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weight and performance calculations for the Caudron R.11 3-seat escort fighter

Afbeeldingsresultaat voor Caudron R.11

Caudron R.11

role : long range heavy escort

importance : ***

first flight : operational : April 1918

country : France

design : René Caudron

production : 370 aircraft

general information :

Designed as bomber but due to it’s limited bombload operationally primarily used as bomber escort. For this purpose a additional machine gun was installed.

Petrol capacity : 220 litre. This R.11 could also be used in adverse weather situations. Climb to 2000m : 8.10 minutes to 3000m : 14.3 min. To 5000m : 39 min.

users : France

crew : 3

armament : 5 movable 7.70 [mm] (0.303 in) Lewis machine-guns

engine : 2 Hispano Suiza 8Bda liquid-cooled 8 -cylinder V-engine 215 [hp](158.1 KW)

dimensions :

wingspan : 17.92 [m], length : 11.22 [m], height : 3.0[m]

wing area : 54.25 [m^2]

weights :

max.take-off weight : 2165 [kg]

empty weight operational : 1422 [kg] bombload : 120 [kg]

performance :

maximum speed : 183 [km/u] op 2000 [m]

climbing speed : 247 [m/min]

service ceiling : 5950 [m]

endurance : 2.15 [hours]

estimated action radius : 177 [km]

description :

3-bay biplane with fixed underwing 4 -wheel landing gear and tail strut

two spar upper and lower wing

engines, landing gear and fuel attached to the wings, bombload in or attached to

fuselage

Afbeeldingsresultaat voor Caudron R.11

airscrew :

two fixed pitch 2 -bladed tractor airscrews with max. efficiency :0.64 [ ]

estimated diameter airscrew 2.49 [m]

angle of attack prop : 18.47 [ ]

reduction : 0.75 [ ]

airscrew revs : 1556 [r.p.m.]

pitch at Max speed 1.96 [m]

blade-tip speed at Vmax and max revs. : 209 [m/s]

calculation : *1* (dimensions)

mean wing chord : 1.51 [m]

calculated wing chord (rounded tips): 1.62 [m]

wing aspect ratio : 11.84 []

gap : 1.45 [m]

gap/chord : 0.96 [ ]

seize (span*length*height) : 603 [m^3]

calculation : *2* (fuel consumption)

oil consumption : 4.4 [kg/hr]

fuel consumption(cruise speed) : 66.0 [kg/hr] (90.1 [litre/hr]) at 58 [%] power

distance flown for 1 kg fuel : 2.49 [km/kg]

estimated total fuel capacity : 220 [litre] (161 [kg])

calculation : *3* (weight)

weight engine(s) dry : 471.2 [kg] = 1.49 [kg/KW]

weight reduction gear : 23.5 [kg]

weight 21 litre oil tank : 1.8 [kg]

oil tank filled with 2.4 litre oil : 2.1 [kg]

oil in engine 18 litre oil : 15.8 [kg]

fuel in engine 2 litre fuel : 1.6 [kg]

weight 38 litre gravity patrol tank(s) : 5.7 [kg]

weight radiator : 45.3 [kg]

weight exhaust pipes & fuel lines 19.1 [kg]

weight self-starter : 3.9 [kg]

weight cowling 6.3 [kg]

weight airscrew(s) (wood) incl. boss & bolts : 47.4 [kg]

total weight propulsion system : 666 [kg](30.7 [%])

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Afbeeldingsresultaat voor Caudron R.11

fuselage skeleton (wood gauge : 6.94 [cm]): 138 [kg]

bracing : 11.8 [kg]

fuselage covering ( 23.8 [m2] doped linen fabric) : 7.6 [kg]

weight controls + indicators: 7.8 [kg]

weight seats : 9.0 [kg]

weight other details, lighting set, etc. : 9.1 [kg]

weight bomb storage : 8.4 [kg]

weight interior + equipment + fuel lines: 37 [kg]

total weight fuselage : 229 [kg](10.6 [%])

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

weight wing covering (doped linen fabric) : 35 [kg]

total weight ribs (117 ribs) : 129 [kg]

weight engine mounts : 16 [kg]

weight two 91 [litre] main fuel tanks empty : 14.5 [kg]

load on front upper spar (clmax) per running metre : 565.0 [N]

load on rear upper spar (vmax) per running metre : 344.6 [N]

total weight 8 spars : 71 [kg]

weight wings : 234 [kg]

weight wing/square meter : 4.31 [kg]

weight 12 interplane struts & cabane : 18.0 [kg]

weight cables (102 [m]) : 11.3 [kg] (= 111 [gram] per metre)

diameter cable : 4.3 [mm]

weight fin & rudder (3.7 [m2]) : 16.6 [kg]

weight stabilizer & elevator (6.1 [m2]): 26.7 [kg]

total weight wing surfaces & bracing : 337 [kg] (15.6 [%])

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weight machine-gun(s) : 63.5 [kg]

weight pivot mounting mg :30.0 [kg]

weight armament : 94 [kg]

