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weight and performance calculations for the Junkers Ju.86C-1
Junkers Ju.86C-1
importance : ****
first flight : 4 November 1934 operational : June 1936
country : Germany
design : Ernst Zindel
production : civil : 50 military ca. 850
General information :
Designed as passenger aircraft / military bomber aircraft. Cabin width : 1.45 [m]
At the start of WWII a high-altitude bomber was developed, designated Ju.86P with
pressurized cabin. Wing span was increased from 22.5 [m] to 25.6 [m]. A
reconnaissance version, designated Ju.86R had an even bigger wing span of 32 [m],
(wing surface 97.06 [m2] with an absolute ceiling of 14.400 [m] it could operate above
England without the RAF being unable to intercept it till the arrival of high altitude
Spitfires in 1942.
Engines :
Jumo 205C 600 hp engine troubles at first, Ju.86C-1 (Lufthansa 6) and Ju.86Z-1
(Swissair 1)
BMW 132H radial 770 hp Ju.86Z-2 Lufthansa
Rolls Royce Krestel 745 hp for SAA, retrofitted with Hornets before delivery
Pratt & Whitney R-1690 Hornet (SAA) Ju.86 Ju.86Z-7
Gnome Rhone (later SAA)
Users : Lufthansa (B-0 and Z-2, 16), Swissair, South African airways (Z-7 18), Airlines of
Australia (Z-1 > 1), LAN Chile (Z-1 > 3), AB Aerotransport (Z-7 > 1), Lloya aero
Boliviano (ZC-7 > 3)
Registrations : D-AKOP (LH), HB-IXI, VH-UYA
crew : 2 passengers : 10
engine : 2 Junkers Jumo 205C liquid-cooled 6-cylinder inline engine 600 [hp]
(447.4 KW) normal rating, supercharged engine, low blower, constant power to height
: 1000 [m] and with 700 [hp](522.0 KW) available for take-off
dimensions :
wingspan : 22.5 [m], length : 17.42 [m], height : 4.8 [m]
wing area : 82.0 [m^2]
weights :
max.take-off weight : 7700 [kg]
empty weight operational : 5050 [kg] useful load : 1180 [kg]
Measured chord at root 4.63 [m] including slotted Junkers flap : 5.14 [m], measured chord at 50% span 2.83 [m] including slotted flap 3.47 [m]
performance :
maximum speed :325 [km/u] op 2000 [m]
cruise speed :309 [km/u] op 2000 [m]
service ceiling : 6100 [m]
range : 1100 [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 :
two Hamilton Standard constant speed 3 -bladed tractor airscrews with max. efficiency
:0.74 [ ]
estimated diameter airscrew 2.90 [m]
power loading prop : 102.86 [KW/m]
angle of attack prop at max. speed : 27.56 [ ]
reduction : 0.63 [ ]
airscrew revs : 1519 [r.p.m.]
pitch at Max speed 3.48 [m]
blade-tip speed at max.continous speed : 247 [m/s]
propellor noise in flight : 86 [Db]
calculation : *1* (dimensions)
measured wing chord : 3.47 [m] at 50% wingspan
mean wing chord : 3.64 [m]
calculated average wing chord tapered wing with rounded tips: 3.57 [m]
wing aspect ratio : 6.2 []
seize (span*length*height) : 1881 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 13.4 [kg/hr]
fuel consumption(cruise speed) : 140.5 [kg/hr] (191.6 [litre/hr]) at 67 [%] power
distance flown for 1 kg fuel : 2.20 [km/kg] at 3050 [m] height, sfc : 233.1 [kg/kwh]
estimated total fuel capacity : 775 [litre] (568 [kg])
Ju.86Z-1 with Jumo 205C engines, one delivered to Swissair.
