RAF B.E.12
role : light bomber
first flight : 28 July 1915 operational : august 1916
country : United-Kingdom
design :
production : 200 aircraft
general information :
The BE12 was a conversion of a BE2c with the observers cockpit in the front replaced by a large fuel tank and the engine replaced by a more powerful 150 hp RAF 4 engine. It was designed for the role of long range reconnaissance and as light bomber. Like contemporary aircraft it was unarmed. The flight trials continued true 1915, the cooling of the rear cylinders of the V-12 gave much trouble. In 1916 it was clear that some kind of armament had to be installed and in may 1916 it was decided to fit a forward firing synchronized Vickers gun (with the idea to create a fighter aircraft ??).
So the BE12 was not developed to stop the Fokker-monoplane fighters, because at the time of the first flight in July 1915 the Fokker-scourge had not even started.
The first B.E.12 squadron, No. 19 did not reach France until 1 August 1916. It was followed by the only other squadron to fly the type in France, No. 21, on the 25th. It was with the 1.5 Strutter one of the first British operational aircraft with a synchronized machine gun. As might have been expected, the new type had all the inherent stability of the B.E.2c and when pressed into service as a fighter proved quite useless, especially in the face of the new German Halberstadt and Albatros fighters coming into service. It was designed for stable flight for bombing and reconnaissance missions and not agile enough for tight manoeuvres needed in dogfights.
It continued to be employed as a bomber but since an effective defensive gun could not be mounted it was too vulnerable and was finally withdrawn from all front line duties in France in March 1917.
General Trenchard, commanding the RFC in France, wrote : “I realise I shall lose two squadrons if I stop using the BE12… but I cannot do anything else but to recommend that no more be sent to this country”
Like the B.E.2c from which it was derived, its stability made it eminently suitable for use as a night fighter. It replaced the B.E.2c in this duty, and its greatest success occurred on 17 June 1917, when Lt L P Watkins of No 37 Squadron, flying 6610, brought down the Zeppelin L48. (The Zeppelin was already set ablaze by other British fighters, but Watkins chasing the falling Zep finished it off with a last burst of his MG.
A few B.E. 12s served with No 17 Squadron at Mikra Bay, near Salonika, from November 1916, being flown as fighters, bombers and reconnaissance aircraft, as opportunity dictated; and it was this Squadron's well-known pilot, Capt. Gilbert Ware Murlis-Green (later Gp Capt, DSO, MC, RAF) who achieved the rare score of three enemy aircraft shot down while flying the B.E.12.
Four Staaken RVI Giants set out for a night raid on London, 29/30 January 1918. 73 British aircraft ascended to intercept. A BE12 managed to encounter a Giant over Essex. Attacked the Giant but could not bring it down. The B.E.12 riddled with bullets fired from the Giant.
users : RFC
crew : 1
armament : 1 synchronized 7.70 [mm] (0.303 in) Vickers machine-gun
engine : 1 RAF 4a air-cooled 12 -cylinder V-engine 163 [hp](119.9 KW) at 1800 rpm
and 150 [hp] at 1650 rpm
dimensions :
wingspan : 11.28 [m], length : 8.31 [m], height : 3.39[m]
wing area : 34.47 [m^2]
weights :
max.take-off weight : 1067 [kg]
empty weight operational : 743 [kg] bombload : 116 [kg]
performance :
maximum speed : 164 [km/hr] at sea-level
climbing speed : 136 [m/min]
service ceiling : 3810 [m]
endurance : 3.0 [hours]
estimated action radius : 221 [km]
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 4 -bladed tractor airscrew with max. efficiency :0.60 [ ]
estimated diameter airscrew 2.98 [m]
angle of attack prop : 23.39 [ ]
reduction : 0.50 [ ]
airscrew revs : 900 [r.p.m.]
pitch at Max speed 3.04 [m]
blade-tip speed at Vmax and max revs. : 148 [m/s]
calculation : *1* (dimensions)
mean wing chord : 1.53 [m]
calculated wing chord (rounded tips): 1.70 [m]
wing aspect ratio : 7.38 []
estimated gap : 1.77 [m]
gap/chord : 1.16 [ ]
seize (span*length*height) : 318 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 2.5 [kg/hr]
fuel consumption(cruise speed) : 32.2 [kg/hr] (44.0 [litre/hr]) at 64 [%] power
distance flown for 1 kg fuel : 4.58 [km/kg]
estimated total fuel capacity : 150 [litre] (110 [kg])
calculation : *3* (weight)
weight engine(s) dry : 308.0 [kg] = 2.57 [kg/KW]
weight reduction gear : 4.8 [kg]
weight 13 litre oil tank : 1.1 [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 19 litre gravity patrol tank(s) : 2.8 [kg]
weight cowling 4.8 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 42.0 [kg]
total weight propulsion system : 369 [kg](34.6 [%])
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fuselage skeleton (wood gauge : 5.77 [cm]): 71 [kg]
bracing : 4.1 [kg]
fuselage covering ( 13.0 [m2] doped linen fabric) : 4.2 [kg]
weight controls + indicators: 6.2 [kg]
weight seats : 3.0 [kg]
weight other details, lighting set, etc. : 5.1 [kg]
weight bomb storage : 8.1 [kg]
weight 131 [litre] main fuel tank empty : 10.5 [kg]
weight engine mounts & firewalls : 6 [kg]
