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weight and performance calculations for the De Havilland D.H.84 Dragon Mk.I
De Havilland D.H.84 Dragon Mk.I
role : light passenger aircraft
importance : ****
first flight : 12 November 1932 operational : April 1933
country : United-Kingdom
design :
production : 202 aircraft
general information :
Pleasant light aeroplane. It could carry 6 passengers, each with 20 kg luggage, on the
London – Paris route on a fuel consumption of 49 litre/hour. Popular as short-haul
airliner.
users : Hillman’s airways
crew : 1 passengers : 6
powerplant : 2 De Haviland Gipsy Major I air-cooled 4 -cylinder inverted inline piston engine 122 [hp](91.0 KW)
normal rating without supercharger
and with 145 [hp](108.1 KW) available for take-off
dimensions :
wingspan : 14.43 [m], length : 10.52 [m], height : 3.07 [m]
wing area : 34.9 [m^2]
weights :
max.take-off weight : 1905 [kg]
empty weight operational : 1043 [kg] useful load : 600 [kg]
performance :
maximum speed :206 [km/hr] at sea-level
cruise speed :196 [km/u] op 100 [m]
service ceiling : 3800 [m]
range : 740 [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
Measured dimensions : Chord at root 1.79m Chord midwing : 1.65m fuselage width : 1.46m fuselage height : 1.72m gap : 1.46m prop diam. : 2.52m wheel diam.: 66 cm
airscrew :
two fixed pitch 2 -bladed tractor airscrews with max. efficiency :0.69 [ ]
estimated diameter airscrew 2.52 [m]
power loading prop : 36.10 [KW/m]
angle of attack prop : 15.40 [ ]
reduction : 1.00 [ ]
airscrew revs : 2100 [r.p.m.]
pitch at Max speed 1.59 [m]
blade-tip speed at max.continous speed : 283 [m/s]
calculation : *1* (dimensions)
measured wing chord : 1.65 [m] at 50% wingspan
mean wing chord : 1.21 [m]
calculated wing chord (square tips): 1.33 [m]
wing aspect ratio : 11.93 []
estimated gap : 1.46 [m]
gap/chord : 1.21 [ ]
seize (span*length*height) : 466 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 4.2 [kg/hr]
fuel consumption(cruise speed) : 38.3 [kg/hr] (52.3 [litre/hr]) at 69 [%] power
distance flown for 1 kg fuel : 5.11 [km/kg] at 1900 [m] height, sfc : 303.8 [kg/kwh]
estimated total fuel capacity : 224 [litre] (164 [kg])
calculation : *3* (weight)
weight engine(s) dry : 272.0 [kg] = 1.49 [kg/KW]
weight 25.7 litre oil tank : 2.18 [kg]
oil tank filled with 1.4 litre oil : 1.2 [kg]
oil in engine 1.0 litre oil : 0.9 [kg]
fuel in engine 1.2 litre fuel : 0.91 [kg]
weight 22.2 litre gravity patrol tank(s) : 3.3 [kg]
weight cowling 3.6 [kg]
weight airscrew(s) incl. boss & bolts : 23.6 [kg]
total weight propulsion system : 308 [kg](16.2 [%])
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fuselage skeleton (wood gauge : 5.50 [cm]): 109 [kg]
cabin layout : pitch : 87 [cm] (1+1) seating in 3.0 rows
weight 1 fire extinguisher : 3 [kg]
weight 8 windows : 7.2 [kg]
weight door : 5.0 [kg]
passenger cabin width : 1.35 [m] cabin length : 3.14 [m] cabin height : 1.70 [m]
weight cabin furbishing : 13.2 [kg]
weight cabin floor : 22.5 [kg]
bracing : 11.6 [kg]
fuselage covering ( 36.9 [m2] plywood 3.7 [mm]) : 83.8 [kg]
fuselage (sound proof) isolation : 10.7 [kg]
weight radio navigation equipment : 6.0 [kg]
weight instruments. : 6.0 [kg]
weight lighting : 1.5 [kg]
weight electricity generator : 1.5 [kg]
weight controls : 5.7 [kg]
weight seats : 35.0 [kg]
weight air conditioning : 9 [kg]
total weight fuselage : 318 [kg](16.7 [%])
***************************************************************
weight wing covering (doped linen fabric) : 28 [kg]
total weight wooden ribs (129 ribs) : 113 [kg]
weight engine mounts : 9 [kg]
weight two 101 [litre] main fuel tanks empty : 16.2 [kg]
load on front upper spar (clmax) per running metre : 826.0 [N]
load on rear upper spar (vmax) per running metre : 396.8 [N]
total weight 8 wooden spars : 76 [kg]
weight wings : 217 [kg]
weight wing/square meter : 6.23 [kg]
weight 8 interplane struts & cabane : 16.9 [kg]
weight cables (76 [m]) : 9.1 [kg] (= 120 [gram] per metre)
diameter cable : 4.4 [mm]
weight fin & rudder (2.4 [m2]) : 15.4 [kg]
weight stabilizer & elevator (3.9 [m2]): 24.7 [kg]
total weight wing surfaces & bracing : 309 [kg] (16.2 [%])
*******************************************************************
Can only operate from paved runways
wheel pressure : 952.5 [kg]
weight 2 wheels (700 [mm] by 78 [mm]) : 27.2 [kg]
weight tailskid : 6.3 [kg]
weight undercarriage with axle 61.9 [kg]
total weight landing gear : 95.4 [kg] (5.0 [%]
