Albatros C.I |aircraft investigation| WWI

aircraft investigation Albatros C.I WWI armed reconnaissance and artillery observation biplane weight and performance calculations

Albatros C.I

role : two-seat armed reconnaissance and artillery observation

first flight : early 1915 operational : May 1915

country : Germany

design :

production : ca.500 aircraft

general information : One of the first of the new German two-seat armed C-class aircraft. The

pilot and observer had switched places and the observer was equipped with a free-firing ring-mounted machine-gun with a much better field of fire to the sides and rear from the back-seat. Also it had a more powerful engine with made the plane superior to most allied aircraft. It was derived from the unarmed B.II and kept it’s fine flying qualities, stability and strength . From late spring 1915 it was used in substantial numbers at the Western Front and in Russia for artillery-observation, photo- and visual reconnaissance. It was also used for light bombing raids. It’s good performance made it possible to use it aggressively as demonstrated by Oswald Boelcke who made his first kill on 4 juli 1915 flying a C.I with Lt.Von Wuhlisch as his gunner. Also Manfred von Richthofen gathered fighting experience as observer flying in the C.I at the Eastern front.

In the Krakow aviation museum a surviving C.I can be seen.

crew : 2

users : Luftwaffe

armament : 1 movable 7.92 [mm] (0.312 in) Parabellum MG 14 machine-gun for the observer

engine : 1 Mercedes D.III liquid-cooled 6 -cylinder inline engine 163 [hp](119.9 KW)

dimensions :

wingspan : 12.9 [m], length : 7.85 [m], height : 3.14[m]

wing area : 40.4 [m^2]

weights :

max.take-off weight : 1190 [kg]

empty weight operational : 875 [kg] bombload : 70 [kg]

performance :

maximum speed : 132 [km/hr] at sea-level

climbing speed : 102 [m/min]

service ceiling : 3000 [m]

endurance : 2.5 [hours]

estimated action radius : 148 [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 :0.63 [ ]

estimated diameter airscrew 2.63 [m]

angle of attack prop : 14.23 [ ]

fine pitch

reduction : 1.00 [ ]

airscrew revs : 1400 [r.p.m.]

pitch at Max speed 1.57 [m]

blade-tip speed at Vmax and max revs. : 196 [m/s]

calculation : *1* (dimensions)

mean wing chord : 1.57 [m]

calculated wing chord (rounded tips): 1.72 [m]

wing aspect ratio : 8.24 []

estimated gap : 1.45 [m]

gap/chord : 0.93 [ ]

seize (span*length*height) : 318 [m^3]

calculation : *2* (fuel consumption)

oil consumption : 2.5 [kg/hr]

fuel consumption(cruise speed) : 33.7 [kg/hr] (46.0 [litre/hr]) at 75 [%] power

distance flown for 1 kg fuel : 3.52 [km/kg]

estimated total fuel capacity : 131 [litre] (96 [kg])

calculation : *3* (weight)

weight engine(s) dry : 299.0 [kg] = 2.49 [kg/KW]

weight 11 litre oil tank : 1.0 [kg]

oil tank filled with 0.9 litre oil : 0.8 [kg]

oil in engine 7 litre oil : 6.0 [kg]

fuel in engine 1 litre fuel : 0.6 [kg]

weight 20 litre gravity patrol tank(s) : 2.9 [kg]

weight radiator : 17.2 [kg]

weight exhaust pipes & fuel lines 10.8 [kg]

weight cowling 4.8 [kg]

weight airscrew(s) (wood) incl. boss & bolts : 19.0 [kg]

total weight propulsion system : 361 [kg](30.3 [%])

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fuselage skeleton (wood gauge : 7.58 [cm]): 115 [kg]

bracing : 6.4 [kg]

fuselage covering ( 11.6 [m2] doped linen fabric) : 3.7 [kg]

weight controls + indicators: 6.3 [kg]

weight seats : 6.0 [kg]

weight other details, lighting set, etc. : 5.1 [kg]

weight bomb storage : 4.9 [kg]

weight 111 [litre] main fuel tank empty : 8.9 [kg]

weight engine mounts & firewalls : 6 [kg]

total weight fuselage : 163 [kg](13.7 [%])

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weight wing covering (doped linen fabric) : 26 [kg]

total weight ribs (62 ribs) : 71 [kg]

load on front upper spar (clmax) per running metre : 841.0 [N]

load on rear upper spar (vmax) per running metre : 254.4 [N]

total weight 8 spars : 80 [kg]

weight wings : 177 [kg]

weight wing/square meter : 4.38 [kg]

weight 8 interplane struts & cabane : 15.8 [kg]

weight cables (72 [m]) : 9.0 [kg] (= 126 [gram] per metre)

diameter cable : 4.5 [mm]

weight fin & rudder (1.9 [m2]) : 8.7 [kg]

weight stabilizer & elevator (4.5 [m2]): 20.2 [kg]

total weight wing surfaces & bracing : 231 [kg] (19.4 [%])

