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20 hours ago, peregrine7 said:

 
Well, there's so much wrong with the engine damage model I think this ends up being far down the list (though I haven't heard if the devs are even considering improving their DM).

My priorities would be:

  1. More iterative damage states for engines - The engine shouldn't die so quickly if overworked (especially in the 109, P39, P40, I pretty much solely fly red but blue really gets shafted on this with their main aircraft getting gimped with it). Damage should be iterative, with oil leaks/gasket failures being the primary overworked failure states.
  2. Realistic engine limits / time limits - Don't use peacetime engine limitations as a guide for when the engine will suddenly die. These are woefully conservative. We have wartime limits for the BF109s but peacetime limits for the P39/P40 - engines that took a far bigger beating at the hands of Russian pilots than the manual allowed. That's a bit odd (and frustrating, the P40 engine is a bit of a running joke)
  3. Complex engine damage - When hit by bullets you should see component based failures e.g. Individual cylinder head perforations, blown gaskets, severed electrical systems (engine may still run on residual heat "glow bulb" style), damaged supercharger, damaged governor, damaged shaft/shaft box. Oh and fires.
  4. Fires - Fire in game is very odd. A blown fuel tank fire should look more like a big (but relatively weak) fireball that quickly subsides with relatively little smoke. We should also see fuel line fires (IRL these are the ones that leak burning fuel through the cockpit guages, as was recounted by several pilots), oil pan fires (smouldering things that produce a ton of black smoke and can easily spread through the engine hoses/electrical) and, more rarely, surface and subframe fires on aircraft with flammable components.
  5. Complex engine management - This is where things like MP/RPM ratio comes in.
  6. Realistic fuel flow management - Yeah, it's not specifically engine related. But if I'm in a plane with a big fat yellow knob next to me that allows me to select feed tanks and turn Xflow on/off then I should probably disable Xflow when my wingtank is ruptured. But no, I have to watch all my fuel from all of my tanks drain through a hole in one wing. Even more frustrating in VR where the knob to disable flow to the wing is right there.

 

Cliffs of Dover has some of this, but as I understand it, this is the reason development of the sim took so long. Modelling all the innards for each aircraft requires a lot of time. In BoX we have a good number of aircraft, modelled to a reasonable approximation. Adding in more complexity means longer development time, fewer releases and less cash for the team. 

 

 

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DCS's engine model has impressed me as the oil pressure varies depending on oil temp. However BoX has impressed me because they can produce an almost as comprehensive simulation of a plane in a tenth of the time. All products are compromises and I recognise it's a difficult call for the producers where to pitch their product. We're lucky that there's several teams covering most bases.

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I read the Spit V pilot notes which are very sparse. Reading the Spit IX pilot notes fleshes out more details.

 

- preliminary landing approach is done at 2650 RPM. The pilot switches to 3000 RPM on final approach when the flaps and gear are down. At that point boost should be -3 or -4.

 

Has anyone tested how long the engine lasts at 3000 RPM and -3 boost? If you cannot fly the plane as set out in the notes, that would be a bug to be fixed.

Edited by Sgt_Joch

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5 minutes ago, Sgt_Joch said:

I read the Spit V pilot notes which are very sparse. Reading the Spit IX pilot notes fleshes out more details.

 

- preliminary landing approach is done at 2650 RPM. The pilot switches to 3000 RPM on final approach when the flaps and gear are down. At that point boost should be -3 or -4.

 

Has anyone tested how long the engine lasts at 3000 RPM and -3 boost? If you cannot fly the plane as set out in the notes, that would be a bug to be fixed.

It lasts a lot longer than 3 minutes. As far as I can remember it was over ten minutes. More than enough for landing

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9 hours ago, 71st_AH_Barnacles said:

CloD in theory has an amazing engine model. Unfortunately they've had to effectively disable or fudge some of the features to make it work. This has resulted in the weird heating and supercharger effects. Eg the engine overheating when shut down on the ground and the high altitude performance of some planes being unhistorical. From @Buzzsaw's posts they are addressing those in upcoming updates and I am looking forward to that. The BoX team as well have said they aspire to simulate things like detonation and turbo superchargers.

 

Edit. The only thing I don't like about CloD is the heat model seems to be there just to prevent you running full power for too long. A la 1946. I hope this is because of a compromise due to the necessity to get the game to be as close a match to historical data rather than gamey feature to modify MP behaviour. When they do the next update I hope they go the historical accuracy route.

Hello Barnacle

 

Since you introduced the discussion, I would like to clear up a few things:

 

In TF 4.5 (CoD-Blitz) we introduced engine modeling changes which corrected the inaccuracies in the original game.  Engine horsepower is now accurate to within 1% throughout the altitude range... so the previous situation whereby some British aircraft had higher ceilings than German types is no longer an issue.  Regarding the situation where by an engine can get hotter after it is shut off... this is not entirely incorrect... without the circulation of the coolant and air passing through the radiators, the core engine parts can experience a rise in temperature as the heat from the cylinder head dissipates through the rest of the of the engine instead of being removed by the coolant as it circulates through the coolant chambers. 

