Sopwith Baby

AIRCRAFT INVESTIGATION

weight and performance calculations for the Sopwith type 8200 Baby

Sopwith type 8200 Baby

role : light maritime single-seat scout (ship based)

importance : ****

first flight : operational : October 1916

country : United-Kingdom

design :

production : 457 aircraft (Sopwith, Kingston 100, Blackburn, Leeds, 186)

general information : Successor of the Schneider floatplane. It was extensively used by

the RNAS from coastal air station and from 11 seaplane carriers over the North see, the

Channel but also in the Mediterranean see for reconnaissance and ASW. One aircraft

was interned by the Dutch (reg.T-1).

Gap : 1.37m chord : 1.57m total area of tail : 3.16m2 area of elevators : 1.39m2 area of

rudder : 0.65m2 area of fin : 0.37m2 tank capacity : Petrol : 25 gallon = 114 litre

oil : 6 gallon = 27.3 litre, climb to 3048m in 35 min.

For ASW it could carry two 65-lb (29.5 kg) bombs under the fuselage.

The Lewis gun and ammunition weighed 55 lb = 25 kgs

users : RNAS, Italy (102, license built), France (33)

crew : 1

armament : 1 mechanical synchronized 7.70 [mm] (0.303 in) Lewis machine-gun

engine : 1 Clerget 9B air-cooled 9 -cylinder two-valve rotary engine 130 [hp](95.6 KW)

dimensions :

wingspan : 7.82 [m], length : 7.01 [m], height : 3.05[m]

wing area : 20.9 [m^2]

weights :

max.take-off weight : 779 [kg]

empty weight operational : 557 [kg] bombload : 56 [kg]

performance :

maximum speed : 158 [km/hr] at sea-level

climbing speed : 87 [m/min]

service ceiling : 3050 [m]

endurance : 2.33 [hours]

estimated action radius : 166 [km]

description :

1-bay two float biplane with tail float

no tip floats

two spar upper and lower wing

Drawing with beaching gear attached

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 2.69 [m]

angle of attack prop : 18.39 [ ]

reduction : 1.00 [ ]

airscrew revs : 1250 [r.p.m.]

pitch at Max speed 2.11 [m]

blade-tip speed at Vmax and max revs. : 181 [m/s]

calculation : *1* (dimensions)

mean wing chord : 1.34 [m]

calculated wing chord (rounded tips): 1.54 [m]

wing aspect ratio : 5.85 []

gap : 1.37 [m]

gap/chord : 1.03 [ ]

seize (span*length*height) : 167 [m^3]

calculation : *2* (fuel consumption)

oil consumption : 6.0 [kg/hr]

fuel consumption(cruise speed) : 31.7 [kg/hr] (43.3 [litre/hr]) at 73 [%] power

distance flown for 1 kg fuel : 4.48 [km/kg]

estimated total fuel capacity : 114 [litre] (84 [kg])

calculation : *3* (weight)

weight engine(s) dry : 173.0 [kg] = 1.81 [kg/KW]

weight 21 litre oil tank : 1.8 [kg]

oil tank filled with 0.7 litre oil : 0.6 [kg]

oil in engine 1 litre oil : 0.5 [kg]

fuel in engine 1 litre fuel : 0.5 [kg]

weight 18 litre gravity patrol tank(s) : 2.8 [kg]

weight cowling 3.8 [kg]

weight airscrew(s) (wood) incl. boss & bolts : 19.0 [kg]

total weight propulsion system : 200 [kg](25.7 [%])

***************************************************************

fuselage skeleton (wood gauge : 6.50 [cm]): 67 [kg]

bracing : 2.9 [kg]

fuselage covering ( 7.2 [m2] doped linen fabric) : 2.3 [kg]

weight controls + indicators: 5.2 [kg]

weight seats : 3.0 [kg]

weight other details, lighting set, etc. : 5.1 [kg]

weight bomb storage : 3.9 [kg]

weight 96 [litre] main fuel tank empty : 7.7 [kg]

weight engine mounts & firewalls : 5 [kg]

total weight fuselage : 102 [kg](13.1 [%])

***************************************************************

weight wing covering (doped linen fabric) : 13 [kg]

total weight ribs (48 ribs) : 46 [kg]

load on front upper spar (clmax) per running metre : 1071.8 [N]

load on rear upper spar (vmax) per running metre : 288.0 [N]

total weight 8 spars : 38 [kg]

weight wings : 97 [kg]

weight wing/square meter : 4.65 [kg]

weight 4 interplane struts & cabane : 9.2 [kg]

weight cables (40 [m]) : 2.4 [kg] (= 59 [gram] per metre)

diameter cable : 3.1 [mm]

weight fin & rudder (0.9 [m2]) : 4.1 [kg]

weight stabilizer & elevator (2.4 [m2]): 11.1 [kg]

total weight wing surfaces & bracing : 124 [kg] (15.9 [%])

