missing info Engine Degraded

[Art-J]

I guess if one doesn't have a habit of checking the MAP gauge often (or doesn't want to loose contact of that enemy spot on the horizon), the only way of telling quickly you're running dry with excessive MAP is noting subtle vibrations of the cockpit appearing and getting stronger. So:

a) up to 52" dry - no vibration, all good;

b) above 52" dry - vibration, bad;

c) above 52" wet - no vibration again, all good.

It's the same as in 109K module, where max ATA without water results in vibrations too, as a friendly reminder of pre-ignition going on (I presume) Although vibrations in 109 are much stronger and impossible to miss I admit.

Edited January 19, 2022 by Art-J

[Tuturuu]

The engine will progressively gain MaP with altitude/speed from the turbocharger which become progressively more performant no ?

While the main engine will lose performance progressively aswell but from a very higher ceiling (even if it way higher)

Just like axis plain got an auto-pitcher modulating RPM to keep constant MaP to counter act altitude/speed variations (at least that is how i understood it)

[grafspee]

@Tuturuu 

You need to separate this topics.

1. MAP gain from speed is due to ram effect and has nothing to do with turbocharger or engine it self, engine inlet is faced forward so faster you fly the higher air pressure enters the plane.

2. MAP changes with alt due to turbocharger regulator unit. Ambient pressure changes with alt it affect whole system as well.

Axis planes has boost regulator which maintains set MAP withing regulating range, constant speed unit has nothing to do with it. Constant speed prop unit job is to maintain steady rpm through the flight so engine can operate at optimal rpm regardless of speed of the plane. Only difference in axis planes is that rpm lever is build in to throttle.

P-47 does not have boost regulator like 109 or p-51 this is why we experience this MAP behavior.

Edited January 21, 2022 by grafspee

[Slumzur]

I've just made 10 test flights with 2700 rpm, 60" and water injection. I got 2 engine failures, due to degradation, which took less than 5 min. Then I repeated 10 tests with 64" and got 1 engine failure, which was below 5 min period. Isn't the engine suppose to hold every time 2700/64" up to 5 min at least? Oil temp was in blue gauge and carb temp was below 50C.

[grafspee]

If maker of the plane states that engine can operate at 64" at 2700rpm for 5 min, and engine brakes before 5 min mark, i think some heads would be chopped off if it would happen.

My pinion is that engine modeling is too sensitive, engine limits are set for respected engine life time, let assume that P-47's engine had to live for 100h, if engine seized up after 30 min  of flight , something is way wrong.

 

Edited January 22, 2022 by grafspee

[Brigg]

19 hours ago, grafspee said:

If maker of the plane states that engine can operate at 64" at 2700rpm for 5 min, and engine brakes before 5 min mark, i think some heads would be chopped off if it would happen.

My pinion is that engine modeling is too sensitive, engine limits are set for respected engine life time, let assume that P-47's engine had to live for 100h, if engine seized up after 30 min  of flight , something is way wrong.

 

Agreed Graff.

 

[Cool-Hand]

On 1/21/2022 at 12:21 PM, Slumzur said:

I've just made 10 test flights with 2700 rpm, 60" and water injection. I got 2 engine failures, due to degradation, which took less than 5 min. Then I repeated 10 tests with 64" and got 1 engine failure, which was below 5 min period. Isn't the engine suppose to hold every time 2700/64" up to 5 min at least? Oil temp was in blue gauge and carb temp was below 50C.

This is the bothersome part, its hard to pin down what is causing the "degradation." Seems like no matter if you baby or abuse it, sometimes the engine ticks on sometimes it decides to pack up.

[VIKBELL]

   I was fly yesterday I had climb to 25,000FT.    When my Aircraft had an engine shutdown and seize up,   However it was not from abuse of the engine.     I had warmed up correctly took off and no water injection I was lean on mixture.   I had used the drop tank but not jettison.    I was using the Aux fuel.   The report says it was engine miss fire.    I don't think I have random failure set.    So what killed the motor in flight.   Was not damaged through combat. ????

[grafspee]

Lean mixture all the time like during take off and climb if so, don't expect engine to feel well after this

I take off climb at 52" up till 35k and my engine is fine, looks like similar problem to Dora when you operate engine at lower rating you get spark plug misfire, but some how i have no clue why this makes engine seized up.

But from your report i can see that main engine bearing was damaged, i assume that you experienced short fule cut off due to empty tank, unfortunately main bearing damage is over done and you can't cut out during flight, this will kill your engine's bearing clean off.

Couple seconds of pure wind milling and engine is gone. 

Edited January 31, 2022 by grafspee

[VIKBELL]

  I had been running on the Aux tank for like 10 minutes.    

[razo+r]

Thats... a pretty useless information without knowing how much fuel you had... 

[grafspee]

@VIKBELL Please elaborate.

[peachmonkey]

I never had any issues with climbs in this bird. I keep it in 2600/46" zone through out + Auto Rich mixture. Come to think of it I've never used Auto Lean ever..

Never had a problem you guys describe. Dials stay in the blue/green and this baby pulls nonstop.

 

[grafspee]

I'm not sure if auto lean/ rich is working at all, i can't spot anything while switching in to lean, i fly too short to notice less fuel consumption.

