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Posted (edited)
19 hours ago, Rekt said:

 

Maybe so...all I'm trying to say here is that the FW190 and La-5, in my limited experience, have some capacity for turning and vertical maneuvers in close combat and a reasonable ability to recoup lost energy in mid-fight. The P-39/40/47 are just pigs by comparison. Yes the 39/40 can participate successfully in an angles fight for a little while but have such a limited ability to recover energy that using their turn superiority against the Germans, effectively all they have going for them in the first place besides dive speed, is asking for trouble. Except for 5 minutes of WEP the P-47 can't really turn, climb or accelerate (except downhill of course) compared to axis or Soviet peers, so hammering people and bolting, pun intended, is all there is. After flying something like the FW-190A3 or even the lowly 109G2 all of the American fighters that we currently have are just a bad joke.

In a way, flying the US planes is the same as in 109/190 against yaks/spitfires.

Flying the 109 against a yak, one can`t just resort to sustained climb or sustained turn because the yak is similar in sus. climb and better in sus. turn. One can joust with it for a limited time until he finds himself in yak`s performance envelope. That is the moment to bug off and reset - with a dive and/or speed advantage to gain separation and enter own performance envelope.

 

While flying the P40/P39 my experience is that this general rule works well until combat power runs out. Then the 109s has substantial performance advantage accross the board by running longer combat power, let alone emergency power when it pretty much turns into a jet. It is a problem since by that time any comparisons are worthless, you have to find help or run and hide. Knowing that I did have much success flying the birds, though never as big as when I maintained discipline while flying the 109/190.

 

In the Mustang I expect to do the same - dogfight the 109 for a moment or two and should disable him with .50cal. If not, zoom or dive away and reset the engagement situation since I should have again energy advantage if I do it correctly.

11 hours ago, -=PHX=-SuperEtendard said:


With the intercooler I always found the best speed was leaving it at the 50% neutral position, and usually that is cool enough to not cause trouble.

For example in the 10km scenario discussed earlier, the top speed of the P-47 with 22000 RPM turbo, full throttle, full RPM, water injection, giving 46" is 375 km/h indicated. This is with 50% intercooler at 0ºC carb air temperature.

If I close the intercooler to 17% to enter the yellow region (slightly less than 40ºC carb air temp) without adjusting anything else, the turbo speed increases to 23000 RPM, manifold pressure drops to 44.5" and speed decreases to 347 km/h IAS.

Never have to worry bout such things when flying 109/190s.

Edited by Mac_Messer
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16 hours ago, -=PHX=-SuperEtendard said:


Uploaded both tracks to YT ^^
 

 


I used full RPM, throttle, turbo and water injection. Since at 10km manifold pressure is down to 47" or so it's considered combat mode and with water injecton it lasts a long time, you will run out of water before getting engine damage. I was overspeeding the turbo, I think at around 25000 RPM, and this can be done for 15 min so no problems there either. If you want to stick to the 22000 RPM limit the turbo needs to be set to 65% at 10 km altitude with full throttle and RPM, you will lose a couple inches of manifold pressure though. Engine shutters were at 10%, oil radiator 20%, intercooler 50%.


I'm going to try this against a D9 when I get home.

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1 hour ago, Rekt said:

 

Good luck m8. I tried again against the Yak using these tips and was still not really able to take him out. There definitely is a substantial skill component.


I flew against a G-14 at around 7km and my only issue was the 5 minute limit on the engine.

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Posted (edited)
7 hours ago, ZachariasX said:

Why? It just leans the mixture that is otherwise up at about 10% and brings it back down to maybe 8% (best power) by adding an alternative heat sink. Besides, the colder your carb air, the more power you have as it contains more oxygen at the same MAP.

 

By keeping carb temp in the yellow range, you just make sure you‘re using the turbocharger to the maximum. 

OK, I don't fly the P-47 at that Altitude a lot. Low down (25000ft and less) you definetly want to keep the Turbo RPM low and the Intercooler Temps up.

Above the 64" Critical Altitude the Water Injection just kills Power Full Stop. So if you can't make at least 64" anymore, just run it on normal Auto Rich and Full Turbo and Throttle.

