Broke Engine In Middle of Dogfight

[DieHard]

Weird! Engine just quit, it seized. I had been flying 20 minutes or so during dogfighting ACG server 1.5 Beta. I had not taken any hits. Governor was on. Auto radiator was set.

 

Only thing might have happened and I forgot to look, maybe coolant gauges were over-heated out of range.

 

I was running wide open throttle with WEP engaged. I try to remember to lay back once in awhile.

 

Any ideas what may have happened?

[Retu81]

IIRC you can use MW-50 system for 10 minutes straight and then you have to back off for 5 minutes. And you only carry enough stuff for about 26 minutes. So maybe you simply ran out, if you followed the cooling periods?

[Gunja]

I'd say i get overheated 1 time out of 5 in P51 Sometimes even with radiators manualy open.

All my fault though.

[ZaltysZ]

Overboost? Low rpm + high boost is bad for engine and normally automatics tries to prevent that by adjusting prop pitch when you operate the throttle. However, prop pitch change is kinda slow on BF, so in certain situations automatics can't follow you fast enough.

 

I.e. if you do a long dive, pick speed up, prop pitch will be adjusted to coarse to load engine and keep it below redline. If you dive with reduced throttle, automatics will try to achieve even coarser pitch and reduced rpm. The problem arises when you bleed energy after such dive quicker when prop pitch can be adjusted. Suddenly engine becomes overloaded, its rpm drop, you firewall the throttle, boost rises, but engine still struggles rpm wise, because prop pitch is still way too coarse. Now you are heavily abusing the engine.

Edited October 30, 2015 by ZaltysZ

[Crumpp]

My engine locked up, on the same server as Diehard for no apparent reason as well.

 

I was flying a P-51 and it locked up on take off roll. No overheats...just stopped.

[Anatoli-Kagari9]

My engine locked up, on the same server as Diehard for no apparent reason as well.

 

I was flying a P-51 and it locked up on take off roll. No overheats...just stopped.

 

Random System failures enabled on the server ?

[MAD-MM]

Or possible you MW-50 was still empty, without mw50 you kill your engine in WEP very fast.

[DieHard]

I think the issue is not to exceed max rpm in a dive. Throttle back in dive. I did a little reading of the DCS Bf-109 .pdf manual concerning engine management. I flew a bunch of sorties yesterday on the ACG WWII server without issue concerning blowing the engine. And I only use the MW-50 WEP in short bursts and watch my total time doing so and not exceed 1.4 ata when throttling back in cruise.

 

It's a pain getting jumped watching out for engine management while eluding the bad guy on my tail.

Edited October 31, 2015 by DieHard

[Crumpp]

Random System failures enabled on the server ?

 

I do not know, maybe...

 

:unsure:

[BIGNEWY]

attach a track, even if it does not play correctly you will know the setup of the mission and circumstance.

[jester_]

Weird! Engine just quit, it seized. I had been flying 20 minutes or so during dogfighting ACG server 1.5 Beta. I had not taken any hits. Governor was on. Auto radiator was set.

 

Only thing might have happened and I forgot to look, maybe coolant gauges were over-heated out of range.

 

I was running wide open throttle with WEP engaged. I try to remember to lay back once in awhile.

 

Any ideas what may have happened?

 

I can tell you without any track or tacview or anything that you pushed your engine too hard, too much. The Kurfürst WEP should be usable for about 10 minutes or so. In DCS, I try to use it no more than 30-60 seconds. Full throttle with WEP engaged is very taxing on the engine. You should only be using it to climb, or in short bursts to run away.

[Aluminum Donkey]

Weird! Engine just quit, it seized. I had been flying 20 minutes or so during dogfighting ACG server 1.5 Beta. I had not taken any hits. Governor was on. Auto radiator was set.

 

Only thing might have happened and I forgot to look, maybe coolant gauges were over-heated out of range.

 

I was running wide open throttle with WEP engaged. I try to remember to lay back once in awhile.

 

Any ideas what may have happened?

 

One thing to keep in mind about the 109 in DCS World is that it has a more realistic throttle & supercharger model than the other two WW2 prop aircraft (P-51 & FW-190). In the DCSW 109, you can apply full throttle (WEP, 1.8 ata boost pressure) even with the MW50 system turned off. In the real-life 109, this was possible too, and must be avoided.

 

If you're regularly blowing engines make sure the MW50 system is turned on with the switch on the lower part of the instrument panel, because applying full throttle will increase manifold pressure to 1.8 ata with no 'speed juice' flowing in if the MW50 system is turned off. This will destroy the engine very quickly, just as in real life. The job of the MW50 is to suppress detonation at very high power levels, and was an absolute must for running 1.8 ata boost.

 

Now, in the P-51D, WEP is a small increase in boost above max normal manifold pressure, so no anti-detonant injection was required. When you press E on the keyboard at full throttle, manifold pressure goes up slightly, engine power increases and the engine tends to run a bit hot. No problem as long as you're going fast enough for cooling air flow. The WEP mode on the P-51D is linked only to the keyboard input (or mapped to a button), not to the throttle axis.

