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Albatros D.III
role : fighter
first flight : operational : January 1917
country : Germany
design : Robert Thelen
production : 800 aircraft
general information :
Superb fighter mainly responsible for “Bloody April”
It was the best fighter plane Albatros built in WWI. Adopted V-struts and monospar lower wing like on the excellent Nieuport 11 and 17. Giving even better performance and better visibility down below for the pilot.
Soon a serious problem occurred. The lower wing spar and ribs failed during flight, a defect shared with the Nieuport 17. On 27 Januar 1917 all D.III were grounded for this reason. Albatros reinforced the lower wing and after 19 februar 1917 the D.III’s took to the sky again.
The lower wing twisted under aerodynamic loads, due to its single-spar layout and this could not be solved and pilots were advised not to perform long steep dives.
There also was a problem with the Teves und Braun airfoil-shaped radiator in the center of the upper wing, where it tended to scald the pilot if punctured. From the 290th D.III onward, the radiator was offset to the right on production machines to prevent this.
Apart from its structural deficiencies, the D.III was considered pleasant and easy to fly, if somewhat heavy on the controls. The sesquiplane arrangement offered improved climb, maneuverability, and downward visibility compared to the preceding D.II. Like most contemporary aircraft, the D.III was prone to spinning, but recovery was straightforward.
With the D.III famous aces like Manfred von Richthofen, Werner Voss, Ernst Udet, Eduard von Schleich and Bruno Lorzer scored many victories.
November 1917 a maximum of 446 D.III’s were flying at the front.
span upper wing : 9.03m
lower wing : 8.75m
tail : 2.40m
Chord upperwing : 1.5m in the center to 1.75m at the tips
stagger : 0.22m gap : 1.5m
"Axial" airscrew diam. 2.73m pitch : 2.20m
users : Luftwaffe, Austria-Hungaria
crew : 1
armament : 2 synchronized 7.92 [mm] (0.312 in) Spandau LMG 08/15 machine-guns
engine : 1 Mercedes D.IIIa liquid-cooled 6 -cylinder inline engine 175 [hp](128.7 KW)
dimensions :
wingspan : 9.03 [m], length : 7.33 [m], height : 2.9[m]
wing area : 20.5 [m^2]
weights :
max.take-off weight : 886 [kg]
empty weight operational : 670 [kg] bombload : 0 [kg]
performance :
maximum speed : 175 [km/u] op 1000 [m]
climbing speed : 303 [m/min]
service ceiling : 5500 [m]
endurance : 2.0 [hours]
estimated action radius : 158 [km]
description :
1-bay biplane with fixed landing gear and tail strut
upper wing 2 spars, lower wing single spar
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 2.73 [m]
angle of attack prop : 17.95 [ ]
reduction : 1.00 [ ]
airscrew revs : 1400 [r.p.m.]
pitch at Max speed 2.08 [m]
blade-tip speed at Vmax and max revs. : 206 [m/s]
calculation : *1* (dimensions)
mean wing chord : 1.14 [m]
calculated wing chord (rounded tips): 1.27 [m]
wing aspect ratio : 7.96 []
gap : 1.50 [m]
gap/chord : 1.32 [ ]
seize (span*length*height) : 192 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 3.6 [kg/hr]
fuel consumption(cruise speed) : 29.2 [kg/hr] (39.9 [litre/hr]) at 65 [%] power
distance flown for 1 kg fuel : 5.39 [km/kg]
estimated total fuel capacity : 91 [litre] (66 [kg])
calculation : *3* (weight)
weight engine(s) dry : 297.0 [kg] = 2.31 [kg/KW]
weight 13 litre oil tank : 1.1 [kg]
oil tank filled with 1.0 litre oil : 0.9 [kg]
oil in engine 7 litre oil : 6.4 [kg]
fuel in engine 1 litre fuel : 0.6 [kg]
weight 17 litre gravity patrol tank(s) : 2.5 [kg]
weight radiator : 18.4 [kg]
weight exhaust pipes & fuel lines 11.6 [kg]
weight cowling 5.1 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 19.0 [kg]
total weight propulsion system : 362 [kg](40.8 [%])
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fuselage skeleton (wood gauge : 5.38 [cm]): 54 [kg]
bracing : 2.8 [kg]
fuselage covering ( 10.1 [m2] doped linen fabric) : 3.2 [kg]
weight controls + indicators: 5.7 [kg]
weight seats : 3.0 [kg]
weight other details, lighting set, etc. : 5.1 [kg]
weight 74 [litre] main fuel tank empty : 5.9 [kg]
weight engine mounts & firewalls : 6 [kg]
total weight fuselage : 87 [kg](9.8 [%])
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weight wing covering (doped linen fabric) : 13 [kg]
total weight ribs (64 ribs) : 53 [kg]
load on front upper spar (clmax) per running metre : 660.5 [N]
load on rear upper spar (vmax) per running metre : 294.6 [N]
total weight 6.0 spars : 31 [kg]
weight wings : 97 [kg]
weight wing/square meter : 4.71 [kg]