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weight machine-gun(s) : 9.5 [kg]

weight pivot mounting mg :5.0 [kg]

weight armament : 14 [kg]

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wheel pressure : 595.0 [kg]

weight 2 wheels (770 [mm] by 97 [mm]) : 30.4 [kg]

weight tailskid : 3.4 [kg]

weight undercarriage with axle 30.6 [kg]

total weight landing gear : 64.3 [kg] (5.4 [%]

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calculated empty weight : 833 [kg](70.0 [%])

weight oil for 3.0 hours flying : 7.6 [kg]

weight cooling fluids : 25.9 [kg]

weight 1 drums empty : 2.3 [kg]

weight ammunition (500 rounds) : 19.8 [kg]

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calculated operational weight empty : 886 [kg] (74.5 [%])

published operational weight empty : 875 [kg] (73.5 [%])

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weight crew : 162 [kg]

weight fuel for 2.0 hours flying : 67 [kg]

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operational weight : 1116 [kg](93.8 [%])

bomb load : 70 [kg]

operational weight bombing mission : 1186 [kg]

weight camera : 20 [kg]

operational weight photo mission : 1136 [kg]

fuel reserve : 28 [kg] enough for 0.84 [hours] flying

possible additional useful load : 26 [kg]

operational weight fully loaded : 1190 [kg] with fuel tank filled for 100 [%]

published maximum take-off weight : 1190 [kg] (100.0 [%])

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calculation : * 4 * (engine power)

power loading (operational without bombload) : 9.31 [kg/kW]

total power : 119.9 [kW] at 1400 [r.p.m]

calculation : *5* (loads)

manoeuvre load : 2.0 [g] at 1000 [m]

limit load : 3.75 [g] ultimate load : 5.6 [g] load factor : 2.5 [g]

design flight time : 2.00 [hours]

design cycles : 525 sorties, design hours : 1050 [hours]

operational wing loading : 276 [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 : -1.16 ["]

max. angle of attack (stalling angle) : 12.13 ["]

angle of attack at max. speed : 2.69 ["]

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 : 0.33 [ ]

induced drag coefficient at max. speed : 0.0076 [ ]

drag coefficient at max. speed : 0.0615 [ ]

drag coefficient (zero lift) : 0.0539 [ ]

calculation : *8* (speeds

stalling speed at sea-level (OW): 71 [km/u]

landing speed at sea-level (OW without bombload): 85 [km/hr]

min. drag speed (max endurance) : 87 [km/hr] at 1500 [m](power :47 [%])

min. power speed (max range) : 99 [km/hr] at 1500 [m] (power:53 [%])

max. rate of climb speed : 82.7 [km/hr] at sea-level

cruising speed : 119 [km/hr] op 1500 [m] (power:71 [%])

design speed prop : 125 [km/hr]

maximum speed : 132 [km/hr] op 100 [m] (power:99 [%])

climbing speed at sea-level (without bombload) : 197 [m/min]

calculation : *9* (regarding various performances)

take-off distance at sea-level : 136 [m]

lift/drag ratio : 8.22 [ ]

max. practical ceiling : 5225 [m] with flying weight :964 [kg]

practical ceiling (operational weight): 4250 [m] with flying weight :1116 [kg]

practical ceiling fully loaded (mtow- 1 hour fuel) : 4000 [m] with flying weight :1156 [kg]

published ceiling (3000 [m]

climb to 1500m (without bombload) : 8.58 [min]

climb to 3000m (without bombload) : 21.83 [min]

max. dive speed : 330.6 [km/hr] at 3000 [m] height

load factor at max. angle turn 1.78 ["g"]

turn radius at 500m: 51 [m]

time needed for 360* turn 11.8 [seconds] at 500m

calculation *10* (action radius & endurance)

operational endurance : 2.13 [hours] with 2 crew and 70 [kg] useful (bomb)load and 75.0 [%] fuel

published endurance : 2.50 [hours] with 2 crew and possible useful (bomb) load : 57 [kg] and 88.1 [%] fuel

action radius : 214 [km] with 2 crew and 20[kg] photo camera/radio transmitter or bombload

max range theoretically with additional fuel tanks for total 344 [litre] fuel : 888 [km]

useful load with action-radius 250km : 110 [kg]

production : 13.08 [tonkm/hour]

oil and fuel consumption per tonkm : 2.77 [kg]

I_°°=/

Literature :

Praktisch handboek vliegtuigen deel 1 page 263

Bombers 1914-19 pages 34,111

Wikipedia

Warplanes WOI page 36,42

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.

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