 

On the FW-190D-9, pressing E activates MW50 flow and also applies full throttle, increasing manifold pressure to full WEP. It's not linked to the throttle axis either, which is not very realistic, but for the purposes of a PC flight sim, it works just fine. In other words, the module developer doesn't allow you to engage WEP without the MW50 system turned on--they assume you'd do it anyway, because you had to in real life.

 

On our Bf-109 module, it's entirely possible to open the throttle to the WEP position with MW50 turned off, as it was in the real airplane. And just like the real thing, you gotta make sure that speed juice switch is on or it's an early death for your powerplant! As long as your MW50 is on you should be able to use your WEP setting for as long as 10 minutes without blowing the engine. That's probably what's been happening--I did it myself a few times before I figured it out.

 

Peace and happy warfare :D

Ian

[Flying-Kane]

Hi Aluminum Donkey,

 

on the FW190, I don't think so.

 

Full throttle is always 3250 RPM, with MW50 or without it.

What changes is the boost pressure.

 

So, the modeling of the throttle in the FW190 is correct. MW50 engages only with the button/circuit breaker in the ON position.

[Yo-Yo]

Hi Aluminum Donkey,

 

on the FW190, I don't think so.

 

Full throttle is always 3250 RPM, with MW50 or without it.

What changes is the boost pressure.

 

So, the modeling of the throttle in the FW190 is correct. MW50 engages only with the button/circuit breaker in the ON position.

 

There are two different ways in real 190 and 109 to shift into mw50: in 190 mw-50 fuel jet pressure shifts a special servo that reajusts desired filling increasing MP, though in 109 mw-50 injection and automatic MP limiter reajustment are independant.

[OutOnTheOP]

One thing to keep in mind about the 109 in DCS World is that it has a more realistic throttle & supercharger model than the other two WW2 prop aircraft (P-51 & FW-190). In the DCSW 109, you can apply full throttle (WEP, 1.8 ata boost pressure) even with the MW50 system turned off. In the real-life 109, this was possible too, and must be avoided.

 

If you're regularly blowing engines make sure the MW50 system is turned on with the switch on the lower part of the instrument panel, because applying full throttle will increase manifold pressure to 1.8 ata with no 'speed juice' flowing in if the MW50 system is turned off. This will destroy the engine very quickly, just as in real life. The job of the MW50 is to suppress detonation at very high power levels, and was an absolute must for running 1.8 ata boost.

 

Now, in the P-51D, WEP is a small increase in boost above max normal manifold pressure, so no anti-detonant injection was required. When you press E on the keyboard at full throttle, manifold pressure goes up slightly, engine power increases and the engine tends to run a bit hot. No problem as long as you're going fast enough for cooling air flow. The WEP mode on the P-51D is linked only to the keyboard input (or mapped to a button), not to the throttle axis.

 

On the FW-190D-9, pressing E activates MW50 flow and also applies full throttle, increasing manifold pressure to full WEP. It's not linked to the throttle axis either, which is not very realistic, but for the purposes of a PC flight sim, it works just fine. In other words, the module developer doesn't allow you to engage WEP without the MW50 system turned on--they assume you'd do it anyway, because you had to in real life.

 

On our Bf-109 module, it's entirely possible to open the throttle to the WEP position with MW50 turned off, as it was in the real airplane. And just like the real thing, you gotta make sure that speed juice switch is on or it's an early death for your powerplant! As long as your MW50 is on you should be able to use your WEP setting for as long as 10 minutes without blowing the engine. That's probably what's been happening--I did it myself a few times before I figured it out.

 

Peace and happy warfare :D

Ian

 

Mostly accurate, but a few points I'd like to make:

1) The Bf109 powerplant isn't modelled any more accurately than the other warbirds currently in. All of them had detonation effects modelled (at least, according to the newsletters). They're all modelled accurately, it's just that the DB605D as installed in the Bf109 is the only one of the powerplants that does not have built-in safeties that prevent detonation.

2) The Mustang could also, when running the exceedingly simple (and common) modifications for 44-1 / 150grade fuel, push significant boost (75" MP), and risked detonation. A leaded anti-detonation additive was used in the fuel to prevent knocking and detonation. The additive had the potential to foul the spark plugs, so the pilot had to work the engine a minute at high power periodically to ensure they stayed clean.

3) The MW50 on the Dora is operated exactly as on the Bf109 in-game. The pilot has to enable the system by turning on the MW50 switch, and then when the throttle is advanced past a certain point, it automatically feeds MW50 to the engine.

[Nerd1000]

Mostly accurate, but a few points I'd like to make:

2) The Mustang could also, when running the exceedingly simple (and common) modifications for 44-1 / 150grade fuel, push significant boost (75" MP), and risked detonation. A leaded anti-detonation additive was used in the fuel to prevent knocking and detonation. The additive had the potential to foul the spark plugs, so the pilot had to work the engine a minute at high power periodically to ensure they stayed clean.

 

You're thinking of tetraethyl lead, which is nasty stuff and historically a common fuel additive even in lower grade petrol. It boosts the octane rating significantly and has the added benefit of coating the valve seats with lead oxide, which reduces wear. Sadly it is of course highly toxic.