total weight fuselage : 118 [kg](11.1 [%])
***************************************************************
weight wing covering (doped linen fabric) : 22 [kg]
total weight ribs (57 ribs) : 63 [kg]
load on front upper spar (clmax) per running metre : 562.7 [N]
load on rear upper spar (vmax) per running metre : 263.5 [N]
total weight 8 spars : 41 [kg]
weight wings : 126 [kg]
weight wing/square meter : 3.67 [kg]
weight 8 interplane struts & cabane : 21.9 [kg]
weight cables (70 [m]) : 4.5 [kg] (= 65 [gram] per metre)
diameter cable : 3.2 [mm]
weight fin & rudder (1.5 [m2]) : 5.6 [kg]
weight stabilizer & elevator (3.9 [m2]): 14.5 [kg]
total weight wing surfaces & bracing : 173 [kg] (16.2 [%])
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weight machine-gun(s) : 15.9 [kg]
weight ammunition magazine(s) :1.8 [kg]
weight synchronizing system : 1.0 [kg]
weight armament : 19 [kg]
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wheel pressure : 533.5 [kg]
weight 2 wheels (720 [mm] by 80 [mm]) : 24.2 [kg]
weight tailskid : 2.0 [kg]
weight undercarriage with axle 29.6 [kg]
total weight landing gear : 55.7 [kg] (5.2 [%]
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calculated empty weight : 735 [kg](68.8 [%])
weight oil for 3.6 hours flying : 9.1 [kg]
weight ammunition (400 rounds) : 13.6 [kg]
*******************************************************************
calculated operational weight empty : 757 [kg] (71.0 [%])
published operational weight empty : 743 [kg] (69.6 [%])
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weight crew : 81 [kg]
weight fuel for 2.0 hours flying : 64 [kg]
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operational weight : 903 [kg](84.6 [%])
bomb load : 116 [kg]
operational weight bombing mission : 1019 [kg]
fuel reserve : 45 [kg] enough for 1.41 [hours] flying
possible additional useful load : 3 [kg]
operational weight fully loaded : 1067 [kg] with fuel tank filled for 100 [%]
published maximum take-off weight : 1067 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (Take-off) : 8.90 [kg/kW]
total power : 119.9 [kW] at 1800 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 2.9 [g] at 1000 [m]
limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 1.6 [g]
design flight time : 2.40 [hours]
design cycles : 312 sorties, design hours : 750 [hours]
wing loading (MTOW) : 304 [N/m^2]
wing stress (3 g) during operation : 237 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.43 ["]
max.angle of attack (stalling angle) : 12.25 ["]
angle of attack at max.speed : 0.98 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° :0.12 [ ]
lift coefficient at max. angle of attack : 1.15 [ ]
lift coefficient at max.speed : 0.20 [ ]
induced drag coefficient at max.speed : 0.0031 [ ]
drag coefficient at max.speed : 0.0358 [ ]
drag coefficient (zero lift) : 0.0327 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 69 [km/u]
landing speed at sea-level (OW without bombload): 83 [km/hr]
min.drag speed (max endurance) : 100 [km/hr] at 1905 [m](power :39 [%])
min. power speed (max range) : 107 [km/hr] at 1905 [m] (power:41 [%])
max.rate of climb speed : 99.3 [km/hr] at sea-level
cruising speed : 148 [km/hr] op 1905 [m] (power:67 [%])
design speed prop : 156 [km/hr]
maximum speed : 164 [km/hr] op 0 [m] (power:100 [%])
climbing speed at sea-level (without bombload) : 254 [m/min]
![[linked image]](images/RAF_B.E.12/image3.png)
calculation : *9* (regarding various performances)
take-off distance at sea-level : 163 [m]
lift/drag ratio : 9.99 [ ]
max. practical ceiling : 4075 [m] with flying weight :841 [kg]
practical ceiling (operational weight): 3775 [m] with flying weight :903 [kg]
practical ceiling fully loaded (mtow- 1 hour fuel) : 3150 [m] with flying weight :1035 [kg]
published ceiling (3810 [m]
climb to 1500m (without bombload) : 6.86 [min]
climb to 3000m (without bombload) : 18.83 [min]
max.dive speed : 339.6 [km/hr] at 2150 [m] height
load factor at max.angle turn 1.79 ["g"]
turn radius at 500m: 53 [m]
time needed for 360* turn 12.0 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 3.40 [hours] with 1 crew and 119 [kg] bombload and 100.0 [%] fuel
published endurance : 3.00 [hours] with 1 crew and possible useful (bomb) load : 132 [kg] and 88.1 [%] fuel
action radius : 478 [km] with 1 crew and 20[kg] photo camera/radio transmitter or bombload
max range theoretically with additional fuel tanks for total 331 [litre] fuel : 1110 [km]
useful load with action-radius 250km : 133 [kg]
production : 19.65 [tonkm/hour]
oil and fuel consumption per tonkm : 1.77 [kg]
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Literature :
Prakt. handb. vliegt. I page 181
Fighters 1914-19 page 30,109
www.flyingmachines.ru
wikepedia
RAF Yearbook '85 page 58
Warplanes WOI page 49,60,131
last check python :
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
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(c) B van der Zalm 04 January 2019 contact : info.aircraftinvestigation@gmail.com python 3.7.2(32-bit)
literatuur : Prakt. handb. vliegt. I blz. 181
Fighters 1914-19 page 30,109
www.flyingmachines.ru
wikepedia
RAF Yearbook '85 blz. 58
Warplanes WOI page 49,60,131