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weight and performance calculations for the De Havilland D.H.86A Express
De Havilland D.H.86A Express
importance : ****
first flight : 14 January 1934 operational : August 1934
country : United-Kingdom
design :
production : 62 aircraft
general information :
Designed for the Australian government which wanted an aircraft that could fly a
regular service on the Brisbane – Singapore route, a distance of 6000 km of which 2900
[km] over water. The DH86 needed to be safe and comfortable and resilient to the hot
and humid climate.
For long distance flights it carried 10 passengers, for short haul flights it could take 12.
During operation it became apparent that the DH86 seriously lacked in directional
stability resulting in fatal accidents. To cure it late production aircraft received “Zulu
Shield” extensions to the tail planes to improve lateral stability, designated as DH86B.
However previously built aircraft flew on merely unchanged, resulting in more
crashes.
users : Railway Air Services, Imperial Airways (12), Quantas, Holymans, Jersey Airways
(6)
registrations : G-ADUG, G-ADEA, G-AZCP, G-ACVY
crew : 2 passengers : 10 – 12
powerplant : 4 De Haviland Gipsy Six I air-cooled 6 -cylinder inverted inline piston engine 200 [hp](149.1 KW)
normal rating without supercharger
dimensions :
wingspan : 19.66 [m], length : 14.05 [m], height : 3.96 [m]
wing area : 59.6 [m^2]
weights :
max.take-off weight : 4649 [kg]
empty weight operational : 2785 [kg] useful load : 1200 [kg]
performance :
maximum speed :267 [km/hr] at sea-level
cruise speed :233 [km/u] op 100 [m]
service ceiling : 5300 [m]
range : 1220 [km]
description :
2-bay biplane with fixed landing gear and tail strut
two spar upper and lower wing
airfoil : RAF
engines and landing gear attached to the wings, fuel tanks in the wings
construction : fuselage covered with plywood, wooden wing covered with fabric
Length : 43ft 11 in = 13.38m for the DH86, the DH86 with 2 crew had a slightly longer nose > length : 14,05 [m].
Measured chord at root : 2.52 [m] at 50% span : 1.79 [m] airscrew : 2.20 [m] wheel diam. 95 [cm] gap : 1.96 [m]
airscrew :
four wooden fixed pitch 2 -bladed tractor airscrews with max. efficiency :0.69 [ ]
estimated diameter airscrew 2.20 [m]
power loading prop : 67.79 [KW/m]
angle of attack prop : 20.07 [ ]
reduction : 1.00 [ ]
airscrew revs : 2350 [r.p.m.]
pitch at Max speed 1.85 [m]
blade-tip speed at max.continous speed : 280 [m/s]
propellor noise in flight : 97 [Db]
calculation : *1* (dimensions)
measured wing chord : 1.79 [m] at 50% wingspan
mean wing chord : 1.52 [m]
calculated wing chord (rounded tips): 1.77 [m]
wing aspect ratio : 13.0 []
corrected wing aspect ratio : 11.1 []
estimated gap : 1.96 [m]
gap/chord : 1.29 [ ]
seize (span*length*height) : 1094 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 10.1 [kg/hr]
fuel consumption(cruise speed) : 112.7 [kg/hr] (153.8 [litre/hr]) at 62 [%] power
distance flown for 1 kg fuel : 2.25 [km/kg] at 2650 [m] height, sfc : 305.0 [kg/kwh]
estimated total fuel capacity : 840 [litre] (616 [kg])
calculation : *3* (weight)
weight engine(s) dry : 852.0 [kg] = 1.43 [kg/KW]
weight 80.1 litre oil tank : 6.81 [kg]
oil tank filled with 4.5 litre oil : 4.0 [kg]
oil in engine 3.3 litre oil : 3.0 [kg]
fuel in engine 4.1 litre fuel : 2.98 [kg]
weight 65.4 litre gravity patrol tank(s) : 9.8 [kg]