weight 4 interplane struts & cabane : 11.7 [kg]
weight cables (45 [m]) : 2.9 [kg] (= 65 [gram] per metre)
diameter cable : 3.3 [mm]
weight fin & rudder (0.9 [m2]) : 4.6 [kg]
weight stabilizer & elevator (2.3 [m2]): 11.0 [kg]
total weight wing surfaces & bracing : 127 [kg] (14.3 [%])
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weight machine-gun(s) : 34.0 [kg]
weight ammunition magazine(s) :3.5 [kg]
weight synchronizing system : 2.0 [kg]
weight armament : 40 [kg]
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wheel pressure : 443.0 [kg]
weight 2 wheels (680 [mm] by 81 [mm]) : 17.9 [kg]
weight tailskid : 1.7 [kg]
weight undercarriage with axle 17.4 [kg]
total weight landing gear : 37.0 [kg] (4.2 [%]
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calculated empty weight : 652 [kg](73.6 [%])
weight oil for 2.4 hours flying : 8.6 [kg]
weight cooling fluids : 27.8 [kg]
weight ammunition (1000 rounds) : 35.0 [kg]
weight signal pistol with cartridges : 3.6 [kg]
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calculated operational weight empty : 727 [kg] (82.0 [%])
published operational weight empty : 670 [kg] (75.6 [%])
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weight crew : 81 [kg]
weight fuel for 1.5 hours flying : 44 [kg]
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operational weight : 852 [kg](96.1 [%])
estimated bomb load : 25 [kg]
operational weight bombing mission : 877 [kg]
fuel reserve : 9 [kg] enough for 0.32 [hours] flying
operational weight fully loaded : 886 [kg] with fuel tank filled for 80 [%]
published maximum take-off weight : 886 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (operational without bombload) : 6.62 [kg/kW]
total power : 128.7 [kW] at 1400 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 2.4 [g] at 1000 [m]
limit load : 4.5 [g] ultimate load : 6.8 [g] load factor : 1.7 [g]
design flight time : 1.60 [hours]
design cycles : 188 sorties, design hours : 300 [hours]
operational wing loading : 407 [N/m^2]
wing stress (3 g) during operation : 259 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.17 ["]
max.angle of attack (stalling angle) : 12.25 ["]
angle of attack at max.speed : 2.46 ["]
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 : 0.31 [ ]
induced drag coefficient at max.speed : 0.0068 [ ]
drag coefficient at max.speed : 0.0557 [ ]
drag coefficient (zero lift) : 0.0488 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 87 [km/u]
landing speed at sea-level (OW without bombload): 104 [km/hr]
min.drag speed (max endurance) : 117 [km/hr] at 2750 [m](power :43 [%])
min. power speed (max range) : 132 [km/hr] at 2750 [m] (power:48 [%])
max.rate of climb speed : 108.8 [km/hr] at sea-level
cruising speed : 158 [km/hr] op 2750 [m] (power:63 [%])
design speed prop : 170 [km/hr]
maximum speed : 175 [km/hr] op 1000 [m] (power:89 [%])
climbing speed at sea-level (without bombload) : 297 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 175 [m]
lift/drag ratio : 8.49 [ ]
max. practical ceiling : 5900 [m] with flying weight :784 [kg]
practical ceiling (operational weight): 5325 [m] with flying weight :852 [kg]
practical ceiling fully loaded (mow- 1 hour fuel) : 5300 [m] with flying weight :857 [kg]
published ceiling (5500 [m]
climb to 1500m (without bombload) : 5.60 [min]
climb to 3000m (without bombload) : 13.56 [min]
max.dive speed : 409.9 [km/hr] at 4300 [m] height
load factor at max.angle turn 2.00 ["g"]
turn radius at 500m: 72 [m]
time needed for 360* turn 12.9 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 1.99 [hours] with 1 crew and 20 [kg] useful load and 87.8 [%] fuel
published endurance : 2.00 [hours] with 1 crew and possible useful (bomb) load : 20 [kg] and 88.1 [%] fuel
action radius : 157 [km] with 1 crew and 20[kg] photo camera/radio transmitter or bombload
max range theoretically with additional fuel tanks for total 159 [litre] fuel : 629 [km]
useful load with action-radius 250km : 24 [kg]
production : 3.78 [tonkm/hour]
oil and fuel consumption per tonkm : 8.68 [kg]
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Literature :
Praktisch handboek vliegtuigen deel 1 page 275
Fighters 1914-19 page 39
German aircraft of the first world war page 48
Wikepedia
Warplanes WOI page 54,56,59,60f,088f,90,94,96
Jane’s fighting aircraft WWI page 127,137,141
Jagdflugzeuge WWI page 45
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 04 January 2019 contact : info.aircraftinvestigation@gmail.com python 3.7.2(32-bit)
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