlin-Vienna route July 1938. It was destroyed on the ground at Stuttgart airport during an air raid on 9 august 1944. There was no one on board.
calculation : *2* (fuel consumption)
oil consumption : 17.9 [kg/hr]
fuel consumption(cruise speed) : 601.3 [kg/hr] (820.3 [litre/hr]) at 87 [%] power
distance flown for 1 kg fuel : 0.55 [km/kg] at 2875 [m] height, sfc : 310.3 [kg/kwh]
estimated total fuel capacity : 3301 [litre] (2420 [kg])
calculation : *3* (weight)
weight engine(s) dry with reduction gear : 2120.0 [kg] = 0.95 [kg/KW]
weight 140.8 litre oil tank : 11.96 [kg]
oil tank filled with 16.8 litre oil : 15.1 [kg]
oil in engine 12.5 litre oil : 11.2 [kg]
fuel in engine 15.3 litre fuel : 11.19 [kg]
weight 348.8 litre gravity patrol tank(s) : 52.3 [kg]
weight Burgess type silencers : 44.7 [kg]
weight NACA-type cowling 25.1 [kg]
weight variable pitch control : 26.7 [kg]
weight airscrew(s) incl. boss & bolts : 346.6 [kg]
total weight propulsion system : 2638 [kg](11.5 [%])
***************************************************************
fuselage aluminium frame : 4067 [kg]
cabin layout : pitch : 87 [cm] (2+2) seating in 10.0 rows
pax density : 1.25 [m2/pax]
weight two toilets : 16 [kg]
weight 4 fire extinguisher : 12 [kg]
weight pantry : 22.7 [kg]
weight garderobe : 20.0 [kg]
weight 22 windows : 19.8 [kg]
weight door : 5.0 [kg]
passenger cabin max.width : 2.83 [m] cabin length : 11.47 [m] cabin height : 1.90 [m]
weight cabin furbishing : 206.8 [kg]
weight cabin floor : 204.0 [kg]
fuselage covering ( 180.0 [m2] duraluminium 2.06 [mm]) : 982.7 [kg]
fuselage (sound proof) isolation : 49.5 [kg]
weight radio transceiver equipment : 7.0 [kg]
weight artificial horizon : 1.1 [kg]
weight instruments. : 8.0 [kg]
weight APU / engine starter: 28.0 [kg]
weight lighting : 10.0 [kg]
weight electricity generator : 21.5 [kg]
weight controls : 12.5 [kg]
weight seats : 220.0 [kg]
weight air conditioning : 60 [kg]
total weight fuselage : 5907 [kg](25.7 [%])
***************************************************************
total weight aluminium ribs (224 ribs) : 820 [kg]
weight engine mounts : 112 [kg]
weight fuel tanks empty for total 2953 [litre] fuel : 236 [kg]
weight wing covering (painted aluminium 1.57 [mm]) : 1559 [kg]
total weight aluminium spars (multi-cellular wing structure) : 2054 [kg]
weight wings : 4433 [kg]
weight wing/square meter : 24.09 [kg]
cantilever wing without bracing cables
weight fin & rudder (14.2 [m2]) : 345.1 [kg]
weight stabilizer & elevator (20.7 [m2]): 500.1 [kg]
weight split flap (9.2 [m2]) : 113.8 [kg]
total weight wing surfaces & bracing : 5740 [kg] (25.0 [%])
*******************************************************************
wheel pressure : 5750.0 [kg]
weight 4 Dunlop main wheels (1640 [mm] by 328 [mm]) : 636.7 [kg]
weight tailwheel(s) : 5.9 [kg]
weight Bendix wheel-brakes : 20.5 [kg]
weight pneumatic-hydraulic shock absorbers : 27.3 [kg]
weight wheel hydraulic operated retraction system : 112.9 [kg]
weight undercarriage with axle 889.9 [kg]
total weight landing gear : 1693.1 [kg] (7.4 [%]
********************************************************************
calculated empty weight : 15979 [kg](69.5 [%])
weight oil for 4.3 hours flying : 76.2 [kg]
calculated operational weight empty : 16055 [kg] (69.8 [%])
published operational weight empty : 16000 [kg] (69.6 [%])
weight crew : 324 [kg]
weight fuel for 2.0 hours flying : 1203 [kg]
weight catering : 56.7 [kg]
weight water : 22.7 [kg]
********************************************************************
operational weight empty: 17661 [kg](76.8 [%])
weight 40 passengers : 3080 [kg]
weight luggage : 488 [kg]
weight cargo : 907 [kg]
operational weight loaded: 22136 [kg](96.2 [%])
fuel reserve : 863.9 [kg] enough for 1.44 [hours] flying
operational weight fully loaded : 23000 [kg] with fuel tank filled for 85 [%]
published maximum take-off weight : 23000 [kg] (100.0 [%])
calculation : * 4 * (engine power)