*******************************************************************

weight machine-gun(s) : 12.7 [kg]

weight mechanical synchronization gear : 1.5 [kg]

weight Aldis gunsight : 0.8 [kg]

weight armament : 15 [kg]

********************************************************************

weight floats : 93 [kg] (11.9 [%])

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N-2079

********************************************************************

calculated empty weight : 534 [kg](68.5 [%])

weight oil for 2.8 hours flying : 16.8 [kg]

weight 5 drums empty : 1.0 [kg]

weight ammunition (235 rounds) : 7.5 [kg]

weight Very pistol with cartridges : 3.6 [kg]

weight automatic pistol with spare magazines : 1.2 [kg]

*******************************************************************

calculated operational weight empty : 563 [kg] (72.3 [%])

published operational weight empty : 557 [kg] (71.5 [%])

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| o |

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= =

weight crew : 81 [kg]

weight fuel for 2.0 hours flying : 63 [kg]

********************************************************************

operational weight : 707 [kg](90.8 [%])

bomb load : 56 [kg]

operational weight bombing mission : 763 [kg]

fuel reserve : 16 [kg] enough for 0.50 [hours] flying

operational weight fully loaded : 779 [kg] with fuel tank filled for 94 [%]

published maximum take-off weight : 779 [kg] (100.0 [%])

I||==|

calculation : * 4 * (engine power)

power loading (operational without bombload) : 7.40 [kg/kW]

total power : 95.6 [kW] at 1250 [r.p.m]

calculation : *5* (loads)

manoeuvre load : 2.3 [g] at 1000 [m]

limit load : 3.5 [g] ultimate load : 5.2 [g] load factor : 2.8 [g]

design flight time : 1.86 [hours]

design cycles : 791 sorties, design hours : 1475 [hours]

operational wing loading : 332 [N/m^2]

wing stress (3 g) during operation : 214 [N/kg] at 3g emergency manoeuvre

calculation : *6* (angles of attack)

angle of attack zero lift : -1.53 ["]

max. angle of attack (stalling angle) : 12.84 ["]

angle of attack at max. speed : 2.09 ["]

calculation : *7* (lift & drag ratios

lift coefficient at angle of attack 0° :0.12 [ ]

lift coefficient at max. angle of attack : 1.13 [ ]

lift coefficient at max. speed : 0.28 [ ]

induced drag coefficient at max. speed : 0.0078 [ ]

drag coefficient at max. speed : 0.0583 [ ]

drag coefficient (zero lift) : 0.0505 [ ]

calculation : *8* (speeds

stalling speed at sea-level (OW): 79 [km/u]

landing speed at sea-level (OW without bombload): 95 [km/hr]

min. drag speed (max endurance) : 106 [km/hr] at 1525 [m](power :49 [%])

min. power speed (max range) : 117 [km/hr] at 1525 [m] (power:53 [%])

max. rate of climb speed : 99.8 [km/hr] at sea-level

cruising speed : 142 [km/hr] op 1525 [m] (power:71 [%])

design speed prop : 150 [km/hr]

maximum speed : 158 [km/hr] op 100 [m] (power:99 [%])

climbing speed at sea-level (without bombload) : 255 [m/min]

calculation : *9* (regarding various performances)

take-off distance at sea-level : 176 [m]

lift/drag ratio : 7.16 [ ]

max. practical ceiling : 4450 [m] with flying weight :647 [kg]

practical ceiling (operational weight): 3900 [m] with flying weight :707 [kg]

practical ceiling fully loaded (mtow- 1 hour fuel) : 3550 [m] with flying weight :747 [kg]

published ceiling (3050 [m]

climb to 1500m (without bombload) : 6.77 [min]

climb to 3000m (without bombload) : 18.18 [min]

max. dive speed : 338.7 [km/hr] at 2550 [m] height

load factor at max. angle turn 1.73 ["g"]

turn radius at 500m: 63 [m]

time needed for 360* turn 13.4 [seconds] at 500m

calculation *10* (action radius & endurance)

operational endurance : 2.50 [hours] with 1 crew and 56 [kg] useful (bomb)load and 94.4 [%] fuel

published endurance : 2.33 [hours] with 1 crew and possible useful (bomb) load : 61 [kg] and 88.1 [%] fuel

Main float submerged displacement 566 kgs

action radius : 258 [km] with 1 crew and 20[kg] photo camera/radio transmitter or bombload

max range theoretically with additional fuel tanks for total 201 [litre] fuel : 661 [km]

useful load with action-radius 250km : 36 [kg]

production : 5.11 [tonkm/hour]

oil and fuel consumption per tonkm : 7.39 [kg]

I_°==/

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Literature :

Praktisch handboek vliegtuigen deel 1 page 199

Bombers 1914-19 page168

Jane’s FAWOI page 59

Armament of British Aircraft 1909-1939 page 323

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

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