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weight and performance calculations for the Felixtowe F.2A
Felixtowe F.2A
role : maritime patrol, ASW
importance : ***
first flight : operational : November 1917
country : United-Kingdom
re-design : Lieutenant Commander John Cyrill Porte
production : 100 aircraft
general information :
Improved Curtiss H-4 “America” flying boat. Redesigned two-step hull by J.C.Porte
RN and more powerful Rolls Royce Eagle VIII engines. Curtiss also started to built this
version under the designation H-16.
Performed well as ASW flying boat, intensively used last year WWI.
users : RNAS
crew : 4
armament : 4 movable 7.70 [mm] (0.303 in) Lewis machine-guns
engine : 2 Rolls Royce Eagle VIII liquid-cooled 12 -cylinder V-engine 345 [hp]
(253.7 KW)
dimensions :
wingspan : 29.15 [m], length : 14.1 [m], height : 5.34[m]
wing area : 105.3 [m^2]
weights :
max.take-off weight : 4980 [kg]
empty weight operational : 3424 [kg] bombload : 209 [kg]
performance :
maximum speed : 153 [km/u] op 600 [m]
climbing speed : 159 [m/min]
service ceiling : 2926 [m]
endurance : 6.0 [hours]
estimated action radius : 413 [km]
description :
4-bay biplane flying boat
2 (aid) tip floats
upper wingtips supported by slanted flying wires
two spar upper and lower wing
engines attached to the wings , landing gear, fuel and bombload in or attached to fuselage
airscrew :
two fixed pitch 4 -bladed tractor airscrews with max. efficiency :0.60 [ ]
estimated diameter airscrew 2.69 [m]
angle of attack prop : 19.44 [ ]
reduction : 0.60 [ ]
airscrew revs : 1140 [r.p.m.]
pitch at Max speed 2.24 [m]
blade-tip speed at Vmax and max revs. : 166 [m/s]
calculation : *1* (dimensions)
mean wing chord : 2.01 [m]
calculated wing chord (rounded tips): 2.12 [m]
wing aspect ratio : 14.53 []
estimated gap : 1.90 [m]
gap/chord : 0.95 [ ]
seize (span*length*height) : 2195 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 7.6 [kg/hr]
fuel consumption(cruise speed) : 122.3 [kg/hr] (166.8 [litre/hr]) at 70 [%] power
distance flown for 1 kg fuel : 1.13 [km/kg]
estimated total fuel capacity : 1136 [litre] (833 [kg])
calculation : *3* (weight)
weight engine(s) dry : 751.1 [kg] = 1.48 [kg/KW]
weight reduction gear : 55.8 [kg]
weight 74 litre oil tank : 9.3 [kg]
oil tank filled with 3.8 litre oil : 3.4 [kg]
oil in engine 28 litre oil : 25.4 [kg]
Felixtowe F.2A reg.nr. N4465 based at Killingholme, mid-1918
fuel in engine 3 litre fuel : 2.5 [kg]
weight 71 litre gravity patrol tank(s) : 6.9 [kg]
weight radiator : 81.2 [kg]
weight exhaust pipes & fuel lines 37.1 [kg]
weight self-starter : 6.2 [kg]
weight cowling 10.1 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 96.4 [kg]
total weight propulsion system : 1132 [kg](22.7 [%])
***************************************************************
fuselage skeleton (wood gauge : 10.78 [cm]): 419 [kg]
bracing : 52.1 [kg]
plywood/wood covering hull (gauche : 1.6 [cm]): 376.2 [kg]
weight controls + indicators: 10.1 [kg]
weight seats : 12.0 [kg]
weight other details, lighting set, etc. : 9.1 [kg]
weight bomb storage : 14.6 [kg]
weight two 532 [litre] main fuel tanks empty : 102.2 [kg]
weight interior + equipment + fuel lines: 73 [kg]
weight 1 fire extinguisher : 3 [kg]
total weight fuselage : 1071 [kg](21.5 [%])
***************************************************************
weight wing covering (doped linen fabric) : 67 [kg]
total weight ribs (203 ribs) : 296 [kg]
weight engine mounts : 25 [kg]
load on front upper spar (clmax) per running metre : 923.5 [N]
load on rear upper spar (vmax) per running metre : 462.3 [N]
total weight 8 spars : 351 [kg]
weight wings : 715 [kg]
weight wing/square meter : 6.79 [kg]
weight 16 interplane struts & cabane : 74.6 [kg]
weight cables (150 [m]) : 83.1 [kg] (= 553 [gram] per metre)
diameter cable : 9.5 [mm]
weight fin & rudder (9.9 [m2]) : 68.4 [kg]
weight stabilizer & elevator (11.8 [m2]): 81.2 [kg]
total weight wing surfaces & bracing : 1047 [kg] (21.0 [%])
*******************************************************************
weight machine-gun(s) : 50.8 [kg]
weight Scarff ring mounting mg :27.7 [kg]
weight armament : 78 [kg]
********************************************************************
weight 2 tip floats : 65 [kg] (1.3 [%])
*******************************************************************
Two petrol tanks inside the fuselage, total capacity = 250 imp.gallon = 1137 litre
********************************************************************
calculated empty weight : 3394 [kg](68.1 [%])
weight oil for 7.2 hours flying : 54.8 [kg]
weight cooling fluids : 104.5 [kg]
weight 20 drums empty : 4.1 [kg]
weight ammunition (940 rounds) : 29.9 [kg]
weight Very pistol with cartridges : 3.6 [kg]
weight automatic pistol with spare magazines : 1.2 [kg]
*******************************************************************
calculated operational weight empty : 3588 [kg] (72.0 [%])
published operational weight empty : 3424 [kg] (68.8 [%])
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~U~
weight crew : 324 [kg]
weight fuel for 2.0 hours flying : 245 [kg]
