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Fokker Dr.I
role: fighter
first flight: 5 July 1917 operational: august 1917
country: Germany
design: Reinhold Platz
production: 320 aircraft
general information:
The famous tri-plane fighter, flown by Richthofen. He scored his last 19 victories with the Dr.I and was killed 21 April 1918 flying one. It was designed by Platz as answer to the excellent Sopwith Triplane. During operation it suffered wing failure. This could not be cured completely and prevented large scale production.
Ace Werner Voss scored many victories with the Dr.1
Climb to 4500m : 17 min. Chord : +- 1.20m airscres : “Axial” 2.60m diameter
users: Germany
crew : 1
armament : 2 Spandau LMG 08/15 7.92 [mm] (0.312 in) machine-gun
engine : 1 Oberursel Ur.II air-cooled 9 -cylinder two-valve rotary engine 110.0 [hp](80.9 KW)
dimensions :
wingspan : 7.19 [m], length : 5.77 [m], height : 2.95[m]
wing area : 18.7 [m^2]
weights :
max.take-off weight : 586 [kg]
empty weight operational : 406 [kg] bombload : 0 [kg]
performance :
maximum speed : 165 [km/u] op 4000 [m]
climbing speed : 342 [m/min]
service ceiling : 6100 [m]
endurance : 1.5 [hours]
estimated action radius : 111 [km]
description :
1-bay triplane with fixed landing gear and tail strut
Airscrew :
fixed pitch 2 -bladed tractor propeller with max. efficiency :0.64 [ ]
diameter airscrew 2.60 [m]
airscrew revs : 1350 [r.p.m.]
pitch at Max speed 2.04 [m]
blade-tip speed at Vmax and max revs. : 189 [m/s]
calculation : *1* (dimensions)
mean wing chord : 0.87 [m]
calculated wing chord (rounded tips): 0.94 [m]
wing aspect ratio : 8.29 []
estimated gap : 1.74 [m]
gap/chord : 2.01 [ ]
seize (span*length*height) : 122 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 5.7 [kg/our]
fuel consumption(cruise speed) : 22.4 [kg/hour] (30.5 [litre/hour]) at 51.2 [KW] power
estimated specific fuel consumption (cruise power) : 437 [gram/kwh]
estimated specific oil consumption (cruise power) : 70 [gram/kwh]
distance flown for 1 kg fuel : 6.64 [km/kg]
estimated total fuel capacity : 52 [litre] (38 [kg])
calculation : *3* (weight)
weight engine(s) dry : 147.2 [kg] = 1.82 [kg/KW]
weight 13 litre oil tank : 1.1 [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) : 1.9 [kg]
weight cowling 3.2 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 19.0 [kg]
total weight propulsion system : 173 [kg](29.5 [%])
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fuselage skeleton (wood gauge : 5.02 [cm]): 37 [kg]
bracing : 1.5 [kg]
fuselage covering (doped linen fabric) : 2.1 [kg]
weight controls + indicators: 5.0 [kg]
weight seats : 3.0 [kg]
weight other details, lighting set, etc. : 5.1 [kg]
weight 39 [litre] main fuel tank empty : 3.1 [kg]
weight engine mount & firewall : 4 [kg]
total weight fuselage : 61 [kg](10.4 [%])
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weight wing covering (doped linen fabric) : 13 [kg]
total weight ribs (55 ribs) : 35 [kg]
load on front upper spar (clmax) per running metre : 772.1 [N]
load on rear upper spar (vmax) per running metre : 261.7 [N]
total weight 6 spars : 20 [kg]
weight wings : 67 [kg]
weight wing/square meter : 3.61 [kg]
gap : 1.74 [m]
weight 2 struts : 9.4 [kg]
weight cables (23 [m]) : 1.1 [kg] (= 48 [gram] per meter)
diameter cable : 2.8 [mm]
weight fin & rudder (0.6 [m2]) : 2.3 [kg]
weight stabilizer & elevator (2.1 [m2]): 7.7 [kg]
total weight wing surfaces & bracing : 88 [kg] (15.0 [%])
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weight machine-gun : 31 [kg]
weight armament : 31 [kg]
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monospar wing
total weight landing gear : 30.8 [kg] (5.3 [%])
