AIRCRAFT INVESTIGATION
weight and performance calculations for the Sopwith 5F.1 Dolphin
Sopwith 5F.1 Dolphin
role : fighter
importance : ****
first flight : May 1917 operational : February 1918
country : United-Kingdom
design :
production : 2072 aircraft
general information :
The Dolphin's design gave special attention to the view from the cockpit, probably
resulting from the very limited view from the Sopwith Camel. The Dolphin had negative wing stagger and the upper wing had an open rectangle, where normal
the centre section was, providing the pilot with a wide view at the sky above. The
flight characteristics were excellent, but the standard 147KW Hispano-Suiza engine gave some problems.
The view was still not very good for the pilot, cramped between the wing struts and bracing wires, with four machine guns just before his nose.
Many pilots therefore removed 1 or 2 machineguns to give more space and better
performance.
Climb to 1520m : 5 minutes.
Patrol capacity : 27 Gallon = 123 litre = ca. 88 kg.
Chord : 1.37m
users : France, US, GB
crew : 1
armament : 2 synchronized 7.70 [mm] (0.303 in) Vickers machine-guns
and 1 or 2 movable 7.70 [mm] (0.303 in) Lewis machine-gun firing upward
engine : 1 Hispano Suiza 8B liquid-cooled 8 -cylinder V-engine 200 [hp](147.1 KW)
dimensions :
wingspan : 9.91 [m], length : 6.78 [m], height : 2.59[m]
wing area : 24.46 [m^2]
weights :
max.take-off weight : 908 [kg]
empty weight operational : 641 [kg] bombload : 45 [kg]
performance :
maximum speed : 206 [km/u] op 3048 [m]
climbing speed : 252 [m/min]
service ceiling : 6400 [m]
endurance : 2.28 [hours]
estimated action radius : 211 [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 2 -bladed tractor airscrew with max. efficiency :0.67 [ ]
estimated diameter airscrew 2.79 [m]
angle of attack prop : 18.35 [ ]
reduction : 0.75 [ ]
airscrew revs : 1575 [r.p.m.]
pitch at Max speed 2.18 [m]
blade-tip speed at Vmax and max revs. : 237 [m/s]
calculation : *1* (dimensions)
mean wing chord : 1.23 [m]
calculated wing chord (rounded tips): 1.37 [m]
wing aspect ratio : 8.03 []
gap : 1.30 [m]
gap/chord : 1.05 [ ]
seize (span*length*height) : 174 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 2.1 [kg/hr]
fuel consumption(cruise speed) : 34.8 [kg/hr] (47.4 [litre/hr]) at 66 [%] power
distance flown for 1 kg fuel : 5.33 [km/kg]
estimated total fuel capacity : 123 [litre] (90 [kg])
calculation : *3* (weight)
weight engine(s) dry : 225.0 [kg] = 1.53 [kg/KW]
weight reduction gear : 10.9 [kg]
weight 10 litre oil tank : 0.8 [kg]
oil tank filled with 1.1 litre oil : 1.0 [kg]
oil in engine 8 litre oil : 7.4 [kg]
fuel in engine 1 litre fuel : 0.7 [kg]
weight 20 litre gravity patrol tank(s) : 3.0 [kg]
weight radiator : 23.5 [kg]
weight exhaust pipes & fuel lines 16.9 [kg]
weight self-starter : 3.6 [kg]
weight cowling 5.9 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 22.1 [kg]
total weight propulsion system : 331 [kg](36.5 [%])
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fuselage skeleton (wood gauge : 5.29 [cm]): 49 [kg]
bracing : 2.3 [kg]
fuselage covering ( 8.7 [m2] doped linen fabric) : 2.8 [kg]
weight controls + indicators: 5.7 [kg]
weight seats : 3.0 [kg]
weight other details, lighting set, etc. : 5.1 [kg]
weight bomb storage : 3.2 [kg]
weight 103 [litre] main fuel tank empty : 8.2 [kg]
weight engine mounts & firewalls : 7 [kg]
total weight fuselage : 86 [kg](9.5 [%])
***************************************************************
weight wing covering (doped linen fabric) : 16 [kg]
total weight ribs (60 ribs) : 54 [kg]
load on front upper spar (clmax) per running metre : 565.7 [N]
load on rear upper spar (vmax) per running metre : 267.5 [N]
total weight 8 spars : 32 [kg]
weight wings : 101 [kg]
weight wing/square meter : 4.15 [kg]
weight 8 interplane struts & cabane : 8.2 [kg]
weight cables (58 [m]) : 2.9 [kg] (= 50 [gram] per metre)
diameter cable : 2.9 [mm]
weight fin & rudder (1.1 [m2]) : 4.9 [kg]
weight stabilizer & elevator (2.8 [m2]): 11.6 [kg]
total weight wing surfaces & bracing : 129 [kg] (14.2 [%])
*******************************************************************
weight machine-gun(s) : 44.5 [kg]
