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Caudron G.4
role : light twin-engined bomber
first flight : march 1915 operational : November 1915
country : France
design : René and Gaston Caudron
production : ca.300 aircraft
general information : The G.4 was an improved and more powerful version of the G.3.
It was the first two-engine aircraft that entered service in numbers with the France air force but it was also used by the other allied countries and hundreds of it were built. It was a pleasant aircraft to fly, thoroughly reliable and had a remarkable good rate of climb. It was used for day bombing into the heart of Germany till the autumn of 1916. Increasing losses forced the France to change to night bombing in which role the G.IV was used till mid 1917.
The movable machinegun was placed in the nose, but this left the airplane unprotected for attacks from behind. Also the gunner could not shoot sideways to much, his field of fire hampered by the two engines and its propellers.
The Italians used it for long range missions over the alps using it good altitude capabilities. The RNAS used it for bombing Zeppelin and seaplane bases in Belgium. The G.4 still used wing-warping for control. A surviving G.4 can be seen in the muse de l’air et de l’espace in Paris.
Users : France, United Kingdom (RNAS 55), Belgium, Italy, Russia, The Netherlands(5, reg C427 – C431, operational from June 1918)
crew : 2
armament : 1 movable 7.70 [mm] (0.303 in) Lewis machine-gun for the observer
engine : 2 Le Rhone 9c air-cooled 9 -cylinder two-valve rotary engine 90 [hp](66.2 KW)
dimensions :
wingspan : 16.88 [m], length : 7.27 [m], height : 2.6[m]
wing area : 36.8 [m^2]
weights :
max.take-off weight : 1330 [kg]
empty weight operational : 820 [kg] bombload : 175 [kg]
performance :
maximum speed : 130 [km/hr] at sea-level
service ceiling : 4300 [m]
endurance : 3.5 [hours]
estimated action radius : 205 [km]
description :
3˝-bay biplane with fixed underwing 4 -wheel landing gear and tail strut
upper wingtips supported by slanted struts
two spar upper and lower wing
tail supported by two open tail booms
engines,landinggear and fuel attached to the wings, bombload in or attached to fuselage
airscrew :
two fixed pitch 2 -bladed tractor airscrews with max. efficiency :0.63 [ ]
estimated diameter airscrew 2.95 [m]
angle of attack prop : 13.48 [ ]
fine pitch
reduction : 1.00 [ ]
airscrew revs : 1300 [r.p.m.]
pitch at Max speed 1.67 [m]
blade-tip speed at Vmax and max revs. : 204 [m/s]
calculation : *1* (dimensions)
mean wing chord : 1.21 [m]
calculated wing chord (rounded tips): 1.30 [m]
wing aspect ratio : 13.94 []
estimated gap : 1.59 [m]
gap/chord : 1.31 [ ]
seize (span*length*height) : 319 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 8.6 [kg/hr]
fuel consumption(cruise speed) : 38.2 [kg/hr] (52.1 [litre/hr]) at 67 [%] power
distance flown for 1 kg fuel : 3.06 [km/kg]
estimated total fuel capacity : 207 [litre] (152 [kg])
calculation : *3* (weight)
weight engine(s) dry : 244.0 [kg] = 1.84 [kg/KW]
weight 44 litre oil tank : 3.7 [kg]
oil tank filled with 1.0 litre oil : 0.9 [kg]
oil in engine 1 litre oil : 0.7 [kg]
fuel in engine 1 litre fuel : 0.7 [kg]
weight 22 litre gravity patrol tank(s) : 3.3 [kg]
weight cowling 2.6 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 30.4 [kg]
total weight propulsion system : 283 [kg](21.3 [%])
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weight tail boom : 30 [kg]
fuselage skeleton (wood gauge : 7.01 [cm]): 91 [kg]
bracing : 5.3 [kg]
fuselage covering ( 6.5 [m2] doped linen fabric) : 2.1 [kg]
weight controls + indicators: 6.7 [kg]
weight seats : 6.0 [kg]
weight other details, lighting set, etc. : 9.1 [kg]
weight bomb storage : 12.3 [kg]
total weight fuselage : 133 [kg](10.0 [%])
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weight wing covering (doped linen fabric) : 24 [kg]
total weight ribs (90 ribs) : 79 [kg]
weight engine mounts : 7 [kg]
weight two 92 [litre] main fuel tanks empty : 14.8 [kg]
load on front upper spar (clmax) per running metre : 653.6 [N]
load on rear upper spar (vmax) per running metre : 228.8 [N]
total weight 8 spars : 72 [kg]
weight wings : 175 [kg]
weight wing/square meter : 4.75 [kg]
weight 16 interplane struts & cabane : 34.6 [kg]
weight cables (93 [m]) : 10.6 [kg] (= 114 [gram] per metre)
diameter cable : 4.3 [mm]
weight fin & rudder (3.3 [m2]) : 16.2 [kg]
weight stabilizer & elevator (4.1 [m2]): 20.0 [kg]
total weight wing surfaces & bracing : 278 [kg] (20.9 [%])
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weight machine-gun(s) : 12.7 [kg]
weight pivot mounting mg :5.0 [kg]
weight armament : 18 [kg]