calculation : *3* (weight)
weight engine(s) dry with reduction gear : 1140.0 [kg] = 1.27 [kg/KW]
weight 86.3 litre oil tank : 7.33 [kg]
oil tank filled with 6.7 litre oil : 6.0 [kg]
oil in engine 49.8 litre oil : 44.7 [kg]
fuel in engine 6.1 litre fuel : 4.47 [kg]
weight 81.5 litre gravity patrol tank(s) : 12.2 [kg]
weight radiator : 134.2 [kg]
weight exhaust pipes & fuel lines 44.0 [kg]
weight Burgess type silencers : 17.9 [kg]
weight starter (E.H.I. - Electric Hand Inertia): 11.0 [kg]
weight cowling 17.9 [kg]
weight variable pitch control : 8.5 [kg]
weight airscrew(s) incl. boss & bolts : 110.2 [kg]
total weight propulsion system : 1550 [kg](20.1 [%])
***************************************************************
fuselage aluminium frame : 781 [kg]
cabin layout : pitch : 87 [cm] (1+1) seating in 5.0 rows
weight toilet : 8 [kg]
weight 2 fire extinguisher : 6 [kg]
weight 12 windows : 10.8 [kg]
weight door : 5.0 [kg]
passenger cabin max.width : 1.47 [m] cabin length : 5.52 [m] cabin height : 1.90 [m]
weight cabin furbishing : 30.5 [kg]
weight cabin floor : 46.0 [kg]
fuselage covering ( 68.6 [m2] duraluminium 2.81 [mm]) : 505.8 [kg]
fuselage (sound proof) isolation : 14.8 [kg]
weight radio transceiver equipment : 7.0 [kg]
weight Sperry gyro auto-pilot - course control equipment : 1.5 [kg]
weight instruments. : 6.0 [kg]
weight lighting : 2.5 [kg]
weight electricity generator : 6.3 [kg]
weight dual controls + indicators: 24.6 [kg]
weight seats : 60.0 [kg]
weight air conditioning : 15 [kg]
total weight fuselage : 1509 [kg](19.6 [%])
***************************************************************
total weight aluminium ribs (108 ribs) : 275 [kg]
weight engine mounts : 45 [kg]
Airlines of Australia Ju.86Z-1 with Jumo 205C engines, 1 delivered
weight two 347 [litre] main fuel tanks empty : 55.5 [kg]
weight wing covering (painted aluminium 1.03 [mm]) : 458 [kg]
total weight aluminium spars (multi-cellular wing structure) : 367 [kg]
weight wings : 1100 [kg]
weight wing/square meter : 13.41 [kg]
cantilever wing without bracing cables
weight fin & rudder (5.9 [m2]) : 79.7 [kg]
weight stabilizer & elevator (9.2 [m2]): 124.3 [kg]
weight fowler flap (6.8 [m2]) : 51.8 [kg]
total weight wing surfaces & bracing : 1456 [kg] (18.9 [%])
*******************************************************************
Can only operate from paved runways
wheel pressure : 3850.0 [kg]
weight 2 Dunlop wheels (1020 [mm] by 185 [mm]) : 285.4 [kg]
weight tailwheel(s) : 5.9 [kg]
weight Bendix wheel-brakes : 6.2 [kg]
weight Dowty shock absorbers : 8.3 [kg]
weight wheel hydraulic operated retraction system : 31.4 [kg]
weight undercarriage with axle 133.6 [kg]
total weight landing gear : 470.8 [kg] (6.1 [%]
*******************************************************************
Ju.86Z-2 with BMW radials
********************************************************************
calculated empty weight : 4985 [kg](64.7 [%])
weight oil for 4.3 hours flying : 57.4 [kg]
weight cooling fluids : 193.3 [kg]
calculated operational weight empty : 5236 [kg] (68.0 [%])
published operational weight empty : 5050 [kg] (65.6 [%])
___o___
"
weight crew : 162 [kg]
weight fuel for 2.0 hours flying : 281 [kg]
weight catering : 14.3 [kg]
weight water : 5.7 [kg]
********************************************************************
operational weight empty: 5699 [kg](74.0 [%])
weight 10 passengers : 770 [kg]
weight luggage & freight : 410 [kg]
operational weight loaded: 6879 [kg](89.3 [%])
fuel reserve : 287.1 [kg] enough for 2.04 [hours] flying
possible additional useful load : 534 [kg]
operational weight fully loaded : 7700 [kg] with fuel tank filled for 100 [%]
published maximum take-off weight : 7700 [kg] (100.0 [%])
calculation : * 4 * (engine power)
power loading (Take-off) : 8.60 [kg/kW]
power loading (operational without useful load) : 6.37 [kg/kW]
power loading (Take-off) 1 PUF: 17.21 [kg/kW]
