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weight and performance calculations for the Fokker D.VIII
Fokker D.VIII
role : fighter
importance : ***
first flight : operational : August 1918
country : Germany
design : Reinhold Platz
production : 381 aircraft
general information :
The parasol-winged D.VIII fighter plane became operational Augustus 1918. It was fast and very agile but some deadly accidents grounded the plane. It was found out the aircraft suffered from wing failure due to bad workmanship. October 1918 it was again active at the front. It was given the nickname “Flying Razor”.
users : Luftwaffe
crew : 1
armament : 2 synchronized 7.92 [mm] (0.312 in) Spandau LMG 08/15 machine-guns
engine : 1 Oberursel UR.II air-cooled 9 -cylinder two-valve rotary engine 110 [hp](80.9 KW)
dimensions :
wingspan : 8.4 [m], length : 5.86 [m], height : 2.82[m]
wing area : 11.7 [m^2]
weights :
max.take-off weight : 562 [kg]
empty weight operational : 405 [kg] bombload : 0 [kg]
performance :
maximum speed : 205 [km/hr] at sea-level
climbing speed : 498 [m/min]
service ceiling : 6300 [m]
endurance : 1.5 [hours]
estimated action radius : 138 [km]
description :
parasol wing with fixed landing gear and tail strut
two spar wing
engines, landing gear, fuel and bombs in or attached to the fuselage
airscrew :
fixed pitch 2 -bladed tractor airscrew with max. efficiency :0.67 [ ]
estimated diameter airscrew 2.62 [m]
angle of attack prop : 26.71 [ ]
coarse pitch
reduction : 1.00 [ ]
airscrew revs : 1100 [r.p.m.]
pitch at Max speed 3.11 [m]
blade-tip speed at Vmax and max revs. : 161 [m/s]
calculation : *1* (dimensions)
mean wing chord : 1.39 [m]
calculated wing chord (rounded tips): 1.79 [m]
wing aspect ratio : 6.03 []
gap : 0.00 [m]
gap/chord : 0.00 [ ]
seize (span*length*height) : 139 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 6.1 [kg/hr]
fuel consumption(cruise speed) : 23.0 [kg/hr] (31.4 [litre/hr]) at 68 [%] power
distance flown for 1 kg fuel : 8.02 [km/kg]
estimated total fuel capacity : 53 [litre] (39 [kg])
calculation : *3* (weight)
weight engine(s) dry : 149.7 [kg] = 1.85 [kg/KW]
weight 14 litre oil tank : 1.8 [kg]
oil tank filled with 0.6 litre oil : 0.5 [kg]
oil in engine 0 litre oil : 0.4 [kg]
fuel in engine 1 litre fuel : 0.4 [kg]
weight 13 litre gravity patrol tank(s) : 1.3 [kg]
weight cowling 3.2 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 19.0 [kg]
total weight propulsion system : 175 [kg](31.1 [%])
***************************************************************
fuselage skeleton (wood gauge : 4.44 [cm]): 30 [kg]
bracing : 1.2 [kg]
fuselage covering ( 6.5 [m2] doped linen fabric) : 2.1 [kg]
weight controls + indicators: 5.2 [kg]
weight seats : 3.0 [kg]
weight other details, lighting set, etc. : 5.1 [kg]
weight 40 [litre] main fuel tank empty : 3.8 [kg]
weight engine mounts & firewalls : 4 [kg]
total weight fuselage : 54 [kg](9.6 [%])
***************************************************************
weight wing covering (doped linen fabric) : 7 [kg]
total weight ribs (33 ribs) : 33 [kg]
load on front upper spar (clmax) per running metre : 471.0 [N]
load on rear upper spar (vmax) per running metre : 195.5 [N]
total weight 4 spars : 19 [kg]
weight wings : 60 [kg]
weight wing/square meter : 5.12 [kg]
weight cables (34 [m]) : 5.3 [kg] (= 159 [gram] per metre)
diameter cable : 5.1 [mm]
weight fin & rudder (0.8 [m2]) : 4.3 [kg]
weight stabilizer & elevator (1.3 [m2]): 6.8 [kg]
total weight wing surfaces & bracing : 76 [kg] (13.6 [%])
*******************************************************************
weight machine-gun(s) : 34.0 [kg]
weight ammunition magazine(s) :3.5 [kg]
weight Fokker Zentralsteuerung synchronization gear : 2.0 [kg]
weight armament : 40 [kg]
********************************************************************
wheel pressure : 281.0 [kg]
weight 2 wheels (700 [mm] by 84 [mm]) : 13.5 [kg]
weight tailskid : 1.2 [kg]
weight undercarriage with axle 13.6 [kg]
total weight landing gear : 28.3 [kg] (5.0 [%]
