AIRCRAFT INVESTIGATION
performance calculations for the Armstrong Siddeley Jaguar III aircraft engine
Jaguar engine at display in the London Science Museum
Armstrong Siddeley Jaguar III air-cooled 14 -cylinder two-row radial engine 385 [hp](287.1 KW)
introduction : 1926 country : United-Kingdom importance : ***
applications : Armstrong Whitworth A.W.155 Argosy Mk.I
normal rating : 385 [hp](287.1 KW) at 1820 [rpm] at 0 [m] above sea level
no reduction, direct drive, valvetrain : SOHC
Throughout its career the Jaguar suffered from vibration due to a lack of
a crankshaft centre bearing.
fuel system : oil system :
weight engine(s) dry : 361.0 [kg] = 1.26 [kg/KW]
bore : 127.0 [mm] stroke : 139.7 [mm]
valve inlet area : 24.6 [cm^2] one inlet and one exhaust valve in cylinder head
gasspeed at inlet valve : 30.7 [m/s]
throttle : 90 /100 open, mixture :13.0 :1
calculated compression ratio : 5.00 : 1
published volume (displacement): 24.800 [litre]
calculated stroke volume (Vs) : 24.775 [litre]
compression volume (Vc): 6.189 [litre]
total volume (Vt): 30.965 [litre]
diam. engine : 106 [cm]
specific power : 11.6 [kW/litre]
torque : 1506 [Nm]
engine weight/volume : 14.6 : [kg/litre]
average piston speed (Cm): 8.5 [m/s]
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intake pressure at 0 [m] altitude Pi : 0.90 [kg/cm2]
mean engine pressure (M.E.P.) at 0 [m] altitude Pm : 6.15 [kg/cm2]
compression pressure at 0 [m] altitude Pc: 6.76 [kg/cm2]
estimated combustion pressure at 0 [m] Pe : 26.98 [kg/cm2]
exhaust pressure at 0 [m] Pu : 3.55 [kg/cm^2 ]
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compression-start temperature at 0 [m] Tic: 361 [°K] (88 [°C])
compression-end temperature at 0 [m] Tc: 526 [°K] (253 [°C])
average engine wall temperature at 0 [m] : 476 [K] (202 [°C])
caloric combustion temperature at 0 [m] Tec: 2147 [°K] (1874 [°C])
polytroph combustion temperature at 0 [m] Tep : 2102 [°K] (1828 [°C])
estimated combustion temperature at 0 [m] Te (T4): 2097 [°K] (1824 [°C])
polytrope expansion-end temperature at 0 [m] Tup: 1172 [°K] (899 [°C])
exhaust stroke end temperature at 0 [m] Tu: 1107 [°K] (834 [°C])
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emergency/take off rating at 2071 [rpm] at sea level : 438 [hp]
Thermal efficiency Nth : 0.331 [ ]
Mechanical efficiency Nm : 0.773 [ ]
Thermo-dynamic efficiency Ntd : 0.256 [ ]
design hours : 1195 [hr] time between overhaul : 29 [hr]
** internal heat transfer (a1): 8089.57 [Kcal/minute/m2)
** high internal heat transfer a1 > check
required cooling surface : 15.28 [m2]
weight cooling ribs : 224.66 [kg]
fuel consumption optimum mixture at 1820.00 [rpm] at 0 [m]: 94.70 [kg/hr]
specific fuel consumption thermo-dynamic : 235 [gr/epk] = 314 [gr/kwh]
estimated specific fuel consumption (cruise power) at 0 [m] optimum mixture : 345 [gr/kwh]
estimated sfc (cruise power) at 2000 [m] rich mixture : 387 [gr/kwh]
specific fuel consumption at 0 [m] at 1820 [rpm] with mixture :13.0 :1 : 330 [gr/kwh]
estimated specific oil consumption (cruise power) : 45 [gr/kwh]
Literature :
Armstrong Siddeley Jaguar - Wikipedia
Handbook of aeronautics Volume II Aero-engines page 6
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 05 February 2021 contact : info.aircraftinvestigation@gmail.com python 3.7.4
notes :