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weight and performance calculations for the LVG B.II
LVG B.II
role : two-seat unarmed reconnaissance
importance : ***
first flight : operational : February 1915
country : Germany
design :
production : 60 aircraft
general information :
Version with more powerful engine, did not perform well at the front and was withdrawn quite quickly and deployed for training purposes. Didn't differ much from the B.I. in appearance. Did have a smaller wingspan.
Many were used as trainer, as such it was equipped with dual controls.
users : Germany
crew : 2
armament : no fixed armament
engine : 1 Mercedes D.II liquid-cooled 6 -cylinder inline engine 120 [hp](89.5 KW)
dimensions :
wingspan : 12.12 [m], length : 8.3 [m], height : 3.2[m]
wing area : 35.4 [m^2]
weights :
max.take-off weight : 1074 [kg]
empty weight operational : 716 [kg] bombload : 40 [kg]
performance :
maximum speed : 110 [km/hr] at sea-level
climbing speed : 126 [m/min]
service ceiling : 3500 [m]
endurance : 4.0 [hours]
estimated action radius : 198 [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 2.60 [m]
angle of attack prop : 13.46 [ ]
fine pitch
reduction : 1.00 [ ]
airscrew revs : 1250 [r.p.m.]
pitch at Max speed 1.47 [m]
blade-tip speed at Vmax and max revs. : 173 [m/s]
calculation : *1* (dimensions)
mean wing chord : 1.46 [m]
calculated wing chord (rounded tips): 1.61 [m]
wing aspect ratio : 8.30 []
estimated gap : 1.62 [m]
gap/chord : 1.11 [ ]
seize (span*length*height) : 322 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 2.1 [kg/hr]
fuel consumption(cruise speed) : 24.4 [kg/hr] (33.3 [litre/hr]) at 71 [%] power
distance flown for 1 kg fuel : 4.05 [km/kg]
estimated total fuel capacity : 151 [litre] (111 [kg])
By the Dutch interned B.II, it received a big orange roundel on the side of the fuselage and on the wings.
calculation : *3* (weight)
weight engine(s) dry : 204.0 [kg] = 2.28 [kg/KW]
weight 13 litre oil tank : 1.7 [kg]
oil tank filled with 0.7 litre oil : 0.6 [kg]
oil in engine 5 litre oil : 4.5 [kg]
fuel in engine 1 litre fuel : 0.4 [kg]
weight 14 litre gravity patrol tank(s) : 1.4 [kg]
weight radiator : 12.8 [kg]
weight exhaust pipes & fuel lines 11.5 [kg]
weight cowling 3.6 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 19.0 [kg]
total weight propulsion system : 258 [kg](24.0 [%])
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fuselage skeleton (wood gauge : 7.33 [cm]): 114 [kg]
bracing : 6.7 [kg]
fuselage covering ( 13.0 [m2] doped linen fabric) : 4.2 [kg]
weight controls + indicators: 6.3 [kg]
weight seats : 6.0 [kg]
weight other details, lighting set, etc. : 5.1 [kg]
weight bomb storage : 2.8 [kg]
weight 137 [litre] main fuel tank empty : 13.2 [kg]
weight engine mounts & firewalls : 4 [kg]
total weight fuselage : 163 [kg](15.2 [%])
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weight wing covering (doped linen fabric) : 23 [kg]
total weight ribs (60 ribs) : 64 [kg]
load on front upper spar (clmax) per running metre : 850.4 [N]
load on rear upper spar (vmax) per running metre : 248.4 [N]
total weight 8 spars : 72 [kg]
weight wings : 158 [kg]
weight wing/square meter : 4.47 [kg]
weight 8 interplane struts & cabane : 21.4 [kg]
weight cables (71 [m]) : 8.0 [kg] (= 113 [gram] per metre)
diameter cable : 4.3 [mm]
weight fin & rudder (1.7 [m2]) : 7.9 [kg]
weight stabilizer & elevator (4.0 [m2]): 18.0 [kg]
total weight wing surfaces & bracing : 213 [kg] (19.9 [%])
*******************************************************************
weight armament : 0 [kg]
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wheel pressure : 537.0 [kg]
weight 2 wheels (700 [mm] by 84 [mm]) : 23.0 [kg]
weight tailskid : 3.2 [kg]
weight undercarriage with axle 29.6 [kg]
total weight landing gear : 55.7 [kg] (5.2 [%]
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calculated empty weight : 690 [kg](64.2 [%])
weight oil for 4.8 hours flying : 9.9 [kg]
weight cooling fluids : 18.4 [kg]
weight automatic pistol with spare magazines : 1.2 [kg]
