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weight and performance calculations for the De Havilland D.H.66 Hercules

De Havilland D.H.66 Hercules

role : multi-engined mail & passenger aircraft

importance : *

first flight : 30 September 1926 operational : December 1926

country : United-Kingdom

design :

production : 11 aircraft

general information : designed to carry mail and passengers on the route to the British empire. Not fast but reliable. Strongly designed to withstand operation in tropical climates.

users : Imperial Airways, West Australian Airways (4)

registrations : G-EBMW, G-AUJQ, G-EBMX, G-EBMZ, G-EBNA, VH-UJO, G-AARY

crew : 2 passengers : 7

engine : 3 Bristol Jupiter VI air-cooled 9 -cylinder radial engine 440 [hp](328.1 KW)

dimensions :

wingspan : 24.23 [m], length : 16.92 [m], height : 5.56[m]

wing area : 143.7 [m^2]

weights :

max.take-off weight : 7103 [kg]

empty weight operational : 4110 [kg] useful load : 2000 [kg]

performance :

maximum speed :206 [km/hr] at sea-level

cruise speed :185 [km/u] op 100 [m]

service ceiling : 4000 [m]

range : 652 [km]

description :

2-bay biplane with fixed landing gear and tail strut

two spar upper and lower wing

2 engines attached to the wings 1 in the nose, landing gear attached to the wings,

. useful load in the fuselage, fuel tanks in the wing

airscrew :

three fixed pitch 2 -bladed tractor airscrews with max. efficiency :0.67 [ ]

estimated diameter airscrew 3.02 [m]

power loading prop : 108.65 [KW/m]

prop efficiency ratio: 9.57 [1/s]

angle of attack prop : 15.85 [ ]

reduction : 1.00 [ ]

airscrew revs : 1700 [r.p.m.]

pitch at Max speed 2.02 [m]

blade-tip speed at Vmax and max revs. : 275 [m/s]

calculation : *1* (dimensions)

wing chord : 3.11 [m]

mean wing chord : 2.97 [m]

calculated wing chord (rounded tips): 3.23 [m]

wing aspect ratio : 8.17 []

estimated gap : 3.02 [m]

gap/chord : 1.02 [ ]

seize (span*length*height) : 2279 [m^3]

calculation : *2* (fuel consumption)

oil consumption : 24.6 [kg/hr]

fuel consumption(cruise speed) : 216.6 [kg/hr] (295.5 [litre/hr]) at 69 [%] power

distance flown for 1 kg fuel : 0.86 [km/kg] at 2000 [m] height, sfc : 319.0 [kg/kwh]

estimated total fuel capacity : 1179 [litre] (864 [kg])

calculation : *3* (weight)

weight engine(s) dry : 1062.0 [kg] = 1.08 [kg/KW]

weight 140.3 litre oil tank : 11.92 [kg]

oil tank filled with 7.4 litre oil : 6.6 [kg]

oil in engine 5.5 litre oil : 4.9 [kg]

fuel in engine 6.7 litre fuel : 4.92 [kg]

weight 125.6 litre gravity patrol tank(s) : 18.8 [kg]

weight inertia starter : 8.0 [kg]

weight airscrew(s) (wood) incl. boss & bolts : 104.1 [kg]

total weight propulsion system : 1209 [kg](17.0 [%])

***************************************************************

fuselage skeleton (steel tubes) : 3.83 [cm]): 793 [kg]

cabin layout : pitch : 87 [cm] (1+1) seating in 3.5 rows

weight 7.0 windows : 6.30 [kg]

passenger cabin width : 1.28 [m] cabin length : 3.04 [m] cabin height : 1.90 [m]

weight cabin furbishing : 15.19 [kg]

weight cabin floor : 24.98 [kg]

bracing : 94.6 [kg]

fuselage covering ( 54.1 [m2] doped linen fabric) : 16.9 [kg]

weight instruments. : 2.5 [kg]

weight lighting : 1.8 [kg]

weight controls : 8.6 [kg]

weight seats : 45.0 [kg]

weight three 351 [litre] main fuel tanks empty : 84.3 [kg]

weight air conditioning : 10 [kg]

weight fuel lines : 6 [kg]

weight engine mount and firewall : 16 [kg]

total weight fuselage : 1126 [kg](15.8 [%])

***************************************************************

weight wing covering (doped linen fabric) : 116 [kg]

total weight ribs (196 ribs) : 422 [kg]

weight engine mounts : 33 [kg]

total weight 8 spars : 353 [kg]

weight wings : 892 [kg]

weight wing/square meter : 6.21 [kg]

weight 8 interplane struts & cabane : 237.7 [kg]

weight cables (138 [m]) : 77.0 [kg] (= 557 [gram] per metre)

diameter cable : 9.5 [mm]

weight fin & rudder (6.8 [m2]) : 43.3 [kg]

weight stabilizer & elevator (16.2 [m2]): 101.4 [kg]

total weight wing surfaces & bracing : 1384 [kg] (19.5 [%])

