Aircraft investigation info>>>>>>> HOME PAGE
weight and performance calculations for the Friedrichshafen FF38 G.II
Friedrichshafen FF38 G.II
role : medium-weight bomber
importance : ***
first flight : operational : April 1916
country : Germany
design :
production : 35 aircraft
general information :
chord : 1.80 – 2.30m gap : 1.95m prop : “imperial” 2.90m
tank capacity petrol : 550 litre
users : Germany
crew : 3
armament : 3 movable 7.92 [mm] (0.312 in) Parabellum MG 14 machine-guns
engine : 2 Benz Bz.IV liquid-cooled 6 -cylinder inline engine 220 [hp](161.8 KW)
dimensions :
wingspan : 19.7 [m], length : 11.41 [m], height : 3.65[m]
wing area : 75.0 [m^2]
weights :
max.take-off weight : 3171 [kg]
empty weight operational : 1930 [kg] bombload : 300 [kg]
performance :
maximum speed : 135 [km/hr] at sea-level
service ceiling : 3000 [m]
endurance : 4.4 [hours]
estimated action radius : 267 [km]
description :
3-bay biplane with fixed underwing 4 -wheel landing gear and tail strut
two spar upper and lower wing
engines and landing gear attached to the wings, fuel and bombload in or attached to fuselage
airscrew :
two fixed pitch 2 -bladed pusher airscrews with max. efficiency :0.63 [ ]
diameter airscrew 2.90 [m]
angle of attack prop : 13.24 [ ]
fine pitch
reduction : 1.00 [ ]
airscrew revs : 1400 [r.p.m.]
pitch at Max speed 1.61 [m]
blade-tip speed at Vmax and max revs. : 216 [m/s]
calculation : *1* (dimensions)
mean wing chord : 1.90 [m]
calculated wing chord (rounded tips): 2.04 [m]
wing aspect ratio : 10.35 []
gap : 1.95 [m]
gap/chord : 1.02 [ ]
seize (span*length*height) : 820 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 4.2 [kg/hr]
fuel consumption(cruise speed) : 80.7 [kg/hr] (110.1 [litre/hr]) at 75 [%] power
distance flown for 1 kg fuel : 1.51 [km/kg]
estimated total fuel capacity : 550 [litre] (403 [kg])
calculation : *3* (weight)
weight engine(s) dry : 740.0 [kg] = 2.29 [kg/KW]
weight 33 litre oil tank : 4.1 [kg]
oil tank filled with 2.4 litre oil : 2.2 [kg]
oil in engine 18 litre oil : 16.2 [kg]
fuel in engine 2 litre fuel : 1.6 [kg]
weight 47 litre gravity patrol tank(s) : 4.6 [kg]
weight radiator : 48.5 [kg]
weight exhaust pipes & fuel lines 17.4 [kg]
weight self-starter : 4.0 [kg]
weight cowling 6.5 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 48.5 [kg]
total weight propulsion system : 889 [kg](28.1 [%])
***************************************************************
fuselage skeleton (wood gauge : 8.34 [cm]): 203 [kg]
bracing : 16.3 [kg]
fuselage covering ( 24.6 [m2] doped linen fabric) : 7.9 [kg]
weight controls + indicators: 8.1 [kg]
weight seats : 9.0 [kg]
weight other details, lighting set, etc. : 9.1 [kg]
weight bomb storage : 21.0 [kg]
weight Görz bomb sight with 90 cm Zeiss-telescope: 2.5 [kg]
weight two 252 [litre] main fuel tanks empty : 48.3 [kg]
weight interior + equipment + fuel lines: 53 [kg]
total weight fuselage : 378 [kg](11.9 [%])
***************************************************************
weight wing covering (doped linen fabric) : 48 [kg]
total weight ribs (136 ribs) : 188 [kg]
weight engine mounts : 16 [kg]
load on front upper spar (clmax) per running metre : 662.4 [N]
load on rear upper spar (vmax) per running metre : 440.7 [N]
total weight 8 spars : 101 [kg]
weight wings : 337 [kg]
weight wing/square meter : 4.49 [kg]
weight 12 interplane struts & cabane : 49.6 [kg]
weight cables (121 [m]) : 22.0 [kg] (= 182 [gram] per metre)
diameter cable : 5.5 [mm]
weight fin & rudder (4.5 [m2]) : 20.9 [kg]
weight stabilizer & elevator (8.4 [m2]): 38.5 [kg]
total weight wing surfaces & bracing : 484 [kg] (15.3 [%])
*******************************************************************
weight machine-gun(s) : 28.5 [kg]
weight Schneider ring mounting mg :11.0 [kg]
weight armament : 40 [kg]
********************************************************************
wheel pressure : 792.8 [kg]
weight 4 wheels (920 [mm] by 115 [mm]) : 70.3 [kg]
weight tailskid : 4.1 [kg]
