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Friedrichshafen FF33E 501 at Travemunde during the winter of 1915/16. The machine has been cleared for flight, indicated by the 'Flugbereit' notice displayed between the floats. Although when delivered this aircraft was a bombing machine, wireless telegraphy appears to have been fitted retrospectively; the windmill-driven generator can be seen fitted to the side of the fuselage near the observer's cockpit.
Friedrichshafen FF33E
role : light maritime two-seat patrol aircraft, ASW
first flight : operational : February 1916
country : Germany
design :
production : 180 aircraft
general information : First major production model. Equipped with wireless.
users : Germany
crew : 2
armament : no fixed armament, later optional MG for observer
engine : 1 Benz Bz.III liquid-cooled 6 -cylinder inline engine 150 [hp](110.3 KW)
dimensions :
wingspan : 16.6 [m], length : 10.22 [m], height : 3.72[m]
wing area : 52.7 [m^2]
weights :
max.take-off weight : 1635 [kg]
empty weight operational (estimation): 1090.0 [kg] bombload : 96 [kg]
performance :
maximum speed : 119 [km/hr] at sea-level
climbing speed : 60 [m/min]
service ceiling : 3500 [m]
estimated action radius : 350 [km]
description :
3-bay two float biplane no tip floats
two spar upper and lower wing
engine, fuel and bombload in or attached to fuselage, landing gear attached to the wing
airscrew :
fixed pitch 2 -bladed tractor airscrew with max. efficiency :0.63 [ ]
estimated diameter airscrew 2.79 [m]
angle of attack prop : 12.00 [ ]
fine pitch
The FF33e could be recognized by the “square” tail planes
reduction : 1.00 [ ]
airscrew revs : 1420 [r.p.m.]
pitch at Max speed 1.40 [m]
blade-tip speed at Vmax and max revs. : 210 [m/s]
calculation : *1* (dimensions)
mean wing chord : 1.59 [m]
calculated wing chord (rounded tips): 1.71 [m]
wing aspect ratio : 10.46 []
estimated gap : 1.82 [m]
gap/chord : 1.15 [ ]
seize (span*length*height) : 631 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 2.2 [kg/hr]
fuel consumption(cruise speed) : 32.7 [kg/hr] (44.6 [litre/hr]) at 70 [%] power
distance flown for 1 kg fuel : 3.27 [km/kg]
estimated total fuel capacity : 331 [litre] (243 [kg])
calculation : *3* (weight)
weight engine(s) dry : 278.0 [kg] = 2.52 [kg/KW]
weight 22 litre oil tank : 1.9 [kg]
oil tank filled with 0.8 litre oil : 0.7 [kg]
oil in engine 6 litre oil : 5.5 [kg]
fuel in engine 1 litre fuel : 0.6 [kg]
weight 19 litre gravity patrol tank(s) : 2.8 [kg]
weight radiator : 15.8 [kg]
weight exhaust pipes & fuel lines 10.9 [kg]
weight cowling 4.4 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 19.0 [kg]
total weight propulsion system : 338 [kg](20.7 [%])
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fuselage skeleton (wood gauge : 8.34 [cm]): 160 [kg]
bracing : 10.2 [kg]
fuselage covering ( 15.3 [m2] doped linen fabric) : 4.9 [kg]
weight controls + indicators: 7.1 [kg]
weight seats : 6.0 [kg]
weight other details, lighting set, etc. : 5.1 [kg]
weight bomb storage : 6.7 [kg]
weight 312 [litre] main fuel tank empty : 25.0 [kg]
weight engine mounts & firewalls : 6 [kg]
total weight fuselage : 231 [kg](14.1 [%])
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weight wing covering (doped linen fabric) : 34 [kg]
total weight ribs (84 ribs) : 97 [kg]
load on front upper spar (clmax) per running metre : 882.2 [N]
load on rear upper spar (vmax) per running metre : 272.4 [N]
total weight 8 spars : 118 [kg]
weight wings : 248 [kg]
weight wing/square meter : 4.72 [kg]
weight 12 interplane struts & cabane : 42.7 [kg]
weight cables (106 [m]) : 22.5 [kg] (= 213 [gram] per metre)
diameter cable : 5.9 [mm]
weight fin & rudder (4.0 [m2]) : 19.5 [kg]
weight stabilizer & elevator (5.9 [m2]): 28.4 [kg]
total weight wing surfaces & bracing : 361 [kg] (22.1 [%])
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weight armament : 0 [kg]
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weight floats : 136 [kg] (8.3 [%])
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Famous FF33e “Wolfschen” reg.841 operated from merchant Raider "Wolf" and through their collaboration they managed to capture or sink 28 enemy ships in the Indian and Pacific Ocean.
