Issues with G-2, G-4 & G-6 high altitude WEP

[HandyNasty]

2 tests make me believe that High-altitude - above full throttle height (FTH) (8km+) engine of the 109G-2, G-4 and G-6 might be wrongly modeled. Discussion was done in this thread :

All velocities are in IAS, tests done on Kuban Autumn map, full fuel load and custom setting unbreakable is on.

 

 

 

Description of Tests

Test1 : Above FTH : Comparison of 3 engine regimes for the G-4 and G-6; 2 engine regimes for the G-2

1a : Comparing top speed for the G-2 between 100% throttle (automatic 2600RPM) and 100% throttle with prop pitch manually set so engine is at 2800RPM

1b : Comparing top speed for the G-4 between 80% throttle (automatic 2600RPM), automatic 100% throttle (2800RPM) and 80% throttle with prop pitch manually set so engine is at 2800RPM.

1c : Same as 1b but for G-6

 

Test2  :  Taking 109G-4/6 at full throttle to top speed at altitudes above FTH. Upon this, switch to manual pitch control and then reduce throttle to 80%.

 

 

 

 

 

Results of Tests and description:

Test1 :

 

 

Between the first and third column, we have a ~20kph IAS difference and this is consistent for all planes.

However, there is a difference of IAS between column 2 and 3 of ~7-10kph IAS, despite the fact that the ata and RPM are the same for column 2 and 3.

 

 

 

 

Test2 :

G-6 at 10km alt : 100% throttle at top speed :

 

 

Then, fixing prop pitch and reducing throttle to 80% (screenshot from ~1-2 seconds after reducing throttle to 80%) :

 

 

We observe the RPM increasing to 2900RPM, which leads to the increase of ata from 0.92 to 0.96.

This means that for given propeller pitch angle and given speed (349 kph IAS), reducing throttle from 100% to 80% leads to an increase of RPM.

 

 

 

 

 

Note that this behavior is NOT present in the F-4!! One does not observe the same results for both tests when trying with the 109F-4.

Ergo, it therefore seems to me that something is wrongly modeled for the DB605.