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View Full Version : The Pony's fuel tanks question.



Freiwillige
07-02-2009, 01:22 PM
I have read and heard many a time that P-51 pilots would deplete their 85 gallon tank located right behind the pilot first as it tended to make the Mustang unstable due to the center of gravity being off. One pilot stated that the Mustang wanted to swap ends if you did even the most basic maneuver with it.

In game it seems that, that is the last tank drained judging by the fuel gauges located on the floor and behind your head rest.

In Game the p-51 is a nightmare to fight in until you are down to that last tank then when that tank depletes a bit she dogfights quite well. Before that tank is drained a bit she wants "To swap ends".

I wonder if the flight model would be better suited if we could select the tanks we wanted drained first?

Freiwillige
07-02-2009, 01:22 PM
I have read and heard many a time that P-51 pilots would deplete their 85 gallon tank located right behind the pilot first as it tended to make the Mustang unstable due to the center of gravity being off. One pilot stated that the Mustang wanted to swap ends if you did even the most basic maneuver with it.

In game it seems that, that is the last tank drained judging by the fuel gauges located on the floor and behind your head rest.

In Game the p-51 is a nightmare to fight in until you are down to that last tank then when that tank depletes a bit she dogfights quite well. Before that tank is drained a bit she wants "To swap ends".

I wonder if the flight model would be better suited if we could select the tanks we wanted drained first?

VMF-214_HaVoK
07-02-2009, 01:33 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I wonder if the flight model would be better suited if we could select the tanks we wanted drained first? </div></BLOCKQUOTE>

Yes, and it has been brought to Oleg's attention many times. Im certain in SoW we will be able to select fuel tanks but as for now we must wait for some clever modder to figure it out.

S!

danjama
07-02-2009, 01:35 PM
Does it really need a new thread?

Viper2005_
07-02-2009, 01:39 PM
Define "new"...

Freiwillige
07-02-2009, 01:43 PM
I thought I was the first guy to figure this out!

Man I should have known better.

danjama
07-02-2009, 02:34 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Freiwillige:
I thought I was the first guy to figure this out!

Man I should have known better. </div></BLOCKQUOTE>

ha ha it's ok i see your still pretty recent, just use search and you will see http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

but you didn't know the history so we will let you off.

horseback
07-02-2009, 03:12 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by danjama:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Freiwillige:
I thought I was the first guy to figure this out!

Man I should have known better. </div></BLOCKQUOTE>

ha ha it's ok i see your still pretty recent, just use search and you will see http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

but you didn't know the history so we will let you off. </div></BLOCKQUOTE>AS nearly as I can remember, the official line is that the CG is 'set' for each individual aircraft's FM, and how full the tanks are doesn't change that. That means that in this game, the Mustang's CG is not affected by the fuselage tank being full.

It is however affected by the huge amount of weight that fuel represents. A Mustang could carry something on the order of 270 US gallons internally and then add another 216 gallons in drop tanks.

Generally, you'll have more than enough fuel if you keep your fuel under 50%.

cheers

horseback

VW-IceFire
07-02-2009, 04:16 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by horseback:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by danjama:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Freiwillige:
I thought I was the first guy to figure this out!

Man I should have known better. </div></BLOCKQUOTE>

ha ha it's ok i see your still pretty recent, just use search and you will see http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

but you didn't know the history so we will let you off. </div></BLOCKQUOTE>AS nearly as I can remember, the official line is that the CG is 'set' for each individual aircraft's FM, and how full the tanks are doesn't change that. That means that in this game, the Mustang's CG is not affected by the fuselage tank being full.

It is however affected by the huge amount of weight that fuel represents. A Mustang could carry something on the order of 270 US gallons internally and then add another 216 gallons in drop tanks.

Generally, you'll have more than enough fuel if you keep your fuel under 50%.

cheers

horseback </div></BLOCKQUOTE>
Correct. COG is not altered by the IL-2 flight model (according to Oleg) based on fuel consumption. The weight will go down with improves the P-51's handling considerably but there is no position of the P-51s fuel tanks in terms of weight. They just exist inside the plane.

Some members of the community have one time or another mistaken that to mean something else despite repeated attempts to get it through to them.

Essentially...use the fuel gauges around the cockpit as a graphic only.

M_Gunz
07-02-2009, 05:41 PM
IL2 3D models do not have distributed weight. SOW will. We were told this around the release of 4.0 - 4.01.

TinyTim
07-02-2009, 05:50 PM
What about loadouts? Do they change cog?

