Tips flying P-47

[Legioneod]

2 hours ago, ZachariasX said:

Indeed. I checked and the supercharger will not give more than ~48 inches. It also seem sto maintain that to critical altitude, suggesting another boost refinement over previos blocks of the P-47. AFAIK the -22, -23 (and how it is modelled in other sims) blocks let you go all the way up to ~62 inches in the superchager alone *at sea level*.

 

The P-47 took a rather remarkable improvement of the systems over time, eventually (P-47 M) they even merged turbo and throttle lever, such as it is in the P-38.

 

Edit: This P-47 training manual explains some more and also shows how in the late models safeguards are put in place to prevent the pilot form destrying his engine.

Sure about the M having merged throttle and turbo? I've never read anything about that happening. Seems odd that they'd have in on the M and not introduce it to the N as well.

[ZachariasX]

4 minutes ago, Legioneod said:

Sure about the M having merged throttle and turbo? I've never read anything about that happening. Seems odd that they'd have in on the M and not introduce it to the N as well.

 

It says so in that training manual:

Spoiler

 

From P-47N-25 on they supposedly had a single lever. Never seen it in any cockpit photo though.

[Legioneod]

1 minute ago, ZachariasX said:

 

It says so in that training manual:

  Hide contents

 

From P-47N-25 on they supposedly had a single lever. Never seen it in any cockpit photo though.

Interesting. Only one P-47M exist and I'm not sure what throttle it has but if they did have one throttle I'd think it would have been implemented on the N much sooner than the N-25.

Interesting none the less. It's a real shame that so few aircraft are left, there's alot we don't know imo.

[Praetor]

Wait...so do you guys link your RPM and throttle?  I thought it best to be around 2700 RPM all the time and adjust manifold as necessary.  

[Garven]

Just now, Praetor said:

Wait...so do you guys link your RPM and throttle?  I thought it best to be around 2700 RPM all the time and adjust manifold as necessary.  

I'll unlink it and drop RPM down to 2550 to get a little extra speed when in flying in a straight line.  2700 is best for climbing and accelerating.  I'll have to try leaving RPM unlinked in combat; right now I've been leaving everything linked when in combat.  

[Praetor]

3 minutes ago, Garven_Dreis said:

I'll unlink it and drop RPM down to 2550 to get a little extra speed when in flying in a straight line.  2700 is best for climbing and accelerating.  I'll have to try leaving RPM unlinked in combat; right now I've been leaving everything linked when in combat.  

Do you touch mixture at all?

[Garven]

Just now, Praetor said:

Do you touch mixture at all?

No, unless it is to save fuel by leaning it out, or go full rich when engine is damaged.

[ZachariasX]

2 hours ago, Praetor said:

Do you touch mixture at all?

For the purpose of this game, I doubt it is required. But in real aircraft you should know that in enconomy  cruise (like 1900 rpm, 35 inches or comparable), leaning the mixture not only gives you higher endurance, ot gives you more power as well. You will increase airspeed by going to auto-lean.

[Guest deleted@83466]

3 hours ago, ZachariasX said:

For the purpose of this game, I doubt it is required. But in real aircraft you should know that in enconomy  cruise (like 1900 rpm, 35 inches or comparable), leaning the mixture not only gives you higher endurance, ot gives you more power as well. You will increase airspeed by going to auto-lean.

 

 

Are you sure about that last part?  I thought Auto Lean corresponds to best Economy, while Auto Rich corresponds to best Power?  If we had a modern fuel analyzer, isn't best power normally found at X degrees rich-of-peak EGT, and best economy would be somewhat leaner, and have a higher EGT?  Getting more power out of Auto Lean than you do out of Auto Rich doesn't sound correct to me.

Edited November 25, 2018 by SeaSerpent

[montag]

It seems some people might need definitions. Rich means you are providing more fuel than the air can react with and lean means you are providing more air than the fuel can react with.

 

With that in mind it is easy to see that running rich is best for power. When you run rich you know you have enough fuel in the engine each cycle, but it is less efficient since you aren't burning all of your fuel. Running rich is also good for starting an engine. On older cars and even on some modern ones you can smell fuel when you start the engine.

 

Running lean means you won't waste any fuel since you are always providing more air than the fuel can react with so. So if you want to save fuel run lean.

