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weight and performance calculations for the SIA 7B.1
SIA 7B.1
role : multi role combat aircraft
importance : ***
first flight : Summer 1917 operational : November 1917
country : Italy
design : Torretta and Carlo Maurilio Lerici
production : 572 aircraft
general information :
Societa Italiana Aviazione, was a sister company of the famous motor-car firm FIAT of
Turin.
In operational service structural weakness was revealed and it was withdrawn from
the front in July 1918.
Francesco Brach Papa set a height record on 14 December 1917, with a passenger he
reached 7025m near Turin. His plane must have been fine-tuned, for with the normal
production aircraft the ceiling would have been around 6000m.
users : Italy
crew : 2
armament : 1 fixed 6.50 [mm] (0.256 in) FIAT Rivelli machine-gun on top plane
and 1 movable 6.50 [mm] (0.256 in) FIAT Rivelli machine-gun for the observer
engine : 1 FIAT A-12 liquid-cooled 6 -cylinder inline engine 260 [hp](191.2 KW)
dimensions :
wingspan : 13.32 [m], length : 9.06 [m], height : 3.24[m]
wing area : 42.74 [m^2]
weights :
max.take-off weight : 1567 [kg]
empty weight operational : 1150 [kg] bombload : 60 [kg]
performance :
maximum speed : 200 [km/hr] at sea-level
service ceiling : 6000 [m]
endurance : 4.0 [hours]
estimated action radius : 360 [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 :0.64 [ ]
estimated diameter airscrew 2.79 [m]
angle of attack prop : 17.28 [ ]
reduction : 1.00 [ ]
airscrew revs : 1630 [r.p.m.]
pitch at Max speed 2.04 [m]
blade-tip speed at Vmax and max revs. : 245 [m/s]
calculation : *1* (dimensions)
mean wing chord : 1.60 [m]
calculated wing chord (rounded tips): 1.76 [m]
wing aspect ratio : 8.30 []
estimated gap : 1.46 [m]
gap/chord : 0.91 [ ]
seize (span*length*height) : 391 [m^3]
calculation : *2* (fuel consumption)
oil consumption : 2.9 [kg/hr]
fuel consumption(cruise speed) : 46.4 [kg/hr] (63.3 [litre/hr]) at 66 [%] power
distance flown for 1 kg fuel : 3.88 [km/kg]
estimated total fuel capacity : 287 [litre] (211 [kg])
calculation : *3* (weight)
weight engine(s) dry : 415.0 [kg] = 2.17 [kg/KW]
weight 20 litre oil tank : 2.5 [kg]
oil tank filled with 1.4 litre oil : 1.3 [kg]
oil in engine 11 litre oil : 9.6 [kg]
fuel in engine 1 litre fuel : 1.0 [kg]
weight 27 litre gravity patrol tank(s) : 2.6 [kg]
weight radiator : 35.4 [kg]
weight exhaust pipes & fuel lines 23.5 [kg]
weight self-starter : 4.7 [kg]
weight cowling 7.6 [kg]
weight airscrew(s) (wood) incl. boss & bolts : 28.7 [kg]
total weight propulsion system : 529 [kg](33.8 [%])
***************************************************************
fuselage skeleton (wood gauge : 7.13 [cm]): 118 [kg]
bracing : 7.5 [kg]
fuselage covering ( 15.5 [m2] doped linen fabric) : 5.0 [kg]
weight controls + indicators: 6.7 [kg]
weight seats : 6.0 [kg]
weight other details, lighting set, etc. : 5.1 [kg]
weight bomb storage : 4.2 [kg]
weight bomb sight : 1.0 [kg]
weight 260 [litre] main fuel tank empty : 25.0 [kg]
weight oxygen/compressed air flasks for high altitude : 8.7 [kg]
weight engine mounts & firewalls : 10 [kg]
total weight fuselage : 197 [kg](12.5 [%])
***************************************************************
weight wing covering (doped linen fabric) : 27 [kg]
total weight ribs (80 ribs) : 93 [kg]
load on front upper spar (clmax) per running metre : 732.9 [N]
load on rear upper spar (vmax) per running metre : 329.9 [N]
total weight 8 spars : 75 [kg]
weight wings : 195 [kg]
weight wing/square meter : 4.56 [kg]
weight 8 interplane struts & cabane : 15.3 [kg]
weight cables (73 [m]) : 8.6 [kg] (= 117 [gram] per metre)
diameter cable : 4.4 [mm]
weight fin & rudder (2.1 [m2]) : 9.7 [kg]
weight stabilizer & elevator (4.8 [m2]): 22.3 [kg]
total weight wing surfaces & bracing : 251 [kg] (16.0 [%])
*******************************************************************
weight machine-gun(s) : 34.0 [kg]
weight pivot mounting mg :6.0 [kg]
weight machine gun-mounting top plane : 1.5 [kg]
weight ammunition magazine(s) :1.5 [kg]
weight armament : 43 [kg]
********************************************************************
wheel pressure : 783.5 [kg]
weight 2 wheels (780 [mm] by 98 [mm]) : 32.3 [kg]
weight tailskid : 3.0 [kg]
weight undercarriage with axle 30.2 [kg]
total weight landing gear : 65.5 [kg] (4.2 [%]
*******************************************************************
********************************************************************
calculated empty weight : 1085 [kg](69.2 [%])
weight oil for 4.8 hours flying : 13.8 [kg]
weight cooling fluids : 39.4 [kg]
weight 1 drums empty : 1.5 [kg]
weight ammunition (800 rounds) : 20.0 [kg]
