No WEP for FW 190 A-9

[KG26_Alpha]

Originally Posted by JtD

The description of the enclosed cowling is that for the V1 prototype model, and as the concept proved unsuccessful, it was dropped for the V2 and later. These aircraft also were powered by a BMW 139, and engine-wise had little in common with serial production models.

The Fw 190 possessed an oil cooler ring, with an adjustable gap to adjust the cooling capacity. The standard size was 10 mm, but it had to be increased to 20 mm for tropical use and F model attack aircraft. This increase cost the plane 15-20 km/h at sea level.

The Fw 190 also had adjustable cooling gills on the side of the aircraft, which allowed the cooling of the engine or more precisely the cylinders. These pretty much worked like any other cooler on any other aircraft, including speed loss as it was opened. One effect I know of was a reduction of 500m in ceiling, therefore about 1 m/s in climb, with open cooling gills.

Lower drag with partially open radiators was a feature of the D-9, where the flush setting was a partially open one. However, even this feature wasn't anything special, other aircraft have this, too. I haven't seen it for the A models.

Il-2 simplifies by treating two cooling mechanisms as one and calling them radiator, and having them both adjustable by the pilot in flight. It also simplifies the drag characteristics of the radiators throughout.

Imho, if the radiator of the Fw 190 gets special attention in terms of cooling and drag relation, all other aircraft need to see the same treatment, as there seems to be nothing especially special about the Fw. A global rework would be nice, but the research alone is a tremendous job.

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What's that got to do with anything posted here.

Were talking about the 801 series.

I suspect the oil cooler isn't even physically modelled on the FW's as its such a simplified cooling code as you mention.

It seems strange to put emphasis on cooling in v4.11 and still have an archaic cooling code.

[JtD]

Originally Posted by KG26_Alpha

?
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What's that got to do with anything posted here.

Were talking about the 801 series.

It was you who posted a wiki quote describing the cooling of the BMW 139 powered V1, which has nothing to do with the BMW 801. If you didn't mean it, fair enough, forget my comment.

It's one thing to make a global code a lot more complex as it previously was and tune given parameters for better accuracy. It's a completely different thing to built individual solutions for each and every plane modelled, from scratch.

[badatflyski]

Originally Posted by AndyJWest

The BMW-engined Fw 19Os had an engine-driven fan to increase airflow through the cowling. Presumably this must have taken some power to drive, and I could just about imagine the back pressure from a fully-closed cowl actually reducing available power - though whether this would be significant is hard to tell.

The engine cowl isn't hermetic at all. Antons didn't need any cooling flaps openning till 1.32ATA included (and even higher, depending on air temperature and pressure), the 801 was actually an overcooled engine, as the time to put the engine to minimal take-off oil temp was the same as the time needed to a Merlin to blow up in the same situation, and Yes it did take some power, from memory 40PS, but the total engine power is calculated on the prop and not on the crankshaft as it is on English or American planes (see definition PS vs Bhp ), so when BWM says it's 1820PS, it is 1820PS on the prop, but when Rolls Royce says it's 1700Bhp you have to reduce that power with the power lost in the gear reductor.

Originally Posted by JtD

The Fw 190 possessed an oil cooler ring, with an adjustable gap to adjust the cooling capacity. The standard size was 10 mm, but it had to be increased to 20 mm for tropical use and F model attack aircraft. This increase cost the plane 15-20 km/h at sea level. .

Source please, nothing about it in the BMW801C/D maintenance and repair manual...or i missed it completely

Originally Posted by JtD

The Fw 190 also had adjustable cooling gills on the side of the aircraft, which allowed the cooling of the engine or more precisely the cylinders. These pretty much worked like any other cooler on any other aircraft, including speed loss as it was opened. One effect I know of was a reduction of 500m in ceiling, therefore about 1 m/s in climb, with open cooling gills..

The difference between a cooling grill with an max openning of about 5 cm, situated in the air flow + high pressurized exhaust gazes and letting out air itself with higher pressure than the surround air (prop fan beeing like a sort of compressor, extracting the heat from the oil radiator and pushing air into the admission intakes build inside the engine cover) and a frontal 1/2m² radiator, even with an adjustable airflow, seems to me like a drag difference between a truck and a race car.
So yes, the grills added certainly some parasite drag because it certainly broke the airflow on the fuselage in a certain matter but the effect should be not so important as 70kmh(from memory) between closed and open as it is in IL2. voilà

[JtD]

Originally Posted by badatflyski

Source please, nothing about it in the BMW801C/D maintenance and repair manual...or i missed it completely.

Fw 190 A-5/A-6 Flugzeughandbuch Teil 7 Triebwerkbedien- und -versorgungsanlage, Dezember 1943, Page 34 gives the 10 and 20mm gaps.

Focke Wulf Bericht 06011 Flugzeugmuster Fw 190 mit BMW 801D Errechnete Flugleistungen Blatt 109 gives the difference of 15 to 20 km/h.

The radiator as large as it may want to be is always there and the only speed difference from adjusting the radiator will come from adjusting the cooling flap and thereby the airflow through it. That's the same thing as with the Fw 190.
Given that the Fw is an aerodynamically clean plane, screwing with these aerodynamics through radiator adjustments will have a large impact on the speed than it has on a plane with poor aerodynamics, like the Hawker Hurrican or a biplane.
In game the Fw 190 loses about 25 km/h due to open radiators.
Had the cooling fan been some sort of a compressor, the Fw 190 would not have achieved higher full throttle altitudes with external intakes - but it did.

[badatflyski]

Thank you for this info JTD! will check that out; as i wrote above, i certainly did miss that part and certainly others too, 4500 technical pages that's a lot

As for the compressor thing, it was more an image than something else, of course it can not be as powerfull as a true compressor, it's a fan.
Like a friend of mine says: sometimes you have to slightly exagerate to make the point and make the other understand your idea.

[KG26_Alpha]

The problem is the engineer will tell you one thing,
and the pilot will tell you another.