AIRCRAFT INVESTIGATION
weight and performance calculations for the Rumpler C.VII
Rumpler C.VII Rubild
role : two-seat armed reconnaissance and artillery observation
importance : ****
first flight : operational : October 1917
country : Germany
design :
production : unknown
general information :
Optimised for high-altitude missions. It had a Maybach Iva engine that kept its power at great heights. The crew had electrically heated clothing and oxygen generators. The C.VII was built in two versions, a standard radio-equipped machine and a photographic version, indicated as Rubild. The "Rubild" was a "stripped-down" version that dispensed with the forward gun and eliminated all other extraneous equipment in order to carry specialized cameras. The Rubild was capable of operating as high as 7,300 m (24,000ft), and could maintain 160 km/h (100 mph) at 6,100 m (20,000 ft).[6] The high-altitude version proved practically invulnerable to interception above 5,500 m (18,000 ft).[7] Allied combat reports most often featured the high-flying Rubild which could operate regularly at altitudes above 6,100 m (20,000 ft). The type was particularly difficult to intercept,[8] as the Allied fighters were seldom able even to climb to such altitude:
users : Luftwaffe
crew : 2
armament : 1 movable 7.92 [mm] (0.312 in) Parabellum MG 14 machine-gun for the observer
engine : 1 Maybach IVa liquid-cooled 6 -cylinder inline engine 245 [hp](180.2 KW)
dimensions :
wingspan : 12.65 [m], length : 8.2 [m], height : 3.2[m]
wing area : 34.8 [m^2]
weights :
max.take-off weight : 1485 [kg]
empty weight operational : 1050 [kg] bombload : 0 [kg]
performance :
maximum speed : 175 [km/hr] at sea-level
service ceiling : 7300 [m]
estimated action radius : 292 [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 3.10 [m]
angle of attack prop : 18.41 [ ]
reduction : 1.00 [ ]
airscrew revs : 1200 [r.p.m.]
pitch at Max speed 2.43 [m]
blade-tip speed at Vmax and max revs. : 201 [m/s]
calculation : *1* (dimensions)
mean wing chord : 1.38 [m]
calculated wing chord (rounded tips): 1.50 [m]
wing aspect ratio : 9.20 []
estimated gap : 1.85 [m]
gap/chord : 1.34 [ ]
seize (span*length*height) : 332 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 3.8 [kg/hr]
fuel consumption(cruise speed) : 42.5 [kg/hr] (58.0 [litre/hr]) at 72 [%] power
distance flown for 1 kg fuel : 3.71 [km/kg]
estimated total fuel capacity : 244 [litre] (179 [kg])
calculation : *3* (weight)
weight engine(s) dry : 400.0 [kg] = 2.22 [kg/KW]
weight 23 litre oil tank : 2.0 [kg]
oil tank filled with 1.4 litre oil : 1.2 [kg]
oil in engine 10 litre oil : 9.0 [kg]
fuel in engine 1 litre fuel : 0.9 [kg]
weight 25 litre gravity patrol tank(s) : 3.7 [kg]
weight radiator : 27.0 [kg]
weight exhaust pipes & fuel lines 16.7 [kg]
weight self-starter : 4.4 [kg]
weight cowling 7.2 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 27.0 [kg]
total weight propulsion system : 497 [kg](33.5 [%])
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fuselage skeleton (wood gauge : 7.28 [cm]): 111 [kg]
bracing : 6.4 [kg]
fuselage covering ( 12.7 [m2] doped linen fabric) : 4.1 [kg]
weight controls + indicators: 6.4 [kg]
weight seats : 6.0 [kg]
weight other details, lighting set, etc. : 5.1 [kg]
weight 220 [litre] main fuel tank empty : 17.6 [kg]
weight oxygen/compressed air flasks for high altitude : 8.1 [kg]
weight engine mounts & firewalls : 9 [kg]
total weight fuselage : 174 [kg](11.7 [%])
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weight wing covering (doped linen fabric) : 22 [kg]
total weight ribs (88 ribs) : 88 [kg]
load on front upper spar (clmax) per running metre : 834.0 [N]
load on rear upper spar (vmax) per running metre : 341.2 [N]
total weight 8 spars : 76 [kg]
weight wings : 187 [kg]
weight wing/square meter : 5.37 [kg]
weight 8 interplane struts & cabane : 32.3 [kg]
weight cables (76 [m]) : 9.1 [kg] (= 120 [gram] per metre)
diameter cable : 4.4 [mm]
weight fin & rudder (1.9 [m2]) : 10.3 [kg]
weight stabilizer & elevator (3.9 [m2]): 21.3 [kg]
total weight wing surfaces & bracing : 260 [kg] (17.5 [%])
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weight machine-gun(s) : 9.5 [kg]
