LFG Roland C.II “Walfisch”
role : multi role combat aircraft
first flight : Oktober 1915 operational : March 1916
country : Germany
design : Dipl. Ing. Tantzen
production : 275 aircraft
general information :
Refined streamlined design. Plywood semi-monocoque fuselage filled the space between upper and lower wing giving the aircraft its distinctive looks and let to its nickname “Wale”. There was only one single I-shaped strut between the wings and the external wiring was reduced as far as possible to avoid drag. It had good performance and the crew had an excellent upward view. Due to its high speed it could only be attacked by fighter planes diving from a greater height but in this case the attacker was exposed to the fire of the observer’s machine gun. It was the smallest C-type aircraft the Luftwaffe used in WWI. The crew had good sight down below thanks to openings in the wings but the pilot’s view forward down to the ground during landing was obscured by the upper wing making landing difficult and many C.II’s crashed on landing. The C.II remained in action at the front till the end of 1917. It had good performance but proved as reconnaissance plane less suited, also the streamlined monocoque plywood fuselage took much time to built and was costly. Therefore it could not be taken in large scale production. The number of aircraft operating at the front reached a peak in December 1916 with 64 aircraft. The first Roland C.II’s went into action in March 1916 over the Verdun battlefield. It proved just as fast as the Nieuport fighters it encountered and later the Sopwith Pup at the Somme battle. The Nieuport 17, entering service May 1916, was a little faster with 177 km/u but at height this advantage was countered by the better height performance of the Mercedes in-line engine compared to the French rotary engine. The C.II was not so manoeuvrable and it took 30 minutes to reach the operational height of 3000m. It was found out that the wings were to weak and deformed during flight with a negative influence on climbing speed and service ceiling. This was cured in the C.IIa with re-inforced wingtips, entering service August 1916.
On 24 march 1916 a C.II was captured intact by the allies and could be studied in detail.
Albert Ball’s first kill, on 02 July 1916, flying a Nieuport 16 was a Roland C.II and he regarded it as the best German aircraft at that moment. Ball’s tactic was to approach the C.II from below unseen and then point his Lewis machine gun on its Foster-mounting upward to fire in the unprotected belly of the “Wale”.
For its good performance the C.II was often used as escort airplane.
First it was only armed with a Parabellum machine gun for the observer but soon also a synchroniched Spandag machine gun was installed.
Diameter prop : 2.70m pitch : 1.85m chord : 1.60m Gap : 1.55m
Climb to 1000m : 8 min, to 2000m : 22 mins
users : Germany
crew : 2
armament : 1 synchronized 7.92 [mm] (0.312 in) Spandau LMG 08/15 machine-gun
and 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 : 10.33 [m], length : 7.52 [m], height : 2.9[m]
wing area : 26.0 [m^2]
weights :
max.take-off weight : 1281 [kg]
empty weight operational (estimation): 825.0 [kg] bombload : 50 [kg]
performance :
maximum speed : 165 [km/hr] at sea-level
climbing speed : 167 [m/min]
service ceiling : 4000 [m]
endurance : 4.0 [hours]
estimated action radius : 297 [km]
description :
1-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 [ ]
diameter airscrew 2.70 [m]
angle of attack prop : 17.16 [ ]
reduction : 1.00 [ ]
airscrew revs : 1400 [r.p.m.]
pitch at Max speed 1.96 [m]
blade-tip speed at Vmax and max revs. : 203 [m/s]
calculation : *1* (dimensions)
mean wing chord : 1.26 [m]
calculated wing chord (rounded tips): 1.40 [m]
wing aspect ratio : 8.21 []
gap : 1.55 [m]
gap/chord : 1.23 [ ]
seize (span*length*height) : 225 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 2.5 [kg/hr]
fuel consumption(cruise speed) : 31.8 [kg/hr] (43.3 [litre/hr]) at 70 [%] power
distance flown for 1 kg fuel : 4.67 [km/kg]
estimated total fuel capacity : 197 [litre] (144 [kg])
calculation : *3* (weight)
weight engine(s) dry : 299.0 [kg] = 2.49 [kg/KW]
weight 16 litre oil tank : 1.4 [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 18 litre gravity patrol tank(s) : 2.8 [kg]
weight radiator : 17.2 [kg]
weight exhaust pipes & fuel lines 11.2 [kg]
weight cowling 4.8 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 19.0 [kg]
total weight propulsion system : 361 [kg](28.2 [%])
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fuselage skeleton (wood gauge : 6.92 [cm]): 92 [kg]
bracing : 4.9 [kg]
fuselage covering ( 10.7 [m2] doped linen fabric) : 3.4 [kg]
weight controls + indicators: 5.9 [kg]
weight seats : 6.0 [kg]
weight other details, lighting set, etc. : 5.1 [kg]
weight bomb storage : 3.5 [kg]
weight 178 [litre] main fuel tank empty : 14.3 [kg]
weight engine mounts & firewalls : 6 [kg]
