Aircraft investigation info>>>>>>> HOME PAGE
weight and performance calculations for the SIAI S.8
SIAI S.8
role : light maritime two-seat patrol aircraft, ASW
importance : ***
first flight : operational : December 1917
country : Italy
design : Raffaele Conflenti
production : 172 aircraft
general information :
First aircraft designed by Raffaele Conflenti. The Royal Italian Navy ordered 800 S.8s,
to be built by SIAI and subcontractors. With the end of the war, production was stopped
when 172 aircraft had been delivered. Early aircraft were powered by an Isotta
Fraschini V4B engine, later aircraft had a more powerful 220 hp (164 kW) Hispano-
Suiza engine.
users : Italy
crew : 2
armament : 1 movable 7.70 [mm] (0.303 in) Lewis machine-gun for the observer
engine : 1 Isotta Fraschini V.4B liquid-cooled 6 -cylinder inline engine 170 [hp](125.0 KW)
dimensions :
wingspan : 12.77 [m], length : 9.84 [m], height : 3.3[m]
wing area : 46.0 [m^2]
weights :
max.take-off weight : 1375 [kg]
empty weight operational : 900 [kg] bombload : 120 [kg]
performance :
maximum speed : 144 [km/hr] at sea-level
service ceiling : 5000 [m]
estimated action radius : 350 [km]
description :
2-bay biplane flying boat
2 (aid) tip floats
two spar upper and lower wing
engine attached to top plane
airscrew :
fixed pitch 2 -bladed pusher airscrew with max. efficiency :0.64 [ ]
estimated diameter airscrew 2.70 [m]
angle of attack prop : 14.12 [ ]
fine pitch
reduction : 1.00 [ ]
airscrew revs : 1500 [r.p.m.]
pitch at Max speed 1.60 [m]
blade-tip speed at Vmax and max revs. : 216 [m/s]
calculation : *1* (dimensions)
mean wing chord : 1.80 [m]
calculated wing chord (rounded tips): 2.00 [m]
wing aspect ratio : 7.09 []
estimated gap : 1.75 [m]
gap/chord : 0.97 [ ]
seize (span*length*height) : 415 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 1.9 [kg/hr]
fuel consumption(cruise speed) : 31.1 [kg/hr] (42.4 [litre/hr]) at 67 [%] power
distance flown for 1 kg fuel : 4.17 [km/kg]
estimated total fuel capacity : 260 [litre] (191 [kg])
calculation : *3* (weight)
weight engine(s) dry : 281.3 [kg] = 2.25 [kg/KW]
weight 17 litre oil tank : 2.1 [kg]
oil tank filled with 0.9 litre oil : 0.8 [kg]
oil in engine 7 litre oil : 6.3 [kg]
fuel in engine 1 litre fuel : 0.6 [kg]
weight 18 litre gravity patrol tank(s) : 1.8 [kg]
weight radiator : 17.9 [kg]
weight exhaust pipes & fuel lines 15.8 [kg]
weight cowling 5.0 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 19.0 [kg]
total weight propulsion system : 349 [kg](25.3 [%])
***************************************************************
fuselage skeleton (wood gauge : 5.36 [cm]): 72 [kg]
bracing : 6.3 [kg]
plywood/wood covering hull (gauche : 1.1 [cm]): 124.5 [kg]
weight controls + indicators: 6.8 [kg]
weight seats : 6.0 [kg]
weight other details, lighting set, etc. : 5.1 [kg]
weight bomb storage : 8.4 [kg]
weight 242 [litre] main fuel tank empty : 23.2 [kg]
weight oxygen/compressed air flasks for high altitude : 11.7 [kg]
weight engine mounts & firewalls : 6 [kg]
total weight fuselage : 271 [kg](19.7 [%])
***************************************************************
weight wing covering (doped linen fabric) : 29 [kg]
total weight ribs (62 ribs) : 82 [kg]
load on front upper spar (clmax) per running metre : 560.6 [N]
load on rear upper spar (vmax) per running metre : 288.1 [N]
total weight 8 spars : 51 [kg]
weight wings : 162 [kg]
weight wing/square meter : 3.52 [kg]
weight 8 interplane struts & cabane : 22.5 [kg]
weight cables (76 [m]) : 6.1 [kg] (= 80 [gram] per metre)
diameter cable : 3.6 [mm]
weight fin & rudder (1.9 [m2]) : 7.0 [kg]
weight stabilizer & elevator (4.4 [m2]): 15.9 [kg]
total weight wing surfaces & bracing : 214 [kg] (15.5 [%])
*******************************************************************
weight machine-gun(s) : 12.7 [kg]
weight pivot mounting mg :6.0 [kg]
weight armament : 19 [kg]
