I thought the bf109 could fly inverted?

[il2crashesnfails]

I always thought the 109 was fuel injected and could fly inverted unlike the spitfire?

 

I tested it out and got some strange results

 

[1PL-Husar-1Esk]

109 engine doesn't cut off  immediately , so yes it can do inverted aerobics without losing power but not forever. 

Edited December 7, 2018 by 307_Tomcat

[JtD]

Both oil and fuel pump don't work in negative g. So after some seconds the engine quits. I don't know any WW2 fighter which could fly inverted for extended periods without facing these problems.

 

On the early Merlin engines as used in early Spitfires, the carburettor did not work under low/zero/negative g, which means almost instant loss of engine power. The Bf109 had fuel injection and did not have these problems.

Edited December 7, 2018 by JtD

[il2crashesnfails]

2 hours ago, JtD said:

Both oil and fuel pump don't work in negative g. So after some seconds the engine quits. I don't know any WW2 fighter which could fly inverted for extended periods without facing these problems.

 

On the early Merlin engines as used in early Spitfires, the carburettor did not work under low/zero/negative g, which means almost instant loss of engine power. The Bf109 had fuel injection and did not have these problems.

Do you know if pilots of the time were told to avoid inverted flight in combat?

[Leon_Portier]

1 hour ago, il2crashesnfails said:

Do you know if pilots of the time were told to avoid inverted flight in combat?

Could see the Hurricane pilots getting told that.

Thats nothing though what a 2G turn couldn´t solve.

[=FEW=ayamoth89]

In my opinion this is uncorrectly modeled. The DB engines had 3 oil pumps, 2 creating pressure "pushing" the oil, 1 creating depression. So I can't find why they cut off while inverted. Also in the game apparently they cut of for lack of fuel... But everything on the fuel sistem works under pressure so negative G won't have any effect

Check here...

https://www.motorwebmuseum.it/en/places/volandia/the-inverted-flight-of-ca113/

Edited December 7, 2018 by =FEW=ayamoth89

[J2_Trupobaw]

6 hours ago, il2crashesnfails said:

I always thought the 109 was fuel injected and could fly inverted unlike the spitfire?

So did this guy...
http://havarikommissionen.dk/index.php?option=com_contentbuilder&view=list&Itemid=161&lang=da&contentbuilder_download_file=c43f2f96ca5292e717bcfe1f71c67b2ddaef0539

 

Quote

During the display flight for a time period of approximately 10 seconds, the aircraft flew inverted. For that period of time, the fuel stand pipes in the fuel tank were not emerged in fuel and air was sucked into the fuel supply system. The engine fuel consumption at that time with 2300 rpm was approximately 2.9 liters/min. Page 12 of 16 After approximately 10 seconds of inverted flight the fuel amount in the fuel supply system was decreased by approximately 0.5 liters and the remaining fuel amount in the fuel supply system was approximately 1.4 liter. Approximately 24 seconds after the inverted flight was completed, the engine started to misfire. In this period of time, the engine consumed approximately 1.2 liter of the above mentioned 1.4 liter of fuel. The test of the fuel tank in inverted position and with various amount of fuel verified that the fuel tank and the fuel supply system were not able to deliver fuel to the engine during inverted flight.

Bf-109 could do a negative-g dive (quickly initiate the dive by pushing the nose down), not sustained inverted flight. Spitfire had to half-roll while pulling the nose up when starting a dive, to keep the positive gs at all time.

Edited December 7, 2018 by J2_Trupobaw

[J2_Trupobaw]

[SCG_PeeGee]

It's usually because the fuel and engine oil pickups get exposed during negative G.

 

[DD_Arthur]

Go to 2.20

 

 

[il2crashesnfails]

wow so you got really under 10 seconds. What would be good  is if developers put in more sputtering on engine restart with backfires after an extended period of inverted flight.

 

I think the engine just comes back on too easy.

Edited December 8, 2018 by il2crashesnfails

[Heckpupper]

Yes, even aircraft with fuel injection will suffer from long periods of inverted flight. That applies even to modern jets, which can hold inverted flight for a very long time but not permanently. At some point, gravity will always win causing problems with feeding fuel to the engine. 

Obviously when comparing the Bf-109 and early Spitfires the fuel injection system of a 109 is vastly superior,  but no piston engine fighter will be able to hold inverted flight indefinitely.

[il2crashesnfails]

22 hours ago, 4./JG26_Onebad said:

Yes, even aircraft with fuel injection will suffer from long periods of inverted flight. That applies even to modern jets, which can hold inverted flight for a very long time but not permanently. At some point, gravity will always win causing problems with feeding fuel to the engine. 

Obviously when comparing the Bf-109 and early Spitfires the fuel injection system of a 109 is vastly superior,  but no piston engine fighter will be able to hold inverted flight indefinitely.

 

long periods? the 109 crashes after 10 seconds

[AndyJWest]

I can't recall ever reading about a WW2 pilot commenting negatively on the inability of fighters to fly inverted for sustained periods. Probably because there was no reason to do it in the first place. It is uncomfortable, and has no tactical advantage.

[Heckpupper]

2 hours ago, il2crashesnfails said:

 

long periods? the 109 crashes after 10 seconds

 

Sounds about right.