total weight fuselage : 141 [kg](11.0 [%])
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weight wing covering (doped linen fabric) : 17 [kg]
total weight ribs (83 ribs) : 76 [kg]
load on front upper spar (clmax) per running metre : 942.2 [N]
load on rear upper spar (vmax) per running metre : 367.2 [N]
total weight 8 spars : 58 [kg]
weight wings : 150 [kg]
weight wing/square meter : 5.78 [kg]
weight 4 interplane struts & cabane : 14.3 [kg]
weight cables (50 [m]) : 4.6 [kg] (= 91 [gram] per metre)
diameter cable : 3.8 [mm]
weight fin & rudder (1.2 [m2]) : 7.3 [kg]
weight stabilizer & elevator (2.9 [m2]): 17.1 [kg]
total weight wing surfaces & bracing : 194 [kg] (15.1 [%])
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weight machine-gun(s) : 26.5 [kg]
weight pivot mounting mg :5.0 [kg]
weight ammunition magazine(s) :2.3 [kg]
weight synchronizing system : 1.0 [kg]
weight armament : 35 [kg]
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wheel pressure : 640.5 [kg]
weight 2 wheels (770 [mm] by 97 [mm]) : 33.3 [kg]
weight tailskid : 2.8 [kg]
weight undercarriage with axle 21.4 [kg]
total weight landing gear : 57.5 [kg] (4.5 [%]
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calculated empty weight : 789 [kg](61.6 [%])
weight oil for 4.8 hours flying : 12.1 [kg]
weight cooling fluids : 25.9 [kg]
weight 1 drums empty : 2.3 [kg]
weight ammunition (1000 rounds) : 37.2 [kg]
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calculated operational weight empty : 864 [kg] (67.4 [%])
estimated operational weight empty : 825 [kg] (64.4 [%])
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weight crew : 162 [kg]
weight fuel for 2.0 hours flying : 64 [kg]
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operational weight : 1090 [kg](85.1 [%])
bomb load : 50 [kg]
operational weight bombing mission : 1140 [kg]
fuel reserve : 81 [kg] enough for 2.54 [hours] flying
possible additional useful load : 61 [kg]
operational weight fully loaded : 1281 [kg] with fuel tank filled for 100 [%]
published maximum take-off weight : 1281 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (operational without bombload) : 9.09 [kg/kW]
total power : 119.9 [kW] at 1400 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 2.1 [g] at 1000 [m]
limit load : 3.75 [g] ultimate load : 5.6 [g] load factor : 1.9 [g]
design flight time : 3.20 [hours]
design cycles : 250 sorties, design hours : 800 [hours]
operational wing loading : 411 [N/m^2]
wing stress (3 g) during operation : 213 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.16 ["]
max. angle of attack (stalling angle) : 12.15 ["]
angle of attack at max.speed : 2.58 ["]
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 : 0.32 [ ]
induced drag coefficient at max. speed : 0.0072 [ ]
drag coefficient at max.speed : 0.0492 [ ]
drag coefficient (zero lift) : 0.0420 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 87 [km/u]
landing speed at sea-level (OW without bombload): 105 [km/hr]
min. drag speed (max endurance) : 116 [km/hr] at 2000 [m](power :53 [%])
min. power speed (max range) : 129 [km/hr] at 2000 [m] (power:58 [%])
max. rate of climb speed : 105.4 [km/hr] at sea-level
cruising speed : 148 [km/hr] op 2000 [m] (power:70 [%])
design speed prop : 157 [km/hr]
maximum speed : 165 [km/hr] op 100 [m] (power:99 [%])
climbing speed at sea-level (without bombload) : 191 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 342 [m]
lift/drag ratio : 9.29 [ ]
max. practical ceiling : 4950 [m] with flying weight :924 [kg]
practical ceiling (operational weight): 3800 [m] with flying weight :1090 [kg]
practical ceiling fully loaded (mtow- 1 hour fuel) : 2775 [m] with flying weight :1249 [kg]
published ceiling (4000 [m]
climb to 1500m (without bombload) : 9.00 [min]
max. dive speed : 394.4 [km/hr] at 1775 [m] height
load factor at max. angle turn 1.68 ["g"]
turn radius at 500m: 78 [m]
time needed for 360* turn 15.3 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 4.54 [hours] with 2 crew and 111 [kg] useful (bomb)load and 100.0 [%] fuel
published endurance : 4.00 [hours] with 2 crew and possible useful (bomb) load : 128 [kg] and 88.1 [%] fuel
action radius : 549 [km] with 2 crew and 20[kg] photo camera/radio transmitter or bombload
max range theoretically with additional fuel tanks for total 522 [litre] fuel : 1789 [km]
useful load with action-radius 250km : 276 [kg]
production : 40.95 [tonkm/hour]
oil and fuel consumption per tonkm : 0.84 [kg]
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Literature :
Praktisch handboek vliegtuigen deel 1 page 292
Bombers 1914-19 page 45,123
Warplanes WOI page 48,54,56,59,61
Jane’s fighter aircraft WOI page 168
Jagdflugzeuge WOI page 35
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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(c) B van der Zalm 04 January 2019 contact : info.aircraftinvestigation@gmail.com python 3.7.4