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weight and performance calculations for the De Havilland D.H.114 Heron Mk.2b
De Havilland D.H.114 Heron Mk.2b
role : medium weight passenger aircraft
importance : ****
first flight : 10 May 1950 G-ALZL flown by Geoffrey Pike at Hatfield
operational : Mk.I April 1953
country : United-Kingdom
design :
production : 149 aircraft (51 Mk.I)
general information :
Development of the two-engine D.H.104 Dove. Designed with fixed landing gear and emphasis on rugged simplicity. 4 Gipsy Queen 30 engines without supercharger and reduction gear for save and reliable operation. Designed to operate economical in remote areas without modern airports.
Fuel capacity : 412 imp.gallon (1870 litres).
With its larger fuselage, passengers could stand up whilst moving down the aisle and large windows were also provided. Baggage was stored in an aft compartment with an additional smaller area in the nose.
Basic price for a new Heron in 1960 was around £60,000, minus radio.
The later Mk.2 version had a retractable landing gear giving 30 km/hr higher cruise speed against a weight penalty of 75 kg. This version made the first flight 14 December 1952.
In service the Heron proved underpowered with its 250 HP Gipsy Queen engines, later Riley offered conversion kits replacing the engines with Lycoming IO-540 engines.
primary users : New Zealand National Airways Corporation, Braathens SAFE, Jersey
Airlines, Cambrian Airways, BEA, Garuda Indonesian Airways, SABENA
flight crew : 2 cabin crew : 0 passengers : 14
powerplant : 4 De Havilland Gipsy Queen 30 Mk.2 air-cooled 6 -cylinder inverted inline
piston engine 245 [hp](182.7 KW) normal rating without supercharger
and with 250 [hp](186.4 KW) available for take-off
dimensions :
wingspan : 21.79 [m], length : 14.78 [m], height : 4.75 [m]
wing area : 46.4 [m^2]
weights :
max.take-off weight : 6123 [kg]
empty weight operational : 3697 [kg] useful load : 1550 [kg]
performance :
maximum continuous speed : 347 [km/u] at sea-level
normal cruise speed : 295 [km/u] op 2590 [m] (70 [%] power)
service ceiling : 5600 [m]
range with max fuel : 2269 [km] and allowance for 158.8 [km] diversion and 30 [min]
hold
description :
low-winged monoplane with retractable landing gear with nose wheel
tapered wing with Fowler flaps airfoil : RAF
engines and landing gear attached to the wings, fuel tanks in the wings
construction : all-metal stressed-skin (Alclad-aluminium) airplane
fuselage shape : 0
airscrew :
four D.H.2/1000/2 constant speed, reversible pitch 3 -bladed tractor airscrews
max. efficiency : 0.83 [ ]
diameter airscrew 2.13 [m]
relative pitch (J) : 1.09 [ ]
power loading prop : 57.18 [KW/m]
theoretical pitch without slip : 2.65 [m]
blade angle prop at max.speed : 28.84 [ ]
tip-speed close to speed of sound (above Mach 0.85) > loose of efficiency
reduction : 1.00 [ ]
G-ALZL Mk.I prototype
airscrew revs : 2490 [r.p.m.]
