Author Topic: Explain this and win the prize!  (Read 22002 times)

Offline Crumpp

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« Reply #450 on: April 03, 2005, 09:20:34 AM »
Quote
After some searching I found out that the tested plane was a Fw 190A-3 (Wnr. 511). It was tested in various configurations depending the purpose of the test, as an example below is one tested configuration (from FWB. Nr. 06006, there is several pics on other configurations too); profiled pylons and ETC in the centerline (with wheel doors, not an operational configuration). In the case of the report UM21 1, the drag at Cd0 is lower than in any configuration tested for the FWB.Nr. 06006 so it's certain that that the tested plane was in the clean configuration.
(Image removed from quote.)


No Gripen,

Those are the Junkers Trager.  Which were one of many different types tested.  Only three types saw operational use.



So beyond a shadow of a doubt you have found one of many drag studies on the FW-190G and are attempting to pass it off as a 190A.

From your demonstrated level of WWII aircraft design knowledge this can hardly be passed off as simple mistake.  

All the best,

Crumpp
« Last Edit: April 03, 2005, 11:39:23 AM by Crumpp »

Offline gripen

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« Reply #451 on: April 03, 2005, 09:50:21 AM »
Dear Crumpp,
Why don't you stop your never ending personal attacks. I have given the reference, get the report and check if it's a drag study for the Fw 190G.

gripen

Offline butch2k

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« Reply #452 on: April 03, 2005, 10:42:00 AM »
Parts of the translated version of Gripen's doc.




Offline Crumpp

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« Reply #453 on: April 03, 2005, 11:35:03 AM »
Thanks Butch!

Gripen the clean configuration of the FW-190G has a MUCH higher drag profile than the FW-190A fighter varient.  This is due to intake changes and the absence of adjustable cooling gills.  You can verify this from the level speed measurements.

The aircraft was designed to  pull high loads for long distances.

All the best,

Crumpp
« Last Edit: April 03, 2005, 11:43:45 AM by Crumpp »

Offline gripen

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« Reply #454 on: April 03, 2005, 02:37:28 PM »
Well, those translations confirm pretty much all I said about the systematical error in the early measurements in the Chalais-Meudon.

The tested plane was a Fw 190A-3 as can be confirmed from the pictures  so it had the adjustable cooling gills.

gripen

Offline Crumpp

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« Reply #455 on: April 03, 2005, 05:59:29 PM »
Quote
Well, those translations confirm pretty much all I said about the systematical error in the early measurements in the Chalais-Meudon.


Yes Gripen for the FW-190G for this report.  Not for your implication that all FW-190 drag polars are wrong but this one.

It has no bearing on the FW-190A drag polars from both earlier and later test's.  I have drag polars on FW-190A's from FW-190V5g to the FW-190A8/A9 (801TH).  For the FW-190A series the polar agreement seems pretty good.

For your report on the FW-190G:

The prototype FW-190G was taken from a FW-190A3.  The first production varients were the FW-190A4/U8, later blanket redesignated as FW-190G1.

No it does not have adjustable cooling gills and it does have a different intake.

Here is the part numbers for the tropical cowlings.  Notice the G series is different.  Why is that?  It had a different intake!



The drag is totally different from an FW-190A series.

I am sure you already knew this though before you even posted.

Quote
Gripen says:
Why don't you stop your never ending personal attacks.


Coming from you this is a laughable comment.  Maybe you should read your past post's starting with the most recent ones.  

All the best,

Crumpp
« Last Edit: April 03, 2005, 10:15:36 PM by Crumpp »

Offline gripen

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« Reply #456 on: April 03, 2005, 10:42:40 PM »
Quote
Originally posted by Crumpp
Not for your implication that all FW-190 drag polars are wrong but this one.


I'm saying that the tests made in the Chalais-Meudon before the error was discovered seem to have a systematical error due to wrong correction factors. The FWB. Nr. 06006 data was tested in the July 1943 and the report is dated August and it has the mentioned error.

Quote
Originally posted by Crumpp
The prototype FW-190G was taken from a FW-190A3.  The first production varients were the FW-190A4/U8, later blanket redesignated as FW-190G1.


The tested plane was a standard Fw 190A-3 and same airframe was used for wide range of tests. Please get the report.

Quote
Originally posted by Crumpp
Coming from you this is a laughable comment.  Maybe you should read your past post's starting with the most recent ones.  


When I bring in the data, you inform me that I can't read the plot, then you inform me that there is nothing wrong with the other plot despite the documentation says so, then you inform me that my translation is bad and so on...

When butch2k brings in the same data you thank him...

gripen

Offline Crumpp

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« Reply #457 on: April 03, 2005, 11:23:14 PM »
Quote
The tested plane was a standard Fw 190A-3 and same airframe was used for wide range of tests. Please get the report.