 

Finally modern cars run exactly an air to fuel mixture that burns as much fuel as air (oxygen in the air really) and this is for best emissions since catalytic converters work best that way. When controlling an engine you need to think what do I want to control for (power, economy, or emissions in the modern setting).

Edited November 25, 2018 by TheKillerSloth

[ZachariasX]

7 hours ago, SeaSerpent said:

 

 

Are you sure about that last part?  I thought Auto Lean corresponds to best Economy, while Auto Rich corresponds to best Power?  If we had a modern fuel analyzer, isn't best power normally found at X degrees rich-of-peak EGT, and best economy would be somewhat leaner, and have a higher EGT?  Getting more power out of Auto Lean than you do out of Auto Rich doesn't sound correct to me.

Best economy you ONLY get by „best power“ at given ratings. Auto-lean is closer to the stoichiometric optimum of fuel-air mixture. At that optimum, the burn will give most power for equal amount of air pumped.

 

In sum, at similar MAP indicated, leaning out the mixture (usually coming from a rich mixture) gives you more power on the prop shaft.

 

Rich mixture are for „power“ only because they allow you to pump air to a degree where lean mixture would lead to overheat.

 

Yes, I‘m sure. It is a basic fact of all gasoline engines.

 

EDIT: A short comment on EGT. When you sith in your fixed  pitch prop Cessna (like 172) and pull the mixture, progressively leaning it, then you have one gauge that measures net power. This is your rpm gauge. Now, why the EGT? You could just pull mixture until you have max. rpm. The problem is that at elevated power settings the burn is simply too hot, putting too much wear on the thermally weakened engine block.

 

The EGT gives you an idea of what is going on in your engine. You will find that a perfect mixture ratio will give you a high EGT and just conservative throttle settings will make the temperatures in your engine go in an unhealthy area. At these power settings, you have to enrich your mixture slightly to cool down the burn in your engine. As soon as you are doing that, your engine will make less power from the same aüvolume of air, something that you can compensate and even override by opening the throttle futher. Although you will not notice a small correction on the mixture. This game works until you put so much air through the engine that the amount of fuel required to cool the burn litterally floods the carburator extinguishing your burn. The idiotic „C3 injection“ is almost that. Just don‘t think you get that much more of power with the extra ata if you start flooding your engine. It is almost like just dumping fuel and for good reason this system was not widely used. The power comes at the cost of a lot of fuel.

 

For practical purposes now:

 

To be safe, on the run up with your aircraft, you lean the engine until you have max. rpm in run up configuration, then enrich it a bit to be safe for take off power.

 

The EGT now comes into play when you are climbing away and, for example you want to make some touch and go‘s at Telluride regional (KTEX) up in the mountains. You will notice the EGT droping as you are climbing. In the thin air your carb will mix rich and richer, the higher you go. But as you know from simulators, at high power settings, „rich is good!“. Well, you will keep on flying at least. Then, you will be entering the pattern at KTEX and ease your throttle in the approach. As you are coming in toward the final, you will be almost at idle and... silence. Oops! Why did the engine quit? Engines are running richer at low rpm than at high rpm with the same mixture setting. You going to idle coming from an overly rich mixture will extinguish the burn in your engine by making it even richer by throttling back.

 

Had you looked at the EGT on your way up in the mountains, you could have seen the needle drop as your mixture progressively righer in the thinner air. Think back in RoF where we always have to follow a climb with keaning out the mixture. Looking at the EGT, you can lean out the mixture such that the engine temps are again in a higher, healthy range without having to look at the tachometer to see whether the rpm increased 5% or so (wich is not easy to see at times). The EGT gives you an immediate and clear reaction. Knowing this, they will not have to remove your aircraft with a broom from in front of the runway.

Edited November 25, 2018 by ZachariasX

[Guest deleted@83466]

1 hour ago, ZachariasX said:

Best economy you ONLY get by „best power“ at given ratings. Auto-lean is closer to the stoichiometric optimum of fuel-air mixture. At that optimum, the burn will give most power for equal amount of air pumped.

 

In sum, at similar MAP indicated, leaning out the mixture (usually coming from a rich mixture) gives you more power on the prop shaft.

 

Rich mixture are for „power“ only because they allow you to pump air to a degree where lean mixture would lead to overheat.

