cruising speeds - Printable Version

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cruising speeds - Sandbag - 31.01.2010

Hi

Anyone know the typical cruising speeds of

B17G
B24

Am trying to make missions but not sure if 300kph is about right for each
Cheers

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- _VR_Aristo - 31.01.2010

B-17:

Cruise at 25,000 Feet Density Altitude
(Charts are for B-17G; figures for B-17F are approximately 2-3
percent less due to slightly lower parasite drag)
Weight IAS Boost RPM BHP GPH MPG
60,000 140 30 2100 628 205 1.01
55,000 140 29 1900 578 188 1.10
50,000 140 29 1800 560 183 1.14
45,000 140 29 1700 540 176 1.18

Cruise at 5,000 Feet Density Altitude
Weight IAS Boost RPM BHP GPH MPG
60,000 150 29 1650 520 170 0.95
55,000 150 29 1500 490 161 1.00
50,000 150 28 1500 475 154 1.04
45,000 150 27 1500 452 148 1.08


B-24:

Cruise at 25,000 Feet Density Altitude
(Charts are for B-24J; figures for B-24D are approximately 1-2
percent better due to slightly lower parasite drag)
Weight IAS Boost RPM BHP GPH MPG
60,000 155 32 2200 754 209 1.09
55,000 155 31.5 2200 735 204 1.13
50,000 155 31 2100 692 192 1.20
45,000 155 31 2050 675 188 1.23


Cruise at 5,000 Feet Density Altitude
Weight IAS Boost RPM BHP GPH MPG
60,000 155 31 1750 540 150 1.10
55,000 155 30.5 1700 517 144 1.15
50,000 155 30 1700 500 140 1.18
45,000 155 30 1690 497 138 1.21

P.S.: The above charts are from an actual operating manual, as such it may and probably will not behave as it's supposed to in IL-2. But it should help you gain insight on how these machines work and the way they meant to be flown. Also bear in mind that the altitudes given above are "density" altitudes, and not pressure altitudes. For those of you that don't know, density altitude is "the" primary environmental factor that determines aircraft performance. Density altitude might be so high one day where the airfield is located(such as in a very hot day), you may not even be able to take-off, even with a very light plane, because the air is so thin.

Weight = lbs
IAS = Indicated air speed(which is what your speed gauge shows) in mph.
Boost = Manifold pressure in Hg/In.
RPM = Revolutions Per Minute
BHP = Break Horse Power
GPH = Gallons Per Hour
MPG = Miles Per Gallon



Aristo

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- Sandbag - 31.01.2010

Thanks

So does that mean for a fully loaded B-17 at 25000ft its airspeed should be set to around 240Km/hr?

cheers

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- _VR_Aristo - 01.02.2010

That's right... Keep in mind though that these settings are a compromise between speed and "long" range. You can go faster if you don't have to worry about fuel, but then again at that altitude with a fully loaded crate, you'll be having a hard time trying to go faster than that... At least in real life that is.

Aristo

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