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weight and performance calculations for the Curtiss HS-2L
HS-2L flying over Pensacola, Florida in the 1920’s
Curtiss HS-2L
role : maritime patrol, ASW
importance : ***
first flight : operational : August 1918
country : United States of America
design :
production : 1178 aircraft
general information :
Used by the US Navy in France (most HS-1L & few HS-2L). Chord : 1.91m Gap : 2.31m
wing curve : Raf no.6. Fuel : 443 kg Vmin : 88.5 km/u fuel tank capacity : 152.8 gallons
(US) = 578 litre (= 423 kg) oil tank capacity : 8 gallons = 36.4 litre
users : US Navy
crew : 3
armament : 1 movable 7.70 [mm] (0.303 in) Lewis machine-gun for the observer
engine : 1 Liberty L-12 liquid-cooled 12 -cylinder V-engine 400 [hp](294.2 KW)
dimensions :
wingspan : 22.58 [m], length : 11.88 [m], height : 4.45[m]
wing area : 72.3 [m^2]
weights :
max.take-off weight : 2917 [kg]
empty weight operational : 1950 [kg] bombload : 200 [kg]
performance :
maximum speed : 133 [km/hr] at sea-level
climbing speed : 72 [m/min]
service ceiling : 1590 [m]
endurance : 4.61 [hours]
estimated action radius : 276 [km]
description :
4-bay biplane flying boat
2 (aid) tip floats
upper wingtips supported by slanted flying wires
two spar upper and lower wing
engine attached to top plane
airscrew :
fixed pitch 4 -bladed pusher airscrew with max. efficiency :0.58 [ ]
estimated diameter airscrew 2.54 [m]
angle of attack prop : 11.95 [ ]
fine pitch
reduction : 1.00 [ ]
airscrew revs : 1750 [r.p.m.]
pitch at Max speed 1.27 [m]
blade-tip speed at Vmax and max revs. : 236 [m/s]
calculation : *1* (dimensions)
mean wing chord : 1.78 [m]
calculated wing chord (rounded tips): 1.90 [m]
wing aspect ratio : 12.69 []
gap : 2.28 [m]
gap/chord : 1.28 [ ]
seize (span*length*height) : 1194 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 4.1 [kg/hr]
fuel consumption(cruise speed) : 80.9 [kg/hr] (110.4 [litre/hr]) at 81 [%] power
distance flown for 1 kg fuel : 1.48 [km/kg]
estimated total fuel capacity : 578 [litre] (423 [kg])
calculation : *3* (weight)
weight engine(s) dry : 383.0 [kg] = 1.30 [kg/KW]
weight 33 litre oil tank : 2.8 [kg]
oil tank filled with 2.2 litre oil : 2.0 [kg]
oil in engine 16 litre oil : 14.7 [kg]
fuel in engine 2 litre fuel : 1.5 [kg]
weight 47 litre gravity patrol tank(s) : 7.0 [kg]
weight radiator : 42.2 [kg]
weight exhaust pipes & fuel lines 35.0 [kg]
weight self-starter : 7.2 [kg]
weight cowling 11.8 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 55.9 [kg]
total weight propulsion system : 560 [kg](19.2 [%])
***************************************************************
fuselage skeleton (wood gauge : 8.57 [cm]): 224 [kg]
bracing : 23.4 [kg]
plywood/wood covering hull (gauche : 1.5 [cm]): 264.3 [kg]
The well known designation HS-2L is explained as: H for hydroplane, S for single engine, 2 for second version and L for Liberty engine.
