RAF B.E.8
role : two-seat unarmed reconnaissance
first flight : end 1912 operational : April 1914
country : United-Kingdom
design :
production : 21 aircraft
general information :
August 1914 also RAF B.E.8’s were sent to France. It saw only limited use at the front without much notice.
Nr.625 was one of the first RFC aircraft to fly to France, arriving at Amiens on 14 august 1914 with no.3 sq. However on 16 august it stalled at 50m height. It crashed and caught fire killing Lt.Evelyn Walter Copland Perry and mechanic H.E. Parfitt. They were the first British airman to die in France. Perry was an experienced test-pilot. In May 1915 there were only 2 B.E.8’s remaining in service in France. All other aircraft were lost or sent back to flying schools in England.
users : RFC
crew : 2
armament : no fixed armament
engine : 1 Gnome 7A Monosoupape air-cooled 7 -cylinder Monosoupape rotary engine 80 [hp](58.8 KW)
dimensions :
wingspan : 12.04 [m], length : 8.31 [m], height : 2.84[m]
wing area : 39.02 [m^2]
weights :
max.take-off weight : 700 [kg]
empty weight operational (estimation): 435.0 [kg] bombload : 45 [kg]
performance :
maximum speed : 112 [km/hr] at sea-level
climbing speed : 84 [m/min]
service ceiling : 3048 [m]
endurance : 2.5 [hours]
estimated action radius : 126 [km]
B.E.8a, version with modified wings and ailerons
description :
2-bay biplane with fixed landing gear and tail strut
two spar upper and lower wing
engines, landing gear, fuel and bombs in or attached to the fuselage
airscrew :
fixed pitch 2 -bladed tractor airscrew with max. efficiency :0.66 [ ]
estimated diameter airscrew 2.09 [m]
angle of attack prop : 17.53 [ ]
reduction : 1.00 [ ]
airscrew revs : 1200 [r.p.m.]
pitch at Max speed 1.56 [m]
blade-tip speed at Vmax and max revs. : 135 [m/s]
calculation : *1* (dimensions)
mean wing chord : 1.62 [m]
calculated wing chord (rounded tips): 1.80 [m]
wing aspect ratio : 7.43 []
estimated gap : 1.84 [m]
gap/chord : 1.14 [ ]
seize (span*length*height) : 284 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 6.5 [kg/hr]
fuel consumption(cruise speed) : 18.0 [kg/hr] (24.5 [litre/hr]) at 73 [%] power
distance flown for 1 kg fuel : 5.61 [km/kg]
estimated total fuel capacity : 70 [litre] (51 [kg])
calculation : *3* (weight)
weight engine(s) dry : 109.4 [kg] = 1.86 [kg/KW]
weight 23 litre oil tank : 2.0 [kg]
oil tank filled with 0.4 litre oil : 0.4 [kg]
oil in engine 0 litre oil : 0.3 [kg]
fuel in engine 0 litre fuel : 0.3 [kg]
weight 10 litre gravity patrol tank(s) : 1.6 [kg]
weight cowling 2.4 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 13.5 [kg]
total weight propulsion system : 128 [kg](18.3 [%])
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fuselage skeleton (wood gauge : 5.56 [cm]): 66 [kg]
bracing : 3.9 [kg]
fuselage covering ( 13.0 [m2] doped linen fabric) : 4.2 [kg]
weight controls + indicators: 6.3 [kg]
weight seats : 6.0 [kg]
weight other details, lighting set, etc. : 5.1 [kg]
weight bomb storage : 3.2 [kg]
weight 59 [litre] main fuel tank empty : 4.7 [kg]
weight engine mounts & firewalls : 3 [kg]
total weight fuselage : 102 [kg](14.6 [%])
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weight wing covering (doped linen fabric) : 25 [kg]
total weight ribs (35 ribs) : 42 [kg]
load on front upper spar (clmax) per running metre : 447.2 [N]
load on rear upper spar (vmax) per running metre : 147.8 [N]
total weight 8 spars : 37 [kg]
weight wings : 104 [kg]
weight wing/square meter : 2.66 [kg]
weight 8 interplane struts & cabane : 22.7 [kg]
weight cables (74 [m]) : 4.3 [kg] (= 59 [gram] per metre)
diameter cable : 3.1 [mm]
weight fin & rudder (1.7 [m2]) : 4.7 [kg]
weight stabilizer & elevator (4.4 [m2]): 12.0 [kg]
total weight wing surfaces & bracing : 147 [kg] (21.1 [%])
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B.E.8 prototype
weight armament : 0 [kg]
