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View Full Version : Oleg's response to my concerns about FW-190A radiator drag.



Hunde_3.JG51
07-13-2004, 07:34 PM
Oleg answered my question in a series of 3 e-mails, and I just wanted to share it/them with you. This is my original e-mail.

Hello Oleg, hope all is well. Just wanted to make my case about FW-190A and radiator drag. I still don't understand why the FW-190A suffers from radiator drag, please hear me out. Here are my points:

-BMW-801 was cooled by internal routing and baffles that took air from outside which would cause drag.

-BMW-801 was cooled by a fan that rotated at 3 times the speed of the propeller.

-These were not adjustable. Actually the angle of the fan blades were adjustable before engine start-up I believe for use in differing conditions.

-This means that any speed results achieved are with these cooling measures in place and active. Essentially the radiator is always open. Early 190A's had no cooling gills/slots and as far as I know had no adjustable cooling measures so top speed would be the same no matter what, there was no adjusting anything.

-Even with cooling gills on later models they were very small and opened minimally. But more importantly they were located right behind exhaust stacks and the exhaust/cowling actually came out much farther than gills so they were not really put into airflow (see pictures below ).

The FW-190A was very unique in its cooling system. The P-47, for example, had large external flaps that opened all around the engine and into airflow.

*As a note the new 190's (with Ash-82) are being made using a cooling fan that only turns at the speed of the propeller, the FW-190's in WWII spun at 3.2 times the speed of the propeller.

A quote.

"Next, the plane was returned to the manufacturer for necessary modifications, especially in the cooling system. In the case of radial engines there was only one possible solution: to increase airflow over the engine. This was done by using a ten blade(later increased to 12 on BMW-801D) fan on the propeller shaft, in front of the engine, near the cowling. The tunnel spinner was replaced by a traditional spinner, covering only the airscrew hub of the VDM metal propeller. It was decided to use this after tunnel trials which had shown that the big spinner had not given proper airflow for efficient engine cooling and its influence on the reduction of pressure drag was not significant. Engine cooling was improved after this modification, but not to the expected level, and the engine still operated in the high range of acceptable temperatures."

Here are two good images showing what I was talking about with gills not really being in airflow and behind exhaust and in from cowling. Also, an imortant point is that the gills were an outlet for hot air, not an intake of any kind.





Compared to the P-47, not the greatest image but it shows what I mean about most other radials having large surfaces extend into airflow.



Looking at these picstures and from statements above I don't see how the FW-190A suffers from any radiator drag at all other than what was there from the beginning (or how it suffers from radiator drag the same as P-47 in game). Yes there is drag coming into engine (as with all radials) but it was always there and speeds obtained were done with this in place from the beginning. FW-190A also has unique cooling system with internal baffles and cooling fan. While others have external surfaces extending into airflow while the 190A has none. The 190A's cooling was considered "ingenious" after the war for a reason, because it allowed an extremely neat engine/cowling design with no external surfaces protruding. But it certainly had its problems early on.

I will understand if nothing is changed in this matter but I wanted to make my case. Thank you for listening and taking the time to read this. And thanks again for everything you have done and I hope all is well.

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Formerly Kyrule2
http://www.jg51.com/

Hunde_3.JG51
07-13-2004, 07:34 PM
Oleg answered my question in a series of 3 e-mails, and I just wanted to share it/them with you. This is my original e-mail.

Hello Oleg, hope all is well. Just wanted to make my case about FW-190A and radiator drag. I still don't understand why the FW-190A suffers from radiator drag, please hear me out. Here are my points:

-BMW-801 was cooled by internal routing and baffles that took air from outside which would cause drag.

-BMW-801 was cooled by a fan that rotated at 3 times the speed of the propeller.

-These were not adjustable. Actually the angle of the fan blades were adjustable before engine start-up I believe for use in differing conditions.

-This means that any speed results achieved are with these cooling measures in place and active. Essentially the radiator is always open. Early 190A's had no cooling gills/slots and as far as I know had no adjustable cooling measures so top speed would be the same no matter what, there was no adjusting anything.

-Even with cooling gills on later models they were very small and opened minimally. But more importantly they were located right behind exhaust stacks and the exhaust/cowling actually came out much farther than gills so they were not really put into airflow (see pictures below ).

The FW-190A was very unique in its cooling system. The P-47, for example, had large external flaps that opened all around the engine and into airflow.

*As a note the new 190's (with Ash-82) are being made using a cooling fan that only turns at the speed of the propeller, the FW-190's in WWII spun at 3.2 times the speed of the propeller.

A quote.

"Next, the plane was returned to the manufacturer for necessary modifications, especially in the cooling system. In the case of radial engines there was only one possible solution: to increase airflow over the engine. This was done by using a ten blade(later increased to 12 on BMW-801D) fan on the propeller shaft, in front of the engine, near the cowling. The tunnel spinner was replaced by a traditional spinner, covering only the airscrew hub of the VDM metal propeller. It was decided to use this after tunnel trials which had shown that the big spinner had not given proper airflow for efficient engine cooling and its influence on the reduction of pressure drag was not significant. Engine cooling was improved after this modification, but not to the expected level, and the engine still operated in the high range of acceptable temperatures."

Here are two good images showing what I was talking about with gills not really being in airflow and behind exhaust and in from cowling. Also, an imortant point is that the gills were an outlet for hot air, not an intake of any kind.





Compared to the P-47, not the greatest image but it shows what I mean about most other radials having large surfaces extend into airflow.



