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Fokker E.IV
role : fighter
first flight : November 1915 operational : June 1916
country : Germany
design :
production : 49 aircraft
general information :
Given the Fokker designation of M.15, the E.IV was essentially a lengthened Fokker E.III powered by the 119 kW (160 hp) Oberursel U.III two-row, 14-cylinder rotary engine, a copy of the Gnome Double Lambda. The more powerful engine was intended to enable the Eindecker to carry two or three 7.92 mm (.312 in) machine guns, thereby increasing its firepower and providing redundancy if one gun jammed - a common occurrence at the time. However, the E.IV was a troubled design that never achieved the success of its predecessor and was soon out-classed by French and British fighters.[citation needed]Anthony Fokker demonstrated the E.IV at Essen, where Boelcke, Immelman and their Staffel were stationed to prevent any French attack on the Krupp munition works, as predicted by spies. (ffs091) but the complicated triple-synchronization gear failed during the demonstration and the propeller was damaged. One machine gun jammed and thereafter it was not synchronized anymore causing the damage. Fokker replaced the propellor and tried it the next day. Satisfied he handed the plane over to Immelman but a week later while chasing an enemy plane over the German lines a rocker arm of the Gnome engine broke and the vibrations neerly shook the engine from it’s bed. Immelman with his skills managed to make an emergency landing and directly phoned Fokker to report the incident. The modified prototype underwent combat evaluation on the Western Front by Oberleutnant Otto Parschau in October 1915, making it the first twin-gun fighter in service. Leading German ace Oswald Boelcke evaluated the E.IV at Fokker's Schwerin factory in November. The pilots discovered that mounting the much heavier Oberursel U.III onto the Eindecker airframe did not produce a better aircraft - one pilot described it as "practically a flying engine." The inertial and gyroscopic forces of the spinning mass made the E.IV less manoeuvrable than the E.III and any loss of efficiency from the notoriously unreliable engine made the aircraft virtually uncontrollable, requiring the engine to be switched off. Turning under such conditions was exceedingly difficult because the E.IV still used wing warping instead of ailerons. Furthermore, the engine worked well when new, but lost power after only a few hours of operation. Only 49 E.IVs were built out of the total Eindecker production run of 416 aircraft. Over half of the E.IVs entered service in June 1916 and the last were delivered in December 1916 by which time they were obsolete. Boelcke reported the E.IV was outclimbed by the Nieuport and that performance at altitude was poor.
users : Luftwaffe
crew : 1
armament : 2 synchronized 7.92 [mm] (0.312 in) Spandau LMG 08/15 machine-guns
engine : 1 Oberursel U.III air-cooled 14 -cylinder atmospheric inlet-valve rotary engine 160 [hp](117.7 KW)
dimensions :
wingspan : 10.0 [m], length : 7.5 [m], height : 2.7[m]
wing area : 15.9 [m^2]
weights :
max.take-off weight : 724 [kg]
empty weight operational (estimation): 499.0 [kg] bombload : 0 [kg]
performance :
maximum speed : 170 [km/hr] at sea-level
climbing speed : 246 [m/min]
service ceiling : 3960 [m]
estimated action radius : 138 [km]
description :
shoulder-winged monoplane 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 :0.63 [ ]
estimated diameter airscrew 2.51 [m]
angle of attack prop : 21.78 [ ]
reduction : 1.00 [ ]
airscrew revs : 1200 [r.p.m.]
pitch at Max speed 2.36 [m]
blade-tip speed at Vmax and max revs. : 165 [m/s]
calculation : *1* (dimensions)
mean wing chord : 1.59 [m]
calculated wing chord (rounded tips): 2.00 [m]
wing aspect ratio : 6.29 []
gap : 0.00 [m]
gap/chord : 0.00 [ ]
seize (span*length*height) : 202 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 10.6 [kg/hr]
fuel consumption(cruise speed) : 40.5 [kg/hr] (55.3 [litre/hr]) at 66 [%] power
distance flown for 1 kg fuel : 3.77 [km/kg]
estimated total fuel capacity : 113 [litre] (83 [kg])
calculation : *3* (weight)
weight engine(s) dry : 203.6 [kg] = 1.73 [kg/KW]
weight 28 litre oil tank : 2.4 [kg]
oil tank filled with 0.9 litre oil : 0.8 [kg]
oil in engine 1 litre oil : 0.6 [kg]
fuel in engine 1 litre fuel : 0.6 [kg]
weight 24 litre gravity patrol tank(s) : 3.5 [kg]
weight cowling 4.7 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 19.0 [kg]
total weight propulsion system : 233 [kg](32.2 [%])
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fuselage skeleton (wood gauge : 5.12 [cm]): 50 [kg]
bracing : 2.7 [kg]
fuselage covering ( 10.6 [m2] doped linen fabric) : 3.4 [kg]
weight controls + indicators: 5.8 [kg]
weight seats : 3.0 [kg]
weight other details, lighting set, etc. : 5.1 [kg]
weight 89 [litre] main fuel tank empty : 7.1 [kg]
weight engine mounts & firewalls : 6 [kg]
total weight fuselage : 83 [kg](11.5 [%])