Anyone claiming they don't, I'd like to encourage you to try to taxi and/or take off with a Yak-9B loaded with 192 PTAB bomblets.

Kocur_
07-03-2009, 01:55 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by horseback:
It is however affected by the huge amount of weight that fuel represents. A Mustang could carry something on the order of 270 US gallons internally and then add another 216 gallons in drop tanks.
</div></BLOCKQUOTE>

To put in in perspective: 180 US gallons plus another 85 in fuselage make 680 + 320 = 1000 liters.
Bf 109 carried 400 liters, earlier Fw 190A 525 liters in main tanks and later ones additional 115 liters in a tank behind pilot. Spitfire basic tankage was 386 liters.

Btw. P-47D carried initially 776 liters and 1020 liters after P-47D-23 IIRC, internally of course.

horseback
07-03-2009, 11:43 AM
The difference between these aircraft was not simply a matter of fuel supply though. On top of having the tremendous fuel capacity, it also got something like 30% better gas mileage than the P-38 or P-47.

It was also better in this regard than the Spitfire, 109, and 190, although the margin may not have been quite so pronounced.

In any case, it may well have been the first 'green' high performance fighter. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

cheers

horseback

Viper2005_
07-03-2009, 12:06 PM
The comparison of air miles per gallon between the P-51, P-38 and P-47 isn't a fair one because the Mustang is a much smaller aeroplane. To get a better idea of the fuel efficiency of such different aeroplanes, you really need to multiply the air mpg by the payload carried (guns + ammunition + pilot). Obviously this sort of comparison will make the P-47 and P-38 look somewhat better than they do in the straight air mpg comparison. A point for debate is whether one should consider armour plate in the "payload" account.

The comparison with the Spitfire, however, is an extremely important one, because on the same power output from essentially the same engine, the Mustang was substantially faster. This is slightly tempered by the fact that contemporary Spitfires were almost always more heavily armed than contemporary Mustangs, so if you want to be really accurate, you should apply the sort of methodology suggested above to account for this.

The biggest problem with the Mustang fuel debate is that because the rear tank gauge is the one which is actually functional in IL2, many people assume this to mean that the model assumes all of the fuel mass to be at the CoG of the aft tank, which would of course put the aeroplane into an extreme aft CoG condition.

Based upon the handling of the aeroplane, it is pretty safe to say that this is not the case, because at aft CoG the Mustang would actually tighten up in turns (see numerous pilot reports) because the elevator force for constant g would reverse. In other words, you'd need to actually push forward on the stick to stop the aeroplane tightening a turn.

What seems to happen in the game is that all the aeroplanes are modelled with a single fuel tank at some position either on the aircraft CoG (most likely) or perhaps at the mean of the CoG of the real aircraft's fuel tanks.

This has some interesting consequences.

The first one is that some aircraft have significantly more benign handling under certain conditions than would have been the case IRL.

The second is that you don't have to worry about your fuel tank selector.

The third is that fuel leaks can be excessively dangerous because they can drain your entire fuel system rather than only the affected tank.

Kocur_
07-03-2009, 01:33 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Viper2005_:
This is slightly tempered by the fact that contemporary Spitfires were almost always more heavily armed than contemporary Mustangs, so if you want to be really accurate, you should apply the sort of methodology suggested above to account for this. </div></BLOCKQUOTE>

Indeed Spitfires were "more heavily armed" but only in terms of firepower, not really so in the actual weight of the armament. Take a look at table no 3 in http://www.quarry.nildram.co.uk/WW2guneffect.htm . By the methodology used there, P-51B/C armament weight was 257 kg.

VW-IceFire
07-03-2009, 02:54 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by TinyTim:
What about loadouts? Do they change cog?

Anyone claiming they don't, I'd like to encourage you to try to taxi and/or take off with a Yak-9B loaded with 192 PTAB bomblets. </div></BLOCKQUOTE>
Good point. I often wondered if that was scripted but thats sort of against Oleg's MO.

horseback
07-03-2009, 07:12 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kocur_:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Viper2005_:
This is slightly tempered by the fact that contemporary Spitfires were almost always more heavily armed than contemporary Mustangs, so if you want to be really accurate, you should apply the sort of methodology suggested above to account for this. </div></BLOCKQUOTE>Indeed Spitfires were "more heavily armed" but only in terms of firepower, not really so in the actual weight of the armament. Take a look at table no 3 in http://www.quarry.nildram.co.uk/WW2guneffect.htm . By the methodology used there, P-51B/C armament weight was 257 kg. </div></BLOCKQUOTE>Please define 'heavily armed'.

