Drag of annular/drum radiator

[spicmart]

Is that based on test results?

I'm not sure but they seemed to go with the sliding system which does not increase the diameter of the cowling when it has to open up when cooling demands.
Contrary to hinged gills which give a speed penalty. German tests also proved this.

 

[spicmart]

Error.

 

[spicmart]

Just look at Reno Unlimited`s, thats been won by annular air cooled (effectively no different to a water cooled annular) and belly scoop systems (p51),
and planes like Sea Fury`s which have both leading edge and annular cooling systems at once.

David Lednicer gave quite higher drag figures for the air-cooled Fw 190A than for the Fw 190D with liquid-cooled annular radiator even though the cross-section is virtually identical.

 

[Deleted member 68059]

David Lednicer gave quite higher drag figures for the air-cooled Fw 190A than for the Fw 190D with liquid-cooled annular radiator even though the cross-section is virtually identical.

I dont think the frontal area sectioned through the engine area of a BMW801 190 and a Jumo213 190 are identical. Sorry if thats not what you`re referring to ?
What I mean is the cooling drag of these two could in fact be more or less the same, but the 801 version could have higher drag overall because the nose
cowling area section is noticably fatter.

I admit the overlay below may not be 100% accurate, but I think its not too bad for general "eyeballing" purposes.

 

[tomo pauk]

What I mean is the cooling drag of these two could in fact be more or less the same, but the 801 version could have higher drag overall because the nose
cowling area section is noticably fatter.

Looks like it was a combo between the reduction of fusealge drag and cooling drag that gave the D9 the advantage. See here for 'Rumpf' and 'Kuhlung' row at the drag analysis, where fuselage is 10% less draggy on the D9, and cooling drag is lower by 50%. Weapon set-up is also less draggy - no wonders here, the D9 lacked two cannons and their associated drag.

 

[spicmart]

Apparently there were several variants of annular radiator tested.
View attachment 674237

ww2aircraft thread at "Hawker Tempest V production batches"

From an engineering and construction perspective, which would be the more complicated/complex solution? The sliding ring cowl or articulated (hinged) gills?

 

[spicmart]

tomo pauk or any one else

Is this file still anywhere to be found and complete?

 

[spicmart]

Looks like it was a combo between the reduction of fusealge drag and cooling drag that gave the D9 the advantage. See here for 'Rumpf' and 'Kuhlung' row at the drag analysis, where fuselage is 10% less draggy on the D9, and cooling drag is lower by 50%. Weapon set-up is also less draggy - no wonders here, the D9 lacked two cannons and their associated drag.

Though I do not quite know what the two different figures at Widerstandsflächen exactly mean it is quite interesting to compare the various models and their differences.

The A and D models have the same wing so the first numbers are identical (0,1647) but the second figures of the Ds differ (34,0/34,0/37,1/37,3).
What does it mean?
The wings of the Ta 152s (34,8/36,0/38,6). Why do the numbers for the wings of C and E, though identical differ?

The tail units of the Doras and Ta 152 models have the same first figures (0,470), which means they must have the uniform or Ta 152 vertical stabilizer.
The second figures differ in all, except for the A models. (9,1/9,1/10,6/10,7/9,3/9,6/9,4). Why is that?

The second figures of tht fuselages and KA (gun installation?) of D-9 and D-12 differ slightly (31,4/31,6). I think this is because of the greater drag of the cowl mounted guns. Ta 152 E and H differ probably because of the recon equipment in the E uselage.

Interesting is the higher drag of the air intake for the supercharger of the Jumo 213E/F compared to the Ta 152C's DB603L.

 

[tomo pauk]

Though I do not quite know what the two different figures at Widerstandsflächen exactly mean it is quite interesting to compare the various models and their differences.

1st one (Schenellflug - max speed flight, done at constant altitude) is for the Cd0, the other one (Steigflug - climbing flight) is for the Cd0 + Cdi (i = induced).

The A and D models have the same wing so the first numbers are identical (0,1647) but the second figures of the Ds differ (34,0/34,0/37,1/37,3).
What does it mean?
The wings of the Ta 152s (34,8/36,0/38,6). Why do the numbers for the wings of C and E, though identical differ?

Those are the percentages of the total drag. Drag (expressed in sq meters) of the fuselage (Rumpf) of the Fw 190A8 is 0.1647 sq m, making 34% of the total drag.
Wing-related drag of the Ta 152H is noted there as 0.194 sq m, or 38.4% of the total drag of that aircraft. Wings of the 152C and 152E make the same drag (0.1755 sq m), even if the percentages can differ (34.8 and 36, respectively).

The second figures of tht fuselages and KA (gun installation?)

K.A. is, per footnote 2), the interference drag + drag due to manufacturing imperfections + leakage + cockpit imperfections. (per my imperfect translation)
Drag due to the guns' installation is noted under 'Waffen' row.

 

[Reluctant Poster]

I dont think the frontal area sectioned through the engine area of a BMW801 190 and a Jumo213 190 are identical. Sorry if thats not what you`re referring to ?
What I mean is the cooling drag of these two could in fact be more or less the same, but the 801 version could have higher drag overall because the nose
cowling area section is noticably fatter.

I admit the overlay below may not be 100% accurate, but I think its not too bad for general "eyeballing" purposes.

View attachment 692433

The 190D is 5 feet longer that the FW190A. This image showing them as equal length makes the 190D appear slimmer. There is a taper on the 190D cowl so there may be some advantage, but I would think the difference in internal cooling drag was a greater factor.

 

[spicmart]

Is it true that German radiators are bulkier than Allied ones and, if so, did thay caught up late-war?

 

[z42]

Is it true that German radiators are bulkier than Allied ones and, if so, did thay caught up late-war?

The Brits spent a lot of effort to develop high(er) pressure radiators, which enabled their radiators to be smaller and thus less draggy. Not sure whether Germany ever succeeded in going down the same path.

 

[elbmc1969]

Is it true that German radiators are bulkier than Allied ones and, if so, did thay caught up late-war?

The Great Horsepower Race covers this. It may have been covered in one of the YouTube videos about the book, on the web site for the book, or in a post here.