 

Superchargers are modeled very accurately, we have the potential to model all varieties, from the standard single stage types such as those in the Merlin II/III/45 or Allison, through the fluid drive two speed types like those in the Daimler Benz, standard two speed types like those in the Jumo 211, Bristol Hercules, Merlin XX, Pratt and Whitney R-1830 export versions, or BMW-801,  two stage multi speed types like those in the Merlin 60 series or Jumo 213, and turbo-supercharged types like those in the Pratt and Whitney R2800 and Wright 1820.   (the Wrights which equipped the B-17's)

 

In many ways, TF has just scratched the surface of what is possible with the game's design... which allows for factors such as number of hours on the engine, reliability as a function of factory recommendations for the number of hours between overhauls, so we have the potential to model random failures based on the number of hours on the engine and its general reliability.  (we did not model this for TF 4.5 as a survey we took indicated players would not be happy with random failures)

 

We continue to work on improving the engine coding, and continue to add detail and complexity.  In TF 5.0 for example, we will model the split radiators of the 109F, allowing players to shut down one side radiator if it develops a leak, thus preserving the coolant in the other side.  We will model the effects of Tropical dust filters, and their negative effect on supercharger intake volume... that causing reduced hp output.   Players will need to use the filters during takeoff to avoid dust damaging their engines, then after they are clear of the ground, will need to move the bypass lever to open a valve which allows free airflow to the carburetor and supercharger venturi... if they don't, they will have reduced hp output and performance.  I could mention a number of other changes.

 

After release we look forward to players trying our new systems and will welcome feedback.  👍

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Wow Buzzsaw that sounds awesome. Cliffs of Dover is what got me back into IL-2 in 2012. I'm glad it is still being worked on. Does it have VR support?

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Just now, Buzzsaw said:

Hello Barnacle

 

Since you introduced the discussion, I would like to clear up a few things:

 

In TF 4.5 (CoD-Blitz) we introduced engine modeling changes which corrected the inaccuracies in the original game.  Engine horsepower is now accurate to within 1% throughout the altitude range... so the previous situation whereby some British aircraft had higher ceilings than German types is no longer an issue.  Regarding the situation where by an engine can get hotter after it is shut off... this is not entirely incorrect... without the circulation of the coolant and air passing through the radiators, the core engine parts can experience a rise in temperature as the heat from the cylinder head dissipates through the rest of the of the engine instead of being removed by the coolant as it circulates through the coolant chambers. 

 

Superchargers are modeled very accurately, we have the potential to model all varieties, from the standard single stage types such as those in the Merlin II/III/45 or Allison, through the fluid drive two speed types like those in the Daimler Benz, standard two speed types like those in the Jumo 211, Bristol Hercules, Merlin XX, Pratt and Whitney R-1830 export versions, or BMW-801,  two stage multi speed types like those in the Merlin 60 series or Jumo 213, and turbo-supercharged types like those in the Pratt and Whitney R2800 and Wright 1820.   (the Wrights which equipped the B-17's)

 

In many ways, TF has just scratched the surface of what is possible with the game's design... which allows for factors such as number of hours on the engine, reliability as a function of factory recommendations for the number of hours between overhauls, so we have the potential to model random failures based on the number of hours on the engine and its general reliability.  (we did not model this for TF 4.5 as a survey we took indicated players would not be happy with random failures)

 

We continue to work on improving the engine coding, and continue to add detail and complexity.  In TF 5.0 for example, we will model the split radiators of the 109F, allowing players to shut down one side radiator if it develops a leak, thus preserving the coolant in the other side.  We will model the effects of Tropical dust filters, and their negative effect on supercharger intake volume... that causing reduced hp output.   Players will need to use the filters during takeoff to avoid dust damaging their engines, then after they are clear of the ground, will need to move the bypass lever to open a valve which allows free airflow to the carburetor and supercharger venturi... if they don't, they will have reduced hp output and performance.  I could mention a number of other changes.

 

We look forward to players trying our new systems and welcome feedback.  👍

Thank you Buzz for your response,

 

Sorry for the misconceptions, I was working from old information I think.

 

I am very interested about how the simulation works. When something is as detailed as this it really stimulates my technical curiosity. It's kind of like reading historical books on the subject, but with interaction!

 

I am particularly looking forward to the implementation of the venting radiator rather than the perforation on overheat we have now and it's really encouraging you listen to feedback.

 

Thanks!

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25 minutes ago, 71st_AH_Barnacles said:

Thank you Buzz for your response,

 

Sorry for the misconceptions, I was working from old information I think.

 

I am very interested about how the simulation works. When something is as detailed as this it really stimulates my technical curiosity. It's kind of like reading historical books on the subject, but with interaction!

 

I am particularly looking forward to the implementation of the venting radiator rather than the perforation on overheat we have now and it's really encouraging you listen to feedback.

 

Thanks!

Yes, I didn't mention we have now modeled a system whereby the radiator over-pressure valve on the fluid cooled types will vent rather than the radiator actually being perforated.

 

This does not mean a pilot can now ignore the effects of overheating his engine... if he continues to overheat it, then the venting will continue and as the reserve of coolant is drained, eventually all the fluid will be lost and the engine will seize due to the lack of circulating coolant.  And fluid lost due to venting will be a permanent reduction to the coolant reserve even if the pilot brings the engine back down to a normal temperature.

26 minutes ago, sealgaire said:

Wow Buzzsaw that sounds awesome. Cliffs of Dover is what got me back into IL-2 in 2012. I'm glad it is still being worked on. Does it have VR support?

Unfortunately due the delay implementing VR for TF 5.0 would require, we will not have it as a feature of that release.

 

We do hope to have VR introduced as a patch to TF 5.0 approx. 6 months after release.

 

------

 

We will post a complete list of all the new engine/FM/DM elements we are introducing with TF 5.0 on the CoD forum section in the future.

 

For example on the damage side, in TF 5.0 we will be introducing the potential for exploding oxygen bottles and exploding ammunition boxes.

