AIRCRAFT INVESTIGATION

WWI aero engine performance calculations

Hispano Suiza 8Fb

liquid-cooled 8 -cylinder V-engine 300 [hp] (220.7 KW)

introduction : may 1918 country : Spain

normal rating : 300 hp at 2100 rpm at 1600m above sea level

high compression engine : cannot run at full power at sea level, constant power to

height : 1600 [m]

applications : SPAD XVII

no reduction, direct drive, weight engine(s) dry : 256.0 [kg] = 1.16 [kg/KW]

bore : 140.0 [mm] stroke : 150.0 [mm]

compression ratio: 5.30 :1

high compression engine cannot run with full power/throttle at sea-level (only for short period)

published volume (displacement): 18.470 [litre]

calculated stroke volume (Vs) : 18.473 [litre]

compression volume (Vc): 4.296 [litre]

total volume (Vt): 22.769 [litre]

power / stroke volume (litervermogen Nl): 11.9 [kW/litre]

torque : 1003 [Nm]

engine weight/volume : 13.9 : [kg/litre]

average piston speed (Cm): 10.5 [m/s]

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intake pressure at 1600 [m] hoogte Pi : 0.78 [kg/cm2]

mean engine pressure (M.E.P.) at 1600 [m] hoogte Pm : 6.02 [kg/cm2]

compression pressure at 1600 [m] hoogte Pc: 6.66 [kg/cm2]

estimated combustion pressure at 1600 [m] Pe : 26.62 [kg/cm2]

exhaust pressure at 1600 [m] Pu : 3.13 [kg/cm^2 ]

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compression-end temperature at 1600 [m] Tc: 579 [°K] (306 [°C])

caloric combustion temperature at 1600 [m] Tec: 2239 [°K] (1966 [°C])

polytrope combustion temperature at 1600 [m] Te (T4): 2310 [°K] (2037 [°C])

exhaust temperature at 1600 [m] Tu: 1256 [°K] (983 [°C])

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compression pressure at sea level Pc: 7.90 [kg/cm2]

estimated combustion pressure at sealevel Pe : 31.60 [kg/cm^2 ]

compression-end temperature at sealevel Tc:587 [°K] (314 [°C])

mean engine pressure at sealevel Pm : 7.14 [kg/cm2]

(emergency/Take Off) rating at 2100 [rpm] at sea level : 328 [pk]

Thermal efficiency Nth : 0.34 [ ]

Mechanical efficiency Nm : 0.72 [ ]

Thermo-dynamic efficiency Ntd : 0.24 [ ]

design hours : 414 time between overhaul : 26

fuel consumption optimum mixture at 2100.00 [rpm] at 1600 [m]: 77.79 [kg/hr]

specific fuel consumption thermo-dynamic : 259 [gr/epk] = 352 [gr/kwh]

specific fuel consumption (cruise power) at 1600 [m] optimum mixture : 345 [gr/kwh]

estimated sfc (cruise power) at 3588 [m] rich mixture : 351 [gr/kwh]

specific fuel consumption at 1600 [m] at 2100 [rpm] optimum mixture : 353 [gr/kwh]

estimated specific oil consumption (cruise power) : 14 [gr/kwh]

last check python :

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/photograps/content please mail to below mail address

(c) B van der Zalm 13 december 2018 contact : bvanderzalm@ziggo.nl python 3.4.1

Martinsyde Buzzard with 300 hp HS 8Fb engine

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literature : H.F.King – Armament of British aircraft 1909-1939