weight signal pistol with cartridges : 3.6 [kg]
weight automatic pistol with spare magazines : 1.2 [kg]
*******************************************************************
calculated operational weight empty : 1163 [kg] (74.2 [%])
published operational weight empty : 1150 [kg] (73.4 [%])
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weight crew : 162 [kg]
weight (electrical heated) clothing for high altitude : 12.0 [kg]
weight fuel for 2.0 hours flying : 93 [kg]
********************************************************************
operational weight : 1430 [kg](91.2 [%])
bomb load : 60 [kg]
operational weight bombing mission : 1490 [kg]
weight transceiver : 27 [kg]
operational weight FAC RT mission : 1457 [kg]
fuel reserve : 110 [kg] enough for 2.37 [hours] flying
operational weight fully loaded : 1567 [kg] with fuel tank filled for 96 [%]
published maximum take-off weight : 1567 [kg] (100.0 [%])
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calculation : * 4 * (engine power)
power loading (operational without bombload) : 7.48 [kg/kW]
total power : 191.2 [kW] at 1630 [r.p.m]
calculation : *5* (loads)
manoeuvre load : 3.7 [g] at 1000 [m]
limit load : 3.75 [g] ultimate load : 5.6 [g] load factor : 1.7 [g]
design flight time : 3.20 [hours]
design cycles : 188 sorties, design hours : 600 [hours]
operational wing loading : 334 [N/m^2]
wing stress (3 g) during operation : 220 [N/kg] at 3g emergency manoeuvre
calculation : *6* (angles of attack)
angle of attack zero lift : -1.16 ["]
max. angle of attack (stalling angle) : 12.11 ["]
angle of attack at max. speed : 0.87 ["]
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 : 0.18 [ ]
induced drag coefficient at max. speed : 0.0021 [ ]
Captain Giulio Laureati, posing for his SIA 7B.1 On the 15th of August 1917, with a FIAT-SIA 7B fitted with supplementary fuel tanks, he set a world record for distance with a nonstop 10 hour 33 minute flight from Turin to Naples and back, taking off from Mirafiori at 10.07, overflying Naples at 14.3
0 and landing back at Mirafiori at 20.40. A non-stop distance of about 1400 km !
On the 24th of September 1917, in a SIA 7B.2 powered by a FIAT A.12bis 300 hp engine, Capt. Laureati and his mechanic Cpl. Michelangelo Tonso from Montalenghe (Turin) took off from the Mirafiori airfield and landed at Hounslow military aerodrome South West of London nearly 7 ˝ hours later. This non-stop flight of some 1200 km lasted 7 hours 22 minutes and was a new World Record for distance and with a passenger. For this exploit, Capt. Laureati was received by King George of England who conferred him the Royal Victorian Order on him personally.
drag coefficient at max. speed : 0.0273 [ ]
drag coefficient (zero lift) : 0.0252 [ ]
calculation : *8* (speeds
stalling speed at sea-level (OW): 78 [km/u]
landing speed at sea-level (OW without bombload): 93 [km/hr]
min. drag speed (max endurance) : 124 [km/hr] at 3000 [m](power :37 [%])
min. power speed (max range) : 131 [km/hr] at 3000 [m] (power:39 [%])
max. rate of climb speed : 119.5 [km/hr] at sea-level
cruising speed : 180 [km/hr] op 3000 [m] (power:62 [%])
design speed prop : 190 [km/hr]
maximum speed : 200 [km/hr] op 100 [m] (power:100 [%])
climbing speed at sea-level (without bombload) : 280 [m/min]
calculation : *9* (regarding various performances)
take-off distance at sea-level : 165 [m]
lift/drag ratio : 12.07 [ ]
max. practical ceiling : 6550 [m] with flying weight :1242 [kg]
practical ceiling (operational weight) : 5800 [m] with flying weight :1430 [kg] line 3385
practical ceiling fully loaded (mtow- 1 hour fuel) : 5450 [m] with flying weight :1521 [kg]
published ceiling (6000 [m]
climb to 1500m (without bombload) : 5.43 [min]
climb to 3000m (without bombload) : 12.50 [min]
max. dive speed : 520.3 [km/hr] at 4450 [m] height
load factor at max. angle turn 2.22 ["g"]
turn radius at 500m: 57 [m]
time needed for 360* turn 10.8 [seconds] at 500m
calculation *10* (action radius & endurance)
operational endurance : 3.92 [hours] with 2 crew and 60 [kg] useful (bomb)load and 86.4 [%] fuel
published endurance : 4.00 [hours] with 2 crew and possible useful (bomb) load : 56 [kg] and 88.1 [%] fuel
action radius : 431 [km] with 2 crew and 20[kg] photo camera or bombload
max range theoretically with additional fuel tanks for total 498 [litre] fuel : 1415 [km]
useful load with action-radius 250km : 236 [kg]
production : 42.46 [tonkm/hour]
oil and fuel consumption per tonkm : 1.16 [kg]
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Literature :
Jane’s fighting aircraft WWI page 206
Praktisch handboek vliegtuigen deel 1 page 224
Bombers 1914-19 page 51
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