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On 9/4/2018 at 6:51 AM, peregrine7 said:

 
Well, there's so much wrong with the engine damage model I think this ends up being far down the list (though I haven't heard if the devs are even considering improving their DM).

My priorities would be:

  1. More iterative damage states for engines - The engine shouldn't die so quickly if overworked (especially in the 109, P39, P40, I pretty much solely fly red but blue really gets shafted on this with their main aircraft getting gimped with it). Damage should be iterative, with oil leaks/gasket failures being the primary overworked failure states.
  2. Realistic engine limits / time limits - Don't use peacetime engine limitations as a guide for when the engine will suddenly die. These are woefully conservative. We have wartime limits for the BF109s but peacetime limits for the P39/P40 - engines that took a far bigger beating at the hands of Russian pilots than the manual allowed. That's a bit odd (and frustrating, the P40 engine is a bit of a running joke)
  3. Complex engine damage - When hit by bullets you should see component based failures e.g. Individual cylinder head perforations, blown gaskets, severed electrical systems (engine may still run on residual heat "glow bulb" style), damaged supercharger, damaged governor, damaged shaft/shaft box. Oh and fires.
  4. Fires - Fire in game is very odd. A blown fuel tank fire should look more like a big (but relatively weak) fireball that quickly subsides with relatively little smoke. We should also see fuel line fires (IRL these are the ones that leak burning fuel through the cockpit guages, as was recounted by several pilots), oil pan fires (smouldering things that produce a ton of black smoke and can easily spread through the engine hoses/electrical) and, more rarely, surface and subframe fires on aircraft with flammable components.
  5. Complex engine management - This is where things like MP/RPM ratio comes in.
  6. Realistic fuel flow management - Yeah, it's not specifically engine related. But if I'm in a plane with a big fat yellow knob next to me that allows me to select feed tanks and turn Xflow on/off then I should probably disable Xflow when my wingtank is ruptured. But no, I have to watch all my fuel from all of my tanks drain through a hole in one wing. Even more frustrating in VR where the knob to disable flow to the wing is right there.

 

 

I want all of this but most of all Complex Engine Damage. This is one thing Cliffs really nails. Damage in a flying game needs to be authentic. As you mention using VR will only make this more important due to the want of maximum immersion. Hopefully, single player will push this as VR evolves.

 

One thing I'd also like to see in addition to your list is fuel and other assorted venting components to have a visual scale. A cannon strike vs a rifle calibre bullet to a fuel tank should look different.

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8 minutes ago, 7./JG26_Smokejumper said:

 

 

I want all of this but most of all Complex Engine Damage. This is one thing Cliffs really nails. Damage in a flying game needs to be authentic. As you mention using VR will only make this more important due to the want of maximum immersion. Hopefully, single player will push this as VR evolves.

 

One thing I'd also like to see in addition to your list is fuel and other assorted venting components to have a visual scale. A cannon strike vs a rifle calibre bullet to a fuel tank should look different.

Yes, we are looking at including this.... also the amount of fuel/coolant leaked being dependent on round size.

 

We already included in TF 4.5 greatly expanded hitboxes for coolant and oil systems....  not just the radiators, but also the lines and pumps... and we would like to add to this with different calibre rounds having different effects... bearing in mind that shrapnel from an exploding 20mm has a different effect from the actual full round penetrating.

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Neat. I think Cliffs did the leak scale well already. That you are adding more fidelity is bad ass.

 

I'd love to see you guys brought into BoX fully so you can tweak the Spit V and other stuff TF did that I really love. Can the graphics be updated to be more BoX like?

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I went through my checklist for the real collection plane I used to fly some years ago. The check list mentions that takeoff is at full power, minimal pitch and 3400 rpm. Once you have taken off, after braking the wheels (stop their rotation)  and having the landing gear up, and are at climb speed (all this btw is pretty fast after takeoff,  less than a minute) you bring the revs down to 3000. You have also to lower the engine inlet pressure (power). Then you have a stabilized climb rpm and speed up to the cruise altitude. If your cruise altitude requests longer climb then you will increase your speed (better cooling) change the climb angle but you keep the rpm as they are. At cruise the revs are set at 2600-2750 rpm. You see that the difference is pretty high between max and cruise. Then during aerobatic maneuvers you would play with rpm and power but up to a point. 

Now to the question will the engine be damaged or fail if you stay at 3400. Yes guaranteed. But when?. No idea because you never try. In fact during the period of time when this plane was used by the military they stressed much more the engines and they had a better idea on that. They also had a large stock of engine spare parts etc. Money was not the issue. In our association we try to preserve the plane that is the air-frame and engine as much as possible to maximize lifetime and minimize maintenance costs. This also means that you do mild aerobatics pulling reasonable g's to again preserve air frame and engine. It has to be mentioned that here in the plane I flew I had no WEP as such as there is no water injection to boost power. 

 

So to be realistic in the simulation max rpm and power is to be used for a very short time. After that engine damage to happen is sure, but when ? In US WWII planes the limit of continuous WEP was considered to be 5 minutes. In german planes it was longer, maybe 15 minutes. Engines had to be checked after flight when WEP was used. And a brand new engine would probably last longer under WEP than a war tired one. Pilots had to register the WEP usage and duration. A lot of info can be found on these issues.

 

Just to put time perspective a minute is long time. Say you fly at 300 km/hr. My plane had a max limit speed (dive speed) at 500 km/hr. One minute at 300 is 5 km distance. In "brutal" combat aerobatics 1 minute is a lot. So if you need WEP to pull out of a delicate combat situation it is for very short periods of time, a few minutes.  It may save your life but if you loose the engine then lot of pain and no gain.