weight Schneider ring mounting mg :5.5 [kg]
weight armament : 15 [kg]
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wheel pressure : 742.5 [kg]
weight 2 wheels (800 [mm] by 101 [mm]) : 30.3 [kg]
weight tailskid : 3.1 [kg]
weight undercarriage with axle 32.2 [kg]
total weight landing gear : 65.7 [kg] (4.4 [%]
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calculated empty weight : 1012 [kg](68.1 [%])
weight oil for 4.5 hours flying : 16.9 [kg]
weight cooling fluids : 38.9 [kg]
weight 1 drums empty : 2.3 [kg]
weight ammunition (500 rounds) : 16.4 [kg]
weight signal pistol with cartridges : 3.6 [kg]
weight automatic pistol with spare magazines : 1.2 [kg]
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calculated operational weight empty : 1089 [kg] (73.3 [%])
published operational weight empty : 1050 [kg] (70.7 [%])
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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 : 85 [kg]
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operational weight : 1348 [kg](90.8 [%])
estimated bomb load : 50 [kg]
operational weight bombing mission : 1398 [kg]
weight camera : 20 [kg]
operational weight photo mission : 1368 [kg]
fuel reserve : 94 [kg] enough for 2.22 [hours] flying
possible additional useful load : 23 [kg]
operational weight fully loaded : 1485 [kg] with fuel tank filled for 100 [%]
published maximum take-off weight : 1485 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (operational without bombload) : 7.48 [kg/kW]
total power : 180.2 [kW] at 1200 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 2.4 [g] at 1000 [m]
limit load : 3.75 [g] ultimate load : 5.6 [g] load factor : 1.8 [g]
design flight time : 2.97 [hours]
design cycles : 236 sorties, design hours : 700 [hours]
operational wing loading : 385 [N/m^2]
wing stress (3 g) during operation : 215 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.13 ["]
max. angle of attack (stalling angle) : 11.73 ["]
angle of attack at max. speed : 1.87 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° :0.10 [ ]
lift coefficient at max. angle of attack : 1.14 [ ]
lift coefficient at max. speed : 0.26 [ ]
induced drag coefficient at max. speed : 0.0043 [ ]
drag coefficient at max. speed : 0.0471 [ ]
drag coefficient (zero lift) : 0.0428 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 84 [km/u]
landing speed at sea-level (OW without bombload): 101 [km/hr]
min. drag speed (max endurance) : 118 [km/hr] at 3650 [m](power :42 [%])
min. power speed (max range) : 133 [km/hr] at 3650 [m] (power:47 [%])
max. rate of climb speed : 106.1 [km/hr] at sea-level
cruising speed : 158 [km/hr] op 3650 [m] (power:61 [%])
design speed prop : 166 [km/hr]
maximum speed : 175 [km/hr] op 100 [m] (power:100 [%])
climbing speed at sea-level (without bombload) : 268 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 200 [m]
lift/drag ratio : 9.74 [ ]
max. practical ceiling : 7950 [m] with flying weight :1170 [kg]
practical ceiling (operational weight): 6975 [m] with flying weight :1348 [kg]
practical ceiling fully loaded (mtow- 1 hour fuel) : 6500 [m] with flying weight :1443 [kg]
published ceiling (7300 [m]
climb to 1500m (without bombload) : 5.56 [min]
climb to 3000m (without bombload) : 11.42 [min]
max. dive speed : 468.4 [km/hr] at 5500 [m] height
load factor at max. angle turn 2.13 ["g"]
turn radius at 500m: 67 [m]
time needed for 360* turn 12.0 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 4.22 [hours] with 2 crew and 55 [kg] useful (bomb)load and 100.0 [%] fuel
published endurance : 3.71 [hours] with 2 crew and possible useful (bomb) load : 76 [kg] and 88.1 [%] fuel
action radius : 397 [km] with 2 crew and 20[kg] photo camera/radio transmitter or bombload
max range theoretically with additional fuel tanks for total 472 [litre] fuel : 1282 [km]
useful load with action-radius 250km : 211 [kg]
production : 33.25 [tonkm/hour]
oil and fuel consumption per tonkm : 1.39 [kg]
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Literature : Wikipedia
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 17 November 2019 contact : info.aircraftinvestigation@gmail.com python 3.7.4