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weight and performance calculations for the Dorand AR.1
Dorand AR.1
role : multi role combat aircraft
importance : ***
first flight : operational : March 1917
country : France
design : Georges Lèpere and Émile Dorand
production : unknown > 200+
general information :
Not an exceptional aircraft but was used in 13 French squadrons at the Western front
and in 5 squadrons at the Italian front. Also the American Expeditionary Force used
the type in France. That the design was sound is shown by the fact that the AR.1 was
still continued to be used after WWI by private company for passenger flights and as
trainer and for private use.
Gap : max : 2.0m min. 1.83m tank capacity : 182 litres
users : France
crew : 2
armament : 1 synchronized 7.70 [mm] (0.303 in) Vickers machine-gun
and 1 movable 7.70 [mm] (0.303 in) Lewis machine-gun for the observer
engine : 1 Renault 8 Bd liquid-cooled 8 -cylinder V-engine 190 [hp](139.7 KW)
dimensions :
wingspan : 13.29 [m], length : 9.14 [m], height : 3.3[m]
wing area : 50.36 [m^2]
weights :
max.take-off weight : 1330 [kg]
empty weight operational : 892 [kg] bombload : 82 [kg]
performance :
maximum speed : 152 [km/hr] at sea-level
service ceiling : 5500 [m]
endurance : 3.35 [hours]
estimated action radius : 229 [km]
description :
2-bay biplane with fixed landing gear and tail strut
two spar upper and lower wing
engines, landing gear, fuel and bombs in or attached to the fuselage
airscrew :
fixed pitch 2 -bladed tractor airscrew with max. efficiency :0.64 [ ]
estimated diameter airscrew 2.78 [m]
angle of attack prop : 12.13 [ ]
fine pitch
reduction : 1.00 [ ]
airscrew revs : 1800 [r.p.m.]
pitch at Max speed 1.41 [m]
blade-tip speed at Vmax and max revs. : 265 [m/s]
calculation : *1* (dimensions)
mean wing chord : 1.89 [m]
calculated wing chord (rounded tips): 2.10 [m]
wing aspect ratio : 7.01 []
estimated gap : 1.84 [m]
gap/chord : 0.97 [ ]
seize (span*length*height) : 401 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 2.9 [kg/hr]
fuel consumption(cruise speed) : 35.2 [kg/hr] (48.0 [litre/hr]) at 70 [%] power
distance flown for 1 kg fuel : 3.89 [km/kg]
estimated total fuel capacity : 182 [litre] (134 [kg])
calculation : *3* (weight)
weight engine(s) dry : 245.0 [kg] = 1.75 [kg/KW]
weight 17 litre oil tank : 2.1 [kg]
oil tank filled with 1.0 litre oil : 0.9 [kg]
oil in engine 8 litre oil : 7.0 [kg]
fuel in engine 1 litre fuel : 0.7 [kg]
weight 20 litre gravity patrol tank(s) : 2.0 [kg]
weight radiator : 25.9 [kg]
weight exhaust pipes & fuel lines 17.4 [kg]
weight cowling 5.6 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 21.0 [kg]
total weight propulsion system : 325 [kg](24.5 [%])
***************************************************************
fuselage skeleton (wood gauge : 7.32 [cm]): 126 [kg]
bracing : 8.1 [kg]
fuselage covering ( 15.8 [m2] doped linen fabric) : 5.0 [kg]
weight controls + indicators: 6.7 [kg]
weight seats : 6.0 [kg]
weight other details, lighting set, etc. : 5.1 [kg]
weight bomb storage : 5.7 [kg]
weight Doran/Lafay bomb sight : 1.5 [kg]
weight 162 [litre] main fuel tank empty : 15.6 [kg]
weight oxygen/compressed air flasks for high altitude : 7.3 [kg]
weight engine mounts & firewalls : 7 [kg]
total weight fuselage : 194 [kg](14.5 [%])
***************************************************************
weight wing covering (doped linen fabric) : 32 [kg]
total weight ribs (57 ribs) : 79 [kg]
load on front upper spar (clmax) per running metre : 717.7 [N]
load on rear upper spar (vmax) per running metre : 259.6 [N]
total weight 8 spars : 73 [kg]
weight wings : 184 [kg]
weight wing/square meter : 3.65 [kg]
weight 8 interplane struts & cabane : 30.2 [kg]
weight cables (79 [m]) : 9.1 [kg] (= 114 [gram] per metre)
diameter cable : 4.3 [mm]
weight fin & rudder (2.1 [m2]) : 7.8 [kg]
weight stabilizer & elevator (5.7 [m2]): 21.1 [kg]
total weight wing surfaces & bracing : 252 [kg] (19.0 [%])
*******************************************************************
weight machine-gun(s) : 28.6 [kg]
weight pivot mounting mg :6.0 [kg]
weight ammunition magazine(s) :1.8 [kg]
weight Birkigt synchronization gear : 1.0 [kg]
weight armament : 37 [kg]