 

 

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4 minutes ago, IckyATLAS said:

In US WWII planes the limit of continuous WEP was considered to be 5 minutes.

It is an arbitrary limitation in the PN as the WEP rating is in excess of the rating that guarantees the specified service life. It even says so in the PN occasionally. And it always says so in the required document putting the PN in context. To ensure specified service life, you had to check the engine as soon as the pilot broke the wire for WEP. As long as the engine is not predetonationg, there is no way that it will blow rods or suffer any other form of catastrophic damage in flight (as long as you keep temps down). Merlin/Packard engines with the automatic governor did simply not do so and you could not destroy them with WEP power in flight (while keeping temp down).

 

11 minutes ago, IckyATLAS said:

Now to the question will the engine be damaged or fail if you stay at 3400. Yes guaranteed. But when?.

You will not have 3400 rpm cleared as possible rpm if you can actually kill your engine such that it seizes in the same flight that you are trying that abusive regimen for the first time. You immediatley reducing rpm just proves that you are a responsible pilot that takes care of his aircraft as well as the financial viability of your association by keeping maintenance costs low.

 

13 minutes ago, IckyATLAS said:

And a brand new engine would probably last longer under WEP than a war tired one.

There are no "tired engines" in that sense. And have not been. Engines were exchanged in the field more readily than crews washing their hands after taking a leak. Generally speaking, if you were handed a plane, you as pilot should be able to count on a working engine. And a working engine performs as specified. Period. You can operate engines for hundert years, as long as you properly maintain them. You can actually make them better as new after 100 years.

 

Having "tired engines" just means that your ground crew is sent to the infantery "because they would be of more use there". There's a lot more tired than just the engine at that point. While there are engines that were brought very close to their breaking point in service, and this appers the case with the DB engines for instance that for various reasons could sometimes be delicate.

 

The "5 minute limit" that we have in game is just to enforce some realities in a very cometitive environment that we have in the sim. It is arbitary as well, but maybe a way to force players to behave in a certain and somewhat realistic way. For practical puropses, it is hard to imagine a real world pilot in a P-51 shoving the throttle through the gate uopn takeoff and leave it there until he's back at the circuit. But guess what? The 1GCAP in his simulator might well do that.

 

As systems damage model, it is just wrong, although practical. If you really care for your engine, then by all means you avoid high torque, low rpm settings as well. In the sim, I can have full power with prop in a max coarse setting and all is fine. Also, I am not punished for low rpm, low power settings, but in reality I would have lead accumulating on the sparks, making the engine run rough and reducing power. I don't need to fly a circuit here on a high rpm, high power setting to clear the sparks just to be in good hope in case of a go around (or the engine not quitting during approach). The engine damage model we have here just does one thing, it compels you to not use a higher power output than stated in the PN for "some fairness" in the very competitive simming environment.

 

 

 

 

 

 

 

 

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Hi folks,

 

Some interesting details on page 224 of this article (link below) regarding Development of the Rolls-Royce Merlin Engine.

http://www.wwiiaircraftperformance.org/merlin-lovesey.pdf

 

Especially noteworthy that standard production Merlin 66 engine, as fitted to the Spitfire Mk IX LF, overload tested @ 3,000 rpm with +18 lbs combat boost for 100 hours endurance (27 hours initially) with no adjustment or replacement and no involuntary stops and usual routine maintenance omitted entirely.  The engine was then stripped down and found to be in excellent condition.  The engine was then rebuilt without any replacement parts being fitted, then fitted to a Spitfire and given a further 100 hours endurance testing.

 

The lecture was by Mr A C Lovesey:

In 1930 Lovesey was awarded Aviators Certificate No. 9350 by the Royal Aero Club.[3] In the late 1930s Lovesey (who had become known as 'Lov' in company shorthand) began working with others on developing the new Rolls-Royce Merlin and just prior to the start of the Battle of Britain was placed in charge of the development programme. His contribution to the Merlin, doubling its power output and improving reliability at the same time, was a major achievement. Post-war, Lovesey adapted the Merlin for civil use and then turned to turbojet development with work on the Rolls-Royce Avon.

https://en.wikipedia.org/wiki/Cyril_Lovesey

 

http://www.wwiiaircraftperformance.org/merlin-lovesey.pdf

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On 9/5/2018 at 10:10 PM, Buzzsaw said:

Yes, I didn't mention we have now modeled a system whereby the radiator over-pressure valve on the fluid cooled types will vent rather than the radiator actually being perforated.

 

This does not mean a pilot can now ignore the effects of overheating his engine... if he continues to overheat it, then the venting will continue and as the reserve of coolant is drained, eventually all the fluid will be lost and the engine will seize due to the lack of circulating coolant.  And fluid lost due to venting will be a permanent reduction to the coolant reserve even if the pilot brings the engine back down to a normal temperature.

 

If the radiator not perforate then the cooler hose breaks if not this then the cylinder head seal breaks if not this then the whole motor block start to distort and ends in total destruction piston seizure what ever..........

