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performance calculations for the Anzani 25 hp WWI aero engine
Anzani 25 hp air-cooled 3 -cylinder radial engine 25 [hp](18.6 KW)
introduction : July 1907 country : France importance : *****
applications : Bleriot XI
normal rating : 25 [hp](18.6 KW) at 1500 [rpm] at 0 [m] above sea level
no reduction, direct drive, valvetrain : Automatic inlet valves, mechanical exhaust valves driven from three separate cams in crankcase
fuel system : Gronville and Arquembourg carburettor, mixing chamber in crankcase.
oil system : splash lubrication
weight engine(s) dry : 66.0 [kg] = 3.54 [kg/KW]
bore : 103.0 [mm] stroke : 120.0 [mm]
Mechanical efficiency/mean pressure correction factor : 0.655 [ ]
valve inlet area : 13.5 [cm^2] one inlet and one exhaust valve in cylinder head
gas speed at inlet valve : 26.0 [m/s]
throttle : 92 /100 open, mixture :13.0 :1
calculated compression ratio : 3.75 : 1
calculated stroke volume (Vs) : 3.000 [litre]
compression volume (Vc): 1.092 [litre]
total volume (Vt): 4.092 [litre]
diam. engine : 93 [cm]
power / stroke volume (litervermogen Nl): 6.2 [kW/litre]
torque : 119 [Nm]
engine weight/volume : 22.0 : [kg/litre]
average piston speed (Cm): 6.0 [m/s]
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intake pressure at 0 [m] altitude Pi : 0.96 [kg/cm2]
mean engine pressure (M.E.P.) at 0 [m] altitude Pm : 4.46 [kg/cm2]
compression pressure at 0 [m] altitude Pc: 5.02 [kg/cm2]
estimated combustion pressure at 0 [m] Pe : 20.04 [kg/cm2]
estimated combustion pressure at 0 [m] Pe : 21.13 [kg/cm2]
exhaust pressure at 0 [m] Pu : 3.79 [kg/cm^2 ]
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compression-start temperature at 0 [m] Tic: 374 [°K] (101 [°C])
compression-end temperature at 0 [m] Tc: 507 [°K] (234 [°C])
average engine wall temperature at 0 [m] : 476 [K] (202 [°C])
caloric combustion temperature at 0 [m] Tec: 2042 [°K] (1769 [°C])
polytroph combustion temperature at 0 [m] Tep : 2026 [°K] (1753 [°C])
estimated combustion temperature at 0 [m] Te (T4): 2016 [°K] (1743 [°C])
polytrope expansion-end temperature at 0 [m] Tup: 1216 [°K] (943 [°C])
exhaust stroke end temperature at 0 [m] Tu: 1150 [°K] (877 [°C])
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A replica of the 25 hp Anzani engine, run for the first time in 2011
Alesandro Anzani developed his engine initially for use in motorbikes.
emergency/take off rating at 1670 [rpm] at sea level : 28 [hp]
Thermal efficiency Nth : 0.281 [ ]
Mechanical efficiency Nm : 0.711 [ ]
Thermo-dynamic efficiency Ntd : 0.200 [ ]
design hours : 218 [hr] time between overhaul : 7 [hr]
required cooling surface : 2.32 [m2]
weight cooling ribs : 25.51 [kg]
fuel consumption optimum mixture at 1500.00 [rpm] at 0 [m]: 8.48 [kg/hr]
According above text cylinders bore 105 mm stroke 130mm, probably this is for a later more powerful version.
specific fuel consumption thermo-dynamic : 301 [gr/epk] = 403 [gr/kwh]
estimated specific fuel consumption (cruise power) at 0 [m] optimum mixture : 450 [gr/kwh]
estimated sfc (cruise power) at 325 [m] rich mixture : 460 [gr/kwh]
specific fuel consumption at 0 [m] at 1500 [rpm] with mixture :13.0 :1 : 455 [gr/kwh]
estimated specific oil consumption (cruise power) : 65 [gr/kwh]
Anzani 3-cyliner engine installed in a Bleriot XI
Literature :
https://www.yesterdays.nl/product/anzani-3-cyl-1910-recreation/
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 07 October 2020 contact : info.aircraftinvestigation@gmail.com python 3.7.4