Edited by 6./ZG26_Klaus_Mann

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Posted (edited)
35 minutes ago, 6./ZG26_Klaus_Mann said:

OK, I don't fly the P-47 at that Altitude a lot. Low down (25000ft and less) you definetly want to keep the Turbo RPM low and the Intercooler Temps up.

Above the 64" Critical Altitude the Water Injection just kills Power Full Stop. So if you can't make at least 64" anymore, just run it on normal Auto Rich and Full Turbo and Throttle.

 

Care to explain that a little? Is there a guide written anywhere that explains what the optimal engine settings are at various altitudes for the P-47? I tend to keep the turbo at max even down low, as this is the only way to get max manifold pressure (with water injection on). If I've been doing something wrong, I'd appreciate more details. :)

Edited by 71st_AH_Yankee_
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Posted (edited)
41 minutes ago, 6./ZG26_Klaus_Mann said:

OK, I don't fly the P-47 at that Altitude a lot. Low down (25000ft and less) you definetly want to keep the Turbo RPM low and the Intercooler Temps up.

Above the 64" Critical Altitude the Water Injection just kills Power Full Stop. So if you can't make at least 64" anymore, just run it on normal Auto Rich and Full Turbo and Throttle.


Activating water injection makes the engine reach higher manifold pressures, even above critical altitude... at 10km with water injection manifold pressure is 46", without it the normal max is just 36", and the performance difference is huge.

You should test how the plane behaves in the game. Maybe it's wrong since I don't know much about how these engines should work, but those are the results I get by testing it in game.

Edited by -=PHX=-SuperEtendard
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1 hour ago, 6./ZG26_Klaus_Mann said:

Low down (25000ft and less) you definetly want to keep the Turbo RPM low and the Intercooler Temps up.

Absolutely. The supercharger (hard liked to the shaft) will otherwise eat up to about 300 hp. Only after opening throttle fully, you get best efficiency of your engine. The supercharger cannot compensate for this bleed of shaft power and what happens is what you describe.

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Are you guys describing how the real P47 works, or the in game P47?  I have a suspicion that there is a pretty big gulf between how the real Thunderbolt engine works and what we have in game.

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1 hour ago, BlitzPig_EL said:

Are you guys describing how the real P47 works, or the in game P47?  I have a suspicion that there is a pretty big gulf between how the real Thunderbolt engine works and what we have in game.

I‘m talking about how the real thing works in principle. What you actually can or cannot do depends on the type of P-47. But as I understood it, Klaus talks about the thing we have in the game. For best power in the game, he is right.

 

Not everything about the supercharger is modeled in the game. The only reason you have for instance to increase the supercharger before maxing out the throttle is if you want to increase carb air temp to avoid icing. It is really a neat feature, but in the game we don‘t have icing at all. 

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Posted (edited)

You want CAT as low as possible (or just above the icing point which isn't modelled). I have no idea where this idea they have to be in the orange zone for WEP. The limit is increased when the engine is running at WEP same how the Cylinder head temperature limit is increased, the engine doesn't become more efficient running at a higher CAT. Higher intake temperature > lower power, simple.

And playing with the turbo vs just having it locked together with the frontal doesn't change the performance that much. 1-2 mph at most. Turbo and throttle shouldn't be fighting each other anyway, according to the manual

Edited by =362nd_FS=RoflSeal
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3 hours ago, =362nd_FS=RoflSeal said:

You want CAT as low as possible (or just above the icing point which isn't modelled). I have no idea where this idea they have to be in the orange zone for WEP. The limit is increased when the engine is running at WEP same how the Cylinder head temperature limit is increased, the engine doesn't become more efficient running at a higher CAT. Higher intake temperature > lower power, simple.

And playing with the turbo vs just having it locked together with the frontal doesn't change the performance that much. 1-2 mph at most. Turbo and throttle shouldn't be fighting each other anyway, according to the manual

Keeping them locked together is less efficient though as you do lose/waste horsepower. Also turbo and throttle do conflict with each other when operated in the wrong order/way (not modeled in-game though)

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4 hours ago, ZachariasX said:

It is really a neat feature, but in the game we don‘t have icing at all

 

Damn, that is true. However as far as I understand it, carburator icing is more of a hot-weather occurance, isn't it? I mean, simulating it would only give us amother degree of complexity about something that would never happen in the geographic station we are flying in. Or am I wrong?

