Pratt & Whitney R-1860 Hornet S1B1|aircraft investigation|aircraft engine

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performance calculations for the Pratt & Whitney R-1860 Hornet S1B1 aircraft engine

Pratt & Whitney R-1860 Hornet S1B1 air-cooled 9 -cylinder radial engine 575 [hp]

(428.8 KW)

gear-driven supercharger, constant power to height : 1829 [m]

introduction : 1930 country : United States importance : ***

applications :

normal rating : 575 [hp] (428.8 KW) at 1950 [rpm] at 1829 [m] above sea level

no reduction, direct drive, valvetrain :

fuel system : oil system :

weight engine(s) dry : 386.0 [kg] = 0.90 [kg/KW]

bore : 158.8 [mm] stroke : 171.4 [mm]

Mechanical efficiency/mean pressure correction factor : 0.605 [ ]

valve inlet area : 38.5 [cm^2] one inlet and one exhaust valve in cylinder head

gasspeed at inlet valve : 40.3 [m/s]

optimum mixture

throttle : 83 /100 open, mixture :13.0 :1

compression ratio: 6.00 :1

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

period)

published volume (displacement): 30.540 [litre]

calculated stroke volume (Vs) : 30.552 [litre]

compression volume (Vc): 6.110 [litre]

total volume (Vt): 36.663 [litre]

diam. engine : 129 [cm]

engine length: 0.32 [m]

specific power : 14.0 [kW/litre]

torque : 2100 [Nm]

engine weight/volume : 12.6 : [kg/litre]

average piston speed (Cm): 11.1 [m/s]

P&W Hornet B (R-1860)

intake pressure at 1829 [m] altitude Pi : 0.95 [kg/cm2]

mean engine pressure (M.E.P.) at 1829 [m] altitude Pm : 6.17 [kg/cm2]

compression pressure at 1829 [m] altitude Pc: 8.92 [kg/cm2]

estimated combustion pressure at 1829 [m] Pe : 35.64 [kg/cm2]

exhaust pressure at 1829 [m] Pu : 3.73 [kg/cm^2 ]

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compression-start temperature at 1829 [m] Tic: 349 [°K] (75 [°C])

compression-end temperature at 1829 [m] Tc: 532 [°K] (259 [°C])

average engine wall temperature at 1829 [m] : 476 [K] (202 [°C])

caloric combustion temperature at 1829 [m] Tec: 2095 [°K] (1822 [°C])

polytroph combustion temperature at 1829 [m] Tep : 2125 [°K] (1852 [°C])

estimated combustion temperature at 1829 [m] Te (T4): 2073 [°K] (1799 [°C])

polytrope expansion-end temperature at 1829 [m] Tup: 1104 [°K] (831 [°C])

exhaust stroke end temperature at 1829 [m] Tu: 1039 [°K] (766 [°C])

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calculations for take-off/emergency power at sea level

OMNIA - Pratt & Whitney

intake pressure at sea level Pi : 0.95 [kg/cm2]

compression-end temperature at sealevel max rpm Tc:548 [°K] (275 [°C])

polytrope combustion temperature at sea level Tec: 2190 [°K] (1917 [°C])

caloric combustion temperature at sea level Tec: 2274 [°K] (2001 [°C])

emergency/take off rating at 2326 [rpm] at sea level : 616 [hp]

bruto emergency/take off rating at 2326 [rpm] at sea level : 756 [hp]

Thermal efficiency Nth : 0.361 [ ]

Mechanical efficiency Nm : 0.805 [ ]

Thermo-dynamic efficiency Ntd : 0.291 [ ]

design hours : 946 [hr] time between overhaul : 23 [hr]

dispersed engine heat by cooling air : 4994.73 [Kcal/minuut/m2]

required cooling surface : 19.97 [m2]

weight cooling ribs : 218.46 [kg]

fuel consumption optimum mixture at 1950.00 [rpm] at 1829 [m]: 111.31 [kg/hr]

specific fuel consumption thermo-dynamic : 207 [gr/epk] = 277 [gr/kwh]

estimated specific fuel consumption (cruise power) at 1829 [m] optimum mixture : 315

[gr/kwh]

estimated sfc (cruise power) at 2000 [m] rich mixture : 315 [gr/kwh]

specific fuel consumption at 1829 [m] at 1950 [rpm] with mixture :13.0 :1 : 260 [gr/kwh]

estimated specific oil consumption (cruise power) : 13 [gr/kwh]

P&W Hornet B (R-1860)

Literature :

Pratt & Whitney Hornet R-1860-B Radial Engine | National Air and Space Museum (si.edu)

P&W Hornet B (R-1860) (enginehistory.org)

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/

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