An ugly surprise

[chris455]

I have noticed that after a period of intense dogfighting, my engine will simply lock. Engine dead, prop frozen, instant engine death..

I need answers.

Because- I do not run my engine at max, nor do I overspeeed my prop. I have noticed that coolant temp is very dynamic on the Mustang, so I watch that carefully. In the most recent instance of this phenomenon,I had just put down the Dora (for the first time!) and throttled way back, reduced RPMs well into the green, checked my coolant and cylinder head temps. All good. Then, for no apparent reason, as I was getting ready to do a Victory roll, my engine locked. I looked at coolant temp and now it's redlined. This is less than 3 seconds after checking it when it was full green.

WTF?

How does an engine go from fat, dumb, and happy to overheat seize-up in three seconds with MAP at 40 inches and RPMs at 2200? Befeore anyone asks, my "Victory" was over a FW with it's teeth pulled, i.e., no ammo. So he didn't damage me prior (I know, I know, it's the only way I can shoot the bastage down right now :( )

What's going on???

I appreciate any constructive feedback- I'd like to get to the bottom of this.

Chris

[Merlin-27]

The coolant temp can rise very quickly. Mostly when flying too slow or if the coolant radiator doors are closed.

[gavagai]

Pick your MP and RPM carefully. You're better off with full military power than some awkward combinations that can damage the engine. I don't think 40 MP and 2200 RPM is a standard setting, FWIW.

 

On the right hand side of the cockpit there is a plate that lists the recommended MP and RPM settings.

[chris455]

Pick your MP and RPM carefully. You're better off with full military power than some awkward combinations that can damage the engine. I don't think 40 MP and 2200 RPM is a standard setting, FWIW.

 

On the right hand side of the cockpit there is a plate that lists the recommended MP and RPM settings.

I tried another fight at Maximum Continuous (46" and 2700 RPM) and seems OK.

I was sure wanting that extra power at times though-

I think this sim will force me to adopt an even more realistic approach to engine management.

[gavagai]

In combat go ahead and use 67" MP and 3000 RPM. Better to kill your adversary as quickly as possible.:thumbup:

[Barfly]

You can get a pretty good feel for how effective an actual Mustang's radiator was by reviewing various max power tests at:

 

http://www.spitfireperformance.com/mustang/mustangtest.html

 

http://www.wwiiaircraftperformance.org/mustang/eglin-p51b-climb.jpg

 

In the second link is a chart showing max power climbs from surface to 30,000 ft :

 

"Climbs were made to thirty thousand feet at the standard, and at the test war emergency ratings. Climbs at seventy-five inches Hg. required about one minute less than was required when climbing at sixty seven inches Hg. All engine temperatures were normal during climb at the increased power."

 

Time to climb for each max power setting was around 11-12 minutes, using 3000 rpm and fully opened radiators.

[ARM505]

My gut feel is that DCS punishes you very harshly and very quickly for any engine exceedance. In a way it's a good thing since it's a workaround for the 'brand new shiny plane every time' syndrome of sims (ie a brand new factory fresh P51 could likely last longer, but would be abused horribly in a fight because we get a new one everytime, unrealistically so), but on the downside it may not represent how well a real Merlin would have held up. IMHO.

[Barfly]

My gut feel is that DCS punishes you very harshly and very quickly for any engine exceedance. In a way it's a good thing since it's a workaround for the 'brand new shiny plane every time' syndrome of sims (ie a brand new factory fresh P51 could likely last longer, but would be abused horribly in a fight because we get a new one everytime, unrealistically so), but on the downside it may not represent how well a real Merlin would have held up. IMHO.

 

The radiators corroded and cooling passages corroded over time...causing higher that normal coolant temps and potentially more than normal restriction on power settings, and I think that's what you see here. They probably just have some bad data points from an old airshow bird that isn't in the condition of a wartime example, it isn't cooling properly. The fact that it works well enough at the power settings used by a modern demo pilot but not at higher settings is a clue.

 

Most examples of late war fighters were relatively low time during their active use...and would not suffer from debilitating corrosion and overheat problems.

