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weight and performance calculations for the Heinkel He.70
Heinkel He.70D Blitz
role : light executive aircraft
importance : ****
first flight : 1 December 1932 operational : January 1934
country : Germany
design :
production : 28 civil and 296 military aircraft
general information :
Fast passenger / mail plane, designed to compete with the Lockheed Orions operated
by Swissair. It had aerodynamic clean lines and an efficient elliptical wing with flush
rivets gave a smooth surface. The landing gear was fully retractable. Ethylene glycol
was used as cooling fluid, allowing a smaller radiator to be used. When entering
service with the Lufthansa in 1934 it was the fastest passenger aircraft in Europe.
It set speed records over 100 km with weights of 500 and 1000 kg at 357 km/hr.
Behind the pilot sat the radio operator in tandem.
The propellor pitch could be adjusted at the ground. If set for max.speed the take of
run would be considerably long.
users : Lufthansa
registrations : D-3, D-UBYL, D-UTIM, D-UZUH, D-UMIM, D-UBOF, D-UGOR, D-UDAS
crew : 2 passengers : 4
engine : 1 BMW VI 7.3z liquid-cooled 12 -cylinder V-engine 630 [hp](469.8 KW)
normal rating, supercharged engine, low blower, constant power to height : 1000 [m]
dimensions :
wingspan : 14.8 [m], length : 11.7 [m], height : 3.1 [m]
wing area : 36.5 [m^2]
weights :
max.take-off weight : 3500 [kg]
empty weight operational : 2360 [kg] useful load : 500 [kg]
performance :
maximum speed :360 [km/hr] at sea-level
cruise speed :342 [km/u] op 100 [m]
service ceiling : 6000 [m]
range : 1820 [km]
description :
low-winged monoplane with retractable landing gear with tail wheel
elliptical wing with no flaps airfoil : unknown
engine in the nose, fueltanks in the wing, landing gear attached to the wing
construction : all-metal stressed-skin (duraluminium) airplane
airscrew :
ground adjustable 2 -bladed metal Hamilton Standard tractor propeller with max.
efficiency :0.73 [ ]
estimated diameter airscrew 3.23 [m]
relative pitch (J) : 1.10 [ ]
power loading prop : 159.30 [KW/m]
theoretical pitch without slip : 4.04 [m]
blade angle prop (fixed) : 27.98 [ ]
tip-speed close to speed of sound (above Mach 0.85) > loose of efficiency
reduction : 1.00 [ ]
airscrew revs : 1650 [r.p.m.]
aerodynamic pitch at max. continuous speed 3.55 [m]
blade-tip speed at max.continuous speed : 296 [m/s]
propellor noise in flight : 102 [Db]
The top view of the He.70 is much similar with the Supermarine Spitfire.
calculation : *1* (dimensions)
measured wing chord : 2.81 [m] at 50% wingspan
mean wing chord : 2.47 [m]
calculated average wing chord tapered wing with rounded tips: 2.45 [m]
wing aspect ratio : 6.0 []
seize (span*length*height) : 537 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 4.6 [kg/hr]
fuel consumption(cruise speed) : 95.4 [kg/hr] (130.1 [litre/hr]) at 59 [%] power
distance flown for 1 kg fuel : 3.59 [km/kg] at 3000 [m] height, sfc : 316.0 [kg/kwh]
estimated total fuel capacity : 786 [litre] (576 [kg])
calculation : *3* (weight)
weight engine(s) dry : 510.0 [kg] = 0.99 [kg/KW]
weight 45.8 litre oil tank : 3.89 [kg]
oil tank filled with 3.9 litre oil : 3.5 [kg]
oil in engine 28.7 litre oil : 25.7 [kg]
fuel in engine 3.5 litre fuel : 2.57 [kg]
weight 55.3 litre gravity patrol tank(s) : 8.3 [kg]
weight radiator : 77.2 [kg]
weight exhaust pipes & fuel lines 46.1 [kg]
weight starter (E.H.I. - Electric Hand Inertia): 12.6 [kg]
weight cowling 20.6 [kg]
weight airscrew(s) incl. boss & bolts : 52.4 [kg]
total weight propulsion system : 763 [kg](21.8 [%])
***************************************************************
fuselage aluminium frame : 292 [kg]
cabin layout : pitch : 87 [cm] (1+1) seating in 2.0 rows
weight 1 fire extinguisher : 3 [kg]
weight 6 windows : 5.4 [kg]
weight door : 5.0 [kg]
passenger cabin max.width : 1.08 [m] cabin length : 2.36 [m] cabin height : 1.80 [m]
weight cabin furbishing : 7.6 [kg]
weight cabin floor : 12.1 [kg]
fuselage covering ( 25.9 [m2] duraluminium 2.79 [mm]) : 187.3 [kg]
fuselage (sound proof) isolation : 9.3 [kg]
weight Sperry gyro auto-pilot - course control equipment : 1.5 [kg]
weight instruments. : 3.5 [kg]
weight lighting : 1.1 [kg]
weight electricity generator : 2.8 [kg]
weight controls : 6.1 [kg]
weight seats : 30.0 [kg]
weight air conditioning : 4 [kg]
weight engine mounts & firewalls : 26 [kg]
total weight fuselage : 582 [kg](16.6 [%])
***************************************************************
total weight aluminium ribs (72 ribs) : 125 [kg]
weight fuel tanks empty for total 731 [litre] fuel : 58 [kg]
weight wing covering (painted aluminium 1.32 [mm]) : 260 [kg]
total weight 4 aluminium spars : 186 [kg]
weight wings : 571 [kg]
weight wing/square meter : 15.64 [kg]
cantilever wing without bracing cables
weight fin & rudder (2.5 [m2]) : 40.1 [kg]
weight stabilizer & elevator (4.1 [m2]): 64.5 [kg]
total weight wing surfaces & bracing : 734 [kg] (21.0 [%])