Now tell us what the single sortie kills record for the Spitfire (any sorty, any Mark during WWII) is.

I can think of at least three occasions where a Mustang pilot scored at least five in a single sortie in the ETO.

James A. Howard
Chuck Yeager
Sidney Woods

There are probably others. "Heavily armed?"

Puh-lease.

cheers

horseback

WTE_Galway
07-03-2009, 07:28 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by horseback:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kocur_:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Viper2005_:
This is slightly tempered by the fact that contemporary Spitfires were almost always more heavily armed than contemporary Mustangs, so if you want to be really accurate, you should apply the sort of methodology suggested above to account for this. </div></BLOCKQUOTE>Indeed Spitfires were "more heavily armed" but only in terms of firepower, not really so in the actual weight of the armament. Take a look at table no 3 in http://www.quarry.nildram.co.uk/WW2guneffect.htm . By the methodology used there, P-51B/C armament weight was 257 kg. </div></BLOCKQUOTE>Please define 'heavily armed'.

Now tell us what the single sortie kills record for the Spitfire (any sorty, any Mark during WWII) is.

I can think of at least three occasions where a Mustang pilot scored at least five in a single sortie in the ETO.

James A. Howard
Chuck Yeager
Sidney Woods

There are probably others. "Heavily armed?"

Puh-lease.

cheers

horseback </div></BLOCKQUOTE>


5 kills in a sortie is not unheard of both in allied and axis aircraft, I just posted a list in another thread which shows aussie Clive Caldwell getting 5 kills in a single sortie in a P40.

As for the Spitfire, 5 kill sorties werent unheard of, hear is an example from the RCAF ....

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> from http://www.acesofww2.com/Canada/aces/Audet.htm :

Canadian Pilot Downs 5 Huns In 5-Minute Battle Over Reich
London, Dec. 31, 1944 - (CP) F/L Richard J. Audet, 22-year-old Spitfire pilot of a Canadian wing operating with the British 2nd Tactical Air Force, had never before downed an enemy aircraft but in five blazing minutes over Osnabruck he racked up five kills on Friday.
His feat was performed as Canadian fliers smashing at German communication targets in the Rhineland were met by stiff enemy aerial opposition.
Audet's victims were three Focke-Wulf 190's, one Messersehmitt 109 and an unspecified aircraft.
Pilots in this wing destroyed a total of nine German aircraft, probably destroyed another two and damaged six. They also smashed at Nazi rail traffic, destroying four locomotives, damaging 13 and damaging 75 freight cars.

</div></BLOCKQUOTE>

horseback
07-03-2009, 08:56 PM
Audet appears to be the record holder for the Spit, but he also appears to have been an exceptional case; Howard got 5 Me-110s in January of 1944, the last one with only one .50 working. Apparently, the rear gunners on those 110s weren't using their mouses to aim...

George Preddy got six in a single sortie in August of 1944; Bill Beyer got 5 in a single mission on 27 September, and there were at least a solid dozen 4 kill sorties flown by Mustang pilots in the ETO alone. You can add another three or four Mustang 'ace in a day' sorties in the Pacific.

Multiple kill sorties were the outstanding exception for Spitfire pilots. One suspects that either the men who flew them weren't very good shots (bull--not even the Yank or 'other' Commonwealth squadrons flying the Spit got a lot of multiples), that the aircraft was a less than ideal firing platform, or that it didn't carry enough rounds to do the job in a target-rich environment.

I lean towards a combination of the last two. 'Weight of fire' was nearly meaningless in the latter half of the war when a sizable chunk of the fire is rifle caliber.

cheers

horseback

Viper2005_
07-03-2009, 09:00 PM
In this context I was mainly talking about the combined mass of guns and ammunition.

Firepower is another short half-life thread of its own...

Kettenhunde
07-03-2009, 10:12 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> at aft CoG the Mustang would actually tighten up in turns </div></BLOCKQUOTE>

All aircraft at aft CG will "tighten up the turn", the Mustang exhibits a stability and control problem called a reversal which is a separate issue. A longitudinal axis reversal is far from ideal but can be acceptable. In many airplanes a longitudinal reversal can be induced if we do not trim the airplane. This is one reason why take off trim is so important to check during run up. An example of an unacceptable reversal is one in the lateral axis.

In general Aft CG has the effect of relieving some of the tail down force which has the effect of raising useable coefficient of lift thereby lowering stall speed and increasing sustained turn.