 

-> Better to model it this way -> Frist the coolant venting start if the player still ignore this effects of overheating the cylinder head seal breaks result into engine power loses :)

 

 

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49 minutes ago, 56RAF_Talisman said:

Hi folks,

 

Some interesting details on page 224 of this article (link below) regarding Development of the Rolls-Royce Merlin Engine.

http://www.wwiiaircraftperformance.org/merlin-lovesey.pdf

 

Especially noteworthy that standard production Merlin 66 engine, as fitted to the Spitfire Mk IX LF, overload tested @ 3,000 rpm with +18 lbs combat boost for 100 hours endurance (27 hours initially) with no adjustment or replacement and no involuntary stops and usual routine maintenance omitted entirely.  The engine was then stripped down and found to be in excellent condition.  The engine was then rebuilt without any replacement parts being fitted, then fitted to a Spitfire and given a further 100 hours endurance testing.

 

 

That is a bench test. You can find those for pretty much every engine. It is easy to make sure an engine on a bench is running cool, has plenty of air and quality.fuel, etc. A lot harder to replicate the same conditions in an engine crammed into the nose of an AC. Do you really think the RAF would limit 3000 RPM/+18 boost to 5 minute if in fact you could run the engine at that setting for 100 hours?

 

As the pilot notes general point out, the 5 minute limit is a margin of safety. Yes, under ideal conditions, you could exceed that limit for a long time and you can find combat reports of pilots running on WEP 10-15 minutes with no problems, although that tends to be under ideal conditions, i.e. dives or straight runs at high altitude where engine overheating would not be an issue. You can also find plenty of anecdotes of engines self destructing in flight when pushed too hard. There is one of a P51 pilot experiencing detonation within 30 seconds of pushing boost to 67 inches in 44.

 

And no, not all ACs were in perfect working order. In the fall of 44, the 9th AF was complaining that many of the replacement P51/P47s they were receiving were hand me downs from the 8th AF which had seen hard service.

 

The pilot notes have to cover all ACs and make sure that if a pilot follows them, he will make it back to base alive, so yes they are conservative, but they are not meaningless.

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36 minutes ago, Livai said:

 

If the radiator not perforate then the cooler hose breaks if not this then the cylinder head seal breaks if not this then the whole motor block start to distort and ends in total destruction piston seizure what ever..........

 

-> Better to model it this way -> Frist the coolant venting start if the player still ignore this effects of overheating the cylinder head seal breaks result into engine power loses :)

 

 

I don't think so.

 

If a pressurised system has a pressure relief, like these systems did, the pressure in the system will not become high enough to cause mechanical damage to coolant hoses as the pressure should not rise above the pressure at which the relief is set at. A sensible engineer would set that pressure below which damage is caused.

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5 minutes ago, 71st_AH_Barnacles said:

I don't think so.

 

If a pressurised system has a pressure relief, like these systems did, the pressure in the system will not become high enough to cause mechanical damage to coolant hoses as the pressure should not rise above the pressure at which the relief is set at. A sensible engineer would set that pressure below which damage is caused.

Exactly. But you will experience the effect from loss of coolant.

 

14 minutes ago, Sgt_Joch said:

The pilot notes have to cover all ACs and make sure that if a pilot follows them, he will make it back to base alive, so yes they are conservative, but they are not meaningless.

The pilots notes depict a regime that ensures the aircraft lives up to is specification. It has less to do with what the pilot may experience on his sortie. That depends on the actual situation as well as on the weather/athmosphere. And they are definitely not meaningless.

 

Taking those values in the PN can only serve als ulterior motive to enforce a certain gameplay. And that works. Taking the PN ratings as base for that is about the only way I can think of that keeps the devs from getting acused of bias. It is really the only "neutral data" we have at hand. But they are not always grounds for assumption on what the engine can do if one hour of runtime is all you care for. All things other than those PN ratings can and will be used as an argument of bias, no matter how correct systems simulation might be.

 

20 minutes ago, Sgt_Joch said:

There is one of a P51 pilot experiencing detonation within 30 seconds of pushing boost to 67 inches in 44. 

If it is one, then obviously this is not common. Given that there are frequent cases of neglected aircraft as you say here:

21 minutes ago, Sgt_Joch said:

And no, not all ACs were in perfect working order. In the fall of 44, the 9th AF was complaining that many of the replacement P51/P47s they were receiving were hand me downs from the 8th AF which had seen hard service.

I'd say it is not a good idea to take broken aircraft as a base of what a propperly serviced aircraft can do. The aircraft in this sim are always factory fresh. The should perform accordingly. Adding persistent damage to aircraft would be cool, but it is not for free in a sim. Still there are more things than just the engines that gets worn out if an aircraft seen inadequate servicing. All things that break as well even when strictly adhereing to PN engine ratings.

 

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1 hour ago, Sgt_Joch said:

 

That is a bench test. You can find those for pretty much every engine. It is easy to make sure an engine on a bench is running cool, has plenty of air and quality.fuel, etc. A lot harder to replicate the same conditions in an engine crammed into the nose of an AC. Do you really think the RAF would limit 3000 RPM/+18 boost to 5 minute if in fact you could run the engine at that setting for 100 hours?

 

As the pilot notes general point out, the 5 minute limit is a margin of safety. Yes, under ideal conditions, you could exceed that limit for a long time and you can find combat reports of pilots running on WEP 10-15 minutes with no problems, although that tends to be under ideal conditions, i.e. dives or straight runs at high altitude where engine overheating would not be an issue. You can also find plenty of anecdotes of engines self destructing in flight when pushed too hard. There is one of a P51 pilot experiencing detonation within 30 seconds of pushing boost to 67 inches in 44.

 

And no, not all ACs were in perfect working order. In the fall of 44, the 9th AF was complaining that many of the replacement P51/P47s they were receiving were hand me downs from the 8th AF which had seen hard service.