weight Burgess type silencers : 11.9 [kg]
weight Rotax starter : 3.7 [kg]
weight cowling 6.0 [kg]
weight airscrew(s) incl. boss & bolts : 42.5 [kg]
total weight propulsion system : 943 [kg](20.3 [%])
***************************************************************
fuselage skeleton (wood gauge : 7.30 [cm]): 256 [kg]
cabin layout : pitch : 87 [cm] (1+1) seating in 6.0 rows
weight 1 fire extinguisher : 3 [kg]
weight 14 windows : 12.6 [kg]
weight door : 5.0 [kg]
Quantas DH86 interior
passenger cabin max.width : 1.72 [m] cabin length : 5.84 [m] cabin height : 1.90 [m]
weight cabin furbishing : 40.6 [kg]
weight cabin floor : 57.4 [kg]
bracing : 36.3 [kg]
fuselage covering ( 60.4 [m2] plywood 8.7 [mm]) : 322.0 [kg]
fuselage (sound proof) isolation : 18.6 [kg]
weight radio transceiver equipment : 7.0 [kg]
weight Sperry gyro auto-pilot - course control equipment : 1.5 [kg]
weight instruments. : 8.0 [kg]
weight lighting : 3.0 [kg]
weight electricity generator : 3.0 [kg]
weight dual controls + indicators: 23.9 [kg]
weight seats : 70.0 [kg]
weight air conditioning : 18 [kg]
total weight fuselage : 863 [kg](18.6 [%])
***************************************************************
weight wing covering (doped linen fabric) : 36 [kg]
total weight wooden ribs (251 ribs) : 276 [kg]
weight engine mounts : 30 [kg]
weight fuel tanks empty for total 774 [litre] fuel : 62 [kg]
total weight 8 wooden spars : 165 [kg]
weight wings : 477 [kg]
weight wing/square meter : 8.01 [kg]
weight 8 interplane struts & cabane : 53.9 [kg]
weight cables (103 [m]) : 26.8 [kg] (= 261 [gram] per metre)
diameter cable : 6.5 [mm]
weight fin & rudder (4.5 [m2]) : 36.6 [kg]
weight stabilizer & elevator (6.7 [m2]): 54.2 [kg]
total weight wing surfaces & bracing : 741 [kg] (15.9 [%])
*******************************************************************
wheel pressure : 2324.5 [kg]
weight 2 Dunlop wheels (950 [mm] by 190 [mm]) : 87.4 [kg]
weight tailskid : 11.1 [kg]
weight Bendix wheel-brakes : 4.0 [kg]
weight Dowty shock absorbers : 5.3 [kg]
weight undercarriage with axle 87.6 [kg]
total weight landing gear : 195.3 [kg] (4.2 [%]
*******************************************************************
********************************************************************
calculated empty weight : 2741 [kg](59.0 [%])
weight oil for 5.8 hours flying : 58.5 [kg]
calculated operational weight empty : 2800 [kg] (60.2 [%])
published operational weight empty : 2785 [kg] (59.9 [%])
_____________
| | o | |
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" "
weight crew : 162 [kg]
weight fuel for 2.0 hours flying : 225 [kg]
weight catering : 20.2 [kg]
weight water : 8.1 [kg]
********************************************************************
operational weight empty: 3216 [kg](69.2 [%])
weight 12 passengers : 924 [kg]
weight luggage & freight : 276 [kg]
operational weight loaded: 4416 [kg](95.0 [%])
fuel reserve : 233.4 [kg] enough for 2.07 [hours] flying
operational weight fully loaded : 4649 [kg] with fuel tank filled for 75 [%]
published maximum take-off weight : 4649 [kg] (100.0 [%])
calculation : * 4 * (engine power)
power loading (Take-off) : 7.79 [kg/kW]
power loading (operational without useful load) : 5.39 [kg/kW]
power loading (Take-off) 1 PUF: 10.39 [kg/kW]
total power : 596.6 [kW] at 2350 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 3.9 [g] at 1000 [m]
limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 1.1 [g]
design flight time : 3.37 [hours]
design cycles : 1758 sorties, design hours : 5920 [hours]
operational wing loading : 529 [N/m^2]
wing stress (3 g) during operation : 198 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.31 ["]
max. angle of attack (stalling angle) : 10.70 ["]
angle of attack at max. speed : 0.42 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° : 0.12 [ ]
lift coefficient at max. speed : 0.16 [ ]
lift coefficient at max. angle of attack : 1.10 [ ]
induced drag coefficient at max.speed : 0.0013 [ ]
drag coefficient at max. speed : 0.0297 [ ]
drag coefficient (zero lift) : 0.0285 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW loaded : 4536 [kg]): 120 [km/u]
landing speed at sea-level (normal landing weight : 3444 [kg]): 120 [km/hr]
DH.86B G-ADVJ of charter airline Bond Air Services at Liverpool (Speke) Airport in March 1950. Note the "Zulu Shield" extensions to the tail planes
max. rate of climb speed : 157 [km/hr] at sea-level
max. endurance speed : 137 [km/u] min.fuel/hr : 74 [kg/hr] at height : 610 [m]
max. range speed : 199 [km/u] min. fuel consumption : 0.447 [kg/km] at cruise height :
4267 [m]
cruising speed : 254 [km/hr] at 2650 [m] (power:80 [%])
max. continuous speed : 260.32 [km/hr]
maximum speed : 267 [km/hr] at 100 [m] (power:111 [%])
climbing speed at sea-level (loaded) : 281 [m/min]
climbing speed at 1000 [m] with 1 engine out (PUF / MTOW) : 102 [m/min]
calculation : *9* (regarding various performances)
take-off speed : 145.5 [km/u]
static prop wash : 136 [km/u]
take-off distance at sea-level gras field : 305 [m]
take-off distance at sea-level over 15 [m] height : 445 [m]
landing run : 183 [m]
lift/drag ratio : 13.12 [ ]
climb to 1000m with max payload : 4.95 [min]
climb to 2000m with max payload : 11.63 [min]
climb to 3000m with max payload : 21.73 [min]
practical ceiling (operational weight 3216 [kg] ) : 6400 [m]
practical ceiling fully loaded (mtow- 30 min.fuel:4593 [kg] ) : 4500 [m]
calculation *10* (action radius & endurance)
published range : 1220 [km] with 2 crew and 1144.9 [kg] useful load and 88.1 [%] fuel
range : 1096 [km] with 2 crew and 1200.0 [kg] useful load and 79.1 [%] fuel
range : 1447 [km] with 12.0 passengers with each 10 [kg] luggage and 104.5 [%] fuel
Available Seat Kilometres (ASK) : 17363 [paskm]
max range theoretically with additional fuel tanks total 2412.2 [litre] fuel : 3957 [km]
useful load with range 500km : 1546 [kg]
useful load with range 500km : 12 passengers
production (useful load): 392 [tonkm/hour]
production (passengers): 3044 [paskm/hour]
oil and fuel consumption per tonkm : 0.31 [kg]
fuel cost per paskm : 0.031 [eur]
crew cost per paskm : 0.038 [eur]
__
I=I°_°°°°°°/
°
time between engine failure : 1301 [hr]
can continue fly on 3 engines, low risk for emergency landing for PUF
writing off per paskm : 0.088 [eur]
insurance per paskm : 0.000 [eur]
rigging cost per paskm : 0.023 [eur]
maintenance cost per paskm : 0.167 [eur]
direct operating cost per paskm : 0.324 [eur]
direct operating cost per tonkm : 3.244 [eur]
Literature :
Piston engined airliners page 39
Handboek vliegtuigen deel 2 page 106,107
de Havilland Express - 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
(c) B van der Zalm 28 November 2021 contact : info.aircraftinvestigation@gmail.com python 3.7.4