*******************************************************************
********************************************************************
calculated empty weight : 373 [kg](66.4 [%])
weight oil for 1.8 hours flying : 10.9 [kg]
weight ammunition (1000 rounds) : 28.2 [kg]
weight signal pistol with cartridges : 3.6 [kg]
weight automatic pistol with spare magazines : 1.2 [kg]
*******************************************************************
calculated operational weight empty : 417 [kg] (74.2 [%])
published operational weight empty : 405 [kg] (72.1 [%])
***o***
"
weight crew : 81 [kg]
weight fuel for 1.5 hours flying : 34 [kg]
********************************************************************
operational weight : 532 [kg](94.7 [%])
estimated bomb load : 25 [kg]
operational weight bombing mission : 557 [kg]
fuel reserve : 5 [kg] enough for 0.20 [hours] flying
possible additional useful load : 0 [kg]
operational weight fully loaded : 562 [kg] with fuel tank filled for 100 [%]
published maximum take-off weight : 562 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (operational without bombload) : 6.58 [kg/kW]
total power : 80.9 [kW] at 1100 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 3.1 [g] at 1000 [m]
limit load : 4.5 [g] ultimate load : 6.8 [g] load factor : 1.8 [g]
design flight time : 1.20 [hours]
design cycles : 250 sorties, design hours : 300 [hours]
operational wing loading : 446 [N/m^2]
wing stress (3 g) during operation : 261 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -2.15 ["]
max. angle of attack (stalling angle) : 12.64 ["]
angle of attack at max. speed : 0.72 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° :0.17 [ ]
lift coefficient at max. angle of attack : 1.17 [ ]
lift coefficient at max. speed : 0.23 [ ]
induced drag coefficient at max. speed : 0.0031 [ ]
drag coefficient at max. speed : 0.0414 [ ]
drag coefficient (zero lift) : 0.0383 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 90 [km/u]
landing speed at sea-level (OW without bombload): 108 [km/hr]
min. drag speed (max endurance) : 128 [km/hr] at 3150 [m](power :38 [%])
Twin guns synchronized by the Zentralsteuerung system in a Fokker D.VIII fighter. The "pipes" connecting the guns and the engine are flexible drive shafts.
min. power speed (max range) : 142 [km/hr] at 3150 [m] (power:41 [%])
max. rate of climb speed : 122.6 [km/hr] at sea-level
cruising speed : 184 [km/hr] op 3150 [m] (power:61 [%])
design speed prop : 199 [km/hr]
maximum speed : 205 [km/hr] op 100 [m] (power:100 [%])
climbing speed at sea-level (without bombload) : 330 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 273 [m]
lift/drag ratio : 10.33 [ ]
max. practical ceiling : 6975 [m] with flying weight :476 [kg] line 3370
practical ceiling (operational weight) : 6325 [m] with flying weight :532 [kg] line 3385
practical ceiling fully loaded (mtow- 1 hour fuel) : 6250 [m] with flying weight :539 [kg]
published ceiling (6300 [m]
climb to 1500m (without bombload) : 4.52 [min]
climb to 3000m (without bombload) : 10.10 [min]
max. dive speed : 476.1 [km/hr] at 5250 [m] height
load factor at max. angle turn 2.34 ["g"]
turn radius at 500m: 74 [m]
time needed for 360* turn 11.8 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 1.70 [hours] with 1 crew and 25 [kg] useful (bomb)load and 100.0 [%] fuel
published endurance : 1.50 [hours] with 1 crew and possible useful (bomb) load : 30 [kg] and 88.1 [%] fuel
action radius : 177 [km] with 1 crew and 20[kg] photo camera/radio transmitter or bombload
max range theoretically with additional fuel tanks for total 133 [litre] fuel : 780 [km]
useful load with action-radius 250km : 35 [kg]
production : 6.43 [tonkm/hour]
oil and fuel consumption per tonkm : 4.52 [kg]
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Fokker E.V flown by Theo Osterkamp
Literature :
Praktisch handboek vliegtuigen deel 1 page 290
Fighters 1914-19 page 80
Warplanes WW1 page 159td
Jane’s fighting aircraft WWI page 152
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 January 2020 contact : info.aircraftinvestigation@gmail.com python 3.7.4