4.101 RC - List of fixes

[1.JaVA_Sjonnie]

Originally Posted by MrBaato

My cockpit position has moved forward alot in all machi's (mc202/205)
after installing 4.10m

When looking in front, only the top instruments can be read even in wide-view

Have you tried the controls increase / decrease FOV? looks like you have, maybe the interpretaion of the resolution is different? Hadn't noticed this one yet btw.

[Romanator21]

I noticed a change as well, but it hasn't been a major problem for me.

[5AF_8FS_Doc]

Has anyone happened to mention the fact that the supercharger in the P47D does not engage?

Didn't read the whole thread, so sorry if its been mentioned. It is a huge problem for any jug driver.

[Azimech]

The P47 uses a Turbocharger.

[Tempest123]

Originally Posted by 5AF_8FS_Doc

Has anyone happened to mention the fact that the supercharger in the P47D does not engage?

Didn't read the whole thread, so sorry if its been mentioned. It is a huge problem for any jug driver.

Its turbo-supercharged, a large exhaust driven turbocharger behind the cockpit delivers air to the intake manifold, that's why the jug is shaped the way it is. Notice in the cockpit the gauge marked "turbo rpm", that is the RPM of the turbocharger turbine supplying forced air to to the engine.
The system is designed to hold a certain manifold pressure constant for a wide range of altitude, i.e you set your manifold pressure via your throttle, and the turbo-supercharger automatically adjusts the amount of forced air going into the engine to hold that pressure constant. Its a genius system, because a P-47 can hold sea level like manifold pressure at very high altitudes.

[IceFire]

Originally Posted by 5AF_8FS_Doc

Has anyone happened to mention the fact that the supercharger in the P47D does not engage?

Didn't read the whole thread, so sorry if its been mentioned. It is a huge problem for any jug driver.

Tempest has explained the details very nicely. I just wanted to ask if you've ever flown the P-47 at high altitudes? Up at 9000 meters it's like a rocket... only the Ta152H-1 has the same kind of feeling. It makes most other fighters look like they are standing still. The sim models it's turbo-supercharger reasonably well actually and there isn't anything to fix in this particular aspect.

[Blackdog_kt]

Originally Posted by Tempest123

Its turbo-supercharged, a large exhaust driven turbocharger behind the cockpit delivers air to the intake manifold, that's why the jug is shaped the way it is. Notice in the cockpit the gauge marked "turbo rpm", that is the RPM of the turbocharger turbine supplying forced air to to the engine.
The system is designed to hold a certain manifold pressure constant for a wide range of altitude, i.e you set your manifold pressure via your throttle, and the turbo-supercharger automatically adjusts the amount of forced air going into the engine to hold that pressure constant. Its a genius system, because a P-47 can hold sea level like manifold pressure at very high altitudes.

Actually, this is partially correct. The Jug did have a turbo-supercharger but i think it was not automatic. In fact, there was a separate "throttle" lever for it.

The way it worked is that you didn't touch it until you reached 8000ft. From that point on you could use it to overboost the engine (it could take more than 30 inches of MP, which is around what the ambient air pressure on sea level is), but taking care not to overdo it and break the engine.

As you went higher, there came a point where the throttle alone was not sufficient to maintain useful MP. From that point onwards, the pilot would leave the throttle at full (which would only generate maybe 20-25 inches of MP due to the high altitude) and only use the turbo lever control for setting the MP. In IL2, the way it works is that a single slider/throttle control on our joysticks controls both of them, the actual throttle up to a certain MP value and the turbo lever from that point on. This is not a problem, it's just a clever interface decision.

What IL2 doesn't model which made the P-47 complicated to fly was turbo lag. The way it worked is that when pushing the turbo lever forward, a couple of waste-gates on the exhausts would gradually close, not letting the exhaust gas escape but sending it to a set of tubes that went to the turbo-supercharger. The more you closed the waste-gates, the more exhaust gas was fed to the turbo-supercharger and the higher RPM it reached. However, this was not instantaneous because the fans in a turbo take time to spool up and down due to inertia, just like a jet engine. I've spent some time with A2A simulations' P-47 payware add-on in FSX and it's almost impossible to get the exact MP value you want on the first try, it requires you to advance the lever first and then fine-tune it a couple of times, plus it's not an option not to because you can't just slam it to full and expect the engine not to break.

Also, just because the turbo can give you a certain boost and the engine can take the extra MP doesn't mean the turbo can maintain it at all altitudes. The higher you go, the harder it is for the turbo to maintain a certain amount of pressure. This translates to higher turbo RPMs for a given MP value and these RPMs come with their own limits that are not to be exceeded.

Combine this with the lack of any penalty (apart from a simplified overheat which is a resettable trigger with no engine damage if you don't stay at overheat for more than 5 minutes) for exceeding the engine's maximum MP limits, the fact that we can run any RPM we want without any issues, that the water injection is automatic (it was only semi-automatic in reality, you had to turn it on before it went to auto mode), the lack of mixture control (it was also semi-automatic and not full auto with four positions: cut-off,auto-lean,auto-rich and full rich), plus the lack of intercooler and oil cooler controls and it's obvious that the P-47 we have is way simpler to operate than it should be and gives too much "free" performance for too little workload.

In a single boom and zoom attack involving a dive of more than 5000ft you would have to:

1) Reduce power by adjusting manifold pressure and RPMs before the dive in order not to pick up excessive speed, keeping turbo lag in mind at high altitudes.
2) Close the cowl flaps in order not to damage them, while keeping an eye on your cylinder head temps. It would be ok mostly, since power has been reduced and temps would fall, so you could get away with closed cowl flaps in the dive.
3) Start diving towards the target.
4) Check your carb temps: on one hand they tend to go lower due to reduced power and increased speed, on the other hand you are descending and the air is warmer at lower altitudes. Too low a carb temp means low power due to icing, too high a carb temp rarifies the air in the carbs and it's like running at too rich a mixture, ie power loss again. Use your intercoolers to manage carb temps.
5) Check your oil temps. These are affected mostly by power settings just like the cylinder head temps, but change at a much slower rate. This would just be a momentary check, since i seem to remember that the Jug had automatic oil cooler flaps.
6) Acquire your target and make your attack.
7) Start pulling up into the zoom climb while adding power by adjusting MP and RPM again. At high altitudes turbo lag is present, plus you also need to take care not to overspeed the turbo.
8 ) Monitor oil, cylinder and carb temps again, reversing your previous actions with regards to intercoolers, cowl flaps etc.
9) Level off.

Of course, most of this is outside the scope of IL2's game engine, but i can't wait to see what happens when CoD starts modeling those late war hot-rods in a few years time.

So why do i mention it? Well, it's a pet peeve of mine that a lot of people think just because an aircraft was a top performer it was also easy to fly. This can't be further from the truth for many late war fighters and having them modeled in a simplified way makes them better than they actually were, because the pilot gets all the performance for free.

[5AF_8FS_Doc]

Good posts.

Why then does the p47 D have a supercharger lever in the throttle quadrant that never moves?

I have flown the jug at high altitude a ton... just tonight I was at 35k feet and was not able to attain anymore than 30 inches of MP. That was with a leaned pitch setting to about 80%. I even tried it at max RPM and it didnt help.

S~

[JtD]

Originally Posted by EJGr.Ost_Caspar

Geeez, I guess, you both need some ampoules with a special brewing, hm?

That would be for me, he's going to have a bomblet instead.

[JtD]

Originally Posted by 5AF_8FS_Doc

Why then does the p47 D have a supercharger lever in the throttle quadrant that never moves?

Because not everything is animated.