It supposed to increase power a bit engine running at leaner mix will develop more hp at same rpm/boost it makes engine hotter and not allow use of higher boost due to decreasing anti detonant mixture properties. 

But i don't know how fast this auto leaning happens if it takes couple seconds it will be unnoticeable. 

Edited February 1, 2022 by grafspee

[VIKBELL]

   My center tank was empty but my Aux tank over half plus mains were full.  I also had been switching between Aux left and Aux right.  I was doing high endurance training.

 

Vikbell

Edited February 1, 2022 by VIKBELL

[grafspee]

13 minutes ago, VIKBELL said:

   My center tank was empty but my Aux tank over half plus mains were full.  I also had been switching between Aux left and Aux right.  I was doing high endurance training.

 

Vikbell

 

I don't know is it fixed or not but as i remember you are unable to anticipate fuel tank goes empty, and if you do it, this mean that engine will cut out for a split second until you switch to full tank, according to manual pilot should watch fuel pressure which would start to drop and this is the time to switch fuel tanks, unfortunate in DCS fuel pressure drops  to 0 in no time, so you can't react in time and engien cuts out and with current main bearing modelling, engine bearing will be damaged and it will deteriorate in short time and kill the engine.

Only way to fly on drop tanks safe right now it to calculate your fuel consumption then you start timers on tank which you are using and with couple minutes safety margin you select other tank, you still can switch between tanks but remember to stop your timer when drop tank is not used, yes you would need 2 timers for left and right drop tank

Manual also states, in case when pilot will miss moment to switch to next tank and engine cuts out, pilot need to reduce throttle and engage full tank, then go back to cruise power, that's it no mention about engine death, it is written in manner to not panic take your time and solve fuel cut out :)nothing like this imidietly switch to full tank your engine is dead any way

Edited February 1, 2022 by grafspee

[peachmonkey]

this may be an unrelated hint, but I remember seeing a post from Yo-Yo warning the pilots not to drop the RPM's below 2,000rpm whilst the throttle is in max continuous/WEP, indicating that the ignition timing will be totally messed up resulting in severe detonation leading to a full on engine seize.

[grafspee]

In this planes ignition timing advance is build in throttle levers like spitfire,p-51 and apparently p-47 as well. At SL you are fine below 2000rpm your throttle will be advance only a little bit but at high alt at this rpm throttle would be wide open this mean that ignition timing will be advanced too much, engine will lose power,  and it will probably increase risk of detonations, but once again i think modeling here is overdone as well.

P-47 manual advice to not operate engine at rpm below 2000 at high alt, but it is only recommendation if it was so dreadful for engine P-47 manual would prohibit that kind of power setting at high alt.  

Edited February 1, 2022 by grafspee

[Slumzur]

22 часа назад, grafspee сказал:

I'm not sure if auto lean/ rich is working at all, i can't spot anything while switching in to lean, i fly too short to notice less fuel consumption.

It supposed to increase power a bit engine running at leaner mix will develop more hp at same rpm/boost it makes engine hotter and not allow use of higher boost due to decreasing anti detonant mixture properties. 

But i don't know how fast this auto leaning happens if it takes couple seconds it will be unnoticeable. 

 

Auto lean/rich is working, but the difference is very minor. I measured fuel consumption on 2000 rpm / 30" and got 0.21 gallon/km on auto rich and 0.19 gallon/km on auto lean.

[VIKBELL]

To me If you are sending fellows to war and this is sometime that kill your engine would you not Have a warning message in bold print in Flight manual?

[grafspee]

6 hours ago, VIKBELL said:

To me If you are sending fellows to war and this is sometime that kill your engine would you not Have a warning message in bold print in Flight manual?

It is not in "bold" but all those things are mentioned in manual and i guess pilot's get some kind engine management lesson so this knowledge was common across pilots.

Remember that in RL you don't just jump in to P-47 or P-51 prior to that you jump in to lesser planes like trainers which could have manual mixture control so this kind of thing pilots knew way befor entering P-47 for the first time.

[VIKBELL]

I continue to learn with Aircraft this is my only one I fly regularly.   

[GUMAR]

On 1/31/2022 at 8:31 AM, VIKBELL said:

   I was fly yesterday I had climb to 25,000FT.    When my Aircraft had an engine shutdown and seize up,   However it was not from abuse of the engine.     I had warmed up correctly took off and no water injection I was lean on mixture.   I had used the drop tank but not jettison.    I was using the Aux fuel.   The report says it was engine miss fire.    I don't think I have random failure set.    So what killed the motor in flight.   Was not damaged through combat. ????

Maybe you overheated high voltage wires? With closed cowl flaps at low speed. If it is 'implemented'.

[NineLine]

Is this still an issue?

I know we are tuning some engine abuse issues, but let me know the specific issue, and please supply a track.

[Cool-Hand]

It has gotten better. Last I was home I managed to use WEP and the engine held up, the next sortie I did a similar run but slightly closed the oil cowl to just open of neutral to set cruise power and a few minutes later I got a 'degraded engine when I get home again ill see what I can do about a track. Doesnt seem to happen if I just leave the oil full open.