 

The pilot notes have to cover all ACs and make sure that if a pilot follows them, he will make it back to base alive, so yes they are conservative, but they are not meaningless.

1.  Also easy for a pilot in the air to run engine cool at speed with 300 mph airflow and quality fuel, etc, perhaps even easier for pilot flying in the air, as this is the design function environment for the engine.  As far as I am aware, an engine running temperature of, for example, 120 degrees, is still 120 degrees just the same whether on the bench or in the air. 

 

2.  Not sure if you missed this bit after the bench test:

"The engine was then stripped down and found to be in excellent condition.  The engine was then rebuilt without any replacement parts being fitted, then fitted to a Spitfire and given a further 100 hours endurance testing." 

 

3.  Regarding aircraft pilot notes, here is a quote from pages 25/26 of pilot notes general (Air Publication 2095), regarding engine limitations for max power take off, 1 hour climbing and 5 minutes combat as stated in individual aircraft pilot notes:

 

"These figures provide a general guide to the reasonable use of the engine.  In combat and emergency other considerations may justify the pilot in disregarding these restrictions." 

 

 

Edited by 56RAF_Talisman
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48 minutes ago, ZachariasX said:

The aircraft in this sim are always factory fresh. The should perform accordingly. 

 

 

True, but that is already an artificial construct since it totally ignores the overall condition of the average plane in German or Allied AFs. If on top of that you model WEP limits very liberally, you quickly get to the point where everyone is flying with WEP on 100% of the time which is totally unrealistic.

 

In the armed forces, you fight like you train or people die. RL pilots follow the operating limits set out in the manual since they know that if they dont, they could die. Crash landing an AC or trying to bail out of an AC is very dangerous, pilots died all the time doing it. A RL pilot would only disregard the operating limits in exceptional circumstances and depending on the AF would have to justify his decision in a written report.

 

In the game players have no fear of death and will push their AC to 100% of its limits all the time. You need to have some mechanism so players will respect the operating limits and operate the ACs more or less as pilots did in RL. At one point everyone will have to decide if they want a simulation or just arcade air combat game.

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3 minutes ago, Sgt_Joch said:

In the armed forces, you fight like you train or people die. RL pilots follow the operating limits set out in the manual since they know that if they dont, they could die.

Oh, I very much agree with you on "real world procedures" if your life is at stake. In a sim, you behave differently and the timer is used for encouraging a more real world like behavior.

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If following the limits means throttling back while being chased, or in the middle of a fight, I very much doubt a real life pilot followed the operating time limits when doing so would likely get them killed.

Edited by Garven_Dreis
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26 minutes ago, ZachariasX said:

Oh, I very much agree with you on "real world procedures" if your life is at stake. In a sim, you behave differently and the timer is used for encouraging a more real world like behavior.

When life is at stake, things like 'by the book' time limitations very often go out of the window.  Pilot notes general allow for this.  Thus, we get the following information given to flyers of British aircraft/engine: 

"These figures provide a general guide to the reasonable use of the engine.  In combat and emergency other considerations may justify the pilot in disregarding these restrictions." 

This is because the pilot notes time limits are in fact an artificial construct in the first place, because it cannot be determined exactly when an engine will fail.  So what we have is the dev's overlaying a real world historical artificial construct that could not be timed with a stopwatch, with a game artificial construct that can be timed with a stop watch.  The main difference being that the dev's artificial construct leads to guaranteed engine failure.

 

Happy landings,

 

Talisman

Edited by 56RAF_Talisman

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A gradual power loss and fluctuating RPM should be the result of excessive WEP use IMO, not insta-kaput/forced down behind enemy lines simply because you lost track of time while in combat.

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1 hour ago, 56RAF_Talisman said:

When life is at stake, things like 'by the book' time limitations very often go out of the window. 

With "real world procedures" I didn't mean emergencies, but regular flying. Real would pilots would not really deviate from the PN for common flight regimes, that I would assume. Then again, if it is all about whacking or get whaked, paperwork is the least of your issues.

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2 hours ago, Garven_Dreis said:

A gradual power loss and fluctuating RPM should be the result of excessive WEP use IMO, not insta-kaput/forced down behind enemy lines simply because you lost track of time while in combat.

This is probably the best option imo without giving players too much leeway in abusing their engines. It's the best compromise between gameplay and reality.

 

You should be able to push your engine beyond the limits in most cases without worrying about it quitting right away. If you do push it beyond the limit you get a higher chance of failure and it can potentially lead to power loss, engine failure, etc.

 

At the same time engine shouldn't immediately start to degrade just because you went over the limit.

It should be something like: Engine degradation chance increases by a % every minute you go over the limit. 

 

So it would look something like this:

 

Engine Limit exceeded - Degradation Chance

1min - 5% chance

2min- 10%

3min- 15%

etc.

 

Engine degradation can occur at any time over the limit but the likelihood increases as time goes on.

 

This would be the best compromise imo, it would give player more freedom but also keep them from running full WEP all the time.

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1 hour ago, ZachariasX said:

With "real world procedures" I didn't mean emergencies, but regular flying. Real would pilots would not really deviate from the PN for common flight regimes, that I would assume. Then again, if it is all about whacking or get whaked, paperwork is the least of your issues.

I have been taking this conversation as in the context of this simulation, as far as is reasonably practicable, and the real life World War 2 fighting for civilisation situation.  I am not looking at this from a modern aviation flying perspective or a civilian flying emergency or a military non combat emergency.  I am thinking in the context of world war, fighting for ones life, the life of ones relatives and the future of ones country.  I see this as the sort of mind set of the engineers, aviators and anyone involved at the time, including in production and at the front line.