It's not the same plane, Gripen.  It's the prototype FW-190G.  Completely different aircraft with different characteristics.  Documented and proven.

How many times does this have to be stated?  It's in the report and it is proven by the photographs you posted.
   
Butch2K simply put what was in the report which is exactly what I said it was!!  

Notice the wording of the document as well, MAY BE due to jet inclination.  Facts are Focke Wulf never did figure out why they got such poor performance out of the FW-190G.  The intake and lack of adjustable cooling fins are not the only changes.  Quite a few changes were made to the engine as well including a completely different ignition harness.  I suspect it was not one thing but a combination of minor performance robbing changes to set the aircraft up to haul large loads over long distances reliably.

The earlier test's from this report are effected!

Not every earlier drag polar as you tried to claim and got called out on!

In short it is useless as representative of the FW-190A.

All the best,

Crumpp
« Last Edit: April 03, 2005, 11:35:31 PM by Crumpp »

Offline gripen

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« Reply #458 on: April 04, 2005, 02:54:36 AM »
Quote
Originally posted by Crumpp

How many times does this have to be stated? It's in the report and it is proven by the photographs you posted.


This plane was tested in the wide range of configurations (including clean) and given the purpose of the tests (which can be figured out from the polar graph), it's certain that that the plane was in the clean configuration. Basicly it was a dedicated wind tunnel airframe which probably never flew.

Quote
Originally posted by Crumpp
   
Butch2K simply put what was in the report which is exactly what I said it was!!  


Why don't you just ask from butch2k what kind test report it is.

Or better, get the report.

Quote
Originally posted by Crumpp

The earlier test's from this report are effected!


This is not what the report says, it says that earlier measurements from the another report (FWB. Nr. 06006) were effected.

"Vergleich mit früheren Messungen von Focke-Wulf"

It also tells how the error was discovered in the yet another measurements with the wing with symmetrical profile.

Besides such translation is unlogical, wrong and also gives an impression that the testers were idiots.

gripen

Offline Crumpp

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« Reply #459 on: April 04, 2005, 05:40:42 AM »
Quote
his plane was tested in the wide range of configurations (including clean) and given the purpose of the tests (which can be figured out from the polar graph), it's certain that that the plane was in the clean configuration. Basicly it was a dedicated wind tunnel airframe which probably never flew.



Gripen,

It was the FW-190G prototype.  

Again proven by your pictures of it:

Gripens picture:




Junkers Trager for the FW-190G:



Your contining to argue the obvious does not change this fact.

Even "clean", an FW-190G has much more drag than an FW-190A.  The internal intake is different and the cooling fins are not adjustable.

Part numbers for ordering intake filters:



Again, your disputing the facts does not change them.

All the best,

Crumpp

Offline gripen

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« Reply #460 on: April 04, 2005, 08:02:40 AM »
Well, people believe the things they want to believe.

gripen

Offline joeblogs

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« Reply #461 on: April 15, 2005, 12:57:09 PM »
...what is the source of all this tabular data you get?

-Blogs


Quote
Originally posted by Badboy
The efficiency factor does work during that kind of maneuvering, what doesn’t work so well is the parabolic drag polar. The fact is that all the theory we have been discussing has evolved around the assumption that the relationships can be fitted with a parabolic polar. That turns out to be a very reasonable assumption for aircraft that have low AoA limits and depend exclusively on conventional lift. However, it is only approximately true, and in situations such as when other forms of lift are involved, or when the flow becomes turbulent near the edge of the envelope, it becomes more difficult to ignore. In those situations, it isn’t the value of e that needs to be modified, something other than a parabolic polar should be used.  

The popularity of parabolic polars, and quadratic relationships and their appeal in aerodynamics stems from the fact that most of the resulting equations can be solved analytically, and generally they do produce good results, and errors are smoothed out to some extent within the coefficients. However, when you work with real aircraft, it isn’t always possible to use those simple relationships, and there are a number of alternatives. Firstly, you can model with non-quadratic relationships, but then the equations do not always have analytical solutions, (but they sometimes do) which doesn’t really matter because you can solve them using numerical methods, it just requires more computer time. There are other ways to match the real curves, very accurately, or at least with any degree of fidelity you wish, but it involves working with large quantities of tabular data. Both of those methods entirely resolve the issues of partial fit discrepancies for parabolic curves and enable very close predictions, even at the extremes of the envelope.  I use those methods when ever I work with real aircraft, for EM analysis for example, but if you are analyzing what is happening in a simulation, such as AH for example, the traditional method is fine, because that is what is being used in the flight model anyway.

Hope that helps…

Badboy