 

I posted a link in Complex Engine Management section for a Merlin overhaul shop that discusses this issue:

 

http://forums.eagle.ru/showthread.php?p=1966170#post1966170

Edited January 12, 2014 by Barfly

[Blech]

Hi,

 

North-American-P-51-Mustang-Pilot-Training-Manual 1945 : War Emergency Power

[Barfly]

Hi,

 

North-American-P-51-Mustang-Pilot-Training-Manual 1945 : War Emergency Power

 

Better worded in this revision of that page:

 

http://i91.photobucket.com/albums/k304/Major_Sharpe/P-51WEP1.jpg

[Blech]

Better worded in this revision of that page:

 

http://i91.photobucket.com/albums/k304/Major_Sharpe/P-51WEP1.jpg

 

 

Hi,

 

Better : ... after 5 hours of emergency boost operation

 

The 1945 manual : ... after 5 hours

Can be complete wrong from the understanding :

Use WEP -> after 5 hours ( cool down the engine ) -> complete engine inspection

[Barfly]

Yes I understand... usually manuals are more clearly worded. The -2 or maintenance manual if their is such a thing available would probably have more specific guidance.

 

Edit:

 

See pg 450-451 of this manual:

 

http://www.scribd.com/doc/34812228/P51D-Mustang-Maintenance-Manual

 

There is a detailed description of post flight checks after wep use, and a note that clarifies 5 total hours of logged wep use requiring teardown. The linked manual is fantastic, every detail of possible field maintenance is included, with lot's of pictures.

Edited January 12, 2014 by Barfly

[chris455]

In combat go ahead and use 67" MP and 3000 RPM. Better to kill your adversary as quickly as possible.:thumbup:

 

Gavagai-do you have, or would you be willing to make, a YouTube of you putting down the Dora?

There are some videos out there but I would be interested in seeing your technique.

I invariably am outdistanced by this guy buy a wide margin, regardless of my power settings.

And even with TrackIR, I lose tally way too often. He separates so quickly that he basically disappears.

Fortunately finding him again is never a problem. All I have to do is look behind me :(

[gavagai]

I'm not much for movie making, I don't even have a fraps license. But I can make a track if you like and you can watch that.

 

Here you go:

P-51.zip

Edited January 12, 2014 by gavagai

[streakeagle]

Here is my typical successful 1v1 with Fw190D9.

A few frames were messed up during the upload, but you can very much see what I am doing.

I am using TrackIR only... no ID tags and no padlock.

generally I have the throttle forward and full rpm without breaking the wire for WEP.

 

[chris455]

@Gavagai- Thanks for the effort to make a track for me, but your track has the same issue as when I make a track- after a while things get out of synch and you ended up chasing and shooting at a shadow while the "phantom" FW was on your tail! Weird, I know..............

 

@ Streakeagle-Thank you. I definitely notice a difference in the AIs "attitude" toward you. Yours was more of a vertical turnfight, whereas mine usually ends up with him going to rocket-assisted takeoff into the stratosphere the instant he passes in front of my 3-9 line.

Going to try again at Military Power, as I could see you close/ recover from stall condition much better than I do @ Maximum Continuous. Do you mind if I ask what percentage of fuel loadout your P-51 is set up with?

PS- great shooting at the Coup de Grace!

[streakeagle]

I just play the stock instant action... so whatever ED set the fuel at is what I fly at.

The AI is mercilessly efficient fighting in the vertical.

I have to trade some energy to get the angle, then fly with as light a stick as possible.

Many times, I burn up my engine trying to hang with him.

So I fly as conservative as I can until I think I can put my nose on him while he is hanging still.

If I misjudge, I either miss, my engine dies, I lose control, or he climbs away.

It takes too long to kill him aiming for the center of mass.

A solid wing shot rips him to shreds quickly.

Edited January 13, 2014 by streakeagle

[streakeagle]

By the way, when he climbs away, you can build up speed and altitude to match, maybe even get above him if you turn away and do your own thing. When you turn back around, he may be engaging you from a neutral start, or he may be flying home and give you the chance to bounce him. I have so little practice against a co-operative straight line target, that I usually blow the bounce. I don't have the patience to close at a lower speed and come in too fast to get solid hits, then overshoot and he re-engages using the same old tricks starting from my 6.

[HotTom]

Yes I understand... usually manuals are more clearly worded. The -2 or maintenance manual if their is such a thing available would probably have more specific guidance.

 

Edit:

 

See pg 450-451 of this manual:

 

http://www.scribd.com/doc/34812228/P51D-Mustang-Maintenance-Manual

 

There is a detailed description of post flight checks after wep use, and a note that clarifies 5 total hours of logged wep use requiring teardown. The linked manual is fantastic, every detail of possible field maintenance is included, with lot's of pictures.

 

Wow! Lots of greatr vintage manuals linked to this link!

 

Thank you!