********************************************************************
wheel pressure : 665.0 [kg]
weight 2 wheels (760 [mm] by 95 [mm]) : 29.8 [kg]
weight tailskid : 3.2 [kg]
weight undercarriage with axle 30.4 [kg]
total weight landing gear : 63.4 [kg] (4.8 [%]
*******************************************************************
********************************************************************
calculated empty weight : 872 [kg](65.5 [%])
weight oil for 4.0 hours flying : 11.8 [kg]
weight cooling fluids : 28.8 [kg]
weight 5 drums empty : 1.0 [kg]
weight ammunition (635 rounds) : 18.5 [kg]
weight signal pistol with cartridges : 3.6 [kg]
weight automatic pistol with spare magazines : 1.2 [kg]
*******************************************************************
calculated operational weight empty : 936 [kg] (70.3 [%])
published operational weight empty : 892 [kg] (67.1 [%])
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weight crew : 162 [kg]
weight (electrical heated) clothing for high altitude : 12.0 [kg]
weight fuel for 2.0 hours flying : 70 [kg]
********************************************************************
operational weight : 1180 [kg](88.7 [%])
bomb load : 82 [kg]
operational weight bombing mission : 1262 [kg]
fuel reserve : 63 [kg] enough for 1.80 [hours] flying
possible additional useful load : 5 [kg]
operational weight fully loaded : 1330 [kg] with fuel tank filled for 100 [%]
published maximum take-off weight : 1330 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (operational without bombload) : 8.44 [kg/kW]
total power : 139.7 [kW] at 1800 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 3.1 [g] at 1000 [m]
limit load : 3.75 [g] ultimate load : 5.6 [g] load factor : 2.1 [g]
design flight time : 2.68 [hours]
design cycles : 317 sorties, design hours : 850 [hours]
operational wing loading : 230 [N/m^2]
wing stress (3 g) during operation : 189 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.21 ["]
max. angle of attack (stalling angle) : 12.64 ["]
angle of attack at max. speed : 1.36 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° :0.10 [ ]
lift coefficient at max. angle of attack : 1.15 [ ]
lift coefficient at max. speed : 0.21 [ ]
induced drag coefficient at max. speed : 0.0036 [ ]
drag coefficient at max. speed : 0.0385 [ ]
drag coefficient (zero lift) : 0.0349 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 65 [km/u]
landing speed at sea-level (OW without bombload): 78 [km/hr]
min. drag speed (max endurance) : 99 [km/hr] at 2750 [m](power :42 [%])
min. power speed (max range) : 106 [km/hr] at 2750 [m] (power:44 [%])
max. rate of climb speed : 92.4 [km/hr] at sea-level
cruising speed : 137 [km/hr] op 2750 [m] (power:64 [%])
design speed prop : 144 [km/hr]
maximum speed : 152 [km/hr] op 100 [m] (power:100 [%])
climbing speed at sea-level (without bombload) : 236 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 88 [m]
lift/drag ratio : 9.42 [ ]
max. practical ceiling : 6575 [m] with flying weight :1011 [kg]
practical ceiling (operational weight): 5600 [m] with flying weight :1180 [kg]
practical ceiling fully loaded (mtow- 1 hour fuel) : 4975 [m] with flying weight :1295 [kg]
published ceiling (5500 [m]
climb to 1500m (without bombload) : 6.42 [min]
climb to 3000m (without bombload) : 14.75 [min]
max. dive speed : 366.9 [km/hr] at 3975 [m] height
load factor at max. angle turn 2.08 ["g"]
turn radius at 500m: 40 [m]
time needed for 360* turn 9.4 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 3.80 [hours] with 2 crew and 99 [kg] useful (bomb)load and 100.0 [%] fuel
published endurance : 3.35 [hours] with 2 crew and possible useful (bomb) load : 115 [kg] and 88.1 [%] fuel
action radius : 413 [km] with 2 crew and 20[kg] photo camera/radio transmitter or bombload
max range theoretically with additional fuel tanks for total 477 [litre] fuel : 1359 [km]
useful load with action-radius 250km : 221 [kg]
production : 30.21 [tonkm/hour]
oil and fuel consumption per tonkm : 1.26 [kg]
_
I_°°=/
°
Bombers 1914-19 page 37
Praktisch handboek vliegtuigen deel 1 page 150
Jane’s Fighting aircraft WWI page 110, 111
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 23 January 2020 contact : info.aircraftinvestigation@gmail.com python 3.7.4