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Mercedes D.IVa

liquid-cooled 6 -cylinder inline engine 260 [hp](191.2 KW)

introduction : October 1916 country : Germany

applications : Gotha G.V

max rating : 260 [hp](191.2 KW) at 1450 [rpm] at 0 [m] above sea level

normal rating : 252 [hp] at 1400 [rpm] at 500 [m] above sea level

high compression engine : cannot run at full power at sea level, constant power to

height : 500 [m]

no reduction, direct drive 4 valves per cilinder

weight engine(s) dry : 425.0 [kg] = 2.22 [kg/KW]

bore : 160.0 [mm] stroke : 180.0 [mm]

compression ratio: 4.94 :1

published volume (displacement): 21.720 [litre]

calculated stroke volume (Vs) : 21.715 [litre]

compression volume (Vc): 5.511 [litre]

total volume (Vt): 27.226 [litre]

power / stroke volume ( Nl): 8.8 [kW/litre]

torque : 1265 [Nm]

engine weight/volume : 19.6 : [kg/litre]

average piston speed (Cm): 8.7 [m/s]

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intake pressure at 500 [m] hoogte Pi : 0.90 [kg/cm2]

mean engine pressure (M.E.P.) at 500 [m] hoogte Pm : 6.10 [kg/cm2]

compression pressure at 500 [m] hoogte Pc: 6.95 [kg/cm2]

estimated combustion pressure at 500 [m] Pe : 27.80 [kg/cm^2 ]

exhaust pressure at 500 [m] Pu : 3.58 [kg/cm^2 ]

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compression-end temperature at 500 [m] Tc: 584 [°K] (311 [°C])

caloric combustion temperature at 500 [m] Tec: 2214 [°K] (1941 [°C])

polytrope combustion temperature at 500 [m] Te (T4): 2332 [°K] (2059 [°C])

exhaust temperature at 500 [m] Tu: 1329 [°K] (1056 [°C])

Mercedes D.IVa from a Gotha G.V bomber

compression pressure at sea level Pc: 7.22 [kg/cm2]

estimated combustion pressure at sealevel Pe : 28.87 [kg/cm^2 ]

compression-end temperature at sealevel Tc: 583 [°K] (310 [°C])

mean engine pressure at sealevel Pm : 6.34 [kg/cm2]

(emergency) rating at sea level : 260 [pk]

Thermal efficiency Nth : 0.33 [ ]

Mechanical efficiency Nm : 0.76 [ ]

Thermo-dynamic efficiency Ntd : 0.25 [ ]

design hours : 978 time between overhaul : 71

fuel consumption optimum mixture at1444.00 [rpm] at 500 [m] : 69.92 [kg/hr]

specific fuel consumption thermo-dynamic : 253 [gram/epk] = 344 [gram/kwh]

estimated specific fuel consumption (cruise power) at 500 [m] optimum mixture : 350

[gr/kwh]

specific fuel consumption at 500 [m] at 1444 [rpm] optimum mixture : 365.66

[gram/kwh]

estimated specific oil consumption (cruise power) : 23 [gram/kwh]

Literature : Jane’s Fighting aircraft WWI page 156,299

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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/photograps/content please mail to below mail address

(c) B van der Zalm 30 november 2018 contact : bvanderzalm@ziggo.nl python 3.4.1