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performance calculations for the Wright SGR-1820-F3 Cyclone aircraft engine
Wright SGR-1820-F3 Cyclone air-cooled 9 -cylinder radial engine 710 [hp](529.4 KW)
gear-driven supercharger, constant power to height : 2134 [m]
introduction : May 1934 country : US importance : ***
applications : Douglas DC-2
normal rating : 710 [hp](529.4 KW) at 2100 [rpm] at 2134 [m] above sea level
reduction : 0.625 , valvetrain : SOHC
weight reduction gear : 22.2 [kg]
fuel system : oil system :
weight engine(s) dry with reduction gear : 432.2 [kg] = 0.77 [kg/KW]
bore : 155.6 [mm] stroke : 174.6 [mm]
valve inlet area : 37.0 [cm^2] one inlet and one exhaust valve in cylinder head
gasspeed at inlet valve : 44.2 [m/s]
throttle : 89 /100 open, mixture :13.0 :1
compression ratio: 6.40 :1
high compression engine cannot run with full power/throttle at sea-level
(only for short period)
stroke volume (Vs) : 29.881 [litre]
compression volume (Vc): 5.534 [litre]
total volume (Vt): 35.415 [litre]
diam. engine : 130 [cm]
engine length: 0.31 [m]
specific power : 17.7 [kW/litre]
torque : 2408 [Nm]
engine weight/volume : 13.7 : [kg/litre]
average piston speed (Cm): 12.2 [m/s]
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intake pressure at 2134 [m] altitude Pi : 0.95 [kg/cm2]
mean engine pressure (M.E.P.) at 2134 [m] altitude Pm : 8.25 [kg/cm2]
compression pressure at 2134 [m] altitude Pc: 9.67 [kg/cm2]
estimated combustion pressure at 2134 [m] Pe : 38.63 [kg/cm2]
exhaust pressure at 2134 [m] Pu : 3.73 [kg/cm^2 ]
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compression-start temperature at 2134 [m] Tic: 343 [°K] (70 [°C])
compression-end temperature at 2134 [m] Tc: 533 [°K] (260 [°C])
average engine wall temperature at 2134 [m] : 476 [K] (202 [°C])
caloric combustion temperature at 2134 [m] Tec: 2152 [°K] (1879 [°C])
polytroph combustion temperature at 2134 [m] Tep : 2129 [°K] (1856 [°C])
estimated combustion temperature at 2134 [m] Te (T4): 2105 [°K] (1832 [°C])
polytrope expansion-end temperature at 2134 [m] Tup: 1104 [°K] (831 [°C])
exhaust stroke end temperature at 2134 [m] Tu: 1046 [°K] (773 [°C])
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calculations for take-off/emergency power at sea level
rich mixture 9 : 1 applied for cooling > carburettor adjustable in flight by the pilot
veel warmte ontwikkeling, gevaar van oververhitten Ekoellucht > 4200!!!
afgevoerde warmte via koellucht per minuut per m2 : 8175.85 [Kcal/min uut/m2]
emergency/take off rating at 2158 [rpm] at sea level : 753 [hp]
Thermal efficiency Nth : 0.371 [ ]
Mechanical efficiency Nm : 0.757 [ ]
Thermo-dynamic efficiency Ntd : 0.281 [ ]
design hours : 920 [hr] time between overhaul : 23 [hr]
dispersed engine heat by cooling air : 5683.89 [Kcal/minuut/m2]
required cooling surface : 24.66 [m2]
weight cooling ribs : 75.61 [kg]
fuel consumption optimum mixture at 2100.00 [rpm] at 2134 [m]: 128.93 [kg/hr]
specific fuel consumption thermo-dynamic : 214 [gr/epk] = 287 [gr/kwh]
estimated specific fuel consumption (cruise power) at 2134 [m] : 320 [gr/kwh]
estimated sfc (cruise power) at 3420 [m] rich mixture : 323 [gr/kwh]
specific fuel consumption at 2134 [m] at 2100 [rpm] with mixture :13.0 :1 : 244 [gr/kwh]
estimated specific oil consumption (cruise power) : 14 [gr/kwh]
Literature :
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 22 October 2021 contact : info.aircraftinvestigation@gmail.com python 3.7.4
notes :