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6 hours ago, =362nd_FS=RoflSeal said:

You want CAT as low as possible (or just above the icing point which isn't modelled). I have no idea where this idea they have to be in the orange zone for WEP. The limit is increased when the engine is running at WEP same how the Cylinder head temperature limit is increased, the engine doesn't become more efficient running at a higher CAT. Higher intake temperature > lower power, simple.

And playing with the turbo vs just having it locked together with the frontal doesn't change the performance that much. 1-2 mph at most. Turbo and throttle shouldn't be fighting each other anyway, according to the manual

Having your intake air temp as low as possible was always what I was taught back in the days when I was interested in forced induction pertaining to auto's. Think it would translate right on over to airplanes as well, colder air is more dense, more dense means more power...

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7 hours ago, danielprates said:

 

Damn, that is true. However as far as I understand it, carburator icing is more of a hot-weather occurance, isn't it? I mean, simulating it would only give us amother degree of complexity about something that would never happen in the geographic station we are flying in. Or am I wrong?

Take this for reference:

carb_ice.gif

 

You see, unless you are flying in very, very dry conditions, carb icing can be an issue when you are throttling back. This is why even some P-40 have a carb heater. You‘re especially at risk when throttling back for landing. Not using the carb heater then can in result in no (or little) power increase when you move throttle forward again (until the ice is gone). With the supercharger, you can up the temperature just that little bit to stay safe. Carb heater „on“ will take a lot of power due to the heated manifold air. Injector engines of course don‘t have that issue. But you can still freeze the pitot.

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I used to see it somewhat frequently in older carburetor equipped cars that for whatever reason had their air cleaner/carb heater hose disconnected, especially on horizontally opposed engines that have the carb mounted high above the engine (VW type 1, older Subaru models) on high humidity days, which are very common in my area in the summer.

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23 hours ago, 71st_AH_Yankee_ said:

 

Care to explain that a little? Is there a guide written anywhere that explains what the optimal engine settings are at various altitudes for the P-47? I tend to keep the turbo at max even down low, as this is the only way to get max manifold pressure (with water injection on). If I've been doing something wrong, I'd appreciate more details. :)

Water Injection is a Bitch essentially.

 

The whole Idea behind Water Injection is to cool down the Air between Supercharger and Combustion Chamber. What is supposed to happen is that the Liquid Water absorbs the Heat from the hot intake Air and beomes Water in the Gaseous State (not condensed Water Vapour).

There is a lot of Energy in the Change of the Aggregate Phase of Water (or Petrol, though less).

 

This does however require that the Intake Air is hot enough to fully Gasify the Injected Water, otherwise the Water Droplets in the Intake will cause Issues with extreme Soot Fouling and Flame Extinguishing, and the Engine will Act like your Headgasket (in a Watercooled Car) has gone to Shit.

 

Petrol also pulls a lot of Heat out of the Intake Air, the fatter the Mixture, the Colder the intake Air, however, if you decrease the intake Temperature, you get the same Problem as with the Water, and that is that the Petrol doesn't fully Gasify, which causes Shitty Burn and Soot Fouling.

However, since Petrol is more easily Gasified and since Fuel Delivery to the Cylinder is less critical than Air, some unburnt Fuel isn't all that bad for Performance, if it means you can cram more Air in.

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So bringing the subject back around to the P-51, how does the Mustang handle it? you can’t use carb heat above 12,000 and you’re supposed to use the ram intake at all times unless in a really dusty environment. At a typical combat altitude of 25,000 feet you could get carb intake temps of -30 or less. Does the rarified atmosphere help vaporise the fuel despite the temperature?

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9 minutes ago, AndytotheD said:

So bringing the subject back around to the P-51, how does the Mustang handle it? you can’t use carb heat above 12,000 and you’re supposed to use the ram intake at all times unless in a really dusty environment. At a typical combat altitude of 25,000 feet you could get carb intake temps of -30 or less. Does the rarified atmosphere help vaporise the fuel despite the temperature?

That is why the Fuel Injection normally happens either in the Supercharger or behind it.