*******************************************************************
wheel pressure : 1750.0 [kg]
weight 2 Dunlop wheels (920 [mm] by 184 [mm]) : 103.8 [kg]
weight tailwheel(s) : 5.9 [kg]
weight shock absorbers : 3.8 [kg]
weight wheel hydraulic operated retraction system : 15.3 [kg]
weight undercarriage with axle 100.3 [kg]
total weight landing gear : 229.0 [kg] (6.5 [%]
*******************************************************************
********************************************************************
calculated empty weight : 2308 [kg](65.9 [%])
weight oil for 6.4 hours flying : 29.6 [kg]
weight ethylene glycol cooling fluids : 83.4 [kg]
calculated operational weight empty : 2421 [kg] (69.2 [%])
published operational weight empty : 2360 [kg] (67.4 [%])
weight crew : 162 [kg]
weight fuel for 2.0 hours flying : 191 [kg]
********************************************************************
operational weight empty: 2774 [kg](79.3 [%])
weight 4 passengers : 308 [kg]
weight luggage & freight : 192 [kg]
operational weight loaded: 3274 [kg](93.5 [%])
fuel reserve : 226.1 [kg] enough for 2.37 [hours] flying
operational weight fully loaded : 3500 [kg] with fuel tank filled for 72 [%]
published maximum take-off weight : 3500 [kg] (100.0 [%])
calculation : * 4 * (engine power)
power loading (Take-off) : 6.80 [kg/kW]
power loading (operational without useful load) : 5.39 [kg/kW]
total power : 514.5 [kW] at 1650 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 5.3 [g] at 1000 [m]
limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 2.6 [g]
design flight time : 3.73 [hours]
design cycles : 8640 sorties, design hours : 32187 [hours]
operational wing loading : 745 [N/m^2]
wing stress (3 g) during operation : 143 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.39 ["]
max. angle of attack (stalling angle) : 12.89 ["]
angle of attack at max. speed : 0.16 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° : 0.11 [ ]
lift coefficient at max. speed : 0.12 [ ]
lift coefficient at max. angle of attack : 1.13 [ ]
induced drag coefficient at max.speed : 0.0011 [ ]
drag coefficient at max. speed : 0.0179 [ ]
drag coefficient (zero lift) : 0.0169 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW loaded : 3405 [kg]): 131 [km/u]
landing speed at sea-level (normal landing weight : 2948 [kg]): 140 [km/hr]
max. rate of climb speed : 213 [km/hr] at sea-level
max. endurance speed : 187 [km/u] min.fuel/hr : 67 [kg/hr] at height : 610 [m]
max. range speed : 271 [km/u] at cruise height : 4267 [m]
cruising speed : 342 [km/hr] at 3000 [m] (power:77 [%])
max. continuous speed : 351.00 [km/hr]
maximum speed : 360 [km/hr] at 100 [m] (power:109 [%])
climbing speed at sea-level (loaded) : 344 [m/min]
calculation : *9* (regarding various performances)
take-off speed : 159.2 [km/u]
emergency/TO power : 750 [hp] at 1720 [rpm]
static prop wash : 88 [km/u]
take-off distance at sea-level gras field : 879 [m]
take-off distance at sea-level over 15 [m] height : 1034 [m]
**this long take-off run is with propellor set for max.speed, to shorten TO-run the blade angle could be reduced (ground adjustable-pitch propellor) , but bit would reduce max.speed. But would be OK for normal passenger flights at cruise speed
landing run : 247 [m]
lift/drag ratio : 14.52 [ ]
climb to 1000m with max payload : 4.16 [min]
climb to 2000m with max payload : 9.82 [min]
climb to 3000m with max payload : 18.51 [min]
practical ceiling (operational weight empty 2774 [kg] ) : 5700 [m]
practical ceiling fully loaded (mtow- 30 min.fuel:3452 [kg] ) : 4500 [m]
calculation *10* (action radius & endurance)
published range : 1820 [km] with 2 crew and 409.2 [kg] useful load and 88.1 [%] fuel
range : 1494 [km] with 2 crew and 500.0 [kg] useful load and 72.3 [%] fuel
range : 2039 [km] with 4.0 passengers with each 10 [kg] luggage and 98.7 [%] fuel
Available Seat Kilometres (ASK) : 8158 [paskm]
max range theoretically with additional fuel tanks total 1361.3 [litre] fuel : 3388 [km]
useful load with range 500km : 858 [kg]
useful load with range 500km : 4 passengers
production (useful load): 294 [tonkm/hour]
production (passengers): 1368 [paskm/hour]
combi aircraft mail/freight/passengers
oil and fuel consumption per tonkm : 0.34 [kg]
fuel cost per paskm : 0.034 [eur]
crew cost per paskm : 0.051 [eur]
economic hours : 12775 [hours] is less then design hours
time between engine failure : 855 [hr]
unreliable engine, high risk of PUF
writing off per paskm : 0.051 [eur]
insurance per paskm : 0.009 [eur]
maintenance cost per paskm : 0.105 [eur]
direct operating cost per paskm : 0.250 [eur]
direct operating cost per tonkm : 2.503 [eur]
Literature :
Praktisch handboek vliegtuigen deel 2 page 138
Piston-engined airliners page 40
Wikipedia
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
Nr 3 : Helice bipale de madera de paso fijo = a fixed pitch propellor !
(c) B van der Zalm 22 January 2022 contact : info.aircraftinvestigation@gmail.com python 3.7.4