*******************************************************************
calculated operational weight empty : 719 [kg] (67.0 [%])
published operational weight empty : 716 [kg] (66.7 [%])
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weight crew : 162 [kg]
weight fuel for 2.0 hours flying : 49 [kg]
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operational weight : 930 [kg](86.6 [%])
bomb load : 40 [kg]
operational weight bombing mission : 970 [kg]
weight camera : 20 [kg]
operational weight photo mission : 950 [kg]
fuel reserve : 62 [kg] enough for 2.54 [hours] flying
possible additional useful load : 62 [kg]
operational weight fully loaded : 1074 [kg] with fuel tank filled for 100 [%]
published maximum take-off weight : 1074 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (operational without bombload) : 10.39 [kg/kW]
total power : 89.5 [kW] at 1250 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 1.4 [g] at 1000 [m]
limit load : 3.75 [g] ultimate load : 5.6 [g] load factor : 2.6 [g]
design flight time : 3.20 [hours]
design cycles : 445 sorties, design hours : 1425 [hours]
operational wing loading : 263 [N/m^2]
wing stress (3 g) during operation : 177 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.16 ["]
max. angle of attack (stalling angle) : 12.11 ["]
angle of attack at max. speed : 4.11 ["]
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 : 0.45 [ ]
induced drag coefficient at max. speed : 0.0141 [ ]
drag coefficient at max. speed : 0.0904 [ ]
drag coefficient (zero lift) : 0.0763 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 69 [km/u]
landing speed at sea-level (OW without bombload): 83 [km/hr]
min. drag speed (max endurance) : 83 [km/hr] at 1750 [m](power :56 [%])
A German pilot was lost and landed LVG B.II s/n 1069/15 on Dutch territory near Herpt near Heusden on 19 March 1916. The LVG B.II was later "purchased" for 20,000 ReichsMark and then used by the LVA from Soesterberg. On 27 april 1917 a 'wireless' set was tested with succes in the air aboard the LVG B.II LA-29. The wireless set was a copy of the set that was taken from a interned Albatros B.III in December 1915.
min. power speed (max range) : 83 [km/hr] at 1750 [m] (power:56 [%])
max. rate of climb speed : 70.8 [km/hr] at sea-level
cruising speed : 99 [km/hr] op 1750 [m] (power:72 [%])
design speed prop : 104 [km/hr]
maximum speed : 110 [km/hr] op 100 [m] (power:99 [%])
climbing speed at sea-level (without bombload) : 161 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 189 [m]
lift/drag ratio : 6.93 [ ]
max. practical ceiling : 4000 [m] with flying weight :811 [kg]
practical ceiling (operational weight) : 3100 [m] with flying weight :930 [kg] line 3385
practical ceiling fully loaded (mtow- 1 hour fuel) : 2275 [m] with flying weight :1050 [kg]
published ceiling (3500 [m]
The Dutch interned this LVG B.II. It was fitted with a machine gun for the observer mounted on a rail to the side of the cockpit. It was registered as LA-29 by the Dutch.
climb to 1500m (operational weight without bombload) : 10.90 [min]
max. dive speed : 254.3 [km/hr] at 1275 [m] height
load factor at max. angle turn 1.55 ["g"]
turn radius at 500m: 53 [m]
time needed for 360* turn 13.4 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 4.54 [hours] with 2 crew and 82 [kg] useful (bomb)load and 100.0 [%] fuel
published endurance : 4.00 [hours] with 2 crew and possible useful (bomb) load : 95 [kg] and 88.1 [%] fuel
action radius : 350 [km] with 2 crew and 20[kg] photo camera or bombload
max range theoretically with additional fuel tanks for total 375 [litre] fuel : 1114 [km]
useful load with action-radius 250km : 152 [kg]
production : 15.01 [tonkm/hour]
oil and fuel consumption per tonkm : 1.77 [kg]
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Literature :
KLu vliegtuigen – W.Schoenmaken en Th. Postma
Van Brik tot Starfighter page 24,26,37
German aircraft of the first world war page 169
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/
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(c) B van der Zalm 28 June 2020 contact : info.aircraftinvestigation@gmail.com python 3.7.4