 

Yes, I‘m sure. It is a basic fact of all gasoline engines.

 

In common aviation usage "best power" and "best economy" mixtures are -NOT- the same thing.  Best Power is going to occur at the stociometric ratio of .075 to about .080 and Best Economy is going to be around .06something.  In the case of Best Economy, we are getting the most power per unit of fuel, thus the highest efficiency, but not the most power possible at that given engine setting.

 

Now I don't know exactly how they tuned up AutoRich and AutoLean on WW2 planes, but there is no way you are going to get more horsepower on AutoLean than you do AutoRich for a given MAP/RPM combo.

 

You can see this in the sim itself.  Take up something like the P-47 or P-40 and establish a stable cruise on Auto Level to eliminate any variables.  Without touching anything else, watch what happens when you go between AutoRich and AutoLean.  You will see that your airspeed is going to slightly increase on AutoRich, and when you pull back to AutoLean, it's going to decelerate.  Take it one step further:  In the same stable cruise configuration, toggle your prop control to manual, so that it behaves like a fixed pitch prop as long as you aren't changing the blade pitch.  Watch what happens to your RPM needle as you go back and forth between AutoLean and AutoRich.  When you go from AutoLean to AutoRich, you will see the RPM almost instantly jump to something slightly higher, and vice versa...you are getting more power out of AutoRich than you are AutoLean, no doubt about it.

Edited November 25, 2018 by SeaSerpent

[ZachariasX]

4 minutes ago, SeaSerpent said:

You can see this in the sim itself.  Take up something like the P-47 or P-40 and establish a stable cruise on Auto Level to eliminate any variables. 

This sim is not that great in systems modelling. Don‘t take it as „the truth“. Systems are modelled in a simplyfied way and there‘s a reason why the sim gives you then the result you observed. But it is not exactly correct. Mixture is a chapter of this sim that could need some further love.

Edited November 25, 2018 by ZachariasX

[Guest deleted@83466]

Well, with all due respect, Zacharias, I think you are simply wrong on this.  AutoLean is not going to give you best power for a given MAP/RPM combo.  It just isn't.

[ZachariasX]

5 minutes ago, SeaSerpent said:

In common aviation usage "best power" and "best economy" mixtures are -NOT- the same thing. 

For all purposes „avation“ it would be put into the context of the range you can cover with given settings. This adds another factor besides what is going on in the engine.

3 minutes ago, SeaSerpent said:

Well, with all due respect, Zacharias, I think you are simply wrong on this.  AutoLean is not going to give you best power for a given MAP/RPM combo.  It just isn't.

Your non understanding is common. It is because the terms „rich“ and „lean“ are in fact misleading, as they are coming from practical use with engines, rather than from thermodynamic reasons.

 

A „lean“ setting is near the optimum fuel/air ratio. Downside is, although per amount of air processed, temps are elevated, permitting only conservative settings. If you want more air at the same time, you have to make your burn cooler by sacrifying some efficiency and enriching your mixture.

 

That‘s the world we are living in.

[Guest deleted@83466]

What I stated above is correct.  You said "leaning the mixture not only gives you higher endurance, ot gives you more power as well. You will increase airspeed by going to auto-lean".  That is incorrect information.  If you want best fuel efficiency for a given engine setting, you want to be in AutoLean.  If you want the best power (and best speed) for a given engine setting, you want to be in AutoRich.

Edited November 25, 2018 by SeaSerpent

[ZachariasX]

52 minutes ago, SeaSerpent said:

What I stated above is correct.  You said "leaning the mixture not only gives you higher endurance, ot gives you more power as well. You will increase airspeed by going to auto-lean".  That is incorrect information.  If you want best fuel efficiency for a given engine setting, you want to be in AutoLean.  If you want the best power (and best speed) for a given engine setting, you want to be in AutoRich.

You‘re making assumptions here.

 

You get the highes efficiency from your burn at the stoichiometric ratio. Any departure from this ratio will give you less burn/less power for the same amount of air.

 

Also: Any fuel in addition to your stoichiometric ratio will leave the engine unburnt. I hope you do understand that fuel that doesn‘t burn cannot give you power.

 

Just stop thinking of your throttle lever as well when trying to understand fuel efficiency. That efficiency happens when you only operate mixture and you do not touch throttle.