********************************************************************
operational weight : 4156 [kg](83.5 [%])
bomb load : 209 [kg]
operational weight bombing mission : 4365 [kg]
F.2A (N4545) in dazzle scheme during an ASW patrol flight
fuel reserve : 588 [kg] enough for 4.81 [hours] flying
possible additional useful load : 26 [kg]
operational weight fully loaded : 4980 [kg] with fuel tank filled for 100 [%]
published maximum take-off weight : 4980 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (operational without bombload) : 8.19 [kg/kW]
total power : 507.5 [kW] at 1900 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 1.4 [g] at 1000 [m]
limit load : 2.5 [g] ultimate load : 3.8 [g] load factor : 1.5 [g]
design flight time : 4.20 [hours]
design cycles : 298 sorties, design hours : 1250 [hours]
F.2A (early) s/n N4512 based at Great Yarmouth, June 1918
operational wing loading : 387 [N/m^2]
wing stress (3 g) during operation : 171 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.26 ["]
max. angle of attack (stalling angle) : 9.21 ["]
angle of attack at max. speed : 2.62 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° :0.12 [ ]
lift coefficient at max. angle of attack : 1.00 [ ]
lift coefficient at max. speed : 0.37 [ ]
induced drag coefficient at max. speed : 0.0040 [ ]
drag coefficient at max. speed : 0.0589 [ ]
drag coefficient (zero lift) : 0.0548 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 90 [km/u]
landing speed at sea-level (OW without bombload): 109 [km/hr]
min. drag speed (max endurance) = minimum speed*1.1 at cruise height : 107 [km/hr] at 1463 [m] (power:39 [%])
min. power speed (max range) : 107 [km/hr] at 1463 [m] (power:39 [%])
max. rate of climb speed : 91.2 [km/hr] at sea-level
cruising speed : 138 [km/hr] op 1463 [m] (power:64 [%])
design speed prop : 145 [km/hr]
maximum speed : 153 [km/hr] op 600 [m] (power:90 [%])
climbing speed at sea-level (without bombload) : 258 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 340 [m]
lift/drag ratio : 12.49 [ ]
max. practical ceiling : 4475 [m] with flying weight :3695 [kg]
Rather fancy painted ! F.2A N4283 was flown by the famous Flight Commander Robert Leckie. On 4 June 1918 Leckie led an offensive patrol of four Felixstowe F.2A flying boats and a Curtiss H.12 towards the Haaks Light Vessel off the Dutch coast. They saw no enemy aircraft until one of the F.2A's, number N.4533, was forced down with a broken fuel feed-pipe. Five enemy seaplanes appeared, but seemed more interested in attacking the crippled F.2A. The remaining aircraft circled N.4533 as it taxied towards to the Dutch coast (where the crew eventually burned their aircraft before being interned), until ten more German seaplanes appeared. Leckie promptly led his small force into a head on attack, and a dogfight ensued which lasted for 40 minutes. Despite further mechanical difficulties – two other F2A's (incl. N4302 who landed on the sea between Terschelling and Vlieland for repairs). also had problems with their fuel pipes and had to effect makeshift repairs while in the middle of the action – two German aircraft were shot down, and four badly damaged before the Germans broke off the action, for the loss of one F.2A and the Curtiss (its crew survived to be interned by the Dutch),[16] and one man killed.[17] Leckie's force returned to Great Yarmouth, and in his report he bitterly remarked "...these operations were robbed of complete success entirely through faulty petrol pipes... It is obvious that our greatest foes are not the enemy..."[16] (from Wikipedia)
practical ceiling (operational weight): 4000 [m] with flying weight :4156 [kg]
practical ceiling fully loaded (mtow- 1 hour fuel) : 3325 [m] with flying weight :4858 [kg]
published ceiling (2926 [m]
climb to 1500m (without bombload) : 6.62 [min]
climb to 3000m (without bombload) : 17.46 [min]
max. dive speed : 396.7 [km/hr] at 2325 [m] height
load factor at max. angle turn 2.16 ["g"]
turn radius at 500m: 76 [m]
time needed for 360* turn 12.7 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 6.81 [hours] with 4 crew and 235 [kg] bombload and 100.0 [%] fuel
published endurance : 6.00 [hours] with 4 crew and possible useful (bomb) load : 334 [kg] and 88.1 [%] fuel
action radius : 590 [km] with 4 crew and 20[kg] photo camera/radio transmitter or bombload
max range theoretically with additional fuel tanks for total 1836 [litre] fuel : 1516 [km]
useful load with action-radius 250km : 902 [kg]
production : 124.19 [tonkm/hour]
oil and fuel consumption per tonkm : 1.05 [kg]
Felixtowe F.2A s/n N4291 “Black Bess” Flown by Capt. Thomas Cooper Pattinson, DFC and Capt.Albert Henry Munday and sgt. Henry Robert Stubbington, DFM, they managed to shot down Zeppelin LZ107 L 62 on 10 May 1918. The Zeppelin crashed north of Helgoland, near Borkum Deep
Literature :
Praktisch handboek vliegtuigen deel 1 page 213
Jane’s Fighting aircraft WWI page 18,32
http://www.roden.eu/HTML/014.htm
Observers and navigators, C.G.Jefford page 28
Flight 16 December 1955
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 January 2020 contact : info.aircraftinvestigation@gmail.com python 3.7.4