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Old 05-17-2010, 12:31 AM
Blackdog_kt Blackdog_kt is offline
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I've found out that simply lowering the RPM in most radial engined birds in the sim can circumvent most problems, in fact it's usually the main defining factor.

This can't be done in RL because the engine assembly goes into over-torque if your throttle is too high for your given RPM setting but we don't have that in IL2 yet, so you can cruise at 100-110%+WEP in most birds if you keep the prop pitch down. Of course that's not practical in combat, as you need the "pull" of high pitch settings in many cases, but it's fine for cruising fast around the map or even cruise climbing and having 2-3 minutes of peak performance plus the 5 minute resettable overheat timer. That's about 5 minutes of peak power and 2-3 minutes left to spare for cooling the engine.

What's interesting is that if what JtD says it's true, then it's modelled backwards. In reality, the cylinder head temperature (CHT) is the one that changes faster and is mainly a function of your power settings. This is controlled by the cowl flaps. Of course cooling too fast can crack or break things, so most of the tricks we do in IL2 also don't apply to real engine use (like opening the cowl flaps in a full out dive for example, in reality either the flaps will jam/get torn off or a few cylinders will crack due to shock cooling).

The oil is used to cool the engine by absorbing the heat and further lowering components' temperature like CHT, while the radiators are in turn used to cool the oil again. Some aircraft like the P47 or the big heavies (like the B17 and B24) actually have intercoolers that don't only cool the oil, but can also be used to deny oil cooling. When the oil is too hot it dissolves, engine lubrication suffers and you get overheats and maybe even fires, but when it's too low it's also a problem, as it somewhat coagulates and the oil pressure increases too much. You could break oil lines or even blow engine components off if the oil is too cold, hence the intercoolers. Oil temperature doesn't change as fast as CHT, which means it's harder to get into trouble but also harder to get out of it.

Maybe in IL2 the cowl flaps and the intercoolers are modelled in tandem under a single function? So for example, when you open the cowl flaps the intercoolers also open and cool the oil? Just a thought.

I don't use the P47 but the FW190 A series is quite similar. I find that later variants take longer to overheat, plus they overheat faster at high altitudes because i use higher RPM settings to keep afloat in the thin air. However, you can still cruise all day long at 100%+WEP and 70%-80% pitch in most cases, which still gives an RPM setting singificantly higher than the one the auto-pitch system keeps.

I think a lot of the perceived imbalances in IL2 aircraft match ups come from the limitations of the engine model. I don't have the numbers handy, but by going through procedural manuals i get the feeling that as far as the auto-management system goes the 190 is pretty accurate, 2700 RPM or thereabouts is the max continuous setting and that's what the auto-pitch tries to keep, it just takes some time for it to get there which could be crucial.
Also, it's the fact that most planes in the sim can exceed their normal operating parameters to gain extra performance that upsets things, which is also why a lot of 190 drivers fly with manual pitch. Similarly, the 47 has top performance but it lacks the complicated controls that the real one had. A 47 has intercoolers, cowl flaps and a supercharger to monitor and keep within acceptable limits. Effectively this means that even when BnZing, you have to be aware of what you're going to do and set everything up before the dive, then set everything up for the climb back to altitude after your attack. It's quite the workload actually, as simply adjusting the throttle and going into a climb or dive affects 2-3 extra things in sequence, so unless someone knows how to work the engine by ear they have to actually look at the gauges in the midst of combat.
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