weight undercarriage with axle 46.0 [kg]
total weight landing gear : 120.4 [kg] (3.8 [%]
*******************************************************************
********************************************************************
calculated empty weight : 1912 [kg](60.3 [%])
weight oil for 5.3 hours flying : 22.2 [kg]
weight cooling fluids : 66.7 [kg]
weight 3 drums empty : 6.8 [kg]
weight ammunition (1500 rounds) : 49.1 [kg]
weight automatic pistol with spare magazines : 1.2 [kg]
*******************************************************************
calculated operational weight empty : 2051 [kg] (64.7 [%])
published operational weight empty : 1930 [kg] (60.9 [%])
_____________
| | |o| | |
-------------
" "
weight crew : 243 [kg]
weight fuel for 2.0 hours flying : 161 [kg]
********************************************************************
operational weight : 2456 [kg](77.4 [%])
bomb load : 300 [kg]
operational weight bombing mission : 2756 [kg]
fuel reserve : 242 [kg] enough for 2.99 [hours] flying
possible additional useful load : 174 [kg]
operational weight fully loaded : 3171 [kg] with fuel tank filled for 100 [%]
published maximum take-off weight : 3171 [kg] (100.0 [%])
||
||
||
||
calculation : * 4 * (engine power)
power loading (Take-off) : 9.80 [kg/kW]
total power : 323.6 [kW] at 1400 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 1.5 [g] at 1000 [m]
limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 1.1 [g]
design flight time : 3.52 [hours]
design cycles : 128 sorties, design hours : 450 [hours]
wing loading (MTOW) : 415 [N/m^2]
wing stress (3 g) during operation : 241 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.10 ["]
max. angle of attack (stalling angle) : 11.24 ["]
angle of attack at max. speed : 3.05 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° :0.10 [ ]
lift coefficient at max. angle of attack : 1.12 [ ]
lift coefficient at max. speed : 0.38 [ ]
induced drag coefficient at max. speed : 0.0077 [ ]
drag coefficient at max. speed : 0.0840 [ ]
drag coefficient (zero lift) : 0.0763 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 78 [km/u]
landing speed at sea-level (OW without bombload): 94 [km/hr]
min. drag speed (max endurance) : 92 [km/hr] at 1500 [m](power :44 [%])
min. power speed (max range) : 92 [km/hr] at 1500 [m] (power:44 [%])
max. rate of climb speed : 82.0 [km/hr] at sea-level
cruising speed : 122 [km/hr] op 1500 [m] (power:69 [%])
design speed prop : 128 [km/hr]
maximum speed : 135 [km/hr] op 100 [m] (power:99 [%])
climbing speed at sea-level (without bombload) : 265 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 192 [m]
lift/drag ratio : 7.74 [ ]
max. practical ceiling : 5925 [m] with flying weight :2122 [kg]
practical ceiling (operational weight) : 4975 [m] with flying weight :2456 [kg] line 3385
practical ceiling fully loaded (mtow- 1 hour fuel) : 3350 [m] with flying weight :3090 [kg]
published ceiling (3000 [m]
climb to 1500m (without bombload) : 6.29 [min]
climb to 3000m (without bombload) : 15.31 [min]
max. dive speed : 328.7 [km/hr] at 2350 [m] height
load factor at max. angle turn 1.75 ["g"]
turn radius at 500m: 69 [m]
time needed for 360* turn 13.9 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 4.99 [hours] with 3 crew and 474 [kg] bombload and 100.0 [%] fuel
published endurance : 4.40 [hours] with 3 crew and possible useful (bomb) load : 522 [kg] and 88.1 [%] fuel
action radius : 645 [km] with 3 crew and 20[kg] photo camera or bombload
max range theoretically with additional fuel tanks for total 1486 [litre] fuel : 1639 [km]
useful load with action-radius 250km : 545 [kg]
production : 66.18 [tonkm/hour]
oil and fuel consumption per tonkm : 1.28 [kg]
_
°
Literature :
Warplanes WWI page 62
Praktisch handboek vliegtuigen deel 1 page 268
Jane’s fighting aircraft WWI page 153
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 25 April 2020 contact : info.aircraftinvestigation@gmail.com python 3.7.4