***************************************************************
weight wing covering (doped linen fabric) : 10 [kg]
total weight ribs (37 ribs) : 43 [kg]
load on front upper spar (clmax) per running metre : 513.3 [N]
load on rear upper spar (vmax) per running metre : 206.8 [N]
total weight 4 spars : 29 [kg]
weight wings : 83 [kg]
weight wing/square meter : 5.20 [kg]
weight cables (40 [m]) : 9.8 [kg] (= 245 [gram] per metre)
diameter cable : 6.3 [mm]
weight fin & rudder (1.2 [m2]) : 6.2 [kg]
weight stabilizer & elevator (1.8 [m2]): 9.4 [kg]
total weight wing surfaces & bracing : 108 [kg] (14.9 [%])
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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]
********************************************************************
wheel pressure : 362.0 [kg]
weight 2 wheels (650 [mm] by 78 [mm]) : 13.8 [kg]
weight tailskid : 1.5 [kg]
weight undercarriage with axle 18.5 [kg]
total weight landing gear : 33.8 [kg] (4.7 [%]
*******************************************************************
********************************************************************
calculated empty weight : 498 [kg](68.7 [%])
weight oil for 2.2 hours flying : 22.8 [kg]
weight ammunition (1000 rounds) : 35.0 [kg]
*******************************************************************
calculated operational weight empty : 555 [kg] (76.7 [%])
estimated operational weight empty : 499 [kg] (68.9 [%])
calculated empty weight higher then actual OWE, pls check
---o---
"
weight crew : 81 [kg]
weight fuel for 1.5 hours flying : 61 [kg]
********************************************************************
operational weight : 697 [kg](96.3 [%])
estimated bomb load : 25 [kg]
operational weight bombing mission : 722 [kg]
fuel reserve : 2 [kg] enough for 0.05 [hours] flying
operational weight fully loaded : 724 [kg] with fuel tank filled for 76 [%]
published maximum take-off weight : 724 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (operational without bombload) : 5.92 [kg/kW]
total power : 117.7 [kW] at 1200 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 2.1 [g] at 1000 [m]
limit load : 4.1 [g] ultimate load : 6.1 [g] load factor : 1.9 [g]
On this photo it is clearly visible that the U.III has only a single valve on the head of the cylinder. Three belt-fed Spandau machine guns are insatlled.
design flight time : 1.44 [hours]
design cycles : 292 sorties, design hours : 420 [hours]
operational wing loading : 430 [N/m^2]
wing stress (3 g) during operation : 248 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.25 ["]
max. angle of attack (stalling angle) : 12.92 ["]
angle of attack at max.speed : 2.72 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° :0.10 [ ]
lift coefficient at max. angle of attack : 1.14 [ ]
lift coefficient at max. speed : 0.32 [ ]
induced drag coefficient at max. speed : 0.0068 [ ]
drag coefficient at max.speed : 0.0721 [ ]
drag coefficient (zero lift) : 0.0653 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 89 [km/u]
landing speed at sea-level (OW without bombload): 107 [km/hr]
min. drag speed (max endurance) = minimum speed*1.1 at cruise height : 108 [km/hr] at 1980 [m] (power:42 [%])
min. power speed (max range) : 124 [km/hr] at 1980 [m] (power:47 [%])
max. rate of climb speed : 103.9 [km/hr] at sea-level
cruising speed : 153 [km/hr] op 1980 [m] (power:67 [%])
design speed prop : 165 [km/hr]
maximum speed : 170 [km/hr] op 100 [m] (power:99 [%])
climbing speed at sea-level (without bombload) : 331 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 214 [m]
lift/drag ratio : 7.53 [ ]
max. practical ceiling : 4700 [m] with flying weight :622 [kg]
practical ceiling (operational weight): 4175 [m] with flying weight :697 [kg]
practical ceiling fully loaded (mtow- 1 hour fuel) : 4275 [m] with flying weight :683 [kg]
published ceiling (3960 [m]
climb to 1500m (without bombload) : 5.20 [min]
climb to 3000m (without bombload) : 13.76 [min]
max. dive speed : 369.2 [km/hr] at 3275 [m] height
load factor at max. angle turn 2.00 ["g"]
turn radius at 500m: 76 [m]
time needed for 360* turn 13.3 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 1.67 [hours] with 1 crew and 20 [kg] useful load and 81.8 [%] fuel
published endurance : 1.80 [hours] with 1 crew and possible useful (bomb) load : 15 [kg] and 88.1 [%] fuel
action radius : 128 [km] with 1 crew and 20[kg] photo camera/radio transmitter or bombload
max range theoretically with additional fuel tanks for total 167 [litre] fuel : 463 [km]
useful load with action-radius 250km : 0 [kg]
production (500 km) : 0 [tonkm/hour]
I-°=/
°
Literature :
They fought fort he sky page 91
Praktisch handbook vliegtuigen deel 1 page 257 (geen data/foto)
Fighters 1914-19 page 162
Warplanes page 49,55,86
wikepedia
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.
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(c) B van der Zalm 04 January 2019 contact : info.aircraftinvestigation@gmail.com python 3.7.4