Wright GR-1820-G102 Cyclone specifications | aircraft investigation into

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performance calculations for the Wright GR-1820-G102A Cyclone aircraft engine

Wright R-1820 Cyclone - Wikipedia

Wright GR-1820-G102A Cyclone air-cooled 9 -cylinder radial engine 900 [hp](671.1 KW)

gear-driven supercharger, constant power to height : 2045 [m] blower ratio : 7.00 [:1]

introduction : 1936 country : USA importance : ***

applications : Boeing 307 Stratoliner, Douglas DC-3

normal rating : 900 [hp](671.1 KW) at 2300 [rpm] at 2045 [m] above sea level

take-off power : 1100 [hp] (820.3 [KW]) at 2350 [rpm]

reduction : 0.6875 , valvetrain : overhead valves, pushrod operated

weight engine(s) dry with reduction gear : 579.0 [kg] = 0.86 [kg/KW]

General information : The G-series had increased cooling fin area to 2800 sq.in per

cylinder = 1.8m2/ cyl. x 9 = 16.26 m2 fin area

fuel system : fuel type : octane grade no. 91 oil system :

engine starter type :

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 : 48.4 [m/s]

blower speed : 16100 [rpm] , mixture :13.0 :1

compression ratio: 6.30 :1

stroke volume (Vs displacement): 29.880 [litre]

compression volume (Vc): 5.638 [litre]

total volume (Vt): 35.519 [litre]

overall engine diameter: 139.0 [cm]

calculated engine length: 119.50 [m]

specific power : 22.5 [kW/litre]

torque : 2786 [Nm]

engine weight/volume : 19.4 : [kg/litre]

average piston speed (Cm): 13.4 [m/s]

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intake manifold absolute pressure (MAP) at 2045 [m] altitude Pi : 1.00 [kg/cm2] (28.96 [inHg])

mean engine pressure (M.E.P.) at 2045 [m] altitude Pm : 9.77 [kg/cm2]

compression pressure at 2045 [m] altitude Pc: 9.98 [kg/cm2]

estimated combustion pressure at 2045 [m] Pe : 39.87 [kg/cm2]

exhaust pressure at 2045 [m] Pu : 3.92 [kg/cm^2 ]

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compression-start temperature at 2045 [m] Tic: 338 [°K] (65 [°C])

compression-end temperature at 2045 [m] Tc: 526 [°K] (253 [°C])

average engine wall temperature at 2045 [m] : 476 [K] (202 [°C])

caloric combustion temperature at 2045 [m] Tec: 2270 [°K] (1997 [°C])

polytroph combustion temperature at 2045 [m] Tep : 2103 [°K] (1830 [°C])

estimated combustion temperature at 2045 [m] Te (T4): 2157 [°K] (1883 [°C])

polytrope expansion-end temperature at 2045 [m] Tup: 1139 [°K] (866 [°C])

exhaust stroke end temperature at 2045 [m] Tu: 1094 [°K] (821 [°C])

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calculations for take-off/emergency power at sea level

average piston speed : 13.7 [m/s]

gasspeed at inlet valve : 49.5 [m/s]

intake pressure at sea level for Take-off Pi : 1.25 [kg/cm2] (36.06 [inHg])

rich mixture 11.5 : 1 applied for cooling > carburettor adjustable in flight by the pilot

high combustion pressure > high loads on piston rod and crankcase > to avoid damage

lower intake pressure.

caloric combustion temperature at sea level Tec: 2094 [°K] (1821 [°C])

insufficient cooling, can run max 2 minutes at this power before overheating

high emergency fact > probably rpm must be higher check

emergency/take off rating at 2350 [rpm] at sea level : 1100 [hp]

Newnes Aeroplane Data Sheet Engine Specifications Wright Cyclone GR-1820 - G102A | eBay

Thermal efficiency Nth : 0.369 [ ]

Mechanical efficiency Nm : 0.748 [ ]

Thermo-dynamic efficiency Ntd : 0.276 [ ]

design hours : 1037 [hr] time between overhaul : 317 [hr]

dispersed engine heat by cooling air : 7856.54 [Kcal/minuut/m2]

required cooling surface : 18.82 [m2]

weight cooling ribs : 56.42 [kg]

fuel consumption optimum mixture at 2300.00 [rpm] at 2045 [m]: 189.43 [kg/hr]

specific fuel consumption thermo-dynamic : 218 [gr/epk] = 292 [gr/kwh]

estimated specific fuel consumption (cruise power) at 2045 [m] : 320 [gr/kwh]

specific fuel consumption (volume*rpm at 1 atm MAP) at 2300 [rpm] : 289 [gr/kwh]

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

Literature :

Jane’s fighting aircraft of WWII page 314,315

World encyclopaedia of aero engines page 199

07 Wright Cyclone R-1820 (williammaloney.com)

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

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