FW190D9 Manifold pressure

[Real_NBD]

Hi, 

 

I've noticed this weird behaviour with the D9 and ambient temperature. When it's cold, the D9 loses manifold pressure, as opposed to every single other aircraft in the game.

 

Tested in the Lapino map at 1500 meters: 

 

D9, MW50 enabled, max throttle:

WInter:     1.68 ATA, 596 kph

Summer:  1.78 ATA, 550 kph

 

A8, Boost enabled, max throttle:

Winter:     1.39 ATA, 566 kph

Summer:  1.34 ATA, 524 kph

 

La5FN, max RPM, max throttle:

Winter:     1180 mmHg, 592 kph

Summer:  1155 mmHg, 554 kph.

 

I haven't found another aircraft that loses manifold pressure when it gets colder. This should not happen, though I'm not sure if it affects performance as is. Hoping some dev has time to take a look at this, probably just something minor.

[JtD]

This is how it is supposed to be, because the D-9 engine, the Jumo213, comes with a mass flow regulator instead of a boost regulator. Since cold air is more dense than hot air, it reduces boost so that the mass entering the cylincers per cycle remains constant.

 

You can also see an increase in boost between 1st and 2nd charger gear due to this reason, the extra work of the second charger gear heats up the intake air and this is compensated with a higher boost.

 

The other aircraft may lose a bit of boost because they are flying at a lower indicated air speed in the summer and thus have less ram effect. At sea level their boost should be constant in winter and summer.

Edited May 2, 2021 by JtD

[D3adCZE]

That is a great point JtD. I would like to ask you another question regarding boost in JU213A engine. Do you know why it takes around 8 seconds to spool up from idle to full emergency power? And around 6 seconds from 50% ?  Personally I find it a bit odd that LW would accept such slowly reacting engine.

[JtD]

We've had this before, imho it is an error.

 

https://forum.il2sturmovik.com/topic/66605-fw-190d-9-current-flight-model/?do=findComment&comment=1020213

  

On 11/6/2020 at 3:09 PM, JtD said:

WRT to the responsiveness of the Jumo213, the prop needed about 8 seconds to go from operating rpm to fully feathered, when the engine was dead and an auxiliary hydraulic pump with a much lower capacity was used. In game, we have about the same figure, but in normal operation. Unfortunately I don't know the exact capacity of the auxiliary pump, so I can't estimate how much faster the pitch adjustment should be with the main pump doing the hydraulics.

 

and