 

That it may be required to enrich the mixture for cooling purposes at higher ratings to enable that rating in the first place has nothing to do with that.

 

Just sit in an aircraft and lean out the mixture. You will see that rpm increases by leaning the mixture from rich to lean. This extra rpm mean higher speed.

 

Edit: „The power of an internal combustion engine ONLY is dependent on the amount of air it pumps over time.“ This is all you have to know. The entire rest is just there to make it happen.

Edited November 25, 2018 by ZachariasX

[LeLv76_Erkki]

Everyone can open up the game and come to the conclusion that lean mix provides slower speeds than rich. If theres air that doesnt get used in combustion it means theres potential unused too. Lean is more fuel efficient (per mile and per unit power output) but one cant handwave efficiency and absolute power output to be the same thing because they're not.

 

Now which setting is closer to optimum stoichiometric ratio in game, and should we care about that at all? I cant tell. How about in the real plane? Cant tell that one either. All I know is I use lean to save fuel when cruising and rich in most other situations, and I've already made a quick test to come to the conclusion that yes it works, lean consumed slightly less fuel when cruising at speed v at altitude h(that was fairly low in my test).

 

edit: since this is the tips & tricks thread I should write the results!

 

40", 2500 RPM, linked turbo and throttle, 0 % outlet, 0 % oil, 2000m using AUTO RICH resulted in 273 mph indicated and consumed about 105 gallons in 30 minutes

43", 2500 RPM, linked turbo and throttle, 0 % outlet, 0 % oil, 2000 m using AUTO LEAN resulted in 275 mph indicated and consumed about 85 gallons in 30 minutes

 

44", 2550 RPM, 285 mph IAS, AUTO RICH, 220 gallons in 60 minutes

47", 2550 PRM, 286 mph IAS, AUTO LEAN, 190 gallons in 60 minutes

 

At tested settings and chosen speed Auto Rich consumes clearly more fuel. You save the more the lower cruising speed you choose, but even at the limit of continuous power manifold pressure the savings are clear 15%+

Edited November 25, 2018 by LeLv76_Erkki
added fuel consumption tests

[Guest deleted@83466]

9 hours ago, ZachariasX said:

You‘re making assumptions here.

<snip>

 This is all you have to know. The entire rest is just there to make it happen.

 [Edited]

Best power mixture and Best economy mixture (max power to units of fuel) are well known concepts in aviation when talking about mixture.  People can google these things for a good explanation of how they differ.  They are not the same thing, and they don't occur at the same stochiometric ratio.  That's the bottom line.

 

Setting mixtures in a plane like the P-47 need not be complicated.  In practice, it comes down to being as simple as Auto Rich for takeoff, climb, combat, landing, or any other time best power is needed.  Economy cruise you want to be in Auto Lean.  The manual for the P-47 says that economical maximum cruise in AutoLean is 32" 2250 RPM for 100 octane.  If you want to cruise above that, you really should be in Auto Rich, and continuous high speed cruise is 42" 2550 at Auto Rich.  42" 2550 is also recommended Climb setting.  I don't think the game's current engine model simulates certain things about an engine, so there is likely a lot of wiggle room for being in Auto Lean at higher MP settings without consequence...i.e, in Erkki's test runs above, you wouldn't want to be in Auto Lean at those power settings in real life. 

 

 

Edited November 25, 2018 by SYN_Haashashin
Way to personal. Respect other members

[Ehret]

Worth seeing:

 

You can lose up to the 300hp in the P-47 if you mismanage the throttle quadrant.

[ZachariasX]

You didn‘t read what I was saying. Of course you get more power when moving the throttle lever forward. That is why they put one in the cockpit.

 

All I‘m saying is this: In the situation you mention here

 

At 32‘‘ MAP and 2250 rpm, moving the mixture to lean will give you a tad more power than moving it to rich.

 

 

3 hours ago, SeaSerpent said:

They are not the same thing, and they don't occur at the same stochiometric ratio.  That's the bottom line.

The bottom line is that there is only one stoichiometric ratio unless you fly in a different athmosphere or use a different fuel.

 

Deviation from this cost you efficiency and you do that only because they enable you to pump way more air through your engine and burn that, drastically increasing your net power output.

