investigating Engine damage after only flying around

[NineLine]

Its very bizarre, I can see the engine quit in the track, but taking control and trying to reproduce I cannot. 

[NineLine]

@ReflectedOk, so I was watching and trying your track (#3) again, and I noticed when you went into boost range, the MW pressure gauge was moving, if I took control, same, if I flew the mission on my own it was fine, so that is super odd, and perhaps a reason for engine issues there.

[Reflected]

Have you found anything about this? I jsut had an engine failure after takeoff, never exceeding 1.3 ATA. I can't fly any missions in the 109...

 

I tried a hot start mission - same result, so it's not the lack of warming up properly.

Edited February 5, 2021 by Reflected

[Reflected]

Found the culprit!

 

the MW50/ fuel switch was by default mapped to one of my HOTAS switches with got synchronized and thus switched to 'fuel' at mission start. With it back to 'MW50' all's good now.

 

However, this  still doesn't explain why my engine died of 1.3 ATA with that switch set to 'fuel'.

[Mud]

I'm glad I found this thread.  I was doing a long distance cruise flight today 10 degrees C, no wind at an altitude of 5000ft.

Engine settings were 1.15 ATA at 2000rpm.

 

I noticed my speed gradually diminishing from approximately 270kn to 220kn TAS, and me being forced to change the prop pitch to maintain 2000rpm over the course of about 1 hour of flying.  I just couldn't figure out what was going on, but I assume it was the spark plug fouling then.

 

Mud

[grafspee]

I still has doubts that 1.15 ATA is fouling range for spark plugs ? Since G-2 max ATA was 1.2 and i think fouling wasn't a problem there.

Edited April 12, 2021 by grafspee

[zerO_crash]

One question, are you doing a proper warmup as per manual? I know for sure that an engine that isn´t correctly warmed up before flight, will explode on you when you run it up to the limits defined by the manual.

[Hiob]

On 2/16/2021 at 10:12 AM, Reflected said:

Found the culprit!

 

the MW50/ fuel switch was by default mapped to one of my HOTAS switches with got synchronized and thus switched to 'fuel' at mission start. With it back to 'MW50' all's good now.

 

However, this  still doesn't explain why my engine died of 1.3 ATA with that switch set to 'fuel'.

I'm not sure if I have understood you correctly.

Just the following the Aft MW-50/Fuel tank can be filled with either.

If it's filled with MW50 and set to fuel it will kill your engine in no time, which is correct.

 

So, the safest way ist to make sure, that it is set to MW50 before engine start....

Edited April 13, 2021 by Hiob

[grafspee]

When selector is set too fuel, and in rear tank is filled with mw50 it will pump this liquid in to fuel system. And this liquid is 50% water, this may result in simply engine refuse to fire up, it may also induce some damage to fuel injection system, but beside this nothing fatal i would say. In flight when you lose your engine, after moving switch in to mw50 selector, and after windmilling for some time, when fuel system clears out from mw50 engine should start up again.

But that depends on how fuel system will react with methanol.

Assuming that rear tank can hold fuel and MW50 at the same time, and that there is potential possibility of setting mw50/fuel switch in to wring position nothing fatal should happen to fuel system.

Edited April 13, 2021 by grafspee

[Hiob]

19 hours ago, grafspee said:

Assuming that rear tank can hold fuel and MW50 at the same time,

 

No, it's either fuel or MW50. The switch must be set accordingly.

[grafspee]

1 hour ago, Hiob said:

No, it's either fuel or MW50. The switch must be set accordingly.

Idea was that, rear tank can hold fuel and mw50 so pump installed in this tank wont get damaged if flood with MW50.

And what happen if it is in wrong position? I think nothing fatal should happen if switch be in fuel position.

Edited April 14, 2021 by grafspee

[Hiob]

If you inject mw50 instead of fuel in the combustion chamber the engine will starve obviously.

If it can seriously damage the engine beyond that, I don't know. I'm not an engineer. Maybe it dilutes the oilfilm on the pistons which may result in a major failure... just guessing here

[grafspee]

2 minutes ago, Hiob said:

If you inject mw50 instead of fuel in the combustion chamber the engine will starve obviously.

If it can seriously damage the engine beyond that, I don't know. I'm not an engineer. Maybe it dilutes the oilfilm on the pistons which may result in a major failure... just guessing here

Fuel dilutes oil as well, in addition mw50 mixture contain small percentage of lubricant.

[Cpt. Weber]

Just a quick copy-paste from the Bf-109 module manual.

"The additional internal tank located behind the pilot’s seat can be used alternatively to store the MW 50 mixture, or conventional aviation fuel, in essence providing extra range at the expense of available extra power. The MW/Fuel Selector Handle is used to set the MW 50 tank status. Normally, it is set on the ground before the engine is started, according to the filled liquid, and left alone for the duration of the flight. Please note that incorrectly setting this switch can have CATASTROPHIC results, by either feeding the water-methanol mixture into the fuel lines, or spraying aviation fuel into the supercharger."