Engine rough running Fuel pressure issue

[IvanK]

Running MW50 on main panel on, Prop Auto, Rad Auto, Max throttle 1.78ATA, MW50 pressure good all temps and pressures good. After about 13 seconds Fuel pressure starts to drop, after 30 seconds Fuel pressure zero, after 44 seconds engine begins to splutter.

 

Reducing ATA causes fuel pressure to rise and normal engine operation resumes.

 

Is this a Bug or a feature ? almost seems that max power the fuel pump cant keep the engine supplied with enough fuel ??

Edited January 24, 2015 by IvanK

[Kurfürst]

Both pumps on? Maybe fuel pump capacity is modelled with one pump only...?

[IvanK]

Yep both pumps on

[sobek]

winter you'll need to set it up prime handle for cold starts.

 

That handle is

 

a) not modelled

 

b) AFAIK only responsible for spark retardation

 

So either way, it's not relevant to the problem the OP is experiencing.

[iFoxRomeo]

Are you sure you have the latest version of DCS installed?

In an earlier version it made a difference whether you switch on the booster pumps with the mouse(bugged), or via the keyboard(not bugged)

http://forums.eagle.ru/showthread.php?t=134838

 

Fox

[BFBunny]

Only does this for me running on p1 / p2. On both it runs at max power till the engine explodes.

 

I only had time to test it in autumn.

 

Did you try the free flight mission too to make sure you did not move the mw switch next to the tail wheel lock when you were starting up?

 

Maybe post a track file?

[IvanK]

Running on P1 + P2 i.e. fully forward. MW50/Fuel switch on left hand cockpit wall set to MW50.

I am selecting the pumps with the Mouse.

Latest version of DCS.

[iFoxRomeo]

Ivan, I think you should provide a .trk

 

Fox

[IvanK]

Yes ok will do tomorrow.

[SkyCaptain109]

Did you turn on the electric fuel pump on the circuit breaker panel?

[IvanK]

Yes though now sorted. Finger trouble on my end I thought I had it in P1+P2 but in fact I didn't .... one more click forward resolved the issue

[GumidekCZ]

Running MW50 on main panel on, Prop Auto, Rad Auto, Max throttle 1.78ATA, MW50 pressure good all temps and pressures good. After about 13 seconds Fuel pressure starts to drop, after 30 seconds Fuel pressure zero, after 44 seconds engine begins to splutter.

 

Reducing ATA causes fuel pressure to rise and normal engine operation resumes.

 

Is this a Bug or a feature ? almost seems that max power the fuel pump cant keep the engine supplied with enough fuel ??

 

This is a known BUG, still NOT corrected. Standart operation was done by two mechanical fuel pumps.

Only for safety of takeoff or landing the electrical fuel pump (located inside of main fuel tank) was switched to operate.

Here is a complete drawing of fuel lines of Bf109K-4 variant.

Note that the rear tank and external fuel tank was pressurized by air pump on engine.

Fuel and MW50 mixture was than pushed out of these tanks. Fuel into main tank and MW50 into engine air inlet.

 

I hope that this will be every moment now REPORTED and corrected soon. Also please move this toppic into "Bugs and Problems" section.

Many thanks :)

Edited February 1, 2015 by GumidekCZ

[MFG62 Joker]

This is a known BUG, still NOT corrected. Standart operation was done by two mechanical fuel pumps.

Only for safety of takeoff or landing the electrical fuel pump (located inside of main fuel tank) was switched to operate.

 

 

You is wrong :music_whistling:

The boost pump (Behälterpumpe) is to be switched on before engine start and remains running until engine stop!

 

Let me correct you directly from

Werksschrift 2109 K-4 Teil7 Triebwerksbedien- und Versorgungsanlage:

 

translated freely:

The fuelpump within the fuel tank is used for additional feeding of fuel while fuel pressure is sinking. It is switched on before engine start and only is switched off after the engine is stopped.

 

About MW-50 and no need for electrical switch (assuming pressurized air is fed to tank always):

MW-50 is fed to compressor (Lader) by connecting pressurized air from the boosted side of the compressor to the MW-50 Tank.

The valve which controls the connecting hose from the compressor to the MW-50 tank is actuated electrically. Refer to Werksschrift 2109 K-4 Teil7 B MW-Anlage / Abschnitt C. 2.Schaltventil.

 

Due to copyright issues I cannot post an 'evidence' e.g. jpg from the reffered pages. You´ld either have to believe or to buy the reffered documents.

Edited February 1, 2015 by I./ZG15_FALKE

[GumidekCZ]

Please send here the screen capture of the german text from Teil 7 Werkschrift. It is hard to believe, because the people who actually flew with Bf109, they tell different things than your document. I will personally post question to Manching Bf109 pilots, they know it exactly.

[MFG62 Joker]

Due to copyright issues I cannot post an 'evidence' e.g. jpg from the reffered pages. You´ld either have to believe or to buy the reffered documents.

 

:music_whistling:

 

 

Buy e.g. from here:

http://www.amazon.de/Messerschmitt-Jagdflugzeug-Bedienungs-Vorschrift-Ersatzteilliste-Reparatur-Anweisung/dp/3939847143/ref=sr_1_3?s=books&ie=UTF8&qid=1422872071&sr=1-3&keywords=Messerschmitt+Bf+109+K%2C+Jagdflugzeug%3A

[GumidekCZ]

I understand to you about copyrights. But I didnt want from you whole book! Just a few senteces, they will not cut your head of because of that.

 

I still have no answer from Manching Messerschmitt museum (from theyr pilots) but I have red many manuals and book of other types of Bf109 and every where is written that elec. pump was there only for help with cold starts and as a backup for P1 and P2 mechanic pumps at takeoffs and landings. Even real pilot who flew with Bf109G variants confirms this.

 

If you think about the elec. fuel pump function as you described it, you will at the end find out, elec. pump is now in DCS modelled not correctly.

[DB 605]

but I have red many manuals and book of other types of Bf109 and every where is written that elec. pump was there only for help with cold starts and as a backup for P1 and P2 mechanic pumps at takeoffs and landings.

 

 

Exactly what finnish G6 manual says as well.

[Kodoss]

I./ZG15 Falke quote is correct.

 

Original text at page 7 from "Werkschrift 2109 K-4; Bf 109 K-4 Flugzeug Handbuch Teil 7":

Die Behälterpumpe dient der zusätlichen Förderung des Kraftstoffes bei absinkendem Kraftsoffdruck und wird vor Anlassen des Triebwerkes eingeschaltet und erst bei Abstellen des Triebwerkes abgeschaltet. Schalter hierfür in Selbstschalterträger (Führerraum rechts).

 

Also interresting last two sentences from page 8, same manual:

Vor Beginn von Kampfhandlungen ist der Kraftstoff des Kraftstoff-Zusatzbehälters im Rumpfende über den Schnellablass abzulassen. Handhebel hierzu im Führerraum rechts.

translated:

Before beginning the battle release the fuel of the auxilary fuel tank in the fuselage end throught the fast drain (valve). Handlever hereto in the cockpit right.

[GumidekCZ]

Andreas Haferkorn

Chief Technician Heritage Flight

Military Aircraft

Airbus Defence and Space

 

operating Bf109G-4/5/10 (Bf109G-10 black 2 with only operating real DB605D engine - same as in 109K-4)

Das

Kraftstoff-Förderpumpe

is able to make enough fuel pressure without

Behälterpumpe

. Only when starting engine, the Behälterpumpe is needed.

And for safety reasons during take off and landing ( this is how we operate ).

my question: is the electric pump needed in higher flight levels due to pressure loss in fuel system?

Can`t Tell you due to the fact that we`ve got to stay bellow 10000 ft because we do not have oxygen installed on board.

 

Original text at page 7 from "Werkschrift 2109 K-4; Bf 109 K-4 Flugzeug Handbuch Teil 7":

Die Behälterpumpe dient der zusätzlichen Förderung des Kraftstoffes bei absinkendem Kraftsoffdruck und wird vor Anlassen des Triebwerkes eingeschaltet und erst bei Abstellen des Triebwerkes abgeschaltet. Schalter hierfür in Selbstschalterträger (Führerraum rechts).

Sorry can`t tell you anything about K4, never seen and I think I won`t .. unfortunately

 

My final conlusion:

Im sorry, but I believe much more to real operating experiences, than to one sentence from one Handbuch, which says complete oposite thing, than all other Handbuchs from previous version of Bf109.

Edited February 12, 2015 by GumidekCZ

[MFG62 Joker]

Andreas Haferkorn

my final conlusion:

Im sorry, but I believe much more to real operating experiences, than to one sentence from one Handbuch, which says complete oposite thing, than all other Handbuchs from previous version of Bf109.

 

 

All references from Messerschmitt Stiftung refer to G-Variants.

And nobody is able to do a correct simulation based on 'I believe'. :huh:

 

We have strong evidence with original material from the manufacturer.

In that case no one with common sense would go for anything else than that.

:music_whistling:

 

No need to feel sorry and no offense meant, you may believe in what ever you like.

Edited February 12, 2015 by I./ZG15_FALKE

[MFG62 Joker]

After reading again, just let me thank you anyway for your effort, trying to get sources which can make the sim even better.

 

We all might name ourselves enthusiasts for those incredible machines. After all, we are brothers in mind, loving the Me109!

 

Have fun flying it!

:joystick::pilotfly:

[TAW_Impalor]

Hi guys, I glanced through the thread, did not find the solution. I get this problem 50% of time running the quick Dogfight mission. I don't touch any switches. Sometimes it happens couple of minutes into the fight, and I must lower the rpm to almost idle. What is it??

[MFG62 Joker]

with sufficient fuel left, fuel cock P1+P2 and booster pump on you should encounter no problem.

 

Make sure that the issue you are seeing is accompanied with a drop of fuel pressure. If not, your problem is different.

[TAW_Impalor]

with sufficient fuel left, fuel cock P1+P2 and booster pump on you should encounter no problem.

 

Make sure that the issue you are seeing is accompanied with a drop of fuel pressure. If not, your problem is different.

 

my issue is this