FW190 D9 ATA Anomaly on Winter maps

[Bert_Foster]

A number of people have observed that the D9 is slower on winter maps than summer maps.... which it shouldn't be.

 

Doing some quick tests reveals a strange ATA anomaly associated with winter maps.

 

Fw190 D9 On the deck MW50 on On Winter maps you only get 1.38 ATA at 3250 RPM.

On all other season maps you get 1.8ATA at 3250RPM

Edited March 20, 2019 by Bert_Foster

[JtD]

Just answered this elsewhere, too:

 

The Jumo uses a different type of regulation, it's a fixed air mass regulation, not fixed boost. Colder (denser) air therefore needs less boost pressure. Manual figures for 3250 rpm at sea level for instance:

 

1.38 ata at -30°

1.47 ata at 0°

1.56 ata at 30°

 

So 0.03 ata per 10° temperature change.

 

Haven't checked forum or game in days, so haven't had a look at the D-9 in game and can't say if things are OK there, but boost at least should vary depending on outside temperature.

 

Also depending on pressure (therefore altitude) and charger gear, given that the second gear heats up intake air far more than the first, boosts in second gear should be noticeably higher.

 

WRT 1.8 on all other maps - maybe the emergency power / MW50 does not work on winter maps, where it works on other maps? I would need to check in game to clarify this.

[Bert_Foster]

saw that JTD and asked a question on the other thread to

[StaB/Tomio_VR***]

3 hours ago, JtD said:

The Jumo uses a different type of regulation, it's a fixed air mass regulation, not fixed boost. Colder (denser) air therefore needs less boost pressure. Manual figures for 3250 rpm at sea level for instance: 

 

1.38 ata at -30°

1.47 ata at 0°

1.56 ata at 30° 

  

So 0.03 ata per 10° temperature change.

 

Very interesting.

Indeed, the engine gives around 1.38 ata on winter maps at sea level...

 

however how do u explain that it climbs to 1.5 and even 1.7 ata when climbing as the temperature is still cold on those winter maps ?

Edited March 20, 2019 by StaB/Tomio_VR***

[Ehret]

Just now, StaB/Tomio_VR*** said:

however how do u explain that it climbs to 1.5 and even 1.7 ata when climbing as the temperature is still cold on those winter maps ?

 

Air pressure drops with altitude and to pull the same mass of air the ATA must increase?

[L3Pl4K]

Checked temp on Stalingrad Winter Map with the temp gauge on the 110 G2. Approximately -15°C.
If this manual is right(page 50):

http://www.avialogs.com/index.php/en/engines/germany/jumo/jumo-213/flugmotor-jumo-213-a-1-u-c-0-entwurf-zu-einem-motoren-handbuch.html

we should have 1.42ATA and not 1.32ATA like ingame, at full throttle.

[CUJO_1970]

supposedly this is going to be addressed in hotfix

[II/JG17_HerrMurf]

Answered in the Russian forums. It is an error and will be addressed on the to do list. It is still very early in the Dora's development.