power loading (Take-off) : 10.28 [kg/kW]
power loading (operational without useful load) : 7.89 [kg/kW]
power loading (Take-off) 1 PUF: 13.71 [kg/kW]
total power : 2237.1 [kW] at 2358 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 4.1 [g] at 1000 [m]
limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 2.4 [g]
design flight time : 2.84 [hours]
design cycles : 10455 sorties, design hours : 29658 [hours]
operational wing loading : 941 [N/m^2]
wing stress (3 g) during operation : 117 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -2.08 ["]
max. angle of attack (stalling angle) : 11.89 ["]
angle of attack at max. speed : 0.47 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° : 0.17 [ ]
lift coefficient at max. speed : 0.21 [ ]
lift coefficient at max. angle of attack : 1.14 [ ]
max.lift coefficient full flaps : 1.24 [ ]
induced drag coefficient at max.speed : 0.0027 [ ]
drag coefficient at max. speed : 0.0218 [ ]
drag coefficient (zero lift) : 0.0191 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW loaded : 22399 [kg]): 149 [km/u]
stalling speed at sea-level with full flaps (normal landing weight): 130 [km/u]
landing speed at sea-level (normal landing weight : 18498 [kg]): 141 [km/hr]
max. rate of climb speed : 162 [km/hr] at sea-level
max. endurance speed : 167 [km/u] min.fuel/hr : 342 [kg/hr] at height : 610 [m]
max. range speed : 266 [km/u] at cruise height : 4267 [m]
cruising speed : 332 [km/hr] at 2875 [m] (power:100 [%])
max. continuous speed : 341.25 [km/hr]
maximum speed : 350 [km/hr] at 2500 [m] (power:115 [%])
climbing speed at sea-level (loaded) : 243 [m/min]
climbing speed at 1000 [m] with 1 engine out (PUF / MTOW) : 124 [m/min]
climbing speed at 1000 [m] with 2 engines out (2xPUF / MTOW) : 0 [m/min]
calculation : *9* (regarding various performances)
take-off speed : 180.8 [km/u]
emergency/TO power : 830 [hp] at 2481 [rpm]
static prop wash : 167 [km/u]
take-off distance at sea-level gras field : 686 [m]
take-off distance at sea-level over 15 [m] height : 853 [m]
landing run : 250 [m]
lift/drag ratio : 14.41 [ ]
climb to 1000m with max payload : 4.76 [min]
climb to 2000m with max payload : 9.77 [min]
climb to 3000m with max payload : 15.86 [min]
practical ceiling (operational weight empty 17661 [kg] ) : 6700 [m]
practical ceiling fully loaded (mtow- 30 min.fuel:22699 [kg] ) : 5100 [m]
calculation *10* (action radius & endurance)
published range : 1179 [km] with 4 crew and 4488.8 [kg] useful load and 88.1 [%] fuel
range : 1187 [km] with 4 crew and 4475.0 [kg] useful load and 88.7 [%] fuel
range : 1688 [km] with 40.0 passengers with each 12.2 [kg] luggage
Available Seat Kilometres (ASK) : 67526 [paskm]
max range theoretically with additional fuel tanks total 9364.1 [litre] fuel : 3879 [km]
useful load with range 500km : 5960 [kg]
useful load with range 500km : 40 passengers
production (theor.max load): 1982 [tonkm/hour]
production (useful load): 1488 [tonkm/hour]
production (passengers): 13300 [paskm/hour]
oil and fuel consumption per tonkm : 0.31 [kg]
fuel cost per paskm : 0.047 [eur]
crew cost per paskm : 0.023 [eur]
economic hours : 12775 [hours] is less then design hours
time between engine failure : 372 [hr]
can continue fly on 3 engines, low risk for emergency landing for PUF
writing off per paskm : 0.078 [eur]
insurance per paskm : 0.004 [eur]
maintenance cost per paskm : 0.198 [eur]
direct operating cost per paskm : 0.350 [eur]
direct operating cost per tonkm (max. load): 2.347 [eur]
direct operating cost per tonkm (normal useful load): 3.125 [eur]
Literature :
Praktisch handboek vliegtuigen deel 5 page 242,243
Piston-engined airliners page 48
Hitler’s luftwaffe page 216
Junkers Ju90 (hugojunkers.bplaced.net)
Junkers Ju 90 (historyofwar.org)
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
“Preussen”, the second prototype crashed on TO Nov.1938 Bathurst, Gambia
(c) B van der Zalm 22 January 2022 contact : info.aircraftinvestigation@gmail.com python 3.7.4