Something changed ( for better ), in the 109s, and I didn't notice

[Guest deleted@50488]

In one of the recent updates the possibility to fly inverted in the F4 or G2, without time limit, has been fixed!!!

 

It now takes a few seconds before your engine get's into trouble because of oil starvation. Whow!  And I wasn't aware it had been fixed!

 

Noticed it for the first time a couple of minutes ago flying on an EXPERT server :-)

[Bearcat]

I think that this team gets a lot right... and they are trying really hard to get as much right as possible..

[-TBC-AeroAce]

im sure that was there before, has trouble after about 10 secs but might be wrong

[Guest deleted@50488]

Wasn't there, at least one month ago... I even posted it should be fixed when possible...

[DD_Arthur]

Interesting....just checked out the F4, 190, LaGG and Pe-2.  They all cut out after a few seconds.  It's fuel starvation.  Return them to normal flight and the engines start up again.  Nice touch.

[Ace_Pilto]

I reckon the sounds got some love too.

 

The other day I thought the G-2 was broken, couldn't trim it out. Turned out I'd mapped the hat switch command for stabiliser the wrong way up...

[Guest deleted@50488]

Interesting....just checked out the F4, 190, LaGG and Pe-2.  They all cut out after a few seconds.  It's fuel starvation.  Return them to normal flight and the engines start up again.  Nice touch.

 

In the case of the Bf109s, it's oil starvation, because they do not use a carburetor. It wasn't modeled in IL2-BoS yet, but recently the last patches must have fixed it.

 

Overall, IL2-BoS is converging towards PERFECTION!

[DD_Arthur]

In the case of the Bf109s, it's oil starvation, because they do not use a carburetor. It wasn't modeled in IL2-BoS yet, but recently the last patches must have fixed it.

 

Overall, IL2-BoS is converging towards PERFECTION!

 

In the case of the '109 its still fuel starvation.  Think about it; if it was because of a failure of the oiling system then the engine would seize.  It dosen't. The engines restart after the 'plane is rolled back to normal flight attitude.  

 

Check the fuel pressure gauge.  You can see the pressure drops during inverted flight.  It's got nothing to do with fuel injection or carbs.  The problem lies in the fuel pick up in the fuel tanks. They are placed in the bottom of the fuel tanks.  During inverted flight the pick ups are sucking on air!  BF109 G4 crashed at Roskiled airshow in 2013 after the pilot put the plane through 12 seconds of inverted flight.  This was enough to starve the engine of fuel and introduce an airlock into the system which use of the manual fuel pump could not over come.

Edited August 17, 2015 by DD_Arthur

[ram0506]

Yes, should be as DD_Arthur described. Also check out the change log of version 1.102:

 

5. The fuel tank simulation was improved to predict correctly how much of the remaining fuel can be pumped to the engine before it falls into negative G

[Guest deleted@50488]

Ok Guys, and thx DD_  - always learning something :-) 

[Matt]

Talking about fuel starvation, shouldn't the fuel pressure gauge go a bit haywire when this happens? 

[-TBC-AeroAce]

Talking about fuel starvation, shouldn't the fuel pressure gauge go a bit haywire when this happens?

One would think that to be the case

Edited August 17, 2015 by [WSB]AeroACE

[DD_Arthur]

Not sure why the fuel pressure gauge should go haywire?  Fuel pressure drops, the engine is starved of fuel, the pressure gauge reflects this drop in pressure.

[Matt]

But it doesn't reflect this drop in pressure. Atleast not in the planes i tested it.

 

Same was (and most likely still is) true when the fuel ran out, fuel pressure was still fine.

[DD_Arthur]

But it doesn't reflect this drop in pressure. Atleast not in the planes i tested it.

 

Same was (and most likely still is) true when the fuel ran out, fuel pressure was still fine.

 

Tested the F4 and LaGG.  Started the F4 on the runway in quick mission. Switched off engine and watched both fuel and oil pressure fall to zero and then watched them as I restarted the engine.  Quite impressively done really - the fuel pressure gauge moves in accordance with the start up procedure when the electric fuel pump is switched on and then off when the pressure changes as the engine-driven pump takes over.

 

When you fly inverted and the engine dies the fuel pressure gauge - and the oil pressure gauge too - reflect this, albeit rather more slowly than I would have thought happens in real life.  I had to take the F4 up to 3km and invert it to give myself enough glide for the fuel pressure gauge to reach the bottom of the "working" limits on the gauge.  However, it did not fall to zero.

 

The LaGG reflected this behaviour too. The oil pressure fell, an indication of the engine turning at low revs and the fuel pressure gauge fell - again, rather more slowly than I would have expected and not as much as the F4. 

 

Oh yeah, as a matter of interest, during these tests I discovered that turning on the cockpit lighting costs around 10 fps!

Edited August 18, 2015 by DD_Arthur

[Matt]

 

 

I had to take the F4 up to 3km and invert it to give myself enough glide for the fuel pressure gauge to reach the bottom of the "working" limits on the gauge.  However, it did not fall to zero.

Yes, that's why i think that it's not working correctly.

 

If you do that in DCS, it will rapidly fall to zero. In BoS, it will slowly and steadily drop and stay inside working limits, which doesn't make much sense.

 

I'm assuming that's WIP and it will probably be fixed in the next update anyway.