Looking at these picstures and from statements above I don't see how the FW-190A suffers from any radiator drag at all other than what was there from the beginning (or how it suffers from radiator drag the same as P-47 in game). Yes there is drag coming into engine (as with all radials) but it was always there and speeds obtained were done with this in place from the beginning. FW-190A also has unique cooling system with internal baffles and cooling fan. While others have external surfaces extending into airflow while the 190A has none. The 190A's cooling was considered "ingenious" after the war for a reason, because it allowed an extremely neat engine/cowling design with no external surfaces protruding. But it certainly had its problems early on.

I will understand if nothing is changed in this matter but I wanted to make my case. Thank you for listening and taking the time to read this. And thanks again for everything you have done and I hope all is well.

http://www.militaryartshop.com/prints/bailey/warwolf.jpg

Formerly Kyrule2
http://www.jg51.com/

Hunde_3.JG51
07-13-2004, 07:37 PM
This is his response, sorry pictures didn't take in above post.

"E-mail #1. BMW-801 cowling is a standard NACA cowling and has nothing unique from the point of view such as aerodynamics flow inside the cowling.
And doesn't matter had it 3 time higher speed fan than propeller or the same.. From aerodynamics poit of view the airflow inside the NACA cowling are different for FW, P-47 or La-5 just in small details (different calculations of airflow) that are modelled.
And if "channels" of airflow are directed like in FW (or LA) this is really sometime worse working system of airflow than radial like on P-47, or JUMO radiator system on Ta, etc... So the real things are very relative. Sorry not time to explain you in more details.

E-mail #2. One more thing for you to think about unique things on FW....
Germans tried to copy the initial cowling on FW from Policarpov's cowling of his prewar design and that was published in 1936 in open public Russian sources. http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif That work was unsuccessful for both design bureaus as you maybe know.
Some western videos in comments has very wrong technical description and such as films "Wings of Lufwaffe" about FW has alot of incorrect info that are coming from illiteracy of authors (enough to listen there what they said about "Komandegerate"....)

E-mail #3. Both FW and LA has very similar airflow inside the NACA cowling. And from aerodynamical point of view that thing is amost equal, so the drag changes on the same manner (not absolutelly the same, but very close http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif).
Differences are in method of adjusting of the amount of airflow going acrross the engine (giils and cowl).
Both adjust it in the end of airflow past engine. Both had them controlled manually and usually doesn't need real input during flight in normal conditions of temperature, etc...(except to close the gills and "flaps" in the winter before the engine will have working temperature on the ground).
FW had a bit better result for external coefficient of aerodynamics than the La in the area of past engine airflow (output holes), but both methods damage the "laminar" airflow in that area by almost the same "method"
The aiflow from LA cowl is going over the flap and then meet the output airflow from the hole - result distorsion of airflow. In case of big speed of airflow from the hole this method would be better then on FW
The aiflow from FW cowl is going directly and meet directly the laminar airflow over fuselage and distort it. If the speed of this output flow is very high then the laminar aiflow may be damaged completely.... In this case it will be even worse then using covering flaps for special tunnel (like on La).

Hope you understand me and understand that in both cases the airflow iover the NACA cowl+fuselage distored by the output airflow from the NACA cowl."

http://www.militaryartshop.com/prints/bailey/warwolf.jpg

Formerly Kyrule2
http://www.jg51.com/

[This message was edited by Hunde_3.JG51 on Tue July 13 2004 at 06:50 PM.]

Hunde_3.JG51
07-13-2004, 07:43 PM
Without debating the matter, I just wanted to post this to show members of the community what type of response is possible when e-mailing Oleg in a polite manner (I've excluded my interim e-mail and my written "thank you").

I am very grateful that Oleg took the time out of his very busy schedule to write to me, and it shows what kind of support we really have.

I hope you find the post interesting, but more importantly I hope people understand what type of open communication and support we have from Oleg/Maddox/1C.

http://www.militaryartshop.com/prints/bailey/warwolf.jpg

Formerly Kyrule2
http://www.jg51.com/

lbhskier37
07-13-2004, 07:47 PM
very interesting response. Its nice hearing some real scientific explanations in here and not just whining for a changehttp://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif

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Jippo01
07-14-2004, 12:44 AM
Many things are said about Oleg here, but a lot of people don't really know the energy and skill he is putting in the game.

He is very knowledgeable person, and I have to say that even when we always don't agree, I still respect his opinion.


-jippo

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NN_EnigmuS
07-14-2004, 02:36 AM
perhaps you should email him about late anton performance http://ubbxforums.ubi.com/images/smiley/59.gif

nice to see he answered and as jippo said,i still respect his opinion because he is very knowledgeable like some here(butch,kurfust and a lot of other i missed http://ubbxforums.ubi.com/images/smiley/10.gif)

we have a great community when they give the time of speacking politely

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JG53Frankyboy
07-14-2004, 06:01 AM
about, how to manipulate the coolingsystem in a Fw190A/F we had a nice discussion on the german board

http://ubbxforums-de.ubi.com/6/ubb.x?q=Y&a=tpc&s=59010161&f=388104122&m=148101314&p=1

perhaps , if you cant read german, you will find interesting pistures.

the question is still open WHAT should be opend in a Fw190A2-4 ?

Tooz_69GIAP
07-14-2004, 07:24 AM
Well, considering that Oleg is a qualified aeronautical engineer with a penchant for WWII birds (he owns a flying Ishak, I think!!), you'd hope he has at least some inkling of what he's talking about!!

whit ye looking at, ya big jessie?!?!

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