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STRIDER_EB
06-04-2004, 10:05 PM
Is fuel weight modeled in FB/AEP? I don't have time to test it at the moment and I'm hoping I can get a quick answer. Thanks!

STRIDER_EB
06-04-2004, 10:05 PM
Is fuel weight modeled in FB/AEP? I don't have time to test it at the moment and I'm hoping I can get a quick answer. Thanks!

RS_Shiesty
06-04-2004, 10:07 PM
If you mean the difference between 25% and 100% fuel loads, yes the weight difference is modeled.

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ucanfly
06-05-2004, 01:51 AM
A simple question and answer, but it seems that in a dive your extra weight is not modelled, only in climb. Also the CG does not seem to be affected (e.g. P-51). hmmmmmm

Atomic_Marten
06-05-2004, 02:47 AM
I guess that also includes different loads on A/C's.(example, difference when flying without ammo-'Empty' or on 'Default' load).

Cajun76
06-05-2004, 04:23 AM
The difference on say a P-47 is rather remarkable if your used to flying at 25%. Put 100% fuel and strap on 2000lbs of bombs and you have a bomber that flies faster than most other bombers, but handling and climb are seriously affected. Then try it with 25% and extra ammo and she feels like a whole other a/c. http://ubbxforums.ubi.com/images/smiley/16x16_smiley-happy.gif

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Tully__
06-05-2004, 04:57 AM
Fuel & ordnance loads are definitely modelled in level flight and climb. Dive would be harder to test for, but I'd suspect they're modelled there too with 1C:Maddox's attention to FM modelling detail.

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Covino
06-05-2004, 10:49 AM
I'm pretty sure ammo loads (bullets/shells) are also accounted for in FM modelling.

Maj_Death
06-05-2004, 11:21 AM
It definatly is, this is why many people online carry 50% fuel or even 25% fuel to get extra speed, climb rate and agility. It does of course restrict range though, so keep an eye on your fuel gauge if you decide to cut your fuel load down.

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Cragger
06-05-2004, 12:27 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by ucanfly:
A simple question and answer, but it seems that in a dive your extra weight is not modelled, only in climb. Also the CG does not seem to be affected (e.g. P-51). hmmmmmm<HR></BLOCKQUOTE>

As pointed out in another thread weight I.E. mass have no effect on terminal velocity due to gravity. The only factors that have an effect on how fast an aircraft can dive are drag and thrust. Mass only effects how quickly thrust is turned into velocity thru momentum (acceleration) and the energy a falling object has at a given velocity (kinetic energy).

Or shortened a P-51 and a P-47 twice the mass but producing the same thrust and having the same resistance would both reach the same theoretical terminal velocity but the P-51 would accelerate faster in the dive due to having less inertia to resist a change in velocity (acceleration).

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DONB3397
06-05-2004, 01:15 PM
With some aircraft, the performance variances with different fuel and ordnance loads is fairly dramatic. The P51D, for example, seems unstable at low speeds with a full tank, while its performance is good to excellent with 25%. What is not modelled is the handling difference you would expect if tanks are emptied in one section of the plane vs. others, e.g., wing vs. fuselage tanks. Test it yourself when you have time.

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Hawgdog
06-05-2004, 01:53 PM
Just my .02USD, seems a few planes I had been used to handling with 25% fly much more stable and handle better with 50%!?!
Is this just imagination or do the planes handle better with half, assuming they were modeled to fly best at "where they got to" in terms of range?
tia

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icrash
06-05-2004, 06:24 PM
I'd posted about prob with getting the He111 off the ground on a certain map. Runway was set up so you had to climb in a hurry to clear the wall of the valley that the base was in. Decrease the amount of fuel was one of the very first things I was told. Lighter is better (although the crashes were a sight to behold).

LEXX_Luthor
06-05-2004, 07:57 PM
late MiG~21s were unstable with less fuel. Don't know how this applies to...The Ancients. http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif


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Hawgdog
06-05-2004, 09:29 PM
Just watched this thing about mustangs and how the fuel you HAD to use first was the tanks behind the pilot or you'd swap ends on manuevering!
wonder if using 25% on stangs imitates this problem?

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ucanfly
06-06-2004, 02:07 AM
When at 100% fuel the Mustang should be very unstable in pitch since its fuselage tank is full. This does not happen in the game. IRL the fuselage tank is drained first, in the game the fuselage tank gauge shows that it drains LAST. Differing fuel tanks are not apparently modelled in IL2 FB sad to say.

ALso a heavier plane can (eventually) accelerate faster in a dive than a lighter plane on the earth (remembering the vertical forces are mg - Drag in the vertical direction) given good drag characteristics of the heavier plane. A five year old knows that an inflated balloon and a water balloon fall at a different rate. This is because the resultant vertical force is much greater in the heavier balloon.

Accel = (mg-Drag)/m or g-Drag/m.

IN a vaccuum is the only condition that everything falls at the same accel given the same starting conditions and external forces. Apparently from tests that others have performed we have no steep dive advantage from the heavier planes and only a weight penalty. This , if proven to be true and not a bug is a serious limitation of the flight model which renders some planes' historical advantage completed nullified in this game.

So yes fuel load is modelled but perhaps not as completely as some would like.

RocketDog
06-06-2004, 03:24 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Cragger:
As pointed out in another thread weight I.E. mass have no effect on terminal velocity due to gravity. The only factors that have an effect on how fast an aircraft can dive are drag and thrust. <HR></BLOCKQUOTE>

Whoa - that's not true. Imagine an aircraft machined out of solid depleted uranium which is put into a vertical dive. It's terminal velocity will be much higher than a real aircraft. Weight is just another force and sums with drag and thrust to determine acceleration and terminal velocity.

Large weight means that drag has to rise to large values so that the net force is zero at terminal velocity. Since drag is approx. proportional to speed squared, the larger drag required can only come from a higher terminal speed.

Regards,

Rocketdog.

(PS - the confusion may have arisen because, in a vacuum, all object will accelerate at the same speed. But in the atmosphere we have friction so this doesn't apply)