The Higher the Plane, the larger the Throttle opening for a given Manifold Pressure, the more Energy is imparted onto the Air, meaning it is heated up and thus even up high it's still just as Warm as down low.

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1 hour ago, 6./ZG26_Klaus_Mann said:

That is why the Fuel Injection normally happens either in the Supercharger or behind it.

The Higher the Plane, the larger the Throttle opening for a given Manifold Pressure, the more Energy is imparted onto the Air, meaning it is heated up and thus even up high it's still just as Warm as down low.

I believe it happens just before the carb in a mustang (Spitfire too). A 5 PSI spray if I read correctly.

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2 hours ago, AndytotheD said:

you can’t use carb heat above 12,000

Sure you can.

 

2 hours ago, AndytotheD said:

how does the Mustang handle it?

You can only switch between ram an filtered air. You will have less MAP on filtered air. Alternatively, you could manually set the supercharger to high gear if you suspect ice in the ducting to raise manifold temp. But not all types of carbs suffer from icing.

 

3 hours ago, 6./ZG26_Klaus_Mann said:

The whole Idea behind Water Injection is to cool down the Air between Supercharger and Combustion Chamber. 

It‘s part of the idea, far from the whole thing.

 

Evaporation energy as a mean to cool the manifold is indeed effective. In case of the P-47, water injection cools the manifold temp from 170 deg centigrades to about 38 degrees. Hence it does allow the engine to run at a MAP that otherwise would lead to knocking. But this is only half of the story. It allows to cool the burn by using water as further heat sink, keeping combustion temperatures within permissible ranges without having to resort to an inefficient rich-rich fuel air mixture.

 

Thus, water injection gives you a a good 10+% more shaft power at the same MAP immediately just due to a more efficient burn.

 

2 hours ago, 6./ZG26_Klaus_Mann said:

That is why the Fuel Injection normally happens either in the Supercharger or behind it.

Injection (for Merlins) takes place directly in the carburetor.

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If you use carb heat in a mustang above 12,000 you run the risk of a lean cut out apparently.

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1 hour ago, AndytotheD said:

If you use carb heat in a mustang above 12,000 you run the risk of a lean cut out apparently.

You have that option AFAIK only in very late model P-51D, where you can select „hot air“ after you switched from ram air to filtered air. The carb heater wouldn’t be functional on ram air. I don‘t think BoBp Mustangs would have that option. It is also missing on British Mustang IV.

 

Icing is more of a problem at low throttle settings, hence overly lean mixture settings will not damage your engine. But you might be at risk it cutting out. But kicking in ram air should make the engine run again at once.

 

12‘000 ft. at least give you sufficient margin to use carb air on most airfields and under most conditions. If you really need to play with carb temps in cruise flight rather than a descent, there are other ways to do that as well. You can select high blower and/or up rpm while compensating with the prop pitch. If you sense that things are somehow going wrong, that is the moment for being creative.

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On 7/19/2019 at 11:33 AM, ZachariasX said:

Absolutely. The supercharger (hard liked to the shaft) will otherwise eat up to about 300 hp. Only after opening throttle fully, you get best efficiency of your engine. The supercharger cannot compensate for this bleed of shaft power and what happens is what you describe.

Are we talking about the P-51 now, or the P-47? The P-47 has a turbo supercharger, which shouldn't eat up HP.

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The P-47 has both a turbocharger and a supercharger. While the supercharger was meant by Zach, both eat HP when working. There's no free lunch in physics.

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Posted (edited)
On 6/17/2019 at 11:53 AM, Voidhunger said:

I just really hope that AI will be more competitive in P51. Im tired of fighting Spitfire all the time. P47 AI is good only as target practice for rookies.

 

Well, the Hurricane is almost as good .... maybe some programmer can adapt either as modded super powered GT version of the two, like a Volkswagen Golf GT.

But yeah, P51; i liked it in IL2-1946.

 

What was that similar plane in that IL2 game with a nose wheel you could land, and use it as a tank shooting objects moving it around on the ground ? Some times it's frustratingly tough to shoot at that nasty little moving object from the air ....

 

Now i am sure some historical correct game players will shoot me for all that sort of cheating lol. J

Edited by jollyjack

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The lack of a DD last week (even with our jokes), might signal an update coming in the next few days. It has in the past anyway. Any bets on the P-51 making the scene?

