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weight and performance calculations for the Wright Flyer II
The Flyer II (picture below) was much identical to the Flyer I (picture above). Note the anhedral wings making the airplane little instable in flight needing constant control by the pilot. The Wright brothers built in this instability on purpose to enhance better control.
Wright Flyer II
role : experimental/research/flying trials
importance : ****
first flight : operational : May 1904
country : United States of America
design : Orville & Wilbur Wright
production : 1 prototype
general information :
After the destruction of the Flyer I by a gust of wind, the Wright brothers built a new aircraft very similar to the Wright I but with a more powerful engine and a reduced wing camber of 1-in-25 (The Flyer I had a camber 1-in-20). Flight test started in May 1904 at Huffman Prairie, a cow pasture outside Dayton, Ohio, but at first the results were poor and the gather press was not impressed to much. The tests continued but resulted often in crash landings due to pitch instability and the brothers had to shift the centre of gravity and added 32 kg of iron bars as ballast under the elevators. On 22 august 1904 they managed to make straight flights of 400m long. At Huffman prairie the wind was not as reliable as in Kitty Hawk and for not to be depending on the wind they built a catapult launching system composed of a 700kg weight suspended in a 8m high derrick connected with a rope and pulleys to the aircraft. On 15 September 1904 Wilbur launched with the catapult made the first turn and on 20 September made the first complete circle, flying 1240m in 1 minute 16 seconds.
A series of flights ending in damage to the aircraft followed, but the run of bad luck ended on November 9, when Wilbur flew four circuits of Huffman Prairie, staying in the air for five minutes and only landing because the engine was beginning to overheat. On 1 December Orville made a similar flight, and on 9 December they stopped flying for the year.
The Wrights disassembled the airframe of the Flyer II during the winter of 1904–05. They salvaged the propeller chain drive, its mounts, and the engine. The tattered fabric, wing ribs, uprights and related wooden parts were burned (according to Orville) in the early months of 1905. The salvaged propeller parts and the engine went into the new airframe of the Wright Flyer III.
users : Wright Brothers
crew : 1
engine : 1 Wright 1904 liquid-cooled 4 -cylinder inline engine 15 [hp](11.2 KW)
dimensions :
wingspan : 12.29 [m], length : 6.43 [m], height : 2.74[m]
wing area : 47.38 [m^2]
At Huffman Prairie there was not as much wind as in the dunes of Kitty Hawk. To be less depending on the wind and for to be able to fly in more calm weather the Wrights developed a catapult launching system. They erected an 8m high derrick in which a 700 kg weight was suspended at 6m height. With pulleys and a rope the Flyer could be accelerated along the 20-23m long launching rail to 47 km/u. Wilbur calculated the minimum flying speed to be 44 km/u
weights :
max.take-off weight : 354 [kg]
empty weight operational (estimation): 280.0 [kg]
performance :
maximum speed : 58 [km/u] op 100 [m]
service ceiling : 150 [m]
endurance : 0.349 [hours]
estimated action radius : 10 [km]
description :
4-bay biplane with fixed landing ski
two spar upper and lower wing
engine, landing gear and useful-load in or attached to fuselage, fuel in gravity tank suspended from a wingstrut
airscrew :
two fixed pitch 2 -bladed pusher airscrews with max. efficiency :0.59 [ ]
diameter airscrew 2.59 [m]
angle of attack prop : 23.31 [ ]
reduction : 0.34 [ ]
airscrew revs : 375 [r.p.m.]
pitch at Max speed 2.63 [m]
blade-tip speed at Vmax and max revs. : 53 [m/s]
calculation : *1* (dimensions)
mean wing chord : 1.93 [m]
calculated wing chord (rounded tips): 2.16 [m]
wing aspect ratio : 6.38 []
gap : 1.89 [m]
gap/chord : 0.98 [ ]
seize (span*length*height) : 217 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 0.3 [kg/hr]
fuel consumption(cruise speed) : 8.0 [kg/hr] (10.9 [litre/hr]) at 98 [%] power
distance flown for 1 kg fuel : 7.28 [km/kg] at 100 [m] cruise height, sfc : 725.0 [kg/kwh]
estimated total fuel capacity : 3.79 [litre] (2.78 [kg])
calculation : *3* (weight)
weight engine(s) dry : 82.0 [kg] = 7.33 [kg/KW]
weight transmission & gear (engines in fuselage) : 4.5 [kg]
weight 0.4 litre oil tank : 0.12 [kg]
oil tank filled with 0.1 litre oil : 0.1 [kg]
oil in engine 0.6 litre oil : 0.6 [kg]
fuel in engine 0.1 litre fuel : 0.06 [kg]
weight 4.6 litre gravity patrol tank(s) : 0.7 [kg]
weight radiator : 1.6 [kg]
weight fuel line 0.15 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 6.9 [kg]
total weight propulsion system : 97 [kg](27.3 [%])
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fuselage skeleton (wood gauge : 4.81 [cm]): 38 [kg]
bracing : 1.7 [kg]
is de romp bekleed met stof ? nee
weight controls : 4.4 [kg]
weight engine mount : 0.6 [kg]
total weight fuselage : 45 [kg](12.7 [%])
***************************************************************
weight wing covering (doped linen fabric) : 30 [kg]
total weight ribs (15 ribs) : 21 [kg]
load on front upper spar (clmax) per running metre : 203.9 [N]
total weight 8 spars : 18 [kg]
weight wings : 69 [kg]
weight wing/square meter : 1.46 [kg]
weight 16 interplane struts & cabane : 22.4 [kg]
weight cables (116 [m]) : 3.2 [kg] (= 28 [gram] per metre)
diameter cable : 2.1 [mm]
weight fin & rudder (1.8 [m2]) : 2.8 [kg]
weight stabilizer & elevator (5.3 [m2]): 8.1 [kg]
total weight wing surfaces & bracing : 106 [kg] (29.8 [%])
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Huffman Prairie, 13km North East of Dayton, now the location of Wright-Paterson AFB.