Edited November 25, 2018 by ZachariasX

[Tapi]

1 hour ago, Ehret said:

You can lose up to the 300hp in the P-47 if you mismanage the throttle quadrant.

 

 

Yes, but (if I understand it correctly) only if you connect throttle and turbo levers together below cca 12 000 ft, ie. below the height where the turbo starts to help to maintain MP. Below that height, to drive the impeller cost your engine 300 hp but turbo doesn't contribute substantially to MP.

[Ehret]

Just now, Tapi said:

Yes, but (if I understand it correctly) only if you connect throttle and turbo levers together below cca 12 000 ft, ie. below the height where the turbo starts to help to maintain MP. Below that height, to drive the impeller cost your engine 300 hp but turbo doesn't contribute substantially to MP.

 

It's unclear about what P-47 version or type of fuel (probably the 91 octane used for training) the video was about but in the sim the turbo adds a significant boost even at the deck. Without the turbo you will get 49" max; move the turbo-lever forward and the MP will increase to 55" without even water-injection. With the latter on the turbo will spin up and deliver MP of around 67".

 

From my experience it's beneficial to open the throttle 100% and use the turbo boost lever as the sole control of MP. It will lag but performance gain will vary from slight to significant.

Edited November 25, 2018 by Ehret

[Guest deleted@83466]

38 minutes ago, ZachariasX said:

You didn‘t read what I was saying. Of course you get more power when moving the throttle lever forward. That is why they put one in the cockpit.

 

All I‘m saying is this: In the situation you mention here

 

At 32‘‘ MAP and 2250 rpm, moving the mixture to lean will give you a tad more power than moving it to rich.

 

 

The bottom line is that there is only one stoichimetric ratio unless you fly in a different athmosphere or use a different fuel.

 

Deviation from this cost you efficiency and you do that only because they enable you to pump way more air through your engine and burn that, drastically increasing your net power output.

 

I didn't say anything about moving the throttle.  I said that leaving all other things the same and moving the mixture lever from AUTO LEAN to AUTO RICH will give you more power.  It will.

 

Whatever.  I stand by what I said regarding the concepts of best power/best economy.   Maybe you're arguing something different altogether, because you refuse to address this concept, or acknowledge it's existence, despite it being in just about every explanantion of proper mixture setting that you can find in any resource on the subject.

 

"At 32‘‘ MAP and 2250 rpm, moving the mixture to lean will give you a tad more power than moving it to rich."  

 

Sure, if you're at FULL RICH or 100% mixture, then it will.  But going from AUTO RICH to AUTO LEAN, you are going to see a less power.   But forget about AUTO This and That.  Again, on a fixed pitch propeller, you can see that 'best power' occurs at the point where RPM peaks, and almost certainly going to be rich of peak EGT and NOT at the lowest specific fuel consumption or best fuel efficiency.  CHT will probably be close to it's maximum at this point.  Lowest specific fuel consumption will occur at peak or slightly south of it....you aren't getting best power there, but you are more fuel efficient in terms of power per unit of fuel consumed.  You continue to insist that these points are the same stochiometrically speaking, but they are not.

 

This is fruitless for me to continue this discussion.  What I'm saying is true, and you simply won't acknowledge the concept, so what's the point.  Like I said, people can do their own homework on this subject.

 

 

Edited November 25, 2018 by SeaSerpent

[ZachariasX]

6 minutes ago, Ehret said:

Without the turbo you will get 49" max; move the turbo-lever forward and the MP will increase to 55" without even water-injection. With the latter on the turbo will spin up and deliver MP of around 67".

This is what puzzeled me. I expected to supercharger alone to deliver 67 inches. It does also so in the A2A version of the P-47 for FSX. Then again, that is for blocks 22 and 23.

 

I cannot find any info on the supercharger compression ratio amongst those blocks of the P-47. Anyone has such info?

 

 

 

2 minutes ago, SeaSerpent said:

I said that leaving all other things the same and moving the mixture lever from AUTO LEAN to AUTO RICH will give you more power.  It will.

And with that you have it exactly the wrong way around.

 

 

Edit: Darn automerge.

