Maybe the 190s arent wrong....or how to be really unpopular in 1 step

[Crumpp]

Getting back to the discussion of the fundamental relationship of power available to power required.

Here is some food for thought in the form of the percentage weight gain of various USAAF Fighters:

 


Generally speaking, all of these weight gains accompanied a power available increase.  I remind the participants that power available increase can come in many forms.  More efficient propeller, drag reductions, etc...

Not solely from an increase in engine power.

Using the Rüstgewicht (empty service weight) the FW-190A BMW801D2 powered fighter variant series gained 5.9%.

All the best,

Crumpp

[Crumpp]

Of course it is the same, the formula is being used to calculate the CL required from the wing to create the required lift under a given set of conditions.

Exactly Justin.

Keep in mind however it is only an estimate and not the absolute and correct CL.  This sheet of comparing measurements to calculations provides a good example for various airfoils provides a clue to the margin of error:
 

So it is easy to see that while the calculated CL required gives good agreement in the majority of cases and provides for reasonable predictions it is not the absolute and correct CL as claimed.

All the best,

Crumpp

[KAntti]

Originally posted by Kev367th
Real warbirds, yup.
But in 'mock' combats theres not the desperation of knowing you could get shot down 'for real'.

Yup regardless of which side.
They are great for reading, but hardly a source of hard quantifiable data.
Not a question of believing or disbelieving anecdotes, you can't build an FM from them, they're not exact.

edit - Apart from that, there's enough disagreement when hard data is posted, imagine the chaos/accusations if FM's started to be built using anecdotes.

Don't fly IL2 so I can't comment, but from speaking to Skuzzy they don't think much of any of the FM's in it.
Apart from that, IL2 has zero to do with this game anyway.

Again I am not talking about comparing AC to annother so 'mock' combats are unnecessary. I am talking about 109's or any other AH AC's stall performance. U dont need any combat to perform such a test.

U really cant build an FM based on anecdotes I think so too, but you cannot calculate the behavior of an AC with just math. If that was the case, any test flight series would be totally useless. There are things a math cannot provide an answer to, thats why the tests are necessary.

In your opinion this would mean that no matter what the test pilot says about the performance,  the engineers would dismiss the remarks as anecdotes.

[Crumpp]

but you cannot calculate the behavior of an AC with just math.

Absolutely.  Just look at the F-18.

All the best,

Crumpp

[justin_g]

Crumpp, it is an exact number. It is the exact CL required[/b] to meet a given set of conditions. See the B747 example from aerospaceweb.org, reproduced below:

Basic physics tells us that the lift and weight should be equal to each other for any aircraft in steady, level flight. If the two forces were not equal, the plane would not remain in level flight. Either the plane would climb to a higher altitude because the lift exceeded the weight and pulled it upward or the plane would descend due to the greater weight pulling it down.

We can use this relationship to rearrange the lift equation and apply it in a new way. Since lift must equal weight for the plane to fly level, lift becomes a known value that we can use to solve for the lift coefficient. The lift equation then becomes:

(Image removed from quote.)

We can again use the values provided above for the 747 to solve this equation.

(Image removed from quote.)

Lo and behold, the lift coefficient is 0.52, exactly the value provided in the original data. This application of the lift equation may seem backwards, but engineers often use it during the preliminary design process of a new aircraft. A cruise speed as well as an approximate weight and size are typically specified when the design effort begins. These values can be used in the above equation to solve for the lift coefficient necessary to maintain cruise flight at those conditions. Once that coefficient in known, designers can determine what wing shape and airfoil section will best provide that lift coefficient while minimizing drag. Other factors obviously come into play since an aircraft does not spend its entire flight at steady and level conditions, but this technique is a common first step in the initial sizing and design of a new flying vehicle.

[justin_g]

What effect does wingloading have on Pr in turns at Clmax?

[hitech]

F4UDOA: Thanks just never have seen density combied with mph to fps conversion along with a 1/density instead of density combiened with the vel term and area term. Net wash is the same equations  either way.

Had me confused for a sec.

Any way I  belive you were correct with the 391 number .

1.4666 is mph to fps conversion

Should be = 1 / (1.4666 * 1.4666 * 0.5 * 0.00237)

HiTech

[Crumpp]

Crumpp, it is an exact number.

Doah!  For some reason I have turning on the brain.  It will be the same for level flight.  Got wrapped around the 2D vs 3D theory on which is better for analysis.

Other factors obviously come into play since an aircraft does not spend its entire flight at steady and level conditions,

Thanks,

Crumpp

[gripen]

Other factors obviously come into play since an aircraft does not spend its entire flight at steady and level conditions,

The calculation for Cl required is absolutely accurate for any given flight condition; level, climb, turn, dive or what ever.

gripen

[KD303]

Originally posted by Crumpp
I can just picture some German POW thinking:







"Why yes Mr interrogator, we hated the damn thing too.  Always ran rough like that.  In fact I was scared to death it was going to fall out of the sky on the flight over!"

That is purely speculative. There were Luftwaffe crew who were happy to help the allies. Men who didn't dig the Nazis and wanted them defeated. Remember the Ju 88 of 10./NJG3,  crewed by  Oblt Heinrich Schmitt,  Ofw Paul Rosenberger and Ofw Erich Kantwill? They flew from Norway to Dyce in Scotland, gifting the British with a shiney new Lichtenstein radar, allowing the boffins to cut the strips of window to the right length, thus jamming German night fighters' radar and enabling Bomber Command to devastate Hamburg with few losses. So it's quite conceivable that a FW pilot would help the British with the 190. They would only need to find one man willing to help and I doubt they were so stupid as to be taken in by some guy feeding them nonsense. We're not talking about back engineering a UFO.

KD

[Crumpp]

That is purely speculative. There were Luftwaffe crew who were happy to help the allies. Men who didn't dig the Nazis and wanted them defeated. Remember the Ju 88 of 10./NJG3, crewed by Oblt Heinrich Schmitt, Ofw Paul Rosenberger and Ofw Erich Kantwill? They flew from Norway to Dyce in Scotland, gifting the British with a shiney new Lichtenstein radar, allowing the boffins to cut the strips of window to the right length, thus jamming German night fighters' radar and enabling Bomber Command to devastate Hamburg with few losses. So it's quite conceivable that a FW pilot would help the British with the 190. They would only need to find one man willing to help and I doubt they were so stupid as to be taken in by some guy feeding them nonsense. We're not talking about back engineering a UFO.

Nice speculation on your part as well.

Facts