********************************************************************
weight 2 tip floats : 19 [kg] (1.4 [%])
*******************************************************************
********************************************************************
calculated empty weight : 871 [kg](63.3 [%])
weight oil for 6.5 hours flying : 12.2 [kg]
weight cooling fluids : 25.8 [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 : 921 [kg] (67.0 [%])
published operational weight empty : 900 [kg] (65.5 [%])
_____________
| | o | |
-------------
~U~
weight crew : 162 [kg]
weight (electrical heated) clothing for high altitude : 12.0 [kg]
weight fuel for 2.0 hours flying : 62 [kg]
********************************************************************
operational weight : 1157 [kg](84.1 [%])
bomb load : 120 [kg]
operational weight bombing mission : 1277 [kg]
fuel reserve : 98 [kg] enough for 3.15 [hours] flying
operational weight fully loaded : 1375 [kg] with fuel tank filled for 84 [%]
published maximum take-off weight : 1375 [kg] (100.0 [%])
||
||
=||I>|
||
||
calculation : * 4 * (engine power)
power loading (operational without bombload) : 9.25 [kg/kW]
total power : 125.0 [kW] at 1500 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 2.6 [g] at 1000 [m]
limit load : 3.75 [g] ultimate load : 5.6 [g] load factor : 1.5 [g]
design flight time : 3.78 [hours]
design cycles : 132 sorties, design hours : 500 [hours]
operational wing loading : 247 [N/m^2]
wing stress (3 g) during operation : 210 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.20 ["]
max. angle of attack (stalling angle) : 12.60 ["]
Picture of a S.9, in appearance very similar to the S.8, but it had a more powerful 300 hp FIAT engine. It was in service after WWI.
angle of attack at max. speed : 1.86 ["]
calculation : *7* (lift & drag ratios
lift coefficient at angle of attack 0° :0.10 [ ]
lift coefficient at max. angle of attack : 1.15 [ ]
lift coefficient at max. speed : 0.25 [ ]
induced drag coefficient at max. speed : 0.0052 [ ]
drag coefficient at max. speed : 0.0439 [ ]
drag coefficient (zero lift) : 0.0387 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 67 [km/u]
landing speed at sea-level (OW without bombload): 81 [km/hr]
min. drag speed (max endurance) : 98 [km/hr] at 2500 [m](power :47 [%])
min. power speed (max range) : 106 [km/hr] at 2500 [m] (power:50 [%])
max. rate of climb speed : 89.6 [km/hr] at sea-level
cruising speed : 130 [km/hr] op 2500 [m] (power:67 [%])
design speed prop : 137 [km/hr]
maximum speed : 144 [km/hr] op 100 [m] (power:99 [%])
climbing speed at sea-level (without bombload) : 204 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 148 [m]
lift/drag ratio : 8.99 [ ]
max. practical ceiling : 5650 [m] with flying weight :1005 [kg]
practical ceiling (operational weight) : 4625 [m] with flying weight :1157 [kg] line 3385
practical ceiling fully loaded (mtow- 1 hour fuel) : 3500 [m] with flying weight :1344 [kg]
published ceiling (5000 [m]
climb to 1500m (without bombload) : 8.22 [min]
climb to 3000m (without bombload) : 20.36 [min]
max. dive speed : 346.7 [km/hr] at 2500 [m] height
load factor at max. angle turn 1.83 ["g"]
turn radius at 500m: 45 [m]
time needed for 360* turn 10.8 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 5.54 [hours] with 2 crew and 120 [kg] bombload and 90.4 [%] fuel
published endurance : 5.40 [hours] with 2 crew and possible useful (bomb) load : 124 [kg] and 88.1 [%] fuel
action radius : 567 [km] with 2 crew and 20[kg] photo camera or bombload
max range theoretically with additional fuel tanks for total 526 [litre] fuel : 1607 [km]
useful load with action-radius 250km : 266 [kg]
production : 34.42 [tonkm/hour]
oil and fuel consumption per tonkm : 0.96 [kg]
_
-°°_I /
~======~
Literature :
Jane’s Fighting Aircraft WWI page 207
Praktisch handboek vliegtuigen deel 1 page 234
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 12 April 2020 contact : info.aircraftinvestigation@gmail.com python 3.7.4