Bf109 G4/G6 too slow and top speed difference wrong?

[the_emperor]

 

With the new DLC for normandy on the horizon I thought to have look on those to variants to see how big of a drawback in perfomence the G6 will have over the G4.

And there seems to  be a bigger difference in top speed with these two models in game than there was according to the german documents we have access to

 

My references are:

http://www.wwiiaircraftperformance.org/me109/me109g-grundausfuhrung-german.html   (its a G1 in G4 trim, bulges for the landing gear and fixed tail wheel it also includes the graph for the G6 from: http://www.wwiiaircraftperformance.org/me109/glce2-109g6.jpg ).

http://www.wwiiaircraftperformance.org/me109/me109g1-grundausfuhrung-speed.jpg

http://www.wwiiaircraftperformance.org/me109/me109g6-combat-emergency.jpg

http://www.wwiiaircraftperformance.org/me109/glce2-109g6.jpg

 

to summarise:

full throttle height for Kampfleistung (1.3ata/2600rpm) and Notleistung  (1.42ata/2600rpm) is ~ 6500m

The G6 is 10kph slower on the deck and 5kph slower at full throttle height (625kph/G6, 630kph/G4, both at 1.3ata/2600rpm), above crititical altitude the difference decreases further.

 

 

But in game the speed difference seems to increase with altitude not decrease and also it seems that the full throttle height is at 6km accourding to the  Boost Indicator instead of the 6.5km rated for the DB605 Engine 

 

I did use http://www.hochwarth.com/misc/AviationCalculator.html to calculate for true air speed and rounded down 

Everything is set to automatic: Spitfire can be some kph faster when the radiators are closed manually. (if any one is interested I also did test the Spitfire with the Merlin 70 engine and clipped wings, and the Bf109 G-14)

Tested on Rheinland Autunm, no wind or weather.

Green G4 Kampfleistung/Notleistung

Blue G6 Kampfleistung/Notleistung

for comparison Spitfire MKIX LF WEP in redpurple.

I also added the table with the gathered Speed of the two G-models in true airspeed. Everyone is of course welcomed to check my data. If a did a mistake somewhere, please let me know.

I would also like to move foreward my suggestions for an optional true air speed indicatiator as I really love to do this kind of charts 

 

Cheers 

 

 

 

 

Edited July 4, 2020 by the_emperor

[nardo]

Yes, the full throttle height is definitely wrong for BF109s with DB605A engine, also the F4 (and FW190A3 on notleistung) suffers from the same issue. It seems like the airplanes from BoS have not been made with the same precision as the ones done later. I have made a post about it some time ago, but unfortunately nothing has been done about it.

[6./ZG26_Klaus_Mann]

Don't worry, you are only one of many who don't yet know the difference between TAS and IAS (called CAS in the Converter). Convert the Speeds and Draw again.

 

http://www.hochwarth.com/misc/AviationCalculator.html

 

Also: Yes, FTHs are too low in Level Flight.

Edited June 21, 2020 by 6./ZG26_Klaus_Mann

[the_emperor]

Thanks for the replay and link to calculate for true airspeed (Iam well aware that my Chart is only indicated airspeed since we infortunately dont have a true air speed indicator. hence my questions if some one could translate it to true air speed   now I can do a Chart on my own. Thank you very much

 

I rough fast use of the link gives me:

 

G6:

612kph/6500m

606kph/6000m (current full throttle height)

 

G4:

629kph/6500m

620kph/6000m

 

So if (and thats a big if!)iIf I put the numbers in correctly the G6 is a quite bit slower in in the game than it was in real life according to the german documents.

but since we dont now the conditions of the maps and invorements in detail, I allready ask for a true airspeed indicator in the suggestions thread.

I will post a chart with the true airspeed later

 

Cheers

Edited June 22, 2020 by the_emperor

[the_emperor]

I did a qick conversion of IAS to TAS. Full throttle hight seems to bee correct but does not correlate with our boost pressure indicator in the cockpit

 

But there seems to a difference in the top speed between these two models (17kph at full throttle height, in contrast to 5kph shown in the documents) we have in the game and we get from the german documents. According to those the difference should decrease with increasing allitude.

Edited June 22, 2020 by the_emperor

[6./ZG26_Klaus_Mann]

Time of Year? Autumn is the Standard Atmosphere.

[the_emperor]

12 hours ago, 6./ZG26_Klaus_Mann said:

Time of Year? Autumn is the Standard Atmosphere.

 

yes, Testet on Rheinland Autunm map

[41Sqn_Skipper]

I think only on Kuban autumn?

[the_emperor]

4 hours ago, 41Sqn_Skipper said:

I think only on Kuban autumn?

 

Well, even if the parameters are a bit different, the issue I have is with the speed difference of the G4 und G6 modell, which seems to be greater in the game than it was in real life according to the german documents.

 

Cheers

[LukeFF]

7 hours ago, 41Sqn_Skipper said:

I think only on Kuban autumn?

 

All autumn maps are set to Standard Atmosphere in Quick Mission mode.

Edited June 23, 2020 by LukeFF

[E69_geramos109]

On 6/15/2020 at 10:46 PM, the_emperor said:

With the new DLC for normandy I thought to have look on those to variants to see how big of a drawback in perfomence the G6 will have over the G4.

And there seems to  be a bigger difference in top speed with these two models in game than there was in reality.

The G4 should do 505kph at sea leve and 630kph at full throttle hight in 6.5-6.6km height at combat rating (1.3ata/2600rpm):

http://www.wwiiaircraftperformance.org/me109/me109g-grundausfuhrung-german.html   (its a G1 in G4 trim, bulges for the landing gear and fixed tail wheel).

http://www.wwiiaircraftperformance.org/me109/me109g1-grundausfuhrung-speed.jpg

 

The G6 should do 495ph at sea level and 625 at full throttle height at combat rating:

http://www.wwiiaircraftperformance.org/me109/me109g6-combat-emergency.jpg

http://www.wwiiaircraftperformance.org/me109/glce2-109g6.jpg

 

and should be about the same above that height:

http://www.wwiiaircraftperformance.org/me109/me109g1-grundausfuhrung-speed.jpg

 

But in game the speed difference seems to increase with altitude not decrease and also it seems that the full throttle height is at 6km accourding to the IAS and Boost Indicator instead of the 6.5km rated for the DB605 Engine (tested on Rheinland autumn, combat rating 1.3ata/2600rpm). When translatet to TAS the full throttle height seems to allright. But we have a speed difference of 17kph instead of 5kph shown in the documents.

Green G4

Red G6:

 

 

 

 

 

Conversion of IAS to TAS:
 

 

On the test you showed max speed with G6 is over 640 km/h at full power not 625

I would like to know what was the radiator position for those test. Germans did a lot of the test for climbs with 50% radiator not on auto. I dont know about speed tests

[the_emperor]

1 hour ago, E69_geramos109 said:

On the test you showed max speed with G6 is over 640 km/h at full power not 625

 

its 640kph für Emergency boost (Notleistung) at 1.42ata/2800rpm

and 625kph for Combat Rating (Steig und Kampfleistung) 1.3ata/2600 which I did use in my testing and what I used for my comparison since wo only have that for the G4 model.

Radiators where set to automatic. Since it is never mentioned in the german documents I assume they where set to automatic, too. But I haven not found any specific information on that topic , only as you say in some climb test, since here the the limits of the cooling system can be much more dramatic.

[ICDP]

You have already created a thread for this topic, please stop spamming threads or keeping track of responses becomes impossible.

 

 

Edited July 2, 2020 by ICDP