Edited November 25, 2018 by ZachariasX

[Tapi]

15 minutes ago, Ehret said:

 

It's unclear about what P-47 version or type of fuel (probably the 91 octane used for training) the video was about but in the sim the turbo adds a significant boost even at the deck. Without the turbo you will get 49" max; move the turbo-lever forward and the MP will increase to 55" without even water-injection. With the latter on the turbo will spin up and deliver MP of around 67".

 

You are right, this is how it works in the sim. But the more I study the subject the more I think it is wrong and up to cca 12 000 ft there should be no considerable increase of MP with the turbo.

But to be fair, on the other hand, Greg in one of his P-47 vid mention that one of four pilots who take off P-47 from the aircraft carrier decided to use turbo. Question is why...

 

EDIT: or maybe IRL the turbo below the height of 12000 ft adds to MP (so it increase MP above max possible limit with the throttle only). But then it has to have some undesirable side effects with higher temperatures etc. and probably it was not usually allowed at least for longer times...

Edited November 25, 2018 by Tapi

[Bilbo_Baggins]

32 minutes ago, Tapi said:

 

Yes, but (if I understand it correctly) only if you connect throttle and turbo levers together below cca 12 000 ft, ie. below the height where the turbo starts to help to maintain MP. Below that height, to drive the impeller cost your engine 300 hp but turbo doesn't contribute substantially to MP.

 

You can not achieve maximum power and 557kmh maximum speed at SL without the turbo on 100%. Turbo is absolutely needed for maximum output below 12 000 ft. 

 

RGDS

[Guest deleted@83466]

15 minutes ago, ZachariasX said:

Quote

I said that leaving all other things the same and moving the mixture lever from AUTO LEAN to AUTO RICH will give you more power.  It will.

And with that you have it exactly the wrong way around.

 

 

 

 

Well, like I said, whatever...you refuse to acknowledge the concepts I've brought forth even exist, or give them any merit, and when I've pointed out that the engine in our P-47 clearly develops more power at AUTO RICH than it does in AUTO LEAN, in the situation where all other parameters are left equal, you then simply brush it away by declaring that the devlopers must have gotten it wrong....(you know the ones who even recently just went so far as to model exhaust smoke as a function of specific fuel consumption).   So, you're just going to think what you're going to think.

 

Correction:  I actually used a P-40 for the test case, not a P-47, but same concept.

Edited November 25, 2018 by SeaSerpent

[Tapi]

4 minutes ago, Bilbo_Baggins said:

 

You can not achieve maximum power and 557kmh maximum speed at SL without the turbo on 100%. Turbo is absolutely needed for maximum output below 12 000 ft. 

 

RGDS

 

I agree, this is how it works in the sim and maybe it is the same IRL (we should assume the dev know what they do). I am only trying to understand the mechanics behind that... So maybe Greg in his vid is not right about that 300 hp loss? Or it was meant in some other way? I would like to understand...

[ZachariasX]

5 minutes ago, SeaSerpent said:

I've pointed out that the engine in our P-47 clearly develops more power at AUTO RICH than it does in AUTO LEAN

This simulator is not the real world. Just beacuse things are as they are here, doesn't mean they are exactly such in real life. Look, I can fly the Spitfire at 60% mixture, not producing smoke trails at max throttle and still be fast without  the engine overheating in the least. So I can do something that is impossible and even when doing so i don't suffer the consequences I should feel if I could do that at all. Hey, this is a sim.

 

Yes, in the sim, things might very well be as you say. And I do believe you when you make your claim regarding the sim, not having tested myself in detail.

 

And no, in the real world, that is not how it works. I explained to you how it works in the real world.

 

Fuel flow and mixture could require some more love in this sim. But since nobody cares about such and everyone is just about dakka dakka, it is also not first priority.

[Atomic_Spaniel]

Having played with our game-P-47, I can't actually find a reason not to have the turbo either linked or fully forward at 100% all the time. At high altitude it overspeeds, but I've not yet had any damage from that. All a bit disappointing - I was hoping to have a lot of engine management rather than a lever I just stick forward at the start of a flight.

 

Has anyone found a reason in-game to vary the turbo lever much?

 

EDIT - if I run the turbo over-speeding at 10 km for 15 mins, the engine does take damage.