 

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Doubt it, have we even seen any cockpit shots of it yet?

 

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Posted (edited)
31 minutes ago, thenorm said:

Doubt it, have we even seen any cockpit shots of it yet?

 

Nope which is kinda surprising since we've seen both the P-38 and Tempest cockpits already.

Edited by Legioneod

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The devs are being coy.

 

I don't blame them.  The P51 will be the most controversial aircraft in the sim, heck, it already is.

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10 minutes ago, BlitzPig_EL said:

The devs are being coy.

 

I don't blame them.  The P51 will be the most controversial aircraft in the sim, heck, it already is.

Over 600 comments in this thread with nearly 28,000 views should say something about the anticipation most of us have for the P-51.

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22 hours ago, 71st_AH_Yankee_ said:

Are we talking about the P-51 now, or the P-47? The P-47 has a turbo supercharger, which shouldn't eat up HP.

A Theoretical, Perfect Charging System which ate up no Power at all, would mean the Engine would become more Powerful at Altitude, as the lower surrounding Air Pressure would make for easier Exhaust Scavenging. At 25000 Feet that can be up to 10% Power gain.

 

The Turbo pretty much completely neutralises that Power gain, so it produces the exact same Power through the Altitude Band, and takes more and more Power the higher you go, at 25000 fett roughly 10% of the Potential Engine Power.

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This is why I fly luftwaffle: no dicking around with turbo's and manifold temps. Just forward throttle to go fast and back throttle to go slow :😋 

On a more relevant note, when did the zero length rockets enter service on the P-51? 

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Posted (edited)
3 hours ago, ShadowStalker887 said:

On a more relevant note, when did the zero length rockets enter service on the P-51? 

In ETO, after WWII (so never).

In PTO and C.B.I. around May/June 1945.

 

Speaking about using HVARs, but planes with capability carry them appeared during early spring 45 (these planes were from late D-20, no D-15!).

Edited by Saburo

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Posted (edited)
15 hours ago, 6./ZG26_Klaus_Mann said:

A Theoretical, Perfect Charging System which ate up no Power at all, would mean the Engine would become more Powerful at Altitude, as the lower surrounding Air Pressure would make for easier Exhaust Scavenging. At 25000 Feet that can be up to 10% Power gain.

 

The Turbo pretty much completely neutralises that Power gain, so it produces the exact same Power through the Altitude Band, and takes more and more Power the higher you go, at 25000 fett roughly 10% of the Potential Engine Power.

 

Huh, then I don't quite understand the point of Turbos, if that's the case. The whole concept is it drives its compressor through exhaust gas instead of running off the engine crankshaft like superchargers (which naturally reduces engine horsepower).

 

After all, that's what all that extremely complex plumbing on the P-47 is all about, and one of the reasons it struggles so much at low altitude, as all that complex machinery only starts making sense at higher altitudes where compression is necessary. And that's why eventually at high altitude the P-47 outperforms most of its contemporary competitors, when it benefits from the full potential of its turbocharger without eating up extra HPs, whereas its supercharged competitors have to give up horsepower in order to maintain comparable compression.

 

That said, there certainly appears to be a lot of esoteric knowledge on how to best run the P-47 engine, with a lot of conflicting information. Is there any chance someone here could summary what is actually the best practices to get the most out of the P-47 (in the simulation, not RL)?

Edited by 71st_AH_Yankee_

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Turbos are more efficient than mechanical superchargers. They eat less hp at high altitude high power settings, but they still eat some. Also, WW2 turbos achieved higher full throttle altitudes than mechanical chargers.

 

For comparison -

R2800-8W, mechanically driven, achieves about 2000hp at 60" boost with water injection with a full throttle altitude of 17000 feet.

R2800-63, turbocharged, achieves about 2500hp at 60" boost with water injection with a full throttle altitude of 28000 feet.

That's quite a difference.

