[Th!rdeye]

Well from what i see, the fuel tank issue doesn't really effect the mustang. So i cannot make the Aft tank drain first, but i do not think it would make a difference the way the game FM is modelled.

I do however, have a hunch that the CoG of the 51 itself is off... Anyone know the CoG of the 51B/C mustangs, and D?

[CUJO_1970]

Well from what i see, the fuel tank issue doesn't really effect the mustang. So i cannot make the Aft tank drain first, but i do not think it would make a difference the way the game FM is modelled.

Correct, Il2 doesn't model the CG shift for the FM - it only calculates the _weight_ changes.

[Th!rdeye]

Well from what i see, the fuel tank issue doesn't really effect the mustang. So i cannot make the Aft tank drain first, but i do not think it would make a difference the way the game FM is modelled.

Correct, Il2 doesn't model the CG shift for the FM - it only calculates the _weight_ changes.

Actually it does model CG shift. When you put flaps and/or gear down, it has a value for CG shift.

[Th!rdeye]

bump. This will greatly determine the performance of my 51 variants if it needs correct. I really do need this guys. Anyone have anything?

[caldrail]

Well from what i see, the fuel tank issue doesn't really effect the mustang. So i cannot make the Aft tank drain first, but i do not think it would make a difference the way the game FM is modelled.

Correct, Il2 doesn't model the CG shift for the FM - it only calculates the _weight_ changes.

Actually it does model CG shift. When you put flaps and/or gear down, it has a value for CG shift.

CG shift? For lowering wheels and flaps? What for? The most important CG change is longitudinal and these circumstances don't affect it. Lowering all the dangly bits does affect drag however so perhaps the values are simply there to model trim changes by another route?

[Scharnhorst1943]

Well from what i see, the fuel tank issue doesn't really effect the mustang. So i cannot make the Aft tank drain first, but i do not think it would make a difference the way the game FM is modelled.

Correct, Il2 doesn't model the CG shift for the FM - it only calculates the _weight_ changes.

Actually it does model CG shift. When you put flaps and/or gear down, it has a value for CG shift.

CG shift? For lowering wheels and flaps? What for? The most important CG change is longitudinal and these circumstances don't affect it. Lowering all the dangly bits does affect drag however so perhaps the values are simply there to model trim changes by another route?

The stang is not the only one with COG issues ...

PE-8
D3A1 Val
Avenger
Kate
Tu-2

And I am going out on a limb to say they are not the only ones ...

[RedChico]

Well from what i see, the fuel tank issue doesn't really effect the mustang. So i cannot make the Aft tank drain first, but i do not think it would make a difference the way the game FM is modelled.

Correct, Il2 doesn't model the CG shift for the FM - it only calculates the _weight_ changes.

Actually it does model CG shift. When you put flaps and/or gear down, it has a value for CG shift.

Actually, no. Thats just a extra force being applied to the CG.

Center of Gravity shifts only with mass changes and nothing else.
That or my aerodynamic university books are wrong.


Edit: Centroids is the more correct term.

[Th!rdeye]

Guys, i do not need to know of others planes that are wrong with the CG.

and this does model CG shift for flaps and gear. Its how the game does it.

Now does anyone have the info i need?

[TurkeyDriver]

Thirdeye,
I may still have it. I located once on a website a few months back.

Alas it is only for the D, no time to look more but the link may provide the info on the B/C.

III Condition of Aircraft Relative to Tests
..... center of gravity at this loading was 27.63% MAC gear down and 27.89% MAC gear up.

This should allow you to calculate the location.

Here is the link for the full report.

http://www.wwiiaircraftperformance.org/m...15342.html

My pay grade does not allow me to qualify the validity of the data on this site I'll let other do that.

[Th!rdeye]

Thirdeye,
I may still have it. I located once on a website a few months back.

Alas it is only for the D, no time to look more but the link may provide the info on the B/C.

III Condition of Aircraft Relative to Tests
..... center of gravity at this loading was 27.63% MAC gear down and 27.89% MAC gear up.

This should allow you to calculate the location.

Here is the link for the full report.

http://www.wwiiaircraftperformance.org/m...15342.html

My pay grade does not allow me to qualify the validity of the data on this site I'll let other do that.

Il-2 CG settings go off the center of the aircraft. Also that test is with only 25gallons in the aft tank.

I do not know how to calculate MAC onto the visual image of the plane.

[TurkeyDriver]

This link should help explain how to find MAC. It is relatively easy to do but hard to explain in a forum text format.

http://www.airfieldmodels.com/informatio..._chord.htm

Also some basic physics will let you solve for adding gas (ie weight) to the aft tank and how it moves the Cg further aft.

Most 3D CAD type programs are able to solve this for you automatically.

[Ramstein]

Is anyone working on the P51? as a new slot? if so any news? info on maybe when work wil start?

Thanx..
8)

I need hope..
:roll:

[Dudok22]

Th!rdeye is working on P-47 and P-51 8)

[zulu64]

IL2 does vary Cof G as a function of weight and ordinance. The YAK 9B with 128 PTAB 2.5s easily demonstrates this.

In the case of the Fuel Burn IL2 assumes all fuel tanks are symmetrically placed around the C of G.
If you want to simulate the stability issues of a P51 with the fuselage tank in use then simply move the C of G. However this will affect the entire FM. Good luck trying to sort out the subsequent stabilty issues.