Pratt & Whitney R-1860 Hornet B1|aircraft investigation|aircraft engine

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performance calculations for the Pratt & Whitney R-1860 Hornet B1 aircraft engine

R-1860-7 is the military indication

Pratt & Whitney R-1860 Hornet B1 air-cooled 9 -cylinder radial engine 575 [hp]

(428.8 KW)

introduction : June 1929 country : United States importance : ***

applications : Fokker F.32

normal rating : 575 [hp](428.8 KW) at 1950 [rpm] at 0 [m] above sea level

no reduction, direct drive, valvetrain :

General information : The large-bore cylinders were difficult to cool. With the low

octane fuel available and the engine quickly running hot caused the engine to

detonate prone. The large cylinders also gave severe vibrations. Later P&W engines

had smaller bore cylinders in double rows giving a smoother running engine with

smaller diameter reducing drag.

fuel system : oil system : pressure pump

weight engine(s) dry : 381.0 [kg] = 0.89 [kg/KW]

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

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

gasspeed at inlet valve : 40.3 [m/s]

rich mixture - additional cooling due to vaporizing fuel

throttle : 86 /100 open, mixture :12.0 :1

compression ratio: 5.00 :1

calculated compression ratio : 5.00 : 1

published volume (displacement): 30.540 [litre]

calculated stroke volume (Vs) : 30.552 [litre]

compression volume (Vc): 7.638 [litre]

total volume (Vt): 38.190 [litre]

diam. engine : 130 [cm]

engine length: 0.32 [m]

specific power : 14.0 [kW/litre]

torque : 2100 [Nm]

engine weight/volume : 12.5 : [kg/litre]

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

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intake pressure at 0 [m] altitude Pi : 0.81 [kg/cm2]

mean engine pressure (M.E.P.) at 0 [m] altitude Pm : 6.15 [kg/cm2]

compression pressure at 0 [m] altitude Pc: 5.95 [kg/cm2]

estimated combustion pressure at 0 [m] Pe : 22.57 [kg/cm2]

exhaust pressure at 0 [m] Pu : 2.97 [kg/cm^2 ]

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compression-start temperature at 0 [m] Tic: 355 [°K] (81 [°C])

compression-end temperature at 0 [m] Tc: 510 [°K] (237 [°C])

average engine wall temperature at 0 [m] : 476 [K] (202 [°C])

caloric combustion temperature at 0 [m] Tec: 1914 [°K] (1641 [°C])

polytroph combustion temperature at 0 [m] Tep : 1935 [°K] (1662 [°C])

estimated combustion temperature at 0 [m] Te (T4): 1890 [°K] (1616 [°C])

polytrope expansion-end temperature at 0 [m] Tup: 1055 [°K] (782 [°C])

exhaust stroke end temperature at 0 [m] Tu: 993 [°K] (720 [°C])

*********************************************************************************

calculations for take-off/emergency power at sea level

intake pressure at sea level Pi : 0.84 [kg/cm2]

compression-end temperature at sealevel max rpm Tc:516 [°K] (243 [°C])

polytrope combustion temperature at sea level Tec: 1958 [°K] (1685 [°C])

caloric combustion temperature at sea level Tec: 1927 [°K] (1654 [°C])

emergency/take off rating at 2245 [rpm] at sea level : 611 [hp]

Thermal efficiency Nth : 0.322 [ ]

Mechanical efficiency Nm : 0.795 [ ]

Thermo-dynamic efficiency Ntd : 0.256 [ ]

design hours : 1676 [hr] time between overhaul : 43 [hr]

dispersed engine heat by cooling air : 5508.42 [Kcal/minuut/m2]

required cooling surface : 19.97 [m2]

weight cooling ribs : 218.05 [kg]

fuel consumption optimum mixture at 1950.00 [rpm] at 0 [m]: 121.71 [kg/hr]

specific fuel consumption thermo-dynamic : 235 [gr/epk] = 315 [gr/kwh]

estimated specific fuel consumption (cruise power) at 0 [m] optimum mixture : 325

[gr/kwh]

estimated sfc (cruise power) at 2000 [m] rich mixture : 329 [gr/kwh]

specific fuel consumption at 0 [m] at 1950 [rpm] with mixture :12.0 :1 : 284 [gr/kwh]

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

OMNIA - Pratt & Whitney

Literature :

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

Pratt & Whitney R-1860 Hornet B - Wikipedia

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

notes :