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performance calculations for the Hispano Suiza 8Aa WWI aero engine
Hispano Suiza 8A on display in the Royal military museum Brussel, April 2019 © B van der Zalm
Hispano Suiza 8Aa liquid-cooled 8 -cylinder V-engine 150 [hp](111.9 KW)
introduction : August 1916 country : Spain importance : ****
applications : SPAD S.VII
max. continuous(take-off) rating : 150 [hp](111.9 KW) at 1700 [rpm] at 0 [m] above sea level
no reduction, direct drive, valvetrain : SOHC
fuel system : oil system :
weight engine(s) dry : 215.0 [kg] = 1.92 [kg/KW]
bore : 120.0 [mm] stroke : 130.0 [mm]
Mechanical efficiency/mean pressure correction factor : 0.632 [ ]
valve inlet area : 22.0 [cm^2] one inlet and one exhaust valve in cylinder head
gasspeed at inlet valve : 26.7 [m/s]
invloed hoogte > cm : 0.31 [ ]
throttle : 95 /100 open, mixture :13.5 :1
compression ratio: 4.70 :1
calculated compression ratio : 4.70 : 1
published volume (displacement): 11.760 [litre]
calculated stroke volume (Vs) : 11.762 [litre]
compression volume (Vc): 3.179 [litre]
total volume (Vt): 14.941 [litre]
power / stroke volume (litervermogen Nl): 9.5 [kW/litre]
torque : 628 [Nm]
engine weight/volume : 18.3 : [kg/litre]
average piston speed (Cm): 7.4 [m/s]
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intake pressure at 0 [m] altitude Pi : 0.99 [kg/cm2]
mean engine pressure (M.E.P.) at 0 [m] altitude Pm : 5.78 [kg/cm2]
compression pressure at 0 [m] altitude Pc: 6.88 [kg/cm2]
estimated combustion pressure at 0 [m] Pe : 27.02 [kg/cm2]
exhaust pressure at 0 [m] Pu : 3.84 [kg/cm^2 ]
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compression-start temperature at 0 [m] Tic: 366 [°K] (92 [°C])
compression-end temperature at 0 [m] Tc: 529 [°K] (256 [°C])
8Aa on display in the Museo de Aeronautica y Astronautica
caloric combustion temperature at 0 [m] Tec: 2083 [°K] (1810 [°C])
polytroph combustion temperature at 0 [m] Tep : 2078 [°K] (1805 [°C])
estimated combustion temperature at 0 [m] Te (T4): 2057 [°K] (1784 [°C])
polytrope exhaust temperature at 0 [m] Tup: 1376 [°K] (1102 [°C])
exhaust end temperature at 0 [m] Tu: 1258 [°K] (985 [°C])
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emergency/take off rating is equal to max.continuous rating : 150 [hp](111.9 KW)
Thermal efficiency Nth : 0.325 [ ]
Mechanical efficiency Nm : 0.750 [ ]
Thermo-dynamic efficiency Ntd : 0.244 [ ]
design hours : 1012 time between overhaul : 87
fuel consumption optimum mixture at 1700.00 [rpm] at 0 [m]: 40.97 [kg/hr]
specific fuel consumption thermo-dynamic : 246 [gr/epk] = 330 [gr/kwh]
estimated specific fuel consumption (cruise power) at 0 [m] optimum mixture : 340 [gr/kwh]
estimated sfc (cruise power) at 2667 [m] rich mixture : 353 [gr/kwh]
specific fuel consumption at 0 [m] at 1700 [rpm] with mixture :13.5 :1 : 366 [gr/kwh]
estimated specific oil consumption (cruise power) : 15 [gr/kwh]
literature :
http://www.all-aero.com/index.php/contactus/64-engines-power/4913-hispano-suiza-8a
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 31 May 2020 contact : info.aircraftinvestigation@gmail.com python 3.7.4