weight controls + indicators: 8.6 [kg]
weight seats : 9.0 [kg]
weight other details, lighting set, etc. : 5.1 [kg]
weight bomb storage : 14.0 [kg]
weight 531 [litre] main fuel tank empty : 42.5 [kg]
weight engine mounts & firewalls : 15 [kg]
total weight fuselage : 605 [kg](20.7 [%])
***************************************************************
weight wing covering (doped linen fabric) : 46 [kg]
total weight ribs (134 ribs) : 173 [kg]
load on front upper spar (clmax) per running metre : 832.5 [N]
load on rear upper spar (vmax) per running metre : 354.8 [N]
total weight 8 spars : 238 [kg]
weight wings : 457 [kg]
weight wing/square meter : 6.33 [kg]
weight 16 interplane struts & cabane : 107.7 [kg]
weight cables (145 [m]) : 54.3 [kg] (= 375 [gram] per metre)
diameter cable : 7.8 [mm]
weight fin & rudder (5.9 [m2]) : 38.3 [kg]
weight stabilizer & elevator (6.9 [m2]): 44.3 [kg]
total weight wing surfaces & bracing : 702 [kg] (24.1 [%])
*******************************************************************
weight machine-gun(s) : 12.7 [kg]
weight pivot mounting mg :6.0 [kg]
weight armament : 19 [kg]
********************************************************************
weight 2 tip floats : 35 [kg] (1.2 [%])
*******************************************************************
********************************************************************
calculated empty weight : 1921 [kg](65.9 [%])
weight oil for 5.5 hours flying : 22.8 [kg]
weight cooling fluids : 63.5 [kg]
weight 5 drums empty : 1.0 [kg]
weight ammunition (235 rounds) : 7.5 [kg]
weight signal pistol with cartridges : 3.6 [kg]
weight automatic pistol with spare magazines : 1.2 [kg]
*******************************************************************
calculated operational weight empty : 2020 [kg] (69.2 [%])
published operational weight empty : 1950 [kg] (66.8 [%])
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~U~
weight crew : 243 [kg]
weight fuel for 2.0 hours flying : 162 [kg]
********************************************************************
operational weight : 2425 [kg](83.1 [%])
bomb load : 200 [kg]
operational weight bombing mission : 2625 [kg]
fuel reserve : 262 [kg] enough for 3.23 [hours] flying
possible additional useful load : 31 [kg]
operational weight fully loaded : 2917 [kg] with fuel tank filled for 100 [%]
published maximum take-off weight : 2917 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (operational without bombload) : 8.24 [kg/kW]
total power : 294.2 [kW] at 1750 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 1.4 [g] at 1000 [m]
limit load : 3.0 [g] ultimate load : 4.5 [g] load factor : 1.8 [g]
design flight time : 3.23 [hours]
design cycles : 325 sorties, design hours : 1050 [hours]
operational wing loading : 329 [N/m^2]
wing stress (3 g) during operation : 156 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.07 ["]
max. angle of attack (stalling angle) : 10.22 ["]
After WWI HS-2L were used in Canada as bush plane
angle of attack at max. speed : 3.17 ["]
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 : 0.40 [ ]
induced drag coefficient at max. speed : 0.0053 [ ]
drag coefficient at max. speed : 0.0753 [ ]
drag coefficient (zero lift) : 0.0701 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 81 [km/u]
landing speed at sea-level (OW without bombload): 97 [km/hr]
min. drag speed (max endurance) = minimum speed*1.1 at cruise height : 93 [km/hr] at 795 [m] (power:43 [%])
min. power speed (max range) : 93 [km/hr] at 795 [m] (power:43 [%])
cruising speed : 120 [km/hr] op 795 [m] (power:71 [%])
design speed prop : 126 [km/hr]
maximum speed : 133 [km/hr] op 100 [m] (power:99 [%])
climbing speed at sea-level (without bombload) : 235 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 158 [m]
lift/drag ratio : 10.33 [ ]
max. practical ceiling : 5225 [m] with flying weight :2129 [kg]
practical ceiling (operational weight): 4500 [m] with flying weight :2425 [kg]
practical ceiling fully loaded (mtow- 1 hour fuel) : 3550 [m] with flying weight :2836 [kg]
published ceiling (1590 [m]
climb to 1500m (without bombload) : 7.14 [min]
climb to 3000m (without bombload) : 17.85 [min]
max. dive speed : 311.2 [km/hr] at 2550 [m] height
load factor at max. angle turn 2.00 ["g"]
turn radius at 500m: 63 [m]
time needed for 360* turn 12.1 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 5.23 [hours] with 3 crew and 231 [kg] bombload and 100.0 [%] fuel
published endurance : 4.61 [hours] with 3 crew and possible useful (bomb) load : 281 [kg] and 88.1 [%] fuel
action radius : 469 [km] with 3 crew and 20[kg] photo camera/radio transmitter or bombload
max range theoretically with additional fuel tanks for total 1130 [litre] fuel : 1225 [km]
useful load with action-radius 250km : 490 [kg]
production : 58.70 [tonkm/hour]
oil and fuel consumption per tonkm : 1.45 [kg]
_
-°_I /
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Literature :
Jane’s fighting aircraft WWI page 229,237
Wikipedia : https://en.wikipedia.org/wiki/Curtiss_HS
HS-1 is 3-bay with smaller span compared to the HS-2 (4.5 bay)
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 23 November 2019 contact : info.aircraftinvestigation@gmail.com python 3.7.4