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Bleriot XI-2 in service of the RFC
Bleriot XI-2 Artillerie
role : two-seat unarmed reconnaissance
first flight : operational : September 1913
country : France
design :
production : unknown
The Bleriot XI aircraft, famous from its channel crossing in 1909, was also used by the military. They were improved versions with stronger 70hp engine and were used by the France and Italy armies, indicated as Bleriot XIbis.
On 22 October 1911 the first operational military mission was carried out by Captain Carlo Piazza during the Italian-Turkish war in North Africa. He flew from Tripoli to Aziza (32°31'54"N, 13°01'20"O).
The XI-2 was a two-seater version and better suited for reconnaissance.
At the start of WWI the XI-2 was one of the most important aircraft in the French army. The French could already take aerial photographs with the XI-2.
After the outbreak of WWI the English sent here complete airforce of 63 aircraft to France. Among this force there were also Bleriot XI’s of no.3 squadron RFC. On 12 august 1914 the aircraft of No.3 sq. took off from Netheravon to fly via Dover to France. At the take off the engine of the overloaded XI-2 flown by Lt.Robin R. Skene and mecanic Keith Barlow failed. The XI crashed in a group of trees and both die.
They were the first war casualties of the RFC.
On 19 August 1914 a XI-2 together with a BE-2a carried out the first RFC reconnaissance mission over the German lines.
It used wingwarping for steering. At the start of WWI it was the most known aircraft of the allies. This was due to its pre-war recordbreaking flights and aerobatics. It had a lot of flyingwires what led to its nickname "Birdcage"
Before the war a series of accidents in which Bleriot aircraft had suffered wing failures led to a ban on the use of monoplanes. Bleriot first strengthened the spars and later the upper bracing wires.
users : France (8 escadrilles), Italy, RFC (1,3,6,7,9,16 squadron)
crew : 2
armament : no fixed armament
engine : 1 Gnome 7B air-cooled 7 -cylinder atmospheric inlet-valve rotary engine 70 [hp](51.5 KW)
dimensions :
wingspan : 10.35 [m], length : 8.48 [m], height : 2.59[m]
wing area : 20.0 [m^2]
weights :
max.take-off weight : 625 [kg]
empty weight operational : 350 [kg] bombload : 25 [kg]
performance :
maximum speed : 120 [km/hr] at sea-level
climbing speed : 72 [m/min]
service ceiling : 2000 [m]
endurance : 3.5 [hours]
estimated action radius : 189 [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 :0.62 [ ]
estimated diameter airscrew 2.38 [m]
angle of attack prop : 16.55 [ ]
reduction : 1.00 [ ]
airscrew revs : 1200 [r.p.m.]
pitch at Max speed 1.67 [m]
blade-tip speed at Vmax and max revs. : 153 [m/s]
calculation : *1* (dimensions)
mean wing chord : 1.93 [m]
calculated wing chord (rounded tips): 2.48 [m]
wing aspect ratio : 5.36 []
seize (span*length*height) : 227 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 4.6 [kg/hr]
fuel consumption(cruise speed) : 19.8 [kg/hr] (27.0 [litre/hr]) at 76 [%] power
distance flown for 1 kg fuel : 5.46 [km/kg]
estimated total fuel capacity : 107 [litre] (79 [kg])
calculation : *3* (weight)
weight engine(s) dry : 100.4 [kg] = 1.95 [kg/KW]
weight 23 litre oil tank : 2.0 [kg]
oil tank filled with 0.4 litre oil : 0.3 [kg]
oil in engine 0 litre oil : 0.3 [kg]
fuel in engine 0 litre fuel : 0.3 [kg]
weight 11 litre gravity patrol tank(s) : 1.7 [kg]
weight cowling 2.1 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 11.8 [kg]
total weight propulsion system : 117 [kg](18.7 [%])
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fuselage skeleton (wood gauge : 5.12 [cm]): 57 [kg]
bracing : 3.4 [kg]
fuselage covering ( 13.6 [m2] doped linen fabric) : 4.3 [kg]
weight controls + indicators: 6.2 [kg]
weight seats : 6.0 [kg]
weight other details, lighting set, etc. : 5.1 [kg]
weight bomb storage : 1.8 [kg]
weight 96 [litre] main fuel tank empty : 7.7 [kg]
weight engine mounts & firewalls : 3 [kg]
total weight fuselage : 94 [kg](15.0 [%])
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weight wing covering (doped linen fabric) : 13 [kg]
total weight ribs (26 ribs) : 37 [kg]
total weight 4 spars : 28 [kg]
weight wings : 78 [kg]
weight wing/square meter : 3.90 [kg]
weight cables (41 [m]) : 9.7 [kg] (= 234 [gram] per metre)
diameter cable : 6.2 [mm]
weight fin & rudder (1.2 [m2]) : 5.0 [kg]
weight stabilizer & elevator (2.2 [m2]): 8.9 [kg]
total weight wing surfaces & bracing : 102 [kg] (16.3 [%])
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weight armament : 0 [kg]
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wheel pressure : 312.5 [kg]
weight 2 wheels (680 [mm] by 80 [mm]) : 14.1 [kg]
weight tailskid : 1.5 [kg]
