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View Full Version : P-51 Fuel Capacity and Performance; Relation?



Franzen
02-16-2004, 07:25 PM
I recently watched a documentary where a couple of WW2 P-51 pilots mentioned that the P-51 handle much better when they burnt off there fuselage tank(I think it was)before enetering combat. They claimed that if you went into combat with a full tank and tried to turn sharp the plane would almost flip end for end. When we first got the patch with the P-51 I flew it but didn't like it because it would stall to easily in certain turns. After seeing this documentary I reduced my fuel by 50% and it seemed to fly better and stall less. Is this just my imagination?

Fritz Franzen

Franzen
02-16-2004, 07:25 PM
I recently watched a documentary where a couple of WW2 P-51 pilots mentioned that the P-51 handle much better when they burnt off there fuselage tank(I think it was)before enetering combat. They claimed that if you went into combat with a full tank and tried to turn sharp the plane would almost flip end for end. When we first got the patch with the P-51 I flew it but didn't like it because it would stall to easily in certain turns. After seeing this documentary I reduced my fuel by 50% and it seemed to fly better and stall less. Is this just my imagination?

Fritz Franzen

rfa0
02-16-2004, 07:42 PM
Every plane will handle better with 50% fuel compared to 100% fuel. On a plane with a big fuel capacity like the P-51 it's even more pronounced. So the handling difference you notice doesn't necessarily prove that the full-fuel instability of the P-51 is modeled in FB.

Franzen
02-16-2004, 07:49 PM
So it is generally modelled in FB, cool. Now I understand La tactics; half a cup of fuel to go along with the ammo capacity http://ubbxforums.ubi.com/images/smiley/16x16_smiley-very-happy.gif Thx for the info.

Fritz Franzen

Maple_Tiger
02-16-2004, 10:16 PM
You may even want to just use 25% fuel for the P-51. Even less prone to stalling. As long as you dont fly around at 3200 combat RPM and 100% power all the time it should last long enough for you to use up most of your amo and still have lots of fule to get you home.

I usualy just keep rad at 2, 3000RPM and 95% power. Once i get to altitude my engine is still rather cool. The i just reduce my RPM down to 2700 wich is about cruze RPM i think and set power to 75% and look for victoms.

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VW-IceFire
02-16-2004, 10:30 PM
In a dogfight room and lots of tactical missions...25% fuel is enough for the duration of the mission and then some. It rolls, manuvers, and generally performs much better here.

All planes do, but some you can't afford to have at such a low percentage.

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MandMs
02-17-2004, 04:06 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Franzen:
I recently watched a documentary where a couple of WW2 P-51 pilots mentioned that the P-51 handle much better when they burnt off there fuselage tank(I think it was)before enetering combat. They claimed that if you went into combat with a full tank and tried to turn sharp the plane would almost flip end for end. When we first got the patch with the P-51 I flew it but didn't like it because it would stall to easily in certain turns. After seeing this documentary I reduced my fuel by 50% and it seemed to fly better and stall less. Is this just my imagination?

Fritz Franzen<HR></BLOCKQUOTE>

When the P-51 had the aft position fuselage tank full, the P-51 had a rearward positioned CG. The Spitfire was simular with its rear fuselage tank. The CG did not get to respectable position until around 50%(preferably less) of the tank was gone. With the fuselage tank empty, the P-51 still had ~68% of its internal fuel load.

WUAF_Badsight
02-17-2004, 04:18 AM
with 100% fuel the Mustang WILL NOT reach its top speed of 700 km/h

this should be looked into as top speeds should be reached with full ammo & fuel

MrMig
02-17-2004, 05:27 AM
Anyone knows how fuel amount affects firing stability? Was it a problem in RL? And if so is it modeled in fb?

thanx

FA_Whisky
02-17-2004, 05:49 AM
There is something else about the P51d in the game. When you take on fuel it will go in the rear tank first!! With 25% its all in the rear tank, with 50% the rear tanks is full and there is some in the wingtanks. This is very weird because we all know the P51 becomes very unstable with the rear tank filled. Pilots also where instructed to empty the rear tank first! I hope this will be fixed in the Ace expasion pack.

MandMs
02-17-2004, 06:15 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by FA_Whisky:
There is something else about the P51d in the game. When you take on fuel it will go in the rear tank first!! With 25% its all in the rear tank, with 50% the rear tanks is full and there is some in the wingtanks. This is very weird because we all know the P51 becomes very unstable with the rear tank filled. Pilots also where instructed to empty the rear tank first! I hope this will be fixed in the Ace expasion pack.<HR></BLOCKQUOTE>

No, all tanks are filled and emptied equally. It has been stated that real life usage is not modelled. Still, once below 75% total fuel capacity, the CG placement of the P-51 should not have any effect on a/c balance.

IAFS_Painter
02-17-2004, 06:25 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by WUAF_Badsight:
with 100% fuel the Mustang WILL NOT reach its top speed of 700 km/h

this should be looked into as top speeds should be reached with full ammo & fuel<HR></BLOCKQUOTE>

Should it?
I can not get my head around the math, but this is a function of lift(=weight), and therefore drag.