aerodynamic pitch at max. continuous speed 2.32 [m]
blade-tip speed at max.continuous speed : 294 [m/s]
propellor noise in flight : 102 [Db]
calculation : *1* (dimensions)
measured wing chord : 2.15 [m] at 50% wingspan
mean wing chord : 2.13 [m]
calculated average wing chord tapered wing with rounded tips: 2.03 [m]
wing aspect ratio : 10.2 []
seize (span*length*height) : 1530 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 7.3 [kg/hr]
fuel consumption (econ. cruise speed) : 157.0 [kg/hr] (214.3 [litre/hr]) at 70 [%] power
distance flown for 1 kg fuel : 1.88 [km/kg] at 2590 [m] height, sfc : 307.0 [kg/kwh]
estimated total fuel capacity : 1870 [litre] (1371 [kg])
calculation : *3* (weight)
weight engine(s) dry : 928.0 [kg] = 1.27 [kg/KW]
weight 93.4 litre oil tank : 7.94 [kg]
oil tank filled with 5.5 litre oil : 4.9 [kg]
oil in engine 4.1 litre oil : 3.7 [kg]
fuel in engine 5.0 litre fuel : 3.65 [kg]
weight 91.1 litre gravity patrol tank(s) : 13.7 [kg]
weight Burgess type silencers : 14.6 [kg]
weight cowling 7.3 [kg]
weight variable pitch control : 2.7 [kg]
weight airscrew(s) incl. boss & bolts : 68.7 [kg]
total weight propulsion system : 1052 [kg](17.2 [%])
***************************************************************
fuselage aluminium frame : 466 [kg]
cabin layout : pitch : 81 [cm] (1+1) seating in 7 rows
pax density (normal seating) : 0.97 [m2/pax]
high density seating passengers : 17 at 2 -abreast seating in 8.5 rows
weight 1 toilets : 8.0 [kg]
weight 2 hand fire extinguisher : 6 [kg]
weight 16 windows : 14.4 [kg]
weight 1 entrance/exit doors : 5.0 [kg]
main deck space for freight/mail/luggage etc. : 2.02 [m3]
additional luggage space in nose compartment : 0.81 [m3]
cabin volume (usable), excluding flight deck : 14.15 [m3]
passenger cabin max.width : 1.48 [m] cabin length : 9.19 [m] cabin height : 1.90 [m]
fuselage covering ( 55.3 [m2] duraluminium 2.08 [mm]) : 295.5 [kg]
weight cabin furbishing : 38.9 [kg]
weight cabin floor : 46.1 [kg]
fuselage (sound proof) isolation : 23.2 [kg]
weight radio transceiver equipment : 7.0 [kg]
weight artificial horizon : 1.1 [kg]
weight instruments. : 8.0 [kg]
weight lighting : 3.5 [kg]
weight electricity generator : 3.5 [kg]
weight dual controls + indicators: 26.0 [kg]
weight seats : 80.0 [kg]
weight air conditioning : 21 [kg]
total weight fuselage : 1029 [kg](16.8 [%])
***************************************************************
total weight aluminium ribs (147 ribs) : 218 [kg]
weight engine mounts : 37 [kg]
weight fuel tanks empty for total 1779 [litre] fuel : 142 [kg]
weight wing covering (painted aluminium 1.33 [mm]) : 334 [kg]
total weight aluminium spars (multi-cellular wing structure) : 228 [kg]
weight wings : 780 [kg]
weight wing/square meter : 16.81 [kg]
cantilever wing without bracing cables
weight rubber de-icing boots : 24.0 [kg]
weight fin & rudder (5.5 [m2]) : 93.4 [kg]
weight stabilizer & elevator (5.2 [m2]): 88.1 [kg]
weight fowler flaps (3.9 [m2]) : 38.5 [kg]
total weight wing surfaces & bracing : 1203 [kg] (19.6 [%])
*******************************************************************
wheel pressure : 2694.1 [kg]
weight 2 Dunlop main wheels (750 [mm] by 125 [mm]) : 115.9 [kg]
weight nose wheel : 29.0 [kg]
weight hydraulic wheel-brakes : 5.2 [kg]
weight Dowty shock absorbers : 7.0 [kg]
weight wheel hydraulic operated retraction system : 75.3 [kg]
weight undercarriage struts with axle 140.5 [kg]
total weight landing gear : 373.0 [kg] (6.1 [%]
*******************************************************************
********************************************************************
calculated empty weight : 3657 [kg](59.7 [%])
weight oil for 9.2 hours flying : 67.5 [kg]
calculated operational weight empty : 3725 [kg] (60.8 [%])
published operational weight empty : 3697 [kg] (60.4 [%])
weight crew : 162 [kg]
weight fuel for 2.0 hours flying : 314 [kg]
weight catering : 37.7 [kg]
weight water : 15.1 [kg]
********************************************************************
operational weight empty: 4254 [kg](69.5 [%])
weight 14 passengers : 1078 [kg]
weight luggage : 171 [kg]
weight cargo : 301 [kg]
operational weight loaded: 5804 [kg](94.8 [%])
fuel reserve : 319.3 [kg] enough for 2.03 [hours] flying
operational weight fully loaded : 6123 [kg] with fuel tank filled for 46 [%]
published maximum take-off weight : 6123 [kg] (100.0 [%])
calculation : * 4 * (engine power)