weight 2 wheels ( 710 [mm] by 85 [mm]) : 12.5 [kg]
weight tailskid : 2.3 [kg]
weight undercarriage with axle 15.9 [kg]
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calculated empty weight : 384 [kg](65.5 [%])
weight oil for 1.8 hours flying : 10 [kg]
weight ammunition (1000 rounds) : 35.0 [kg]
weight signal pistol with cartridges : 3.6 [kg]
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calculated operational weight empty : 432 [kg] (73.8 [%])
published operational weight empty : 406 [kg] (69.3 [%])
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weight crew : 90 [kg]
weight fuel for 1.5 hours flying : 34 [kg]
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operational weight : 556 [kg](94.9 [%])
estimated bomb load : 25 [kg]
operational weight bombing mission : 581 [kg]
fuel reserve : 5 [kg] enough for 0.20 [hours] flying
possible additional useful load : 1 [kg]
operational weight fully loaded : 586 [kg] with fuel tank filled for 100 [%]
published maximum take-off weight : 586 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
engine total stroke volume (displacement): 15.0 [litre]
mean engine pressure : 17.98 [kg/cm2]
compression ratio : 3.26 : 1
power loading(operational without bombload) : 6.87 [kg/kW]
total power : 80.9 [kW] at 1350 [r.p.m]
power / cylinder : 9.0 [kW]
calculation : *5* (loads)
manoeuvre load : 3.6 [g] op 1000 [m]
limit load : 4.5 [g] ultimate load : 6.8 [g]
design flight time : 1.20 [hours]
design cycles : 375 sorties, design hours : 450 [hours]
operational wing loading : 292 [N/m^2]
wing stress (3 g) during operation : 242 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.16 ["]
max.angle of attack (stalling angle) : 13.54 ["]
angle of attack at max.speed : 2.77 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° :0.10 [ ]
lift coefficient at max.speed : 0.34 [ ]
lift coefficient at max. angle of attack : 1.27 [ ]
induced drag coefficient at max.speed : 0.0080 [ ]
drag coefficient at max.speed : 0.0420 [ ]
drag coefficient (zero lift) : 0.0339 [ ]
calculation : *8* (speeds
stalling speed at sea level : 70 km/u
landing speed at sea-level (OW without bombload): 83.7 [km/u]
min.power speed (max endurance) : 108.6 [km/u] op 2867 [m](P:28.1 [KW])
min.drag speed (max range) : 142.9 [km/u] op 2867 [m] (P:38.8 [KW])
max.rate of climb speed : 105.4 [km/u] at sea-level
Cruise speed : 148.5 [km/u] op 2867 [m](P:41.7 [KW])
Design speed prop : 160.0 [km/u]
Maximum speed : 165.0 [km/u] op 4000 [m] (P:49 [KW])
climbing speed at sea-level (without bombload) : 324 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 117 [m]
lift/drag ratio : 10.25 [ ]
practical ceiling : 6275 [m] with flying weight :556 [kg]
climb to 1500m (without bombload) : 5.06 [min]
climb to 3000m (without bombload) : 11.87 [min]
max.dive speed : 558.2 [km/hr] at 5275 [m] height
load factor max angle turn 2.30 ["g"]
turn radius at 500m: 45 [m]
time needed for 360* turn 9.3 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 1.70 [hours] with 1 crew and 26 [kg] useful (bomb)load
published endurance : 1.50 [hours] with possible useful (bomb) load : 30 [kg]
action radius : 145 [km] with 1 crew and 20[kg] bombload
max range theoretically with additional fuel tanks for total 139 [litre] fuel : 679 [km]
useful load with action-radius 250km : 27 [kg]
production : 4.00 [tonkm/hour]
oil and fuel consumption per tonkm : 7.01 [kg]
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Literature :
Warplanes WW1
Fighters 1914-19
Praktisch handboek vliegtuigen deel 1
Jane’s Fighting aircraft WWI
(c) B van der Zalm 01 april 2018 python 3.4.1
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