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calculated empty weight : 1065 [kg](65.2 [%])
weight oil for 7.8 hours flying : 17.3 [kg]
weight cooling fluids : 23.8 [kg]
weight automatic pistol with spare magazines : 1.2 [kg]
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calculated operational weight empty : 1108 [kg] (67.7 [%])
estimated operational weight empty : 1090 [kg] (66.7 [%])
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weight crew : 162 [kg]
weight fuel for 2.0 hours flying : 65 [kg]
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operational weight : 1335 [kg](81.7 [%])
bomb load : 96 [kg]
operational weight bombing mission : 1431 [kg]
fuel reserve : 177 [kg] enough for 5.42 [hours] flying
possible additional useful load : 27 [kg]
operational weight fully loaded : 1635 [kg] with fuel tank filled for 100 [%]
published maximum take-off weight : 1635 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (operational without bombload) : 12.10 [kg/kW]
total power : 110.3 [kW] at 1420 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 1.7 [g] at 1000 [m]
limit load : 3.5 [g] ultimate load : 5.2 [g] load factor : 2.4 [g]
design flight time : 4.58 [hours]
design cycles : 382 sorties, design hours : 1750 [hours]
operational wing loading : 248 [N/m^2]
wing stress (3 g) during operation : 158 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.10 ["]
max. angle of attack (stalling angle) : 11.19 ["]
angle of attack at max. speed : 3.03 ["]
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 : 0.37 [ ]
induced drag coefficient at max. speed : 0.0076 [ ]
drag coefficient at max. speed : 0.0594 [ ]
drag coefficient (zero lift) : 0.0518 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 69 [km/u]
landing speed at sea-level (OW without bombload): 82 [km/hr]
min. drag speed (max endurance) = minimum speed*1.1 at cruise height : 82 [km/hr] at 1750 [m] (power:49 [%])
min. power speed (max range) : 82 [km/hr] at 1750 [m] (power:49 [%])
max. rate of climb speed : 74.9 [km/hr] at sea-level
cruising speed : 107 [km/hr] op 1750 [m] (power:70 [%])
design speed prop : 113 [km/hr]
maximum speed : 119 [km/hr] op 100 [m] (power:99 [%])
climbing speed at sea-level (without bombload) : 151 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 196 [m]
lift/drag ratio : 9.44 [ ]
max. practical ceiling : 4100 [m] with flying weight :1204 [kg]
practical ceiling (operational weight): 3475 [m] with flying weight :1335 [kg]
practical ceiling fully loaded (mtow- 1 hour fuel) : 2275 [m] with flying weight :1602 [kg]
published ceiling (3500 [m]
climb to 1500m (without bombload) : 11.46 [min]
max. dive speed : 291.0 [km/hr] at 1275 [m] height
load factor at max. angle turn 1.75 ["g"]
turn radius at 500m: 47 [m]
time needed for 360* turn 11.5 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 7.42 [hours] with 2 crew and 123 [kg] useful (bomb)load and 100.0 [%] fuel
published endurance : 6.54 [hours] with 2 crew and possible useful (bomb) load : 152 [kg] and 88.1 [%] fuel
action radius : 565 [km] with 2 crew and 20[kg] photo camera/radio transmitter or bombload
max range theoretically with additional fuel tanks for total 611 [litre] fuel : 1465 [km]
useful load with action-radius 250km : 295 [kg]
production : 31.58 [tonkm/hour]
oil and fuel consumption per tonkm : 1.11 [kg]
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Literature :
bombers 1914-19 page 170
van Farman tot Neptune page 24,44
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
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(c) B van der Zalm 23 September 2019 contact : info.aircraftinvestigation@gmail.com python 3.7.4