P-47 Engine Failure during landing approach.

[Lykurgus]

My engine always seems to die approaching an airfield. Everything is good with the engine...all the temps and pressures are good. Boost is set to off for quite some time. Throttle is not pulled back to idle or anything like that. Prop pitch is set to auto and full forward. Then it gradually loses power and I can hear the bearings I think.

[Diesel_Thunder]

You may be windmilling the engine, which puts the load on the wrong side of the crankshaft and can wreck the bearings and engine depending on how badly the engine was being windmilled. The loaded side of the crankshaft journals feature a lubrication hole that protects the crank from the forces of the power stroke from each cylinder, since each power stroke applies force to the same spot on the crankshaft. When being windmilled, the forces are reversed, applying force to the opposite side of the crankshaft without the lubrication hole.

 

Try keeping a little more power on, so that the engine is driving the prop during your approach.

[Brigg]

Rpm lever shouldn't be all the way forward for landing, set it to 2550rpm

[Nealius]

I thought the manuals said to cut throttle to idle? When I do that at 2550rpm, I land, but at the end of my landing rollout the engine quits.

[grafspee]

22 minutes ago, Nealius said:

I thought the manuals said to cut throttle to idle? When I do that at 2550rpm, I land, but at the end of my landing rollout the engine quits.

yes you need to cut throttle, but question is when ?

you can cut throttle just before touch down or after cut down.

I land at 2550rpm and i descend and make approach with 25"-26"

[Nealius]

What is "cut down?"

 

I land at 2550rpm and whatever MP I need to keep 150~160mph in the base turn, and 120mph in the final. I cut throttle just before crossing the threshold, flare to 3-point landing. Then as I'm hitting the wheel brakes my engine quits.

Edited January 10, 2021 by Nealius

[Yo-Yo]

13 minutes ago, grafspee said:

yes you need to cut throttle, but question is when ?

you can cut throttle just before touch down or after cut down.

I land at 2550rpm and i descend and make approach with 25"-26"

If the approach speed is standard, I think, you need to have sufficient MP to get 2550, in my case I see that the prop is at fine stop and rpm are lower.

 

[Nealius]

2 minutes ago, Yo-Yo said:

If the approach speed is standard, I think, you need to have sufficient MP to get 2550, in my case I see that the prop is at fine stop and rpm are lower.

 

 

"Fine stop" means prop lever full forward? 

[Yo-Yo]

3 minutes ago, Nealius said:

 

"Fine stop" means prop lever full forward? 

No, it means that though the rpm lever is at 2550 position, the prop pitch is minimal, and the speed and low MP are insufficient to maintain 2550.

[grafspee]

 

[Nealius]

At the time my engine died on the runway, instruments were indicating 200rpm and 30" MP. Any idea what would cause that? I did not exceed 2550/42 during the duration of the flight (except takeoff at max rpm 46"), and I smoothly reduced throttle to idle before crossing the threshold, just as in grafspee's video.

[grafspee]

2 minutes ago, Nealius said:

At the time my engine died on the runway, instruments were indicating 200rpm and 30" MP. Any idea what would cause that? I did not exceed 2550/42 during the duration of the flight (except takeoff at max rpm 46"), and I smoothly reduced throttle to idle before crossing the threshold, just as in grafspee's video.

Did you take off at 2550 or 2700 rpm ?

Got your engine warmed up ?? Oil pressure and temp in limits ?

Edited January 10, 2021 by grafspee

[Nealius]

4 minutes ago, grafspee said:

Did you take off at 2550 or 2700 rpm ?

Got your engine warmed up ?? Oil pressure and temp in limits ?

 

 

Takeoff at 2700 and 46", as she would not give me 52" even with full throttle. Engine warmed up at 900rpm until temps within limits, plus the magneto checks at 30" and 2000rpm. CHT between 150~200 the entire flight.

Edited January 10, 2021 by Nealius

[grafspee]

Drop track from this flight then. The easiest way to check it.

[Nealius]

Didn't save the track, only VR capture that doesn't have wide-enough FOV to see engine instruments during approach. I'll save the next one when it happens.

