Rolls Royce Krestel XVI |aircraft investigation|aircraft engines

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performance calculations for the Rolls Royce Krestel XVI aircraft engine

See the source image

Krestel XVI on display in the Royal Air Force museum, Cosford

Rolls Royce Krestel XVI liquid-cooled 12 -cylinder V-engine 670 [hp](499.6 KW)

gear-driven supercharger, constant power to height : 1000 [m] blower ratio :

introduction : 1936 country : United Kingdom importance : ***

applications : Miles Master, Junkers Ju.86Z-7

normal rating : 670 [hp](499.6 KW) at 2250 [rpm] at 1000 [m] above sea level

take-off power : 745 [hp] (555.5 [KW]) at 2625 [rpm]

reduction : 0.553 , valvetrain : SOHC

General information :

First Rolls Royce cast-block engine, inspired by the first successful cast-block engine

being the Curtiss D-12. Before the cylinders were bolted to the crankcase, the cast-

block was one block of aluminium that was machined to form cylinders. Resulting in

a lighter and stronger engine. Arthur Rowledge broke with Napier and working now

with Rolls Royce developed the Krestel. Another new feature of the Krestel was the

use of a pressurized cooling system. With the cooling fluids under pressure it could

keep the boiling point at ca. 150 C. This reduced the amount of cooling liquid and

the radiator could be small.

fuel system : fuel type : octane grade no. 95 oil system :

engine starter type :

weight engine(s) dry with reduction gear : 450.0 [kg] = 0.90 [kg/KW]

weight reduction gear : 21.0 [kg]

bore : 127.0 [mm] stroke : 140.0 [mm]

valve inlet area : 24.6 [cm^2] one inlet and one exhaust valve in cylinder head

gasspeed at inlet valve : 37.9 [m/s]

throttle : 86 /100 open, mixture :13.0 :1

compression ratio: 7.00 :1

published stroke volume (Vs displacement): 21.240 [litre]

compression volume (Vc): 3.547 [litre]

total volume (Vt): 24.829 [litre]

engine height : 90.5 [cm] engine width : 62 [cm]

engine length: 1.89 [m]

specific power : 23.5 [kW/litre]

torque : 2120 [Nm]

engine weight/volume : 21.2 : [kg/litre]

average piston speed (Cm): 10.5 [m/s]

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intake manifold absolute pressure (MAP) at 1000 [m] altitude Pi : 0.95 [kg/cm2]

mean engine pressure (M.E.P.) at 1000 [m] altitude Pm : 10.09 [kg/cm2]

compression pressure at 1000 [m] altitude Pc: 10.82 [kg/cm2]

estimated combustion pressure at 1000 [m] Pe : 43.21 [kg/cm2]

exhaust pressure at 1000 [m] Pu : 3.72 [kg/cm^2 ]

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compression-start temperature at 1000 [m] Tic: 344 [°K] (71 [°C])

compression-end temperature at 1000 [m] Tc: 551 [°K] (278 [°C])

average engine wall temperature at 1000 [m] : 476 [K] (202 [°C])

caloric combustion temperature at 1000 [m] Tec: 2200 [°K] (1927 [°C])

polytroph combustion temperature at 1000 [m] Tep : 2200 [°K] (1927 [°C])

estimated combustion temperature at 1000 [m] Te (T4): 2177 [°K] (1903 [°C])

polytrope expansion-end temperature at 1000 [m] Tup: 1119 [°K] (846 [°C])

exhaust stroke end temperature at 1000 [m] Tu: 1076 [°K] (802 [°C])

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

calculations for take-off/emergency power at sea level

average piston speed : 12.2 [m/s]

gasspeed at inlet valve : 44.2 [m/s]

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

caloric combustion temperature at sea level Tec: 2136 [°K] (1863 [°C])

emergency/take off rating at 2625 [rpm] at sea level : 743 [hp]

Thermal efficiency Nth : 0.385 [ ]

Mechanical efficiency Nm : 0.741 [ ]

Thermo-dynamic efficiency Ntd : 0.285 [ ]

design hours : 911 [hr] time between overhaul : 243 [hr]

dispersed heat by cooling fluids at 2250.00 [rpm] at 1000 [m]: 36.65 [Kcal/minuut/litre]

fuel consumption optimum mixture at 2250.00 [rpm] at 1000 [m]: 135.41 [kg/hr]

specific fuel consumption thermo-dynamic : 211 [gr/epk] = 282 [gr/kwh]

estimated specific fuel consumption (cruise power) at 1000 [m] : 305 [gr/kwh]

specific fuel consumption (volume*rpm) at 2250 [rpm] : 271 [gr/kwh]

estimated specific oil consumption (cruise power) : 17 [gr/kwh]

Literature :

Rolls-Royce Kestrel - 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 :