 

On the downside, the mechanically driven chargers produce a lot of exhaust thrust, while the turbocharged aircraft don't, as it goes into driving the turbo. As power = thrust * speed, for a power comparison, this is more relevant at high speed than at low speed. At high speed, exhaust thrust makes up about 20% of total power produced by a typical WW2 aero-engine. So in the above comparison, at high speed, engine total power production is fairly similar at medium altitudes. At low altitudes, the advantage lies with the mechanically driven charger (2300hp on the shaft plus ~20% exhaust thrust for low gear), at high altitude the turbo rules. That wouldn't change even if you built a mechanical charger to achieve a similar full throttle altitude, because that would easily eat up another 200 to 300hp.

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1 hour ago, 71st_AH_Yankee_ said:

 

Huh, then I don't quite understand the point of Turbos, if that's the case. The whole concept is it drives its compressor through exhaust gas instead of running off the engine crankshaft like superchargers (which naturally reduces engine horsepower).

 

After all, that's what all that extremely complex plumbing on the P-47 is all about, and one of the reasons it struggles so much at low altitude, as all that complex machinery only starts making sense at higher altitudes where compression is necessary. And that's why eventually at high altitude the P-47 outperforms most of its contemporary competitors, when it benefits from the full potential of its turbocharger without eating up extra HPs, whereas its supercharged competitors have to give up horsepower in order to maintain comparable compression.

 

That said, there certainly appears to be a lot of esoteric knowledge on how to best run the P-47 engine, with a lot of conflicting information. Is there any chance someone here could summary what is actually the best practices to get the most out of the P-47 (in the simulation, not RL)?

Greg actually has a pretty nice Graoh demonstrating Turbo vs. Super vs Perfect Charging System at 9:35.

 

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Posted (edited)
16 minutes ago, 6./ZG26_Klaus_Mann said:

Greg actually has a pretty nice Graoh demonstrating Turbo vs. Super vs Perfect Charging System at 9:35.

 

Not just a graph, but a video of a graph with a commentator to explain it too :) 

 

I'm willing to bet that this is a first, so you get the upvote for the graphideo and I'd give you another just for this 1st if I could :good:

Edited by Pict
Spelling, tweaking etc.

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2 hours ago, 6./ZG26_Klaus_Mann said:

Greg actually has a pretty nice Graoh demonstrating Turbo vs. Super vs Perfect Charging System at 9:35.

 

 

So, if I understand this properly, you're still ending up with more "useful" horsepower with a turbocharger, yes? That's what what the "net engine power" indicator at the top would indicate, no?

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1 hour ago, 71st_AH_Yankee_ said:

So, if I understand this properly, you're still ending up with more "useful" horsepower with a turbocharger, yes? That's what what the "net engine power" indicator at the top would indicate, no?

 

In principle, yes. In practice, it depends. Turbochargers are big and they set coarse limits on your airframe. Superchargers are small. You can make a smaller plane with supercharging.

 

Also, when you are talking about 

1 hour ago, 71st_AH_Yankee_ said:

"useful" horsepower

then this is not just shaft hp, but net power of everything pushing your plane forward. As JtD explained, exhaust pressure force is a significant factor in fast WW2 aircraft and the power required to compensate for the loss of an exhaust jet is often rather close to the loss of shaft power due to cranking the supercharger. The  graphs presented in the video don‘t show a bottom line of all things pushing forward, it shows net shaft power. What you do with that is a different question.

 

The great thing about the turbocharger lies in the flexibility of the critical altitude. You can optimize your engine to any given flight altitude. This way, the difference between the two is much more a question of mileage (achievable fuel economy) over a wider range of conditions than net performance.

 

An advantage of turbocharged engines thus is that you can set your critical altitude to your cruise altitude, giving the engine best mileage. In practice this is applied in the B-17. There, you have 4 engines and each of those engines have hooked up different systems to them. As those systems (cabin heater, generator, etc.) draw a different amount of shaft power, you have de facto 4 engines with 4 different critical altitudes. Since you are cruising very near these altitudes, you notice the different power outputs on the 4 shafts. By having turbochargers, can then (in flight) tune the turbos such that they synchronize the power on all four engines. (There‘s a lot more to flying B-17‘s than being flak bait, some shooting gallery and using the Norden once.) You couldn‘t do that with supercharged engines and you‘d get a slight penalty in mileage. It might make the difference between reaching Tunis or not with some unexpected head wind... (Ah, bomber problems, again.)

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