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wheel pressure : 3551.5 [kg]

weight 2 wheels (1540 [mm] by 199 [mm]) : 255.9 [kg]

weight tailskid : 19.9 [kg]

weight undercarriage with axle 86.6 [kg]

total weight landing gear : 362.4 [kg] (5.1 [%]

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calculated empty weight : 4082 [kg](57.5 [%])

weight oil for 4.2 hours flying : 103.8 [kg]

calculated operational weight empty : 4185 [kg] (58.9 [%])

published operational weight empty : 4110 [kg] (57.9 [%])

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weight crew : 162 [kg]

weight fuel for 2.0 hours flying : 433 [kg]

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operational weight empty: 4780 [kg](67.3 [%])

weight 7 passengers : 539 [kg]

weight luggage & freight : 1461 [kg]

operational weight loaded: 6780 [kg](95.5 [%])

fuel reserve : 322.5 [kg] enough for 1.49 [hours] flying

operational weight fully loaded : 7103 [kg] with fuel tank filled for 87 [%]

published maximum take-off weight : 7103 [kg] (100.0 [%])

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calculation : * 4 * (engine power)

power loading (Take-off) : 7.22 [kg/kW]

power loading (operational without useful load) : 4.86 [kg/kW]

power loading (Take-off) 1 PUF: 10.82 [kg/kW]

total power : 984.3 [kW] at 1700 [r.p.m]

calculation : *5* (loads)

manoeuvre load : 4.1 [g] at 1000 [m]

limit load : 2.5 [g] ultimate load : 3.8 [g] load factor : 1.3 [g]

design flight time : 2.81 [hours]

design cycles : 2406 sorties, design hours : 6770 [hours]

operational wing loading : 326 [N/m^2]

wing stress (3 g) during operation : 158 [N/kg] at 3g emergency manoeuvre

calculation : *6* (angles of attack)

angle of attack zero lift : -1.39 ["]

max. angle of attack (stalling angle) : 11.93 ["]

angle of attack at max. speed : 0.51 ["]

calculation : *7* (lift & drag ratios

lift coefficient at angle of attack 0° :0.12 [ ]

lift coefficient at max. angle of attack : 1.15 [ ]

lift coefficient at max. speed : 0.16 [ ]

induced drag coefficient at max. speed : 0.0019 [ ]

drag coefficient at max. speed : 0.0396 [ ]

drag coefficient (zero lift) : 0.0377 [ ]

calculation : *8* (speeds

stalling speed at sea-level (OW loaded : 6886 [kg]): 93 [km/u]

landing speed at sea-level: 109 [km/hr]

min. drag speed (max endurance) : 128 [km/hr] at 2000 [m](power :37 [%])

min. power speed (max range) : 128 [km/hr] at 2000 [m] (power:37 [%])

max. rate of climb speed : 119.5 [km/hr] at sea-level

cruising speed : 185 [km/hr] op 2000 [m] (power:71 [%])

design speed prop : 196 [km/hr]

maximum speed : 206 [km/hr] op 100 [m] (power:104 [%])

climbing speed at sea-level : 491 [m/min]

calculation : *9* (regarding various performances)

take-off speed : 113.5 [km/u]

emergency/TO power : 475 [hp] at 1870 [rpm]

static prop wash : 161 [km/u]

take-off distance at sea-level : 134 [m]

lift/drag ratio : 9.78 [ ]

climb to 1000m with max payload : 4.21 [min]

climb to 2000m with max payload : 9.84 [min]

climb to 3000m with max payload : 17.07 [min]

practical ceiling (operational weight 4780 [kg] ) : 7208 [m]

practical ceiling fully loaded (mtow- 30 min.fuel:6995 [kg] ) : 5163 [m]

calculation *10* (action radius & endurance)

published range : 652 [km] with 2 crew and 1994.0 [kg] useful load and 88.1 [%] fuel

range : 647 [km] with 2 crew and 2000.0 [kg] useful load and 87.4 [%] fuel

range : 1838 [km] with 7.0 passengers with each 10 [kg] luggage and 248.3 [%] fuel

Available Seat Kilometres (ASK) : 12864 [paskm]

max range theoretically with additional fuel tanks total 3869.9 [litre] fuel : 2428 [km]

useful load with range 500km : 2253 [kg]

useful load with range 500km : 7 passengers

production (useful load): 417.63 [tonkm/hour]

production (passengers): 1297.80 [paskm/hour]

combi aircraft mail/freight/passengers

oil and fuel consumption per tonkm : 0.58 [kg]

oil and fuel consumption per paskm : 0.06 [kg]

fuel cost per paskm : 0.06 [eur]

crew cost per paskm : 0.04 [eur]

time between engine failure : 60 [hr]

writing off per paskm : 0.11 [eur]

insurance per paskm : 0.03 [eur]

rigging cost per paskm : 0.00 [eur]

maintenance cost per paskm : 0.30 [eur]

direct operating cost per paskm : 0.53 [eur]

direct operating cost per tonkm : 5.27 [eur]

Literature :

Praktisch handboek vliegtuigen deel 2 page 78,79

Piston engined airliners page 19,22

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