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RNAS H-12 “Large America”
Curtiss H-12A
role : maritime patrol, ASW
first flight : operational : May 1917
country : United States of America
design :
production : 50 aircraft
general information :
Wing Curve : RAF no.6 fuel tank capacity : 300 gallons = 1364 litre, oil capacity : 10
gallons = 45.5 litre. Gap : 2.45m
Zeppelin LZ64 L 22 was destroyed by RNAS Curtis H12 flying boat flown by Flight Commander Robert Leckie (later Air Vice Marshal) near Terschelling on 14 May 1917 during a reconnaissance mission. (Leckie was also credited in the downing of LZ 112)
users : H-12A : RNAS, H-12L: USN
crew : 4
armament : 5 movable 7.70 [mm] (0.303 in) Lewis machine-guns
engine : 2 Rolls Royce Eagle I liquid-cooled 12 -cylinder V-engine 275 [hp](202.3 KW)
dimensions :
wingspan : 28.26 [m], length : 14.18 [m], height : 5.03[m]
wing area : 112.97 [m^2]
weights :
max.take-off weight : 4614 [kg]
empty weight operational : 3155 [kg] bombload : 210 [kg]
performance :
maximum speed : 137 [km/hr] at sea-level
climbing speed : 102 [m/min]
service ceiling : 3292 [m]
endurance : 7.94 [hours]
estimated action radius : 490 [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 2 -bladed tractor airscrews with max. efficiency :0.64 [ ]
estimated diameter airscrew 3.11 [m]
angle of attack prop : 10.39 [ ]
fine pitch
reduction : 1.00 [ ]
airscrew revs : 1700 [r.p.m.]
pitch at Max speed 1.34 [m]
blade-tip speed at Vmax and max revs. : 279 [m/s]
calculation : *1* (dimensions)
mean wing chord : 2.22 [m]
calculated wing chord (rounded tips): 2.36 [m]
wing aspect ratio : 12.72 []
gap : 2.45 [m]
gap/chord : 1.10 [ ]
seize (span*length*height) : 2016 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 6.1 [kg/hr]
fuel consumption(cruise speed) : 111.0 [kg/hr] (151.4 [litre/hr]) at 69 [%] power
distance flown for 1 kg fuel : 1.11 [km/kg]
estimated total fuel capacity : 1364 [litre] (1000 [kg])
calculation : *3* (weight)
weight engine(s) dry : 627.0 [kg] = 1.55 [kg/KW]
weight 75 litre oil tank : 6.3 [kg]
oil tank filled with 3.0 litre oil : 2.7 [kg]
oil in engine 23 litre oil : 20.2 [kg]
fuel in engine 3 litre fuel : 2.0 [kg]
weight 64 litre gravity patrol tank(s) : 9.7 [kg]
weight radiator : 58.0 [kg]
weight exhaust pipes & fuel lines 28.5 [kg]
weight self-starter : 5.0 [kg]
weight cowling 8.1 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 60.7 [kg]
total weight propulsion system : 822 [kg](17.8 [%])
***************************************************************
fuselage skeleton (wood gauge : 10.48 [cm]): 399 [kg]
bracing : 49.9 [kg]
plywood/wood covering hull (gauche : 1.6 [cm]): 390.8 [kg]
weight controls + indicators: 10.0 [kg]
weight seats : 12.0 [kg]
weight other details, lighting set, etc. : 9.1 [kg]
weight bomb storage : 14.7 [kg]
weight two 650 [litre] main fuel tanks empty : 104.0 [kg]
weight interior + equipment + fuel lines: 64 [kg]
total weight fuselage : 1054 [kg](22.8 [%])
***************************************************************
weight wing covering (doped linen fabric) : 72 [kg]
total weight ribs (170 ribs) : 274 [kg]
weight engine mounts : 20 [kg]
load on front upper spar (clmax) per running metre : 860.3 [N]
load on rear upper spar (vmax) per running metre : 421.7 [N]
total weight 8 spars : 318 [kg]
weight wings : 665 [kg]
weight wing/square meter : 5.88 [kg]
weight 16 interplane struts & cabane : 152.0 [kg]
weight cables (167 [m]) : 83.8 [kg] (= 501 [gram] per metre)
diameter cable : 9.0 [mm]
weight fin & rudder (9.3 [m2]) : 55.9 [kg]
weight stabilizer & elevator (12.7 [m2]): 75.6 [kg]
total weight wing surfaces & bracing : 1052 [kg] (22.8 [%])
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weight machine-gun(s) : 63.5 [kg]
weight pivot mounting mg :25.0 [kg]
weight armament : 88 [kg]
********************************************************************
weight 2 tip floats : 75 [kg] (1.6 [%])
*******************************************************************
********************************************************************
calculated empty weight : 3091 [kg](67.0 [%])
