AIRCRAFT INVESTIGATION
weight and performance calculations for the AEG J.I
AEG J.I
role : armoured ground attack aircraft
importance : ****
first flight : operational : June 1917
country : Germany
design :
production : 600 aircraft
general information :
designed for ground attack and close support. It was fitted with 2 downward firing Spandau MG’s under 45° angle. For protection of engine, crew & fuel tank it had for 390 kgs of armour plating. 5.1 mm thick, total area : 9.83 m2 (105.8 sq.ft. jf1135)
chord : 1.62m prop : 3.12m petrol capacity : 38 gallons = 173 litre
oil capacity : 3 gallons = 13.6 litre
users : Germany
crew : 2
armament : 2 fixed, downwards-firing 7.92 [mm] (0.312 in) Spandau LMG 08/15
machine-guns and 1 movable 7.92 [mm] (0.312 in) Parabellum MG 14 machine-gun for
the observer
engine : 1 Benz Bz.IV liquid-cooled 6 -cylinder inline engine 220 [hp](161.8 KW)
dimensions :
wingspan : 13.46 [m], length : 7.2 [m], height : 3.35[m]
wing area : 33.3 [m^2]
weights :
max.take-off weight : 1740 [kg]
empty weight operational : 1455 [kg] bombload : 0 [kg]
performance :
maximum speed : 150 [km/hr] at sea-level
climbing speed : 166 [m/min]
service ceiling : 3000 [m]
endurance : 2.37 [hours]
estimated action radius : 160 [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 [ ]
diameter airscrew 3.12 [m]
angle of attack prop : 13.65 [ ]
fine pitch
reduction : 1.00 [ ]
airscrew revs : 1400 [r.p.m.]
pitch at Max speed 1.79 [m]
blade-tip speed at Vmax and max revs. : 232 [m/s]
calculation : *1* (dimensions)
mean wing chord : 1.24 [m]
calculated wing chord (rounded tips): 1.34 [m]
wing aspect ratio : 10.88 []
gap : 1.98 [m]
gap/chord : 1.60 [ ]
seize (span*length*height) : 325 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 2.1 [kg/hr]
fuel consumption(cruise speed) : 47.2 [kg/hr] (64.3 [litre/hr]) at 87 [%] power
distance flown for 1 kg fuel : 2.86 [km/kg]
estimated total fuel capacity : 173 [litre] (127 [kg])
calculation : *3* (weight)
weight engine(s) dry : 370.0 [kg] = 2.29 [kg/KW]
weight 11 litre oil tank : 0.9 [kg]
oil tank filled with 1.2 litre oil : 1.1 [kg]
oil in engine 9 litre oil : 8.1 [kg]
fuel in engine 1 litre fuel : 0.8 [kg]
weight 27 litre gravity patrol tank(s) : 4.1 [kg]
weight radiator : 24.3 [kg]
weight exhaust pipes & fuel lines 14.2 [kg]
weight self-starter : 4.0 [kg]
weight cowling 6.5 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 24.3 [kg]
total weight propulsion system : 457 [kg](26.3 [%])
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weight 5.1 [mm] armour plating engine, crew and fuel tank (9.8 [m^2]) : 390 [kg]
percentage fuselage armoured : 80.0 [%]
Armour plating forms integral part of the fuselage, extra strong wooden frame
fuselage skeleton (wood gauge : 8.31 [cm]): 25 [kg]
bracing : 4.3 [kg]
fuselage covering ( 9.8 [m2] doped linen fabric) : 3.1 [kg]
weight controls + indicators: 6.2 [kg]
weight seats : 6.0 [kg]
weight other details, lighting set, etc. : 5.1 [kg]
weight 146 [litre] main fuel tank empty : 11.7 [kg]
weight engine mounts & firewalls : 3 [kg]
total weight fuselage : 455 [kg](26.1 [%])
***************************************************************
weight wing covering (doped linen fabric) : 21 [kg]
total weight ribs (115 ribs) : 103 [kg]
load on front upper spar (clmax) per running metre : 696.9 [N]
load on rear upper spar (vmax) per running metre : 384.6 [N]
total weight 8 spars : 72 [kg]
weight wings : 197 [kg]
weight wing/square meter : 5.92 [kg]
weight 8 interplane struts & cabane : 37.3 [kg]
weight cables (80 [m]) : 9.1 [kg] (= 114 [gram] per metre)
diameter cable : 4.3 [mm]
weight fin & rudder (2.1 [m2]) : 12.8 [kg]
weight stabilizer & elevator (3.7 [m2]): 22.4 [kg]
total weight wing surfaces & bracing : 279 [kg] (16.0 [%])
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weight machine-gun(s) : 43.5 [kg]
weight Schneider ring mounting mg :5.5 [kg]
weight ammunition magazine(s) :7.0 [kg]
weight armament : 56 [kg]
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wheel pressure : 870.0 [kg]
weight 2 wheels (770 [mm] by 97 [mm]) : 29.3 [kg]
weight tailskid : 2.7 [kg]
weight undercarriage with axle 46.4 [kg]
total weight landing gear : 78.4 [kg] (4.5 [%]
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American soldiers posing with a downed AEG J.I , at Cunel, Lorraine November 1918. The two downward firing Spandau mg’s are visible. Also note remark armour ½ cm thick.