The downside is our spins tend to flatten due to the lower moment produced by the shorter arm and our reduced tail forces further hamper recovery. Depending on the tail design, recovery can be impossible from a spin at an aft CG position for many aircraft designs. This is a common cause for the "spins prohibited" placard.

All the best,

Crumpp

M_Gunz
07-04-2009, 01:49 AM
How often were Spitfires active in places where piles of poorly trained targets threw themselves up to be shot down?
IE deep enough into enemy territory to get such a response late enough in the war to meet such noob-heavy numbers?

Great Marianas Turkey Shoot or waves of Kamikazes or defense of Germany homeland actions? Others? I don't see much
on Spitfires in these battles, they seem to lack the range for one but just because I didn't see doesn't mean it didn't
happen on any regular basis.

TinyTim
07-04-2009, 02:16 AM
I'd agree with you Gunz, and add that many German fighters fighting allied heavy bombers deep above Germany had to give up their tactical advantages (like altitude) to be able to attack bombers - and thus exposed themselves to the escorts. This is often forgotten when discussing late war air combat over Germany. USAAF fighters were targetting German interceptors. These were targetting bombers, not fighters. Comparing kill ratios in this regard is fundamentaly flawed.

horseback
07-04-2009, 01:37 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by M_Gunz:
How often were Spitfires active in places where piles of poorly trained targets threw themselves up to be shot down?
IE deep enough into enemy territory to get such a response late enough in the war to meet such noob-heavy numbers?

Great Marianas Turkey Shoot or waves of Kamikazes or defense of Germany homeland actions? Others? I don't see much
on Spitfires in these battles, they seem to lack the range for one but just because I didn't see doesn't mean it didn't
happen on any regular basis. </div></BLOCKQUOTE>Europe, second half of 1944 saw many clashes of Spit Wings based in the continent with large formations of German fighters of less than uniformly well trained pilots. Most of these were low or medium altitude clashes, where the Spitfire's virtues should have shined most brightly.

I did a quick survey of my many books about the Spit (and I am a lifelong fan of it by the way) and the pilots who flew them, and it was the rarity of mentions about multiple kills that stands out; if a Spitfire pilot got a double it was considered worth mentioning, even in periods where large enemy formations were routinely encountered, like Malta, the Battle of Britain, or the cross Mediterannean interdictions of German supply flights during the waning days of the North Africa campaign.

Audet's encounter was only one such target rich sortie, and he was both exceptionally skilled and lucky to get five. That he was the only one to do so makes me question the belief that a Spitfire was more 'heavily armed' than a Mustang --or P-40, Hellcat, Corsair, or even the lowly Wildcat, all of which had multiple occasions of 'ace in a day' sorties.

10+ kill pilots who flew US fighters with the 'base' 4 or 6x.50 wing mounted armament usually listed at least one triple or double on their scorecards, and many could boast multiples almost every time they encountered enemy aircraft even when there there slews of other Allied fighters competing to get those same aircraft..

These occured both early in the war against well trained opponents as well as late in the war after some of the opposition's 'pros' had been pared away, and Axis training levels had deteriorated.

Jim Howard's five victories with four or less working guns against the relatively robust Me-110G (flown by more experienced pilots than Preddy or Yeager probably faced) has to tell you something not only about his skills but also about the effectiveness of his weapons.

When you have a great Sunday punch, but cannot land it before you run out of ammo, you might as well be flying an unarmed recon plane. In a knife fight with lots of high G turns and wing flexing spoiling your firing solution, limited firing time is a liability, regardless of your instantaneous 'weight of fire'.

Shooting down an airplane from another airplane was very hard in real life, and the perception that this game gives, no matter how well reasoned and detailed, is still very disorted, even if considerably less so than the rear gunner's mouse fire control system.

For an average pilot of limited marksmanship, a short total firing time is next to useless; this has been brought home to me forcefully while flying a Yak-1b offline campaign, and that bird has nose mounted guns. If the Spit's FM included the wingflex distortion combined with the complications of wing mounted convergence in its gunnery solution, the wails of frustration would be deafening.

If you added propwash and the turbulence behind the enemy aircraft you finally got on the six of, well it's just too ugly to contemplate.

The historical record says something different about the Spit's 'weight of fire' than the game says. That the RAF eagerly augmented their late war 'e' wing armament with a pair of .50 M2s closer to the wing root in place of the 4x.303 setup they had for most of the war speaks volumes.

cheers

horseback