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wheel pressure : 350.0 [kg]
weight 2 wheels (680 [mm] by 76 [mm]) : 16.0 [kg]
weight tailskid : 1.8 [kg]
weight undercarriage with axle 22.0 [kg]
total weight landing gear : 39.8 [kg] (5.7 [%]
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calculated empty weight : 417 [kg](59.6 [%])
weight oil for 3.0 hours flying : 19.4 [kg]
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calculated operational weight empty : 437 [kg] (62.4 [%])
estimated operational weight empty : 435 [kg] (62.1 [%])
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weight crew : 162 [kg]
weight fuel for 2.0 hours flying : 36 [kg]
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operational weight : 635 [kg](90.6 [%])
bomb load : 45 [kg]
operational weight bombing mission : 680 [kg]
weight camera : 20 [kg]
operational weight photo mission : 655 [kg]
fuel reserve : 15 [kg] enough for 0.84 [hours] flying
possible additional useful load : 30 [kg]
operational weight fully loaded : 700 [kg] with fuel tank filled for 100 [%]
published maximum take-off weight : 700 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (operational without bombload) : 10.78 [kg/kW]
total power : 58.8 [kW] at 1200 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 2.4 [g] at 1000 [m]
limit load : 3.75 [g] ultimate load : 5.6 [g] load factor : 2.3 [g]
design flight time : 2.00 [hours]
design cycles : 440 sorties, design hours : 880 [hours]
operational wing loading : 165 [N/m^2]
wing stress (3 g) during operation : 186 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.19 ["]
max.angle of attack (stalling angle) : 12.47 ["]
angle of attack at max.speed : 2.04 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° :0.10 [ ]
lift coefficient at max. angle of attack : 1.15 [ ]
lift coefficient at max.speed : 0.27 [ ]
induced drag coefficient at max.speed : 0.0056 [ ]
drag coefficient at max.speed : 0.0533 [ ]
drag coefficient (zero lift) : 0.0477 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 54 [km/u]
landing speed at sea-level (OW without bombload): 65 [km/hr]
min.drag speed (max endurance) : 70 [km/hr] at 1524 [m](power :43 [%])
min. power speed (max range) : 78 [km/hr] at 1524 [m] (power:47 [%])
max.rate of climb speed : 68.9 [km/hr] at sea-level
cruising speed : 101 [km/hr] op 1524 [m] (power:69 [%])
design speed prop : 106 [km/hr]
maximum speed : 112 [km/hr] op 100 [m] (power:99 [%])
B.E.8 ready for a loading test
climbing speed at sea-level (without bombload) : 187 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 114 [m]
lift/drag ratio : 8.30 [ ]
max. practical ceiling : 5150 [m] with flying weight :527 [kg]
practical ceiling (operational weight): 4100 [m] with flying weight :635 [kg]
practical ceiling fully loaded (mtow- 1 hour fuel) : 3675 [m] with flying weight :682 [kg]
published ceiling (3048 [m]
climb to 1500m (without bombload) : 9.11 [min]
climb to 3000m (without bombload) : 23.43 [min]
max.dive speed : 281.5 [km/hr] at 2675 [m] height
load factor at max.angle turn 1.88 ["g"]
turn radius at 500m: 30 [m]
time needed for 360* turn 8.6 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 2.84 [hours] with 2 crew and 50 [kg] useful (bomb)load and 100.0 [%] fuel
published endurance : 2.50 [hours] with 2 crew and possible useful (bomb) load : 56 [kg] and 88.1 [%] fuel
action radius : 228 [km] with 2 crew and 20[kg] photo camera/radio transmitter or bombload
max range theoretically with additional fuel tanks for total 249 [litre] fuel : 1023 [km]
useful load with action-radius 250km : 93 [kg]
production : 9.40 [tonkm/hour]
oil and fuel consumption per tonkm : 2.60 [kg]
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Literature :
Early aviation page 24
Fighters 1914-19 page 55,132
Praktisch handboek vliegtuigen deel 1
They fought for the sky page 19,20
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 3.7.2(64-bit)