Edited November 25, 2018 by NickM

[Guest deleted@83466]

34 minutes ago, ZachariasX said:

This simulator is not the real world. Just beacuse things are as they are here, doesn't mean they are exactly such in real life. Look, I can fly the Spitfire at 60% mixture, not producing smoke trails at max throttle and still be fast without  the engine overheating in the least. So I can do something that is impossible and even when doing so i don't suffer the consequences I should feel if I could do that at all. Hey, this is a sim.

 

Yes, in the sim, things might very well be as you say. And I do believe you when you make your claim regarding the sim, not having tested myself in detail.

 

And no, in the real world, that is not how it works. I explained to you how it works in the real world.

 

Fuel flow and mixture could require some more love in this sim. But since nobody cares about such and everyone is just about dakka dakka, it is also not first priority.

 

 

So to recap, according to you:  'Best Power'/'Best Economy' mixture settings are a fantasy that isn't even worth acknowledging exists;  I'm wrong;  Developers got Auto Rich/Auto Lean all wrong; and I guess all the countless CFIs who have written Mixture 101 style articles backing up what I've said are wrong too.  So everyone is wrong but you....Okay?.  DakkaDakkaDakka then.

Edited November 25, 2018 by SeaSerpent

[183_IAP_Baranov]

Is anyone adjusting their prop RPM to increase speed ?  At 48 inches, I adjust my prop RPM to maintain something like 2680 RPM's and I can cruise at under 300 mph.   Close them cowl flaps as well.  Some refinement is needed when experimenting.  

[LeLv76_Erkki]

22 minutes ago, 392FS_Collins said:

Is anyone adjusting their prop RPM to increase speed ?  At 48 inches, I adjust my prop RPM to maintain something like 2680 RPM's and I can cruise at under 300 mph.   Close them cowl flaps as well.  Some refinement is needed when experimenting.  

 

Yeh you can pretty much keep cowl flaps completely closed at altitudes of under 20 kft or so, even when climbing.

[ZachariasX]

30 minutes ago, SeaSerpent said:

'Best Power'/'Best Economy' mixture settings are a fantasy that isn't even worth acknowledging exists; 

I never touched any of that at all.

 

"Best power" is a result of the possibility by burning more air, using a less efficient, overly rich and "cooler" mixture. That will be a net higher power output. But that "best power" implies that you walk the throttle forward to get more power, beyond what is permissible with a "hot" lean mixture. Did i make myself clear now?

 

The "lean mixture" is the better mixture, however as it runs hotter, it will generate cooling issues much sooner than what the engine otherwise could absorb. Enriching the mixture to allow to burn more air (read: move throttle forward) requires additional cooling of your burn. You do that by making the burn slower and slightly less efficient, by enrichting the mixture a tad (or a lot) above chemically optimal proportions. Then, you MUST use "Auto rich". Auto rich is like an additional cooler that also creates some drag.

 

Have you ever played with the mixture setting of a real, running engine?

[Guest deleted@83466]

2 hours ago, ZachariasX said:

I never touched any of that at all.

 

"Best power" is a result of the possibility by burning more air, using a less efficient, overly rich and "cooler" mixture. That will be a net higher power output. But that "best power" implies that you walk the throttle forward to get more power, beyond what is permissible with a "hot" lean mixture. Did i make myself clear now?

 

The "lean mixture" is the better mixture, however as it runs hotter, it will generate cooling issues much sooner than what the engine otherwise could absorb. Enriching the mixture to allow to burn more air (read: move throttle forward) requires additional cooling of your burn. You do that by making the burn slower and slightly less efficient, by enrichting the mixture a tad (or a lot) above chemically optimal proportions. Then, you MUST use "Auto rich". Auto rich is like an additional cooler that also creates some drag.

 

Have you ever played with the mixture setting of a real, running engine?

 

You "never touched any of it" because it would have forced you to acknowledge that I was absolutely correct when I said "Best Power" mixture will result in more horsepower and occurs at at a richer mixture (let's say a F/A ratio of about 0.075) that does not coincide with lowest possible consumption of fuel per horsepower obtained (best economy, let's say probably around F/A 0.065 ballpark, or whatever it is).   And yes, I mean for a given throttle setting, like say when you are maxxed out at 27" in your Cessna, and your throttle isn't going anywhere.