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calculated empty weight : 1325 [kg](76.2 [%])
weight oil for 2.8 hours flying : 6.0 [kg]
weight cooling fluids : 35.0 [kg]
weight 1 drums empty : 4.5 [kg]
weight ammunition (3000 rounds) : 89.2 [kg]
weight signal pistol with cartridges : 3.6 [kg]
weight automatic pistol with spare magazines : 1.2 [kg]
*******************************************************************
calculated operational weight empty : 1460 [kg] (83.9 [%])
published operational weight empty : 1455 [kg] (83.6 [%])
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weight crew : 162 [kg]
weight fuel for 2.0 hours flying : 94 [kg]
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operational weight : 1716 [kg](98.6 [%])
bombload could not be carried with fuel for 2 hours flying time
fuel reserve : 24 [kg] enough for 0.50 [hours] flying
operational weight fully loaded : 1740 [kg] with fuel tank filled for 93 [%]
published maximum take-off weight : 1740 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (operational without bombload) : 10.61 [kg/kW]
total power : 161.8 [kW] at 1400 [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 : 1.4 [g]
design flight time : 1.90 [hours]
design cycles : 253 sorties, design hours : 480 [hours]
operational wing loading : 505 [N/m^2]
wing stress (3 g) during operation : 256 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.09 ["]
max. angle of attack (stalling angle) : 11.01 ["]
angle of attack at max. speed : 4.16 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° :0.10 [ ]
lift coefficient at max. angle of attack : 1.11 [ ]
lift coefficient at max. speed : 0.48 [ ]
induced drag coefficient at max. speed : 0.0120 [ ]
drag coefficient at max. speed : 0.0693 [ ]
drag coefficient (zero lift) : 0.0573 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 98 [km/u]
landing speed at sea-level (OW without bombload): 118 [km/hr]
min. drag speed (max endurance) = minimum speed*1.1 at cruise height : 110 [km/hr] at 300 [m] (power:58 [%])
min. power speed (max range) : 110 [km/hr] at 300 [m] (power:58 [%])
cruising speed : 135 [km/hr] op 300 [m] (power:78 [%])
design speed prop : 142 [km/hr]
maximum speed : 150 [km/hr] op 100 [m] (power:99 [%])
climbing speed at sea-level (without bombload) : 152 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 265 [m]
lift/drag ratio : 9.16 [ ]
max. practical ceiling : 3850 [m] with flying weight :1471 [kg]
practical ceiling (operational weight): 2825 [m] with flying weight :1716 [kg]
practical ceiling fully loaded (mtow- 1 hour fuel) : 2900 [m] with flying weight :1693 [kg]
published ceiling (3000 [m]
climb to 1500m (without bombload) : 11.73 [min]
max. dive speed : 379.6 [km/hr] at 1900 [m] height
load factor at max. angle turn 1.50 ["g"]
turn radius at 500m: 107 [m]
time needed for 360* turn 19.6 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 2.08 [hours] with 2 crew and 20 [kg] useful load and 77.3 [%] fuel
published endurance : 2.37 [hours] with 2 crew and possible useful (bomb) load : 6 [kg] and 88.1 [%] fuel
action radius : 140 [km] with 2 crew and 20[kg] photo camera/radio transmitter or bombload
max range theoretically with additional fuel tanks for total 400 [litre] fuel : 839 [km]
useful load with action-radius 250km : 118 [kg]
production : 15.98 [tonkm/hour]
oil and fuel consumption per tonkm : 3.08 [kg]
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I_°°=/
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Literature :
Warplanes WOI page 95
Bombers 1914-19 page 118
Jane’s Fighting aircraft WWI page 132
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 23 November 2019 contact : info.aircraftinvestigation@gmail.com python 3.7.4