total power : 894.8 [kW] at 2400 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 4.8 [g] at 1000 [m]
limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 2.1 [g]
SAA Ju.86Z-7 interior
design flight time : 2.85 [hours]
design cycles : 7219 sorties, design hours : 20576 [hours]
operational wing loading : 682 [N/m^2]
wing stress (3 g) during operation : 152 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -2.12 ["]
max. angle of attack (stalling angle) : 12.05 ["]
angle of attack at max. speed : -0.05 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° : 0.17 [ ]
lift coefficient at max. speed : 0.17 [ ]
lift coefficient at max. angle of attack : 1.14 [ ]
max.lift coefficient full flaps : 1.39 [ ]
induced drag coefficient at max.speed : 0.0019 [ ]
drag coefficient at max. speed : 0.0202 [ ]
drag coefficient (zero lift) : 0.0183 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW loaded : 7560 [kg]): 130 [km/u]
stalling speed at sea-level with full flaps (normal landing weight): 105 [km/u]
landing speed at sea-level (normal landing weight : 6037 [kg]): 121 [km/hr]
South African Ju.86Z-7 with P& Hornet engines
max. rate of climb speed : 139 [km/hr] at sea-level
max. endurance speed : 150 [km/u] min.fuel/hr : 79 [kg/hr] at height : 610 [m]
max. range speed : 238 [km/u] min. fuel consumption : 0.455 [kg/km] at cruise height :
4267 [m]
cruising speed : 309 [km/hr] at 3050 [m] (power:83 [%])
max. continuous speed : 316.88 [km/hr]
maximum speed : 325 [km/hr] at 2000 [m] (power:100 [%])
climbing speed at sea-level (loaded) : 397 [m/min]
climbing speed at 1000 [m] with 1 engine out (PUF / MTOW) : 96 [m/min]
calculation : *9* (regarding various performances)
take-off speed : 157.1 [km/u]
emergency/TO power : 700 [hp] at 2592 [rpm]
static prop wash : 158 [km/u]
high wheel pressure, can only take off from paved runways
take-off distance at sea-level concrete runway : 313 [m]
take-off distance at sea-level over 15 [m] height : 400 [m]
landing run : 182 [m]
lift/drag ratio : 14.22 [ ]
climb to 1000m with max payload : 3.18 [min]
climb to 2000m with max payload : 7.40 [min]
climb to 3000m with max payload : 13.48 [min]
practical ceiling (operational weight empty 5699 [kg] ) : 6800 [m]
practical ceiling fully loaded (mtow- 30 min.fuel:7630 [kg] ) : 5100 [m]
calculation *10* (action radius & endurance)
published range : 1100 [km] with 2 crew and 1801.9 [kg] useful load and 88.1 [%] fuel
range : 2467 [km] with 2 crew and 1180.0 [kg] useful load and 197.6 [%] fuel
range : 3148 [km] with 10.0 passengers with each 10 [kg] luggage and 252.2 [%] fuel
Available Seat Kilometres (ASK) : 31485 [paskm]
max range theoretically with additional fuel tanks total 3251.5 [litre] fuel : 5239 [km]
useful load with range 500km : 2156 [kg]
useful load with range 500km : 10 passengers
production (useful load): 666 [tonkm/hour]
production (passengers): 3088 [paskm/hour]
combi aircraft mail/freight/passengers
oil and fuel consumption per tonkm : 0.23 [kg]
fuel cost per paskm : 0.023 [eur]
crew cost per paskm : 0.023 [eur]
economic hours : 12775 [hours] is less then design hours
time between engine failure : 60 [hr]
can continue fly on 1 engine, low risk for emergency landing for PUF
writing off per paskm : 0.049 [eur]
insurance per paskm : 0.038 [eur]
maintenance cost per paskm : 0.144 [eur]
direct operating cost per paskm : 0.277 [eur]
direct operating cost per tonkm : 2.766 [eur]
Literature :
Jane’s fighting aircraft WWII page 171
Hitler’s Luftwaffe page 204
Piston-engined airliners page 40
Praktisch handboek vliegtuigen deel 2 page 140,141
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
Ju-86C-1 with Junkers Jumo 205C engines
V7 prototype with RR Krestel engines, 6 built for South African Airways, flown with those engines but then refitted with P&W Hornets before delivery.
Lufthansa Ju-86Z-2
(c) B van der Zalm 28 November 2021 contact : info.aircraftinvestigation@gmail.com python 3.7.4
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