*******************************************************************
********************************************************************
calculated empty weight : 1030 [kg](54.1 [%])
weight oil for 4.5 hours flying : 19.0 [kg]
calculated operational weight empty : 1049 [kg] (55.1 [%])
published operational weight empty : 1043 [kg] (54.8 [%])
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weight crew : 81 [kg]
weight fuel for 2.0 hours flying : 77 [kg]
********************************************************************
operational weight empty: 1207 [kg](63.4 [%])
weight 6 passengers : 462 [kg]
weight luggage & freight : 138 [kg]
operational weight loaded: 1807 [kg](94.8 [%])
fuel reserve : 87.8 [kg] enough for 2.29 [hours] flying
possible additional useful load : 10 [kg]
operational weight fully loaded : 1905 [kg] with fuel tank filled for 100 [%]
published maximum take-off weight : 1905 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (Take-off) : 10.47 [kg/kW]
power loading (operational without useful load) : 6.63 [kg/kW]
power loading (Take-off) 1 PUF: 20.94 [kg/kW]
high power loading if engine failure, can not stay airborne
total power : 182.0 [kW] at 2100 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 3.5 [g] at 1000 [m]
limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 1.6 [g]
design flight time : 3.03 [hours]
design cycles : 3386 sorties, design hours : 10242 [hours]
operational wing loading : 339 [N/m^2]
wing stress (3 g) during operation : 163 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.29 ["]
max. angle of attack (stalling angle) : 10.34 ["]
angle of attack at max. speed : 0.55 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° : 0.12 [ ]
lift coefficient at max. speed : 0.17 [ ]
lift coefficient at max. angle of attack : 1.08 [ ]
induced drag coefficient at max.speed : 0.0014 [ ]
drag coefficient at max. speed : 0.0336 [ ]
drag coefficient (zero lift) : 0.0322 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW loaded : 1867 [kg]): 101 [km/u]
landing speed at sea-level (normal landing weight : 1384 [kg]): 100 [km/hr]
max. rate of climb speed : 122 [km/hr] at sea-level
max. endurance speed : 109 [km/u] min. brpu : 24 [kg/hr] at height : 610 [m]
max. range speed : 157 [km/u] min. fuel consumption : 0.184 [kg/km] at cruise height :
4267 [m]
cruising speed : 196 [km/hr] at 1900 [m] (power:86 [%])
max. continuous speed : 200.85 [km/hr]
maximum speed : 206 [km/hr] at 100 [m] (power:112 [%])
climbing speed at sea-level (loaded) : 200 [m/min]
climbing speed at 1000 [m] with 1 engine out (reduced useful load : 300 [kg]) : 0
[m/min] can not stay in the air on 1 engine
calculation : *9* (regarding various performances)
take-off speed : 122.9 [km/u]
emergency/TO power : 145 [hp] at 2289 [rpm]
static prop wash : 165 [km/u]
high wheel pressure, can only take off from paved runways
take-off distance at sea-level : 105 [m]
lift/drag ratio : 12.79 [ ]
climb to 1000m with max payload : 7.15 [min]
climb to 2000m with max payload : 17.13 [min]
climb to 3000m with max payload : 33.28 [min]
practical ceiling (operational weight 1207 [kg] ) : 6400 [m]
practical ceiling fully loaded (mtow- 30 min.fuel:1886 [kg] ) : 3900 [m]
calculation *10* (action radius & endurance)
published range : 740 [km] with 1 crew and 629.9 [kg] useful load and 88.1 [%] fuel
range : 892 [km] with 1 crew and 600.0 [kg] useful load and 106.3 [%] fuel
range : 1291 [km] with 6.0 passengers with each 10 [kg] luggage and 153.7 [%] fuel
Available Seat Kilometres (ASK) : 7744 [paskm]
max range theoretically with additional fuel tanks total 1057.0 [litre] fuel : 4210 [km]
useful load with range 500km : 677 [kg]
useful load with range 500km : 6 passengers
production (useful load): 132 [tonkm/hour]
production (passengers): 1174 [paskm/hour]
oil and fuel consumption per tonkm : 0.32 [kg]
fuel cost per paskm : 0.032 [eur]
crew cost per paskm : 0.113 [eur]
time between engine failure : 2512 [hr]
could not fly on 1 engine, reliable engine : low risk for emergency landing for PUF
writing off per paskm : 0.056 [eur]
insurance per paskm : 0.003 [eur]
rigging cost per paskm : 0.057 [eur]
maintenance cost per paskm : 0.292 [eur]
direct operating cost per paskm : 0.496 [eur]
direct operating cost per tonkm : 4.964 [eur]
Literature :
Piston-engined airliners page 39
Praktisch handboek vliegtuigen deel 2 page 105
de Havilland Dragon - 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/
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(c) B van der Zalm 28 November 2021 contact : info.aircraftinvestigation@gmail.com python 3.7.4