 

I would prefer to see a less crude method of engine damage modeled, perhaps with more emphasis on engine temperatures.  For example, damage to engine if flying over the max time limits/settings but only if at too slow airspeed for cooling.  So, for example, perhaps climbing for too long at too slow an airspeed (140 mph being probably too slow if sustained too long at max engine settings), or continuous turning in combat at too slow an airspeed with max settings and not throttling back, so overheat occurs.  This seems to be the approach of some other simulations.  Perhaps even taking in historical engine reliability issues for different aircraft.  However, the dev's will probably not have the time or resources for this at the moment.  But perhaps one day they will be able to introduce more sophistication.  Overall, I think the dev's are doing a very good job for us. 

Edited by 56RAF_Talisman

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20 minutes ago, 56RAF_Talisman said:

I would prefer to see a less crude method of engine damage modeled, perhaps with more emphasis on engine temperatures.  For example, damage to engine if flying over the max time limits/settings but only if at too slow airspeed for cooling.  So, for example, perhaps climbing for too long at too slow an airspeed (140 mph being probably too slow if sustained too long at max engine settings), or continuous turning in combat at too slow an airspeed with max settings and not throttling back, so overheat occurs. 

That would be nice, especially if you included other forms like high torque/low rev and spark fouling.

 

Although I would really like that, I also see downsides. First one is that some will right away allege the devs of bias („The 109 diesn‘t overheat, it has an automatic radiator!“), crap like that, plus added cost for development. Some would be sensible to price increase.

 

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9 hours ago, Livai said:

 

If the radiator not perforate then the cooler hose breaks if not this then the cylinder head seal breaks if not this then the whole motor block start to distort and ends in total destruction piston seizure what ever..........

 

-> Better to model it this way -> Frist the coolant venting start if the player still ignore this effects of overheating the cylinder head seal breaks result into engine power loses :)

 

 

CoD system models any number of detailed failures... including cylinder head seal failures... which are linked with radiator failures or overheating.

 

And yes, the final result of a system which is not longer being cooled effectively is typically piston seizure.

 

In CoD is also possible to do mechanical damage to your engine which does not completely destroy it... it will simply run worse than normal and produce less power.  But the player will be able to fly back to base and land.  This type of damage typically comes from the player running excessive rpms for long periods.... the damage manifests itself as valve spring failure.  It is also possible to see a catastrophic failure from excessive rpms... typically crankshaft rods.

 

CoD has two important hierarchies of failure... failures resulting from coolant system malfunctions, and failures resulting from oil lubrication system malfunctions.  These are directly linked in many instances and less often linked in others.  For example, Propellor governor lubrication failures are less likely to be a function of a coolant system failure.  But obviously even if an oil cooler radiator system is still functioning, a failure in the coolant radiator sytem will increase the overall heat of the engine and therefore affect oil temperatures and the likelyhood of failures in that hierarchy.

 

As mentioned, CoD can include parameters for number of hours the player's aircraft engine currently has, as well as overall reliability... i.e. number of recommended hours between overhauls.  It would be possible for a mission builder to create a campaign for someone playing a single player campaign... which would have the player be assigned a particular aircraft, with a particular number of hours... as the player continues his campaign, the number of hours increases, and therefore the likelyhood of a mechanical failure.  Of course, when the player is assigned a new aircraft, the counter for engine hours resets to zero.  At the moment these parameters are not implemented as they require extensive testing and experimentation.

 

CoD also models cooling efficiency based on the atmospheric density...  at higher altitudes, cooling systems work less efficiently due to the less dense atmosphere... this is despite the fact overall atmospheric temperature declines with altitude.

 

I will add there is a negative to all this complex modeling... it requires a great deal of study for a programmer to understand all the complex interactions.

 

I do not believe the 2nd group developers at Maddox games, (after Oleg and his chief coder left) understood the engine systems completely.  There were many instances of systems in the game being bypassed by the programmers... for example, the Daimler Benz engines in the the vanilla CoD 109's were given values in certain areas which would make it impossible for them to overheat.... likely this was done because the programmers were frustrated with trying to understand the engine code systems.   TF had a tremendous degree of difficulty in learning all the systems when we came in, especially since we didn't have the Source Code initially.  Even now, the complexity is such that a great deal of care has to be taken in the programming of the individual engine types.  The various carburetor mixture systems are particularly nasty minefields.... this was the reason the Fiat G-50 was basically unflyable in the original game... the mix system programming was completely in error.

 

The other negative of course... adding all these additional features means more work for the CPU and therefore lower performance from the game.

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4 hours ago, ZachariasX said:

With "real world procedures" I didn't mean emergencies, but regular flying. Real would pilots would not really deviate from the PN for common flight regimes, that I would assume. Then again, if it is all about whacking or get whaked, paperwork is the least of your issues.

 

Agreed, but that is what the "emergency power" is for, namely you fly the Spit IX in combat at 2850 rpm/+12 boost. If you are caught in a jam, you have 3000 rpm/+18 boost for 5 minutes to get you out of it.

 

It is not fly in combat at 3000 rpm/+18 boost, after 5 mins you realize you are in trouble and then fly an unlimited time at that setting.

6 hours ago, 56RAF_Talisman said:

When life is at stake, things like 'by the book' time limitations very often go out of the window.  Pilot notes general allow for this.  Thus, we get the following information given to flyers of British aircraft/engine: 

"These figures provide a general guide to the reasonable use of the engine.  In combat and emergency other considerations may justify the pilot in disregarding these restrictions." 

