AC Fuel Burn affected by Load out in AH?

[Pongo]

Is the range of an aircraft in AH curtailed by a heavy load out?
I noted in another thread that the range of a Sterling was quartered by taking the 14k bomb load. I assume a similar effect would apply to the Lancaster. Well I often take a Lanc with 14k and ¼ fuel and have plenty of fuel for what ever I need to do. Is this realistic? Would I be forced to take more fuel, wich greatly increases climb time, which greatly decreases destruction per hour ratios, which greatly decreases the overall impact of an Aircraft in the game…
I note that the extra weight of more ordinance greatly effects climb performance..Does it also accurately impact fuel usage?

[Lephturn]

Yes and No.

Not because it isn't modelled, but simply because we fly around with our throttles at 100% all the time.  In a real life situation, carrying more weight would force you to increase your throttle setting and hence your fuel usage just to maintain cruise flight.  In AH, we are all at 100% anyway, so we are burning the same amount of fuel anyway, it's just a matter of how fast we fly or climb using that power.  Weight has the right effect on the flight model, we just have a different situation in terms of throttle settings.  In WWII, it was long stretches of boredom punctuated by very brief bits of action.  Since in AH we want action most of the time, the game really has to be set up this way.

I think the difference is that the strategic bombers generally had huge fuel loads anyway, and even with the fuel multiplier we aren't likely to hit those limits due to time constraints and the smaller size of the game world.

[Pongo]

Makes scence. Thanks Leph

[funkedup]

For internal ordnance here is what's going on:

Fuel flow rate rate (gal/hr) is not a function of weight.  In AH (and real world) it's a function of manifold pressure.  It should also be a function of RPM but I'm not sure it is in AH.  But the point is (as Lephturn explained) that you will burn up your fuel in the same amount of time at 100% throttle regardless of what load you put in the aircraft.

Specific range (mi/gal or nm/gal) IS a function of weight.  A heavier load requires more lift which causes more induced drag.  So at a given throttle setting and altitude you will fly slower in level flight when you have a heavier load.  Since you fly slower, and you have the same flying time before your fuel is depleted, you have a shorter range.  

But remember that induced drag is a relatively small percentage of total drag when you are flying near the maximum level speed of the aircraft.  So if you fly at wide open throttle all the time, you are not going to see a large decrease in top speed and thus range.

External ordnance is a little different.  You have the effects described above, plus an increase in the zero-lift drag.  This will be most significant at high speeds and there should be a measurable decrease in maximum level speed and range for an aircraft carrying a bunch of external ordnance.

[ 08-01-2001: Message edited by: funkedup ]

[HoHun]

Hi Pongo,

it's important to understand that bombers in WW2 usually were limited by the maximum take-off weight. Lifting heavier armament could only be done by decreasing the fuel load - and thereby limiting range.

Of course, a heavier aircraft would be less fuel efficient - the Lancaster's pilot's notes for example quote a figure of 1.14 air miles per gallon (at 20000 ft) for the outbound journey (loaded with bombs), but a figure of 1.21 air miles per gallon for the homeward journey.

British practice for economical flying was to use the highest attainable manifold pressure to achieve the recommended cruise speed at the (resulting) lowest possible RPM.

Regards,

Henning (HoHun)

[funkedup]

Good stuff HoHun