AIRCRAFT INVESTIGATION
performance calculations for the Pratt & Whitney R-1340-S1H1-G Wasp aircraft engine
Pratt & Whitney R-1340-S1H1-G Wasp air-cooled 9 -cylinder radial engine 550 [hp]
(410.1 KW)
gear-driven supercharger, constant power to height : 2438 [m]
introduction : May 1931 country : United States importance : ***
applications : Boeing 247D
normal rating : 550 [hp](410.1 KW) at 2250 [rpm] at 2438 [m] above sea level
reduction : 0.667 , valvetrain : overhead valves
weight reduction gear : 17.6 [kg]
fuel system : oil system :
weight engine(s) dry with reduction gear : 439.6 [kg] = 1.03 [kg/KW]
bore : 146.0 [mm] stroke : 146.0 [mm]
valve inlet area : 32.5 [cm^2] one inlet and one exhaust valve in cylinder head
gasspeed at inlet valve : 39.7 [m/s]
throttle : 87 /100 open, mixture :13.0 :1
compression ratio: 6.03 :1
high compression engine cannot run with full power/throttle at sea-level (only for short
period)
stroke volume (displacement): 22.020 [litre]
compression volume (Vc): 4.373 [litre]
total volume (Vt): 26.372 [litre]
specific power : 18.6 [kW/litre]
torque : 1741 [Nm]
engine weight/volume : 19.2 : [kg/litre]
average piston speed (Cm): 10.9 [m/s]
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intake pressure at 2438 [m] altitude Pi : 0.95 [kg/cm2]
mean engine pressure (M.E.P.) at 2438 [m] altitude Pm : 7.78 [kg/cm2]
compression pressure at 2438 [m] altitude Pc: 8.98 [kg/cm2]
estimated combustion pressure at 2438 [m] Pe : 35.86 [kg/cm2]
exhaust pressure at 2438 [m] Pu : 3.73 [kg/cm^2 ]
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compression-start temperature at 2438 [m] Tic: 337 [°K] (64 [°C])
compression-end temperature at 2438 [m] Tc: 519 [°K] (246 [°C])
average engine wall temperature at 2438 [m] : 476 [K] (202 [°C])
caloric combustion temperature at 2438 [m] Tec: 2124 [°K] (1851 [°C])
polytroph combustion temperature at 2438 [m] Tep : 2074 [°K] (1801 [°C])
estimated combustion temperature at 2438 [m] Te (T4): 2071 [°K] (1798 [°C])
polytrope expansion-end temperature at 2438 [m] Tup: 1106 [°K] (833 [°C])
exhaust stroke end temperature at 2438 [m] Tu: 1060 [°K] (787 [°C])
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calculations for take-off/emergency power at sea level
rich mixture 11 : 1 applied for cooling > carburettor adjustable in flight by the pilot
polytrope combustion temperature at sea level Tec: 2005 [°K] (1731 [°C])
emergency/take off rating at 2350 [rpm] at sea level : 598 [hp]
Thermal efficiency Nth : 0.362 [ ]
Mechanical efficiency Nm : 0.770 [ ]
Thermo-dynamic efficiency Ntd : 0.279 [ ]
design hours : 1443 [hr] time between overhaul : 40 [hr]
dispersed engine heat by cooling air : 5508.72 [Kcal/minute/m2]
required cooling surface : 19.11 [m2]
weight cooling ribs : 58.77 [kg]
fuel consumption optimum mixture at 2250.00 [rpm] at 2438 [m]: 91.12 [kg/hr]
specific fuel consumption thermo-dynamic : 216 [gr/epk] = 289 [gr/kwh]
estimated specific fuel consumption (cruise power) at 2438 [m] : 305 [gr/kwh]
estimated sfc (cruise power) at 3850 [m] rich mixture : 308 [gr/kwh]
specific fuel consumption at 2438 [m] at 2250 [rpm] with mixture :13.0 :1 : 222 [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