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FA_Whisky
02-17-2004, 09:22 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>No, all tanks are filled and emptied equally. It has been stated that real life usage is not modelled. Still, once below 75% total fuel capacity, the CG placement of the P-51 should not have any effect on a/c balance.<HR></BLOCKQUOTE>

Take 25% and look at your guages. You will see the wingtanks empty and the reartank at about 60% full. When you tanke 50% fuel the rear tank will be full and you will see some fuel in the wingtanks. The gauges say it is modeled.

Strange_361st
02-17-2004, 09:33 AM
Oleg has mentioned this about the pony's fuel management system is not modeled correctly. And most likely never will be.

That rear tank should be burned first then the wing tanks. The issue screwed badly with the a/c CG. Once in flight they would burn that tank first and then switch to the wing tanks. But we'll never to see that properly modeled.

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Maple_Tiger
02-17-2004, 09:45 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by IAFS_Painter:
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by WUAF_Badsight:
with 100% fuel the Mustang WILL NOT reach its top speed of 700 km/h

this should be looked into as top speeds should be reached with full ammo & fuel<HR></BLOCKQUOTE>

Should it?
I can not get my head around the math, but this is a function of lift(=weight), and therefore drag.

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I've given up correcting my own spelling
Unless I've corrected it here<HR></BLOCKQUOTE>



But its Ok for the La7 to reach its top speed at 6000m with 100% fuel and amo wihout over heating?

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Platypus_1.JaVA
02-17-2004, 10:08 AM
Just basic aerodynamics.

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georgeo76
02-17-2004, 10:48 AM
I don't think that IL2 models separate fuel tanks. Think about it. Take the P-39 for example. It has two fuel tanks, one in each wing. One fuel tank is larger than the other to provide space for auxiliary fuel.

Now, your fighting against a G2 and he rails *one* of your wings badly enough to cause a fuel leak. You escape only to run out of fuel on the RTB.

Also notice that there is no control to switch fuel tanks. Seems to me that FB has modeled a volume, weight, and consumption of fuel, but not it's location. The DM dose account for fuel location, but that only effects the actual fuel amount in case of an explosion or leak.

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BlindHuck
02-17-2004, 12:28 PM
If Mustang CG/fuel thing was modeled then with full fuel (w/ tanks) you would get stick reversal at 2g. That might show up in game simply as a stall, but it would be at 2g (60 deg. bank, level turn). Not sure I've ever really duplicated this. http://ubbxforums.ubi.com/images/smiley/16x16_smiley-sad.gif Stick should require no back pressure with considerable forward stick needed if it tightens up at all. RL pilots would sometimes leave a certain amount in center tank (maybe 15 gals.) as CG trim (like 747-400 http://ubbxforums.ubi.com/images/smiley/16x16_smiley-happy.gif) to reduce stick force and shorten turn radius slightly.

It's all so very complex. http://ubbxforums.ubi.com/images/smiley/16x16_smiley-happy.gif

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tttiger
02-17-2004, 01:09 PM
Bud Anderson ("Old Crow") on the P-51 fuselage fuel tank (from an interview I found on line):

"Bud: I still have great memories of the P-51's combat performance and have not changed my mind at all. It did have some bad characteristics, which I mention in my book. For example, when the fuselage fuel tank was full it had an aft center of gravity that made the aircraft unstable. This gave you a stick force reversal when maneuvering. Further, it made instrument flying more difficult. Once you used half of the fuel in the fuselage tank you gained stability and it flew normally."

And, yes, St. Oleg has admitted the fuel system is incorrectly modeled. If I choose 25% fuel, it should be in the wing tanks (which don't exist in FB), not in the fuselage tank. Instead, ALL of the fuel goes into that fuselage tank.

That's why I only use 25%, you can fly a loooooong time on 25%

Aloha,

ttt

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DynamicBass
02-17-2004, 01:49 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Franzen:
I recently watched a documentary where a couple of WW2 P-51 pilots mentioned that the P-51 handle much better when they burnt off there fuselage tank(I think it was)before enetering combat. They claimed that if you went into combat with a full tank and tried to turn sharp the plane would almost flip end for end.
Fritz Franzen<HR></BLOCKQUOTE>

I am busy reading a book on the South African's 2nd squadron (the flying cheetahs) who fought in Korea using p-51's (later Sabres). This particular issue is mentioned as they performed ground attack duties during the war and they talk of at least one pilot not being able to pull out of a bombing/rocket attack and crashing into the ground proberly due to him not using his fuselage fuel tank up first which was known to them to cause complete instability in a dive with total loss of stick control.

Chuck_Older
02-17-2004, 03:41 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by MandMs:
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by FA_Whisky:
There is something else about the P51d in the game. When you take on fuel it will go in the rear tank first!! With 25% its all in the rear tank, with 50% the rear tanks is full and there is some in the wingtanks. This is very weird because we all know the P51 becomes very unstable with the rear tank filled. Pilots also where instructed to empty the rear tank first! I hope this will be fixed in the Ace expasion pack.<HR></BLOCKQUOTE>

No, all tanks are filled and emptied equally. It has been stated that real life usage is not modelled. <HR></BLOCKQUOTE>

Very good point!

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