Daidalos Team's Room -QUESTIONS AND REQUESTS ONLY on IL2 Authorized Addons

[Daiichidoku]

i thought that trading 3 control axies for PK was quite teh funneh


about the fuel leak bug:

i do remember that 190s (and P47s), after one patch, would catch fire VERY easily
after an outcry, the easy-fire stopped after the next patch..funny thing was, the "fuel leak bug" appeared then, as light puffy cloud at engine area trailing light smoke...IMO, as a "feelings experten", this was the same fire from before but cosmetically changed from fire to smoke to appease/fool the whiners

the really funny thing was, i found, that 2 patches later, the exact same thing could happen to (at least) all the other US types, F4Us, P47, P51, P38

in any event, it is what it is, i dont see why any type with seal-sealing tanks could not suffer catastrophic failure and lose all fuel in short order IRL...its annoying, but live with it, and set your glide hdg towards home



about TD looking into CoG issues with P51 (or any other type for that matter), AFAIK, il2 does not model separate fuel tanks in P51, hence there is no real problem in that regards?

[Voyager]

Originally Posted by Daiichidoku

i thought that trading 3 control axies for PK was quite teh funneh
[...]

the really funny thing was, i found, that 2 patches later, the exact same thing could happen to (at least) all the other US types, F4Us, P47, P51, P38

in any event, it is what it is, i dont see why any type with seal-sealing tanks could not suffer catastrophic failure and lose all fuel in short order IRL...its annoying, but live with it, and set your glide hdg towards home



about TD looking into CoG issues with P51 (or any other type for that matter), AFAIK, il2 does not model separate fuel tanks in P51, hence there is no real problem in that regards?

On the fuel drain debate, I believe the argument is that planes with multiple discrete fuel tanks a catastrophic hit in one tank would most likely drain just that tank, rather than the entire fuel system, but with the basic limitations of the Il-2 engine, a catastrophic hit in one tank would behave as a catastrophic hit in all fuel tanks. This is true for all aircraft in the game; it shows up most often on the US aircraft, because the USAAF and USN fighters have 3-4 times the max fuel of other comparable aircraft.

The "burning planes" was the same sort of thing. When someone sprung a leak, you could light it off by firing tracers through the leak cloud, and it would burn until the plane exploded, or the fuel ran out. People just noticed more often on the 190 and P-47, because those two took a whole lot more damage to bring down than other planes, but I found you could do the same thing to 109's, and pretty much anything else that took more than two burps of 0.50 cal. Was great fun until they fixed it.

The issue with the P-51 CoG is that as I understand it, Il-2 models the plane's fuel tank system as a single larger fuel tank placed at the aggregate CoG of the entire system, and as a consequence, all tanks are treated, in effect as though they were being drained equally. On most planes that is fine, because the fuel system as a whole is balanced around the aircraft's Center of Gravity. The P-51's is not. The Mustang has two 540lb (245kg) fuel tanks placed in the wing spars, placed very close the to CoG, and in the P-51B-10, they added a 3rd 510lb (230kg) fuel tank behind the pilot, about 3-4 feet behind the CoG. Picture, if you will, a P-51 with a 500lb bomb hung off of the radiator.

The upshot of this is, during flight, the center of mass of the P-51's fuel system move forward several feet during the first third of the flight, and then for the next 1,200 miles, just wobbles right a left a bit, as the pilot juggles the wing tanks to keep some semblance of roll balance.

Actually, after reading through all of what I just wrote, I just realized, a balanced fuel system isn't going to induce large CoG shifts as it drains. Does Il-2 even have the capacity to model CoG shifts as the fuel system empties?

Harry Voyager

Addendum: If you guys are able to produce a solution for the P-51 CoG, could you flow it over to the BoP dev team? At the moment, the P-51D is about the only USAAF fighter they've got right now, it could really use that balance fix.

[IvanK]

Voyager said:

"Actually, after reading through all of what I just wrote, I just realized, a balanced fuel system isn't going to induce large CoG shifts as it drains. Does Il-2 even have the capacity to model CoG shifts as the fuel system empties?"

Precisely and at present no, IL2 doesn't vary C of G for fuel burn off.

Which is why comments like the P51 (at present) flies like crap because the C of G with the rear fuselage tank and its incorrect feed schedule are wrong shows a basic lack of understanding of the how the stock IL2 fuel system and C of G model is used. It also shows (imo) a lack of understanding of Pitch stability and the effect of C of G has on it.

One thing IL2 can do is vary C of G dynamically as a function of weapons use. If you want to get a feel for what flying with an Aft C of G in a fighter is like in IL2 then try this.

Jump in the YAK 7B set 25% fuel and 128 Ptabs. This results in a C of G way aft as the PTABS are internally stored aft of the cockpit.
Go for a fly to get a feel for it . Then do a 1 v 1 with a comparable opponent. I think you will agree its not pleasant to fly in this configuration. Drop the PTABS the C of G moves forward to a more respectable position and pitch stability improves dramatically and it becomes a comfortable old Yak again.

The P51 with fuel in the fuselage tank will behave similarly. So if modeling C of G movement as a function of Fuel usage is achieved, and manual fuel tank selection is possible in IL2 (so as was done IRL the Fuselage tank can be selected to feed first) then P51 pitch stability is going to be a whole bunch worse than what you now have in Il2 with fuel in the fuselage tank. As the fuselage tank fuel is burnt pitch stability will return to something close to what we now have in game.

The P51 with fuel in the fuselage tank was not a pleasant aeroplane to fly the various Flight manuals are full of advice like:

RAAF P51 Flight Manual AP780 :
When the fuselage tank is full, the aircraft is longitudinally unstable in all conditions of flight and tends to tighten up in turns .... no maneuvers other than gentle turns should be attempted.

USAAF AAF Manual 51-127-5 (PG 67)
Be especially careful in handling the stick when the fuselage tank contains more than 25 gallons of gas. In this case the flying characteristics of the airplane change considerably....The weight of this fuel shifts the centre of gravity back so the airplane is unsuitable for anything but straight and level flight.

....With the fuselage tank full the centre of gravity of the airplane moves back so far that it is almost impossible to trim the airplane for hands off level flight.

[Voyager]

So, let me make sure I'm understanding this exactly. Currently the P-51 CoG is where it would be when the fuselage tank is empty?

What is making it so spin happy then?

[GF_Mastiff]

low speeads and quike inputs on the joystick will cause it to snap roll..