power loading (Take-off) : 8.21 [kg/kW]
power loading (operational without useful load) : 5.82 [kg/kW]
power loading (Take-off) 1 PUF: 10.95 [kg/kW]
max.total take-off power : 745.7 [kW]
calculation : *5* (loads)
manoeuvre load : 2.8 [g] at 1000 [m]
limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 1.9 [g]
design flight time : 5.38 [hours]
design cycles : 7062 sorties, design hours : 38020 [hours]
operational wing loading : 1241 [N/m^2]
wing stress (3 g) during operation : 222 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.32 ["]
max. angle of attack (stalling angle, clean) : 10.85 ["]
max. angle of attack (full flaps) : 9.96 ["]
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 : 1.11 [ ]
max.lift coefficient full flaps : 1.54 [ ]
induced drag coefficient at max.speed : 0.0010 [ ]
drag coefficient at max. speed : 0.0233 [ ]
drag coefficient (zero lift) : 0.0223 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW loaded : 5966 [kg]): 155 [km/u]
stalling speed at sea-level with full flaps (normal landing weight): 107 [km/u]
landing speed at sea-level (normal landing weight : 5624 [kg]): 123 [km/hr]
max. rate of climb speed : 159 [km/hr] at sea-level
max. endurance speed : 156 [km/u] min.fuel/hr : 54 [kg/hr] at height : 610 [m]
max. range speed : 220 [km/u] min. fuel consumption : 0.324 [kg/km] at cruise height :
3962 [m]
cruising speed : 295 [km/hr] at 2590 [m] (power:55 [%])
max. continuous speed* : 347.06 [km/hr] at 0 [m] (power:100 [%])
climbing speed at sea-level (loaded) : 478 [m/min]
climbing speed at 1000 [m] with 1 engine out (PUF / MTOW) : 223 [m/min]
climbing speed at 1000 [m] with 2 engines out (2xPUF / MTOW) : 79 [m/min]
calculation : *9* (regarding various performances)
take-off speed : 172.5 [km/u]
emergency/TO power : 250 [hp] at 2500 [rpm]
static prop wash : 177 [km/u]
high wheel pressure, can only take off from paved runways
take-off distance at sea-level concrete runway : 279 [m]
take-off distance at sea-level over 15 [m] height : 362 [m]
landing run : 298 [m]
landing run from 15 [m] : 732 [m]
lift/drag ratio : 16.85 [ ]
climb to 1000m with max payload : 2.80 [min]
climb to 2000m with max payload : 6.39 [min]
climb to 3000m with max payload : 11.29 [min]
BEA G-ALZL prototype landing with full flaps deployed
climb to 5000 [m] with max payload : 41.21 [min]
practical ceiling (operational weight empty 4254 [kg] ) : 7500 [m]
practical ceiling fully loaded (mtow- 30 min.fuel:6044 [kg] ) : 5700 [m]
calculation *10* (action radius & endurance)
published range : 2269 [km] with 2 crew and 1028.2 [kg] useful load and 88.1 [%] fuel
(no reserves)
range : 1289 [km] with 2 crew and 1550.0 [kg] useful load and 50.1 [%] fuel
Published range 1473 km (wikipedia) is with 1475 kg useful load (=14 passengers with 400 kg / freight luggage or 17 passengers with 170 kg luggage 50% fuel)
range : 1855 [km] with 14.0 passengers with each 12.2 [kg] luggage and 72.0 [%] fuel
Available Seat Kilometres (ASK) : 25966 [paskm]
max range theoretically with additional fuel tanks total 3161.2 [litre] fuel : 7161 [km]
useful load with range 500km : 2051 [kg]
useful load with range 500km : 14 passengers
production (theor.max load): 605 [tonkm/hour]
production (useful load): 457 [tonkm/hour]
production (passengers): 4130 [paskm/hour]
oil and fuel consumption per tonkm : 0.272 [kg]
fuel cost per paskm : 0.040 [eur]
crew cost per paskm : 0.073 [eur]
economic hours : 22300 [hours] is less then design hours
time between engine failure : 5188 [hr]
can continue fly on 3 engines, low risk for emergency landing for PUF
writing off per paskm : 0.033 [eur]
insurance per paskm : 0.0001 [eur]
maintenance cost per paskm : 0.099 [eur]
direct operating cost per paskm : 0.245 [eur]
direct operating cost per tonkm (max. load): 1.670 [eur]
direct operating cost per tonkm (normal useful load): 2.210 [eur]
Literature :
Praktisch handboek deel 5 page 138,139
Verkeersvliegtuigen Moussault page 31,109
piston-engined airliners page 62
verkeersvliegtuigen – B. van der Klaauw page 45
Onze burgervloot B.van der Klaauw page 23
Verkeersvliegtuigen nu en straks page 27
.
To accommodate 17 passengers the toilet and rear luggage hold had to be removed
* max. continuous speed : max. level speed maintainable for minimal 30 min.
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 03 April 2022 contact : info.aircraftinvestigation@gmail.com