 

And no, I've never set the mixture of a real, running engine.  I'm only a flight simmer, but I sure as heck know that if I've set my power and I'm leaning it, that peak RPM (fixed prop) or peak torque is going to be richer than the mixture for best economy at the same RPM/MAP, and I'm not wrong about that.  And yes, I do understand that if going for best economy power and you see your RPM drop off by x revs as you leaned it, that you would just walk it back forward, provided you weren't already maxxed out....but I'm still saying that if throttle remains fixed, that you are going to get more power from a slightly rich of peak egt mixture than one at peak or slightly leaner than peak.  Leaning it back until your engine coughs and then just a hair forward until it is smooth again is close to best economy, but if you want peak RPM, best power, you'll have to enrich it a little further still.  I stand by that, because I feel I'm firmly backed up on that by just about anything you can google regarding mixture setting theory.

 

Bottom line, is that you can set your mixture however you want in your real plane, and in your sim, and if you think that the behavior of Auto Lean and Auto Rich in this sim is incorrect, you're welcome to think that, or make a bug report, or whatever.  Now I'm done with this, and if you feel you need the last word, that's fine, I really don't much care.

Edited November 25, 2018 by SeaSerpent

[montag]

Zacharias is wrong. Anyone with a PPL or engineering backround would know this or even most mechanics.

Edited November 25, 2018 by TheKillerSloth

[ZachariasX]

8 hours ago, TheKillerSloth said:

Zacharias is wrong. Anyone with a PPL or engineering backround would know this or even most mechanics.

And you have those? Or are you a mechanic?

 

What is lean mixture to you? What is rich mixture?

 

You make your argment probably looking from the "official" lamda curve showing mixture vs power, such as this:

Oh, boy, you are right. I am so wrong. Am I?

 

What kind of engine do we have? Is it just a well dimensioned motor built to last forever, or is it actually a high performance racer item? The former and the latter differ in the way they set the mixture over trottle settings. The higher performance engine will enrich sooner. In case of the (early) Merlin engines, mixture automation will exceed the "Maximum power" at about 68% throttle setting in "Auto Rich" (and further increase from there considerably). Above the "best/maximum power" (about 8% fuel/air mixture ratio) this is what you call a rich-rich mixture. Now the "Auto-lean" will follow that mixture curve. It is essentially a very same mixture curve just shifted downwards (but converging towards maximum power), making it crossing the "Best Power" point at 8% fuel/air mixture at about 70% power output (where "auto rich" is already at 9% fuel/air mixture).

 

And around 70% power output is where you have your throttle lever for most flight regimes if you really want to go somehwere. (Especially flight simmers.) And this is why, depending on how far forward you are with your throttle lever (>40'' MAP is well forward) Auto lean produces more power. It is closer to the "maximum power" point on the graph above that "auto rich". But at that power, you will be reluctant to go on "auto lean", because your engine might run hot.

 

Water injection bypasses the inefficient rich-rich mixture by providing the additional cooling in the form of water.

 

It is important that one is aware that "Auto mixture" varies fuel/air mixture ratio over the different throttle settings. It doesn't just mix stoically according to he chart above.

Edited November 26, 2018 by ZachariasX
Clarification

[Legioneod]

16 hours ago, NickM said:

Having played with our game-P-47, I can't actually find a reason not to have the turbo either linked or fully forward at 100% all the time. At high altitude it overspeeds, but I've not yet had any damage from that. All a bit disappointing - I was hoping to have a lot of engine management rather than a lever I just stick forward at the start of a flight.

 

Has anyone found a reason in-game to vary the turbo lever much?

 

EDIT - if I run the turbo over-speeding at 10 km for 15 mins, the engine does take damage.

 

Turbo damage model is simplified at the moment so there's no ill effects from keeping it full forward all the time. In reality this would cause many problems but unfortunately we don't see this in-game.

[Dutchvdm]

Hi Guys,

 

I'm having a great time with the Jug. I think it might become my favorite aircraft. One thing that kept me wondering though, was the range. The ingame notes state it has 2,4 hours flight time at 350 kph/3000m. Converting that to TAS and actual range, it gives me roughly between 950 and 1000 km's. Sources on the net differ very much, with some some giving 600 miles as combat radius and other 1000 miles at cruising speed. What was considered cruising speed and do you guys think the current range is somewhat realistic?

 

Grt M