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calculated empty weight : 279 [kg](78.8 [%])
weight oil for 0.4 hours flying : 0.1 [kg]
weight cooling fluids : 2.4 [kg]
calculated operational weight empty : 281 [kg] (79.5 [%])
estimated operational weight empty : 280 [kg] (79.1 [%])
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weight crew : 68 [kg]
!! amount fuel more than capacity fuel tanks ! flyingtime 0.4 hrs to high or tank to small
weight fuel for 0.4 hours flying : 3 [kg]
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operational weight : 353 [kg](99.6 [%])
fuel reserve : -0 [kg] enough for -0.05 [hours] flying
possible additional useful load : 2 [kg]
operational weight fully loaded : 354 [kg] with fuel tank filled for 100 [%]
published maximum take-off weight : 354 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (operational without bombload) : 31.52 [kg/kW]
total power : 11.2 [kW] at 1100 [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 : 3.4 [g]
design flight time : 0.28 [hours]
design cycles : 135 sorties, design hours : 23 [hours]
operational wing loading : 73 [N/m^2]
wing stress (3 g) during operation : 150 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.24 ["]
max. angle of attack (stalling angle) : 12.89 ["]
angle of attack at max. speed : 4.28 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° :0.10 [ ]
lift coefficient at max. angle of attack : 1.14 [ ]
lift coefficient at max. speed : 0.45 [ ]
induced drag coefficient at max. speed : 0.0176 [ ]
drag coefficient at max. speed : 0.0454 [ ]
drag coefficient (zero lift) : 0.0278 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 37 [km/u]
landing speed at sea-level: 44 [km/hr]
min. drag speed (max endurance) : 53 [km/hr] at 100 [m](power :86 [%])
min. power speed (max range) : 55 [km/hr] at 100 [m] (power:90 [%])
max. rate of climb speed : 45.6 [km/hr] at sea-level
cruising speed : 58 [km/hr] op 100 [m] (power:95 [%])
design speed prop : 59 [km/hr]
maximum speed : 59 [km/hr] op 100 [m] (power:98 [%])
climbing speed at sea-level : 19 [m/min]
calculation : *9* (regarding various performances)
static prop wash : 6 [m/s]
take-off distance at sea-level : 19 [m]
lift/drag ratio : 10.07 [ ]
max. theoretical ceiling : 978 [m] with flying weight :352 [kg] line 3370
max attainable height is limited by amount of fuel carried
published ceiling (150 [m]
practical ceiling (operational weight) : 312 [m] with flying weight :353 [kg]
after 5 minutes flight the engine got overheated, and they had to land. for this reason the max. attainable height would have been max.100m
max attainable height is also limited by amount of fuel carried, if the engine would not overheat then a height of 422m could have been reached before running out of fuel.
practical ceiling (operational weight) : 422 [m] with flying weight :352 [kg]
But the Flyer II never reached this height, max. height will have been around 50m for the Wrights had difficulty enough to keep the airplane stable in flight.
At Huffman Prairie the Wright brothers built a small shed to shelter the Flyer II
turning speed at CLmax : 38.9 [km/u] at 50 [m] height
turn radius at 50m: 25 [m]
time needed for 360* turn 14.4 [seconds] at 50m
load factor at max. angle turn 1.11 ["g"]
calculation *10* (action radius & endurance)
operational endurance : 0.35 [hours] with 1 crew and 1.9 [kg] useful load and 100.0 [%] fuel
published endurance : 0.35 [hours] with 1 crew and possible useful load : 1.9 [kg] and 100.0 [%] fuel
The Wright flyer maximum time in the air was 5 mins before the engine started to overheat. So the operational endurance is only hypothetical as for the maximum action radius.
maximum action radius : 17 [km] with 1 crew and 0 [kg] useful load ( 6.3 [liter] additional fuel neeeded)
max range theoretically with additional fuel tanks for total 6.3 [litre] fuel : 33.9 [km]
useful load with action-radius 250km : 0 [kg]
production (500 km) : 0 [tonkm/hour]
Literature :
Historische vliegtuigen page 173
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/
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(c) B van der Zalm 19 July 2020 contact : info.aircraftinvestigation@gmail.com python 3.7.4