Lewis machine gun cross tube swivel-mounting : 2.0 [kg]
weight ammunition magazine(s) :2.7 [kg]
weight C.C.(Constaninesco-Colley)hydraulic synchronization gear : 2.0 [kg]
weight Aldis gunsight : 0.8 [kg]
weight armament : 52 [kg]
********************************************************************
wheel pressure : 454.0 [kg]
weight 2 wheels (690 [mm] by 77 [mm]) : 19.5 [kg]
weight tailskid : 3.0 [kg]
weight undercarriage with axle 17.3 [kg]
total weight landing gear : 39.9 [kg] (4.4 [%]
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calculated empty weight : 638 [kg](70.3 [%])
weight oil for 2.7 hours flying : 5.6 [kg]
weight cooling fluids : 31.8 [kg]
weight 5 drums empty : 1.0 [kg]
weight ammunition (1035 rounds) : 29.4 [kg]
weight Very pistol with cartridges : 3.6 [kg]
weight automatic pistol with spare magazines : 1.2 [kg]
*******************************************************************
calculated operational weight empty : 710 [kg] (78.2 [%])
published operational weight empty : 641 [kg] (70.6 [%])
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weight crew : 81 [kg]
weight fuel for 1.5 hours flying : 52 [kg]
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operational weight : 843 [kg](92.8 [%])
bomb load : 45 [kg]
operational weight bombing mission : 888 [kg]
fuel reserve : 20 [kg] enough for 0.58 [hours] flying
operational weight fully loaded : 908 [kg] with fuel tank filled for 80 [%]
published maximum take-off weight : 908 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (operational without bombload) : 5.73 [kg/kW]
total power : 147.1 [kW] at 2100 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 3.9 [g] at 1000 [m]
limit load : 4.5 [g] ultimate load : 6.8 [g] load factor : 1.6 [g]
design flight time : 1.82 [hours]
design cycles : 156 sorties, design hours : 285 [hours]
operational wing loading : 338 [N/m^2]
wing stress (3 g) during operation : 244 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.40 ["]
max. angle of attack (stalling angle) : 11.99 ["]
angle of attack at max. speed : 1.26 ["]
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 : 0.23 [ ]
induced drag coefficient at max. speed : 0.0037 [ ]
drag coefficient at max. speed : 0.0358 [ ]
drag coefficient (zero lift) : 0.0321 [ ]
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) : 121 [km/hr] at 3200 [m](power :32 [%])
min. power speed (max range) : 130 [km/hr] at 3200 [m] (power:33 [%])
max. rate of climb speed : 122.1 [km/hr] at sea-level
cruising speed : 185 [km/hr] op 3200 [m] (power:57 [%])
design speed prop : 200 [km/hr]
maximum speed : 206 [km/hr] op 3048 [m] (power:75 [%])
climbing speed at sea-level (without bombload) : 403 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 122 [m]
lift/drag ratio : 10.51 [ ]
max. practical ceiling : 7325 [m] with flying weight :774 [kg]
practical ceiling (operational weight): 6900 [m] with flying weight :843 [kg]
practical ceiling fully loaded (mtow- 1 hour fuel) : 6700 [m] with flying weight :873 [kg]
published ceiling (6400 [m]
climb to 1500m (without bombload) : 3.69 [min]
climb to 3000m (without bombload) : 8.17 [min]
max. dive speed : 469.9 [km/hr] at 5700 [m] height
load factor at max. angle turn 2.66 ["g"]
turn radius at 500m: 56 [m]
time needed for 360* turn 9.5 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 2.08 [hours] with 1 crew and 45 [kg] useful (bomb)load and 80.3 [%] fuel
published endurance : 2.28 [hours] with 1 crew and possible useful (bomb) load : 38 [kg] and 88.1 [%] fuel
action radius : 259 [km] with 1 crew and 20[kg] photo camera/radio transmitter or bombload
max range theoretically with additional fuel tanks for total 207 [litre] fuel : 808 [km]
useful load with action-radius 250km : 58 [kg]
production : 10.70 [tonkm/hour]
oil and fuel consumption per tonkm : 3.44 [kg]
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Literature :
praktisch handboek vliegtuigen deel I page 208
Jane's Fighting Aircraft WWI page 86
RAF Yearbook '85 page 63
Armament of British Aircraft 1909-1939 page 338, 339
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 address
(c) B van der Zalm 23 November 2019 contact : info.aircraftinvestigation@gmail.com python 3.7.4