[cw4ogden]

On 1/3/2021 at 1:25 PM, Lykurgus said:

My engine always seems to die approaching an airfield. Everything is good with the engine...all the temps and pressures are good. Boost is set to off for quite some time. Throttle is not pulled back to idle or anything like that. Prop pitch is set to auto and full forward. Then it gradually loses power and I can hear the bearings I think.

Carburetor icing possibly?

[Cool-Hand]

On 1/10/2021 at 12:29 PM, cw4ogden said:

Carburetor icing possibly?

Are they modeling carb icing now?

[Tiger-II]

What does mission debrief say? If you damaged the bearings, it will say so there.

[Cgjunk2]

On 1/19/2021 at 8:14 PM, Tiger-II said:

What does mission debrief say? If you damaged the bearings, it will say so there.

Good tip!  Do you know if there is any way to see if bearing damage was cause of failure when you are playing multiplayer?   

 

I am among the ones frustrated with with the tenderness of the engine.   No matter how gently it’s treated, it  seems the engine is only seconds away from destruction if subjected to momentary windmilling.  If this is true behavior, i guess it’s acceptable.  But it’s really hard to tell when that transition to windmilling occurs because of the lack of physical feedback.  

 

Edit: took another long cross country flight.   Kept rpms 2550 and mp pressure as high as I could during approach and landing.   Another engine failure on roll out.  Frustrating end to a nice flight.    Think Ill try again tonight with linked prop/throttle to see if that helps

Edited January 21, 2021 by Cgjunk2

[Tiger-II]

Yes... while I don't doubt that it could be quite sensitive to mis-handling, I'd think it is more robust than we are seeing in the sim otherwise there would be a lot of destroyed engines IRL, and AFAIK that simply isn't the case (and if it was, those engines would be replaced with something better pretty darn quick).

 

Something that is often forgotten is these WW2 birds were flown by pilots with very little experience, and they'd need to be fairly robust to survive war and the low-time pilots that were flying them.

 

I really think the sim is over-exaggerating these things.

Edited January 22, 2021 by Tiger-II

[Nealius]

I also suspect the sim is exaggerating things for the reason that a lot of data is probably sourced from air-worthy survivors, which are undoubtedly pampered and coddled unlike a wartime machine would have been.

Edited January 22, 2021 by Nealius

[Ketchup]

@Tiger-III wouldn't say VERY little experience… in mid 44’, pilots went through 10 weeks each of primary, basic, and advanced flight training, plus another 5+ weeks? of transition training before being assigned to an operational fighter unit. Certainly a lot more training than many of us sim pilots will ever get.

Personally, myself nor the other P-47 pilots I fly with have had significant difficulty with engine management or engine failure. Only when temperatures and operational limits are neglected have I experienced engine damage. Not to say that the modeling may not be inaccurate or bugged. I’m only speaking from my own experience with the plane.

Edited January 23, 2021 by Ketchup

[PL_Harpoon]

13 hours ago, Ketchup said:

Personally, myself nor the other P-47 pilots I fly with have had significant difficulty with engine management or engine failure. Only when temperatures and operational limits are neglected have I experienced engine damage. Not to say that the modeling may not be inaccurate or bugged. I’m only speaking from my own experience with the plane.

That's my current experience with the Jug.

In fact IMHO engine handling in the Jug can be summed up by these rules (at least they work for me):

 

NEVER exceed MP limits (52 without water, 64 with water)

NEVER dive with full RPM (1550 works best)

NEVER dive with less than 30 InHg of MP

NEVER leave turbo in front of the throttle

Avoid high RPM/low throttle and low RPM/high throttle settings

Keep the throttle and turbo interconnected at all times below 25k ft (for simplicity's sake)

 

Follow those rules and you should have no problems operating the engine.

[Nealius]

15 hours ago, PL_Harpoon said:

Avoid high RPM/low throttle and low RPM/high throttle settings

 

This one always confuses me. It's not quite possible to avoid these situations during takeoff and landing phases. 

[PL_Harpoon]

1 hour ago, Nealius said:

 

This one always confuses me. It's not quite possible to avoid these situations during takeoff and landing phases. 

It's the actual prop rpm that counts, not prop lever position.

 

At low speeds you can have your prop lever fully forward and still have low prop rpm.

 

On the flip side, if you're very fast (for ex. when diving). You can have the prop lever fully aft and high prop rpm.