 

That quote is not a license to blindly disregard operating limits. Other paragraphs in the same chapter make it clear that disregarding the limits can result in "immediate breakdown" of the engine or "severe damage" from overheating, so yes the pilot has the discretion of disregarding the instructions, but runs the risk of blowing the engine. It is not an invention of the devs.

Edited by Sgt_Joch
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11 minutes ago, Ojisan_Mjoelner said:

Apparently NOT with the 40

 

Oh, yes they did. It's just that they are very conservative values. 

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12 hours ago, Sgt_Joch said:

That quote is not a license to blindly disregard operating limits.

I don't think anybody claimed that. And I'm sure the ground crew would use unquatable phrases if a pilot constantly comes back with a broken wire at the throttle gate just because he likes it.

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2 hours ago, ZachariasX said:

I don't think anybody claimed that. And I'm sure the ground crew would use unquatable phrases if a pilot constantly comes back with a broken wire at the throttle gate just because he likes it.

 

Am pretty sure it would be more than just the ground crew, and it would not just be unquotable phrases when (as per usual 'gameplay') the entire squadron would be grounded for engine changes 😎

 

Cheers, Dakpilot 

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Z

On 9/5/2018 at 1:00 PM, AtomicP said:

We have wartime limits for the BF109s but peacetime limits for the P39/P40 -

 

No we don’t. 109s had no restriction on WEP when cleared, contrary to the in game representation.

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16 hours ago, Sgt_Joch said:

Spit IX in combat at 2850 rpm/+12 boost

 

This might as well be Continuous for the Spit IX because you get 1hr of engine life and 1hr of fuel at this setting. Flying any lower is pointless.

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35 minutes ago, Talon_ said:

 

This might as well be Continuous for the Spit IX because you get 1hr of engine life and 1hr of fuel at this setting. Flying any lower is pointless.

There is: to save fuel! Think of your carbon footprint

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3 hours ago, =EXPEND=SchwarzeDreizehn said:

Z

 

No we don’t. 109s had no restriction on WEP when cleared, contrary to the in game representation. 

 

You mean that e.g. the F-4 could go 1.42 ATA forever?

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5 minutes ago, ethelward said:

 

You mean that e.g. the F-4 could go 1.42 ATA forever?

 

No, nothing goes forever.

The manuals do not have a restriction for 1.42 ATA. That’s what I said. 1.31 and above is 30 min. That includes 1.42. But no restriction on 1.42

Edited by =EXPEND=SchwarzeDreizehn
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16 hours ago, Sgt_Joch said:

 

Agreed, but that is what the "emergency power" is for, namely you fly the Spit IX in combat at 2850 rpm/+12 boost. If you are caught in a jam, you have 3000 rpm/+18 boost for 5 minutes to get you out of it.

 

It is not fly in combat at 3000 rpm/+18 boost, after 5 mins you realize you are in trouble and then fly an unlimited time at that setting.

 

That quote is not a license to blindly disregard operating limits. Other paragraphs in the same chapter make it clear that disregarding the limits can result in "immediate breakdown" of the engine or "severe damage" from overheating, so yes the pilot has the discretion of disregarding the instructions, but runs the risk of blowing the engine. It is not an invention of the devs.

No not license to blindly disregard, because the pilot is the trained, knowledgeable and responsible captain of his aircraft, against the backdrop of a desperate world war scenario.  But remember, breakdown or damage is not a definite given in real life if max setting are used over a time limit,  in fact it is stated in official publications as a might, a may be, a possibility, not a guarantee.  The 5 minute combat limit is an attempt at some kind of insurance.  

The efforts by the manufacturer to continually destructive test engines and components to achieve longevity under such extreme conditions is not for nothing, it is also a kind of insurance.  Being aware that an engine is so very reliable under testing to extremes well over and above stated limits for operational use is good information for pilot decision making in desperate combat.  I am not suggesting that something like a 5 minute combat setting should be totally or blindly ignored, but by the same token, I am suggesting that the real life proved and documented longevity of an engine under extreme conditions, well over stated time limits, should not be ignored either.  

I would also draw attention to the real life very ambiguous nature of the 5 minute combat setting limit.  It is totally ambiguous because the 5 minutes is not put into context at all.  For example, is it 5 minutes per flight, 5 minutes in every 20 minutes, 5 minutes per day, what?  You decide, LOL.  It seems to be left up to the pilot to decide and to give the pilot maximum discretion and freedom of action.  The only official guidance that puts the British aircraft/engine 5 minute combat setting into context is officially this:

"These figures provide a general guide to the reasonable use of the engine.  In combat and emergency other considerations may justify the pilot in disregarding these restrictions." 

And remember, we know that in the Battle of Britain some RAF pilots used combat boost at any and every opportunity because it is documented as such.

Evidence, logic and common sense indicates that the British 5 minute combat setting was, in reality, an artificial construct for the best of intentions.  The reality is that the 5 minute combat limit was ambiguous in terms of the context of its application (for example, how many periods of 5 minutes and how long between uses) and was officially sanctioned as something that could be disregarded in combat.  It clearly gives the widest possible leeway for interpretation by the pilot so as not to overly restrict local command and control.  When considered against the backdrop of a world war and hundreds of hours of documented beyond combat limit physical endurance testing of, for example the Merlin 66, I submit that the pilot of a Spitfire Mk IX would be justified in having the utmost confidence in pushing well beyond 5 minutes when need be.

 

Happy landings,

 

Talisman 

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