weight undercarriage with axle 14.6 [kg]
total weight landing gear : 30.2 [kg] (4.8 [%]
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calculated empty weight : 343 [kg](54.8 [%])
weight oil for 4.2 hours flying : 19.5 [kg]
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calculated operational weight empty : 362 [kg] (58.0 [%])
published operational weight empty : 350 [kg] (56.0 [%])
---o---
"
weight crew : 162 [kg]
weight fuel for 2.0 hours flying : 40 [kg]
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operational weight : 564 [kg](90.2 [%])
bomb load : 25 [kg]
operational weight bombing mission : 589 [kg]
weight camera : 20 [kg]
operational weight photo mission : 584 [kg]
fuel reserve : 39 [kg] enough for 1.97 [hours] flying
possible additional useful load : 2 [kg]
operational weight fully loaded : 625 [kg] with fuel tank filled for 100 [%]
published maximum take-off weight : 625 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (operational without bombload) : 10.95 [kg/kW]
total power : 51.5 [kW] at 1200 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 1.5 [g] at 1000 [m]
limit load : 3.75 [g] ultimate load : 5.6 [g] loadfactor : 2.2 [g]
design flight time : 2.80 [hours]
design cycles : 336 sorties, design hours : 940 [hours]
operational wing loading : 286 [N/m^2]
wing stress (3 g) during operation : 220 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.31 ["]
max.angle of attack (stalling angle) : 13.28 ["]
angle of attack at max.speed : 4.07 ["]
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 : 0.41 [ ]
induced drag coefficient at max.speed : 0.0133 [ ]
drag coefficient at max.speed : 0.0699 [ ]
drag coefficient (zero lift) : 0.0565 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 73 [km/u]
landing speed at sea-level (OW without bombload): 87 [km/hr]
min.drag speed (max endurance) : 87 [km/hr] at 1000 [m](power :59 [%])
min. power speed (max range) : 99 [km/hr] at 1000 [m] (power:67 [%])
max.rate of climb speed : 79.6 [km/hr] at sea-level
Serbian Bleriot XI-2 Storm flown by Miodrag Tomic On August 15, 1914, Sergeant Miodrag Tomic of the 1st Danube Division encountered an enemy plane while conducting a reconnaissance flight over Misar in western Serbia in his Bleriot. The Austro-Hungarian aviator initially waved at Tomic as they passed, then turned and began shooting at Tomic's plane with a pistol. Tomic had his own pistol and fired back. This incident is considered the first recorded dogfight of the war. Within weeks, all Serbian aircraft were armed and they contributed to early Serbian victories at Cer Mountain, Kolubara and Drina River. The first Serbian aircraft equipped with a machine gun was named OLUJ (STORM), and its pilot was the above-mentioned Sergeant Tomic. The Bleriot XI B.2 was armed with a Schwarzlose M.07/12 machine gun, 6 boxes of 100-round ammunition and taken into combat with observer Lieutenant Milutin Mihajlovic who flew numerous missions with Tomic.
cruising speed : 108 [km/hr] op 1000 [m] (power:76 [%])
design speed prop : 114 [km/hr]
maximum speed : 120 [km/hr] op 100 [m] (power:98 [%])
climbing speed at sea-level (without bombload) : 137 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 268 [m]
lift/drag ratio : 7.47 [ ]
max. practical ceiling : 3350 [m] with flying weight :453 [kg]
practical ceiling (operational weight): 2200 [m] with flying weight :564 [kg]
practical ceiling fully loaded (mtow- 1 hour fuel) : 1800 [m] with flying weight :605 [kg]
published ceiling (2000 [m]
climb to 1500m (without bombload) : 13.85 [min]
max.dive speed : 282.2 [km/hr] at 800 [m] height
load factor at max.angle turn 1.42 ["g"]
turn radius at 500m: 64 [m]
time needed for 360* turn 15.9 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 3.83 [hours] with 2 crew and 25 [kg] useful (bomb)load and 96.4 [%] fuel
published endurance : 3.50 [hours] with 2 crew and possible useful (bomb) load : 31 [kg] and 88.1 [%] fuel
action radius : 220 [km] with 2 crew and 20[kg] photo camera/radio transmitter or bombload
max range theoretically with additional fuel tanks for total 248 [litre] fuel : 992 [km]
useful load with action-radius 250km : 90 [kg]
production : 9.73 [tonkm/hour]
oil and fuel consumption per tonkm : 2.51 [kg]
Also the French experimented with machine guns on the Bleriot XI-2, as seen here on BL 877
Literature :
Jane s fighting aircraft WWI page 103
Bombers 1914-19 page 17
Fighting aircraft WOI page 103
Historische vliegtuigen page 107
Praktisch handboek vliegtuigen deel 1 page162
The friendless sky page 30
They fought fort he sky page 35
Warplanes page 28
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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