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Neg g engine cut-outs?

Posted By: Mace71

Neg g engine cut-outs? - 04/01/11 06:54 PM

Are negative g engine cut-outs modelled? It didnt seem so when flying the spit and hurri....
Posted By: BKHZ_Furbs

Re: Neg g engine cut-outs? - 04/01/11 06:58 PM

You got CEM turned on?
Posted By: calmer133

Re: Neg g engine cut-outs? - 04/01/11 07:07 PM

The plane should do what it does, even if you haven't got the fiddly knob thing turned on. Non CEM should mean that the AI manages the fiddly bits. It should not mean that the plane behaves in an unrealistic manner.

Broken software.
Posted By: sascha

Re: Neg g engine cut-outs? - 04/01/11 07:39 PM

^Agreed. I already posted something to the effect that realism settings could use a lot more options. Including a seperate option for "neg-G cutout on/off".

Maybe if they hadn't bothered putting all these "can't jump to another plane"-options in there ... biggrin



S.
Posted By: sharpe26

Re: Neg g engine cut-outs? - 04/01/11 07:46 PM

Originally Posted By: BKHZ_Furbs
You got CEM turned on?


correct answer.
Posted By: calmer133

Re: Neg g engine cut-outs? - 04/01/11 07:50 PM

Originally Posted By: sharpe26
Originally Posted By: BKHZ_Furbs
You got CEM turned on?


correct answer.


Wrong mate. Engine management is different from engine performance. AI engine management should manage the knob fiddling. It should not change how the engine works. The carb should cut out with neg-g regardless of whether it is me or AI doing the knob fiddle thing. Pretty basic really screwy
Posted By: Mace71

Re: Neg g engine cut-outs? - 04/01/11 08:09 PM

I havent got CEM on. Are you saying with it on the engine cuts out under neg g's?
Posted By: sharpe26

Re: Neg g engine cut-outs? - 04/01/11 08:11 PM

Originally Posted By: MaceUK33
I havent got CEM on. Are you saying with it on the engine cuts out under neg g's?


with the Spit and that on, my experience is yes. With the Hurricane and without it; no.
Posted By: IvanK

Re: Neg g engine cut-outs? - 04/01/11 09:43 PM

Yes -ve G cut outs are there and imo are overdone. Its not possible to perform a slow lowering of the nose say setting up a gradual descent without the engine coughing. I wouldnt mind the -ve G issue with a solid -1 to -2G push but coughing when setting up a gradual descent using perhaps only 0.8G in the nose position change is crazy
Posted By: sascha

Re: Neg g engine cut-outs? - 04/01/11 10:02 PM

Quote:
I wouldnt mind the -ve G issue with a solid -1 to -2G push but coughing when setting up a gradual descent using perhaps only 0.8G in the nose position change is crazy



I didn't find it impossible to push the nose down slightly without the engine cutting out. Only when I pushed a bit harder, did is cut.

Remember that even when you're just sitting at your PC, you're experiencing +0.9 G. So even with 0 G (weightlessness) the thingie in your carb should stop working. -1 or -2 are pretty serious negative G already. Engine should cut out before that.
Posted By: Winny

Re: Neg g engine cut-outs? - 04/01/11 10:45 PM

The engine will start to cut out under any ammount of negative G, this is why it was such a problem to the RAF and why diving away in a 109 was so effective.

It will add a new dimension to the 109 vs Spit dogfights.
I think it should be available option wise aside from CEM , just for those who really don't want to be worrying about overheating whilst trying desperatley to not die.. But would like to have a go at exploiting(LW)/managing(RAF)the cut outs. It's seems that using AI engine management also means you get a bonus gravity defying carb.
Posted By: xnomad

Re: Neg g engine cut-outs? - 04/01/11 11:24 PM

So I'm guessing that doing a bunt against AI opponents isn't going to be of any advantage either?
Posted By: No457_Squog

Re: Neg g engine cut-outs? - 04/01/11 11:27 PM

Originally Posted By: IvanK
Yes -ve G cut outs are there and imo are overdone. Its not possible to perform a slow lowering of the nose say setting up a gradual descent without the engine coughing. I wouldnt mind the -ve G issue with a solid -1 to -2G push but coughing when setting up a gradual descent using perhaps only 0.8G in the nose position change is crazy


I think you're right. The negative G cutout feels like it happens WAY too early. Couple that with head shake/movement means that it is VERY hard to shoot accurately at an evading target.
Posted By: KraziKanuK

Re: Neg g engine cut-outs? - 04/02/11 01:29 PM

From Graham White's book 'Allied Piston Engines of WW2', pg 66.

An idiosyncrasy of the SU carb wasa condition known as rich "cutout" caused by -G. In fact, the -G cutout was a two stage event. At the onset of -G, fuel was forced to the top of the float chamber, which exposed the main jets to air. This caused the first momentary , lean cutout. If the -G condition continued, the floats reacted to the reverse of normal conditions and floated the wrong way, that is, they floated to the bottom of the float chamber. The needle valve opened wide, allowing full fuel pressure from the engine driven pump to flood the carb. An excessively rich mixture was then admitted into the supercharger causing the more serious rich cutout.

For a fighter pilot this could pose a severe limitation: if the stick was pushed forward a momentary loss of power or a complete cutout would result.
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