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

wheel pressure : 541.2 [kg]

weight 4 wheels (690 [mm] by 81 [mm]) : 45.0 [kg]

weight tailskid : 3.1 [kg]

weight undercarriage with axle 38.9 [kg]

total weight landing gear : 87.0 [kg] (4.0 [%]

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Afbeeldingsresultaat voor Caudron R.11

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calculated empty weight : 1413 [kg](65.2 [%])

weight oil for 2.6 hours flying : 11.4 [kg]

weight cooling fluids : 68.3 [kg]

weight 25 drums empty : 5.2 [kg]

weight ammunition (1175 rounds) : 37.4 [kg]

weight signal pistol with cartridges : 3.6 [kg]

weight automatic pistol with spare magazines : 1.2 [kg]

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

calculated operational weight empty : 1534 [kg] (70.9 [%])

published operational weight empty : 1422 [kg] (65.7 [%])

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weight crew : 243 [kg]

weight fuel for 2.0 hours flying : 132 [kg]

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operational weight : 1910 [kg](88.2 [%])

bomb load : 120 [kg]

operational weight bombing mission : 2030 [kg]

fuel reserve : 29 [kg] enough for 0.44 [hours] flying

possible additional useful load : 106 [kg]

operational weight fully loaded : 2165 [kg] with fuel tank filled for 100 [%]

published maximum take-off weight : 2165 [kg] (100.0 [%])

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calculation : * 4 * (engine power)

power loading (operational without bombload) : 6.04 [kg/kW]

total power : 316.3 [kW] at 2075 [r.p.m]

Afbeeldingsresultaat voor Caudron R.11

calculation : *5* (loads)

manoeuvre load : 2.7 [g] at 1000 [m]

limit load : 3.5 [g] ultimate load : 5.2 [g] load factor : 1.2 [g]

design flight time : 1.72 [hours]

design cycles : 160 sorties, design hours : 275 [hours]

operational wing loading : 345 [N/m^2]

wing stress (3 g) during operation : 240 [N/kg] at 3g emergency manoeuvre

calculation : *6* (angles of attack)

angle of attack zero lift : -1.08 ["]

max. angle of attack (stalling angle) : 10.59 ["]

angle of attack at max. speed : 1.78 ["]

calculation : *7* (lift & drag ratios

lift coefficient at angle of attack 0° :0.10 [ ]

lift coefficient at max. angle of attack : 1.08 [ ]

lift coefficient at max. speed : 0.27 [ ]

induced drag coefficient at max. speed : 0.0034 [ ]

drag coefficient at max. speed : 0.0421 [ ]

drag coefficient (zero lift) : 0.0387 [ ]

calculation : *8* (speeds

stalling speed at sea-level (OW): 82 [km/u]

landing speed at sea-level (OW without bombload): 99 [km/hr]

Afbeeldingsresultaat voor Caudron R.11

min. drag speed (max endurance) = minimum speed*1.1 at cruise height : 105 [km/hr] at 2975 [m] (power:28 [%])

min. power speed (max range) : 121 [km/hr] at 2975 [m] (power:31 [%])

max. rate of climb speed : 110.1 [km/hr] at sea-level

cruising speed : 165 [km/hr] op 2975 [m] (power:53 [%])

design speed prop : 174 [km/hr]

maximum speed : 183 [km/hr] op 2000 [m] (power:75 [%])

climbing speed at sea-level (without bombload) : 390 [m/min]

calculation : *9* (regarding various performances)

take-off distance at sea-level : 176 [m]

lift/drag ratio : 11.62 [ ]

max. practical ceiling : 6825 [m] with flying weight :1606 [kg]

practical ceiling (operational weight): 6100 [m] with flying weight :1910 [kg]

Afbeeldingsresultaat voor Caudron R.11

practical ceiling fully loaded (mtow- 1 hour fuel) : 5675 [m] with flying weight :2099 [kg]

published ceiling (5950 [m]

climb to 1500m (without bombload) : 4.24 [min]

climb to 3000m (without bombload) : 10.09 [min]

max. dive speed : 494.4 [km/hr] at 4675 [m] height

load factor at max. angle turn 2.83 ["g"]

turn radius at 500m: 60 [m]

time needed for 360* turn 9.5 [seconds] at 500m

calculation *10* (action radius & endurance)

operational endurance : 2.44 [hours] with 3 crew and 226 [kg] bombload and 100.0 [%] fuel

published endurance : 2.15 [hours] with 3 crew and possible useful (bomb) load : 246 [kg] and 88.1 [%] fuel

action radius : 458 [km] with 3 crew and 20[kg] photo camera/radio transmitter or bombload

max range theoretically with additional fuel tanks for total 807 [litre] fuel : 1476 [km]

useful load with action-radius 250km : 391 [kg]

production : 64.44 [tonkm/hour]

oil and fuel consumption per tonkm : 1.09 [kg]

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Literature :

Praktisch handboek vliegtuigen deel 1 page 161

Bombers 1914-19 page 71

Jane´s FAWOI page 107

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 November 2019 contact : info.aircraftinvestigation@gmail.com python 3.7.4