weight oil for 9.5 hours flying : 57.8 [kg]
weight cooling fluids : 87.4 [kg]
weight 25 drums empty : 5.2 [kg]
weight ammunition (1175 rounds) : 45.1 [kg]
weight signal pistol with cartridges : 3.6 [kg]
*******************************************************************
calculated operational weight empty : 3285 [kg] (71.2 [%])
published operational weight empty : 3155 [kg] (68.4 [%])
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~U~
weight crew : 324 [kg]
weight fuel for 2.0 hours flying : 222 [kg]
********************************************************************
operational weight : 3831 [kg](83.0 [%])
bomb load : 210 [kg]
operational weight bombing mission : 4041 [kg]
fuel reserve : 573 [kg] enough for 5.16 [hours] flying
operational weight fully loaded : 4614 [kg] with fuel tank filled for 79 [%]
published maximum take-off weight : 4614 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (operational without bombload) : 9.47 [kg/kW]
total power : 404.5 [kW] at 1700 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 1.5 [g] at 1000 [m]
limit load : 2.5 [g] ultimate load : 3.8 [g] load factor : 1.5 [g]
design flight time : 5.56 [hours]
design cycles : 270 sorties, design hours : 1500 [hours]
The US Navy used the Curtiss H-12L, it had Liberty engines
operational wing loading : 333 [N/m^2]
wing stress (3 g) during operation : 170 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.07 ["]
max. angle of attack (stalling angle) : 10.21 ["]
angle of attack at max.speed : 2.97 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° :0.10 [ ]
lift coefficient at max. angle of attack : 1.06 [ ]
lift coefficient at max. speed : 0.38 [ ]
induced drag coefficient at max. speed : 0.0048 [ ]
drag coefficient at max.speed : 0.0669 [ ]
drag coefficient (zero lift) : 0.0621 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 82 [km/u]
landing speed at sea-level (OW without bombload): 98 [km/hr]
min. drag speed (max endurance) = minimum speed*1.1 at cruise height : 97 [km/hr] at 1646 [m] (power:42 [%])
RNAS H-12
min. power speed (max range) : 97 [km/hr] at 1646 [m] (power:42 [%])
cruising speed : 123 [km/hr] op 1646 [m] (power:66 [%])
design speed prop : 130 [km/hr]
maximum speed : 137 [km/hr] op 100 [m] (power:99 [%])
climbing speed at sea-level (without bombload) : 226 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 155 [m]
lift/drag ratio : 10.98 [ ]
max. practical ceiling : 4675 [m] with flying weight :3373 [kg]
practical ceiling (operational weight): 4075 [m] with flying weight :3831 [kg]
practical ceiling fully loaded (mtow- 1 hour fuel) : 3225 [m] with flying weight :4503 [kg]
published ceiling (3292 [m]
climb to 1500m (without bombload) : 7.53 [min]
climb to 3000m (without bombload) : 19.55 [min]
max. dive speed : 342.9 [km/hr] at 2225 [m] height
load factor at max. angle turn 2.03 ["g"]
turn radius at 500m: 63 [m]
time needed for 360* turn 12.0 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 7.16 [hours] with 4 crew and 210 [kg] bombload and 79.5 [%] fuel
published endurance : 7.94 [hours] with 4 crew and possible useful (bomb) load : 124 [kg] and 88.1 [%] fuel
action radius : 547 [km] with 4 crew and 20[kg] photo camera/radio transmitter or bombload
max range theoretically with additional fuel tanks for total 1769 [litre] fuel : 1440 [km]
useful load with action-radius 250km : 847 [kg]
production : 104.37 [tonkm/hour]
oil and fuel consumption per tonkm : 1.12 [kg]
Curtiss F-5L version, adapted version of the H-12, entered service with the USN at the end of WWI. It was the US Navy standard patrol aircraft until 1928.
Literature :
praktisch handbook vliegtuigen deel 1 page 242
Wikipedia
Jane’s fighting aircraft WWI page 237
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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(c) B van der Zalm 04 January 2019 contact : info.aircraftinvestigation@gmail.com python 3.7.4
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