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wheel pressure : 332.5 [kg]
weight 4 wheels (620 [mm] by 73 [mm]) : 29.8 [kg]
weight tailskid : 3.3 [kg]
weight undercarriage with axle 38.6 [kg]
total weight landing gear : 71.7 [kg] (5.4 [%]
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calculated empty weight : 783 [kg](58.8 [%])
weight oil for 4.2 hours flying : 36.1 [kg]
weight 5 drums empty : 1.0 [kg]
weight ammunition (235 rounds) : 9.0 [kg]
weight automatic pistol with spare magazines : 1.2 [kg]
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calculated operational weight empty : 829 [kg] (62.3 [%])
published operational weight empty : 820 [kg] (61.7 [%])
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weight crew : 162 [kg]
weight fuel for 2.0 hours flying : 76 [kg]
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operational weight : 1067 [kg](80.2 [%])
bomb load : 175 [kg]
operational weight bombing mission : 1242 [kg]
fuel reserve : 75 [kg] enough for 1.97 [hours] flying
possible additional useful load : 12 [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 (Take-off) : 10.05 [kg/kW]
total power : 132.4 [kW] at 1300 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 1.3 [g] at 1000 [m]
limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 2.1 [g]
design flight time : 2.80 [hours]
design cycles : 518 sorties, design hours : 1450 [hours]
wing loading (MTOW) : 354 [N/m^2]
wing stress (3 g) during operation : 209 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.05 ["]
max. angle of attack (stalling angle) : 9.68 ["]
angle of attack at max. speed : 2.73 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° :0.10 [ ]
lift coefficient at max. angle of attack : 1.02 [ ]
lift coefficient at max. speed : 0.36 [ ]
induced drag coefficient at max. speed : 0.0039 [ ]
drag coefficient at max. speed : 0.0779 [ ]
drag coefficient (zero lift) : 0.0740 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 77 [km/u]
landing speed at sea-level (OW without bombload): 92 [km/hr]
min. drag speed (max endurance) = minimum speed*1.1 at cruise height : 94 [km/hr] at 2150 [m] (power:40 [%])
min. power speed (max range) : 94 [km/hr] at 2150 [m] (power:40 [%])
cruising speed : 117 [km/hr] op 2150 [m] (power:63 [%])
design speed prop : 124 [km/hr]
maximum speed : 130 [km/hr] op 100 [m] (power:99 [%])
climbing speed at sea-level (without bombload) : 276 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 187 [m]
lift/drag ratio : 10.53 [ ]
max. practical ceiling : 6100 [m] with flying weight :919 [kg]
practical ceiling (operational weight): 5275 [m] with flying weight :1067 [kg]
practical ceiling fully loaded (mtow- 1 hour fuel) : 4125 [m] with flying weight :1292 [kg]
published ceiling (4300 [m]
climb to 1500m (without bombload) : 5.98 [min]
Above and below: A Caudron G-IV of the type flown by Bill Thaw at Esc. C. 42 in late 1915-early 1916. The Commander of C. 42 was Capt. Thenault, who became Commander of the Lafayette N.124.
climb to 3000m (without bombload) : 14.37 [min]
max. dive speed : 308.8 [km/hr] at 3125 [m] height
load factor at max. angle turn 1.90 ["g"]
turn radius at 500m: 67 [m]
time needed for 360* turn 12.9 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 3.97 [hours] with 2 crew and 187 [kg] bombload and 100.0 [%] fuel
published endurance : 3.50 [hours] with 2 crew and possible useful (bomb) load : 205 [kg] and 88.1 [%] fuel
action radius : 489 [km] with 2 crew and 20[kg] photo camera/radio transmitter or bombload
max range theoretically with additional fuel tanks for total 587 [litre] fuel : 1318 [km]
useful load with action-radius 250km (with no gunner/observer) : 267 [kg]
useful load with action-radius 250km : 176 [kg]
production : 20.57 [tonkm/hour]
oil and fuel consumption per tonkm : 2.28 [kg]
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Caudron G.IV shot down by Boelcke wit gruesome result. Drillancourt, May1916
Literature :
Praktisch handboek vliegtuigen deel 1 page138
Bombers 1914-19 page 92,166
Tussen vleugels van linnen page.23
Jane’s fighter aircraft WO I page 64f,108
Warplanes WOI page 42
Wreckage of a G.IV which was interned in Holland. Registration C-427. It crashed after a mid-air collision with a Farman HF.20 (reg. HF-19). The flyers of both aircraft eerste-luitenant-vlieger J.P. van Oosten and eerste-luitenant-waarnemer B. van Doorn perished in the crash.
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
Version of the G.IV with the machine gun not positioned in the nose. This is a G.IV built in the UK.Betreft een in de UK gebouwde G.IV.
(c) B van der Zalm 21 August 2019 contact : info.aircraftinvestigation@gmail.com python 3.7.4