 

The 150 grade fuel also contained aniline, meaning that it smelled of rotten fish and was even more toxic than normal leaded Avgas.

[OutOnTheOP]

You're thinking of tetraethyl lead, which is nasty stuff and historically a common fuel additive even in lower grade petrol. It boosts the octane rating significantly and has the added benefit of coating the valve seats with lead oxide, which reduces wear. Sadly it is of course highly toxic.

 

The 150 grade fuel also contained aniline, meaning that it smelled of rotten fish and was even more toxic than normal leaded Avgas.

 

All true, but in the 44-1 mix, its primary purposes (and the reason for such a high amount) was as an anti-knocking (anti-detonation) agent.

[Nerd1000]

All true, but in the 44-1 mix, its primary purposes (and the reason for such a high amount) was as an anti-knocking (anti-detonation) agent.

 

Well, that's what the octane rating is all about: the anti-knock performance of the fuel compared to n-heptane (rated as 0) and 2,2,4 trimethylpentane (rated as 100, and also known as isooctane :smilewink:). The higher the better.

[Kurfürst]

One thing to keep in mind about the 109 in DCS World is that it has a more realistic throttle & supercharger model than the other two WW2 prop aircraft (P-51 & FW-190). In the DCSW 109, you can apply full throttle (WEP, 1.8 ata boost pressure) even with the MW50 system turned off. In the real-life 109, this was possible too, and must be avoided.

 

If you're regularly blowing engines make sure the MW50 system is turned on with the switch on the lower part of the instrument panel, because applying full throttle will increase manifold pressure to 1.8 ata with no 'speed juice' flowing in if the MW50 system is turned off. This will destroy the engine very quickly, just as in real life. The job of the MW50 is to suppress detonation at very high power levels, and was an absolute must for running 1.8 ata boost.

 

Peace and happy warfare :D

Ian

 

Not neccesarily, it actually depends on the fuel.

 

On the 109's DB 605D, you could use either 87 octane B4 or cca. 150 grade C-3 fuel with the engine. At 1.8ata boost, which we have, MW was a must to be used for 1.8ata when using B-4 fuel, but the knocking properties of C-3 were much better and could easily sustain up to 1.8ata, which is a lot lower pressure than the 67" the Mustang here uses.

 

So bottomline, if we actually have C-3 fuel properties avgas in the 109, 1.8 ata could be useable without MW, though engine temperatures could be higher since MW also provides considerable cooling to the engine. But there is not much of an advantage to it, the real advantage of using C-3 was that, when combined with MW boost, you could go up to 1.98 and even, 2.3ata boost (cca 2000-2300 HP).

[MiloMorai]

which is a lot lower pressure than the 67" the Mustang here uses

What Kurfy failed to mention was the DB605 was running a much higher CR than the Merlin.

 

Merlin 6:1

DB605 8.5/8.3:1 with C3

[Zimmerdylan]

My engine locked up, on the same server as Diehard for no apparent reason as well.

 

I was flying a P-51 and it locked up on take off roll. No overheats...just stopped.

 

 

 

Wow!!! I just left that server for the same exact reason. Was doing some air to ground. Nothing taxing at all. Wasn't driving the plane hard by any means and out of nowhere...BAM.....engine just seized. Was looking for the guy who shot me :lol:.

Must be something that's set up on the server. I rarely overheat the P-51 and haven't seized an engine in quite a while.

What a coincidence that I just left the server and found this thread.

:music_whistling:

[BIGNEWY]

attach a track of the issue / incident and we will take a look.

 

If you can reproduce in a short track even better.

[Aluminum Donkey]

Not neccesarily, it actually depends on the fuel.

 

On the 109's DB 605D, you could use either 87 octane B4 or cca. 150 grade C-3 fuel with the engine. At 1.8ata boost, which we have, MW was a must to be used for 1.8ata when using B-4 fuel, but the knocking properties of C-3 were much better and could easily sustain up to 1.8ata, which is a lot lower pressure than the 67" the Mustang here uses.

 

So bottomline, if we actually have C-3 fuel properties avgas in the 109, 1.8 ata could be useable without MW, though engine temperatures could be higher since MW also provides considerable cooling to the engine. But there is not much of an advantage to it, the real advantage of using C-3 was that, when combined with MW boost, you could go up to 1.98 and even, 2.3ata boost (cca 2000-2300 HP).

 

Interesting discussion going on here :)

 

Actually, what I meant is that in the real 109K-4, pushing the throttle lever all the way forward raised manifold pressure to 1.8 ata. It still did it, even if the MW50 system was turned off. This would result in 'considerably shortened' engine life when running on B4 fuel because it would cause detonation. The only fuel modelled in the sim is B4, so the MW50 switch must be in the on position before applying full throttle and running 1.8 ata boost.

 

You're right about C3 fuel, it would allow very high manifold pressures (and correspondingly high power levels) without MW50, but my best guess is that MW50 injection was much cheaper and more plentiful, and hence more practical, than filling every 109 up with C3 gasoline.

 

Someone should write a bit of code to allow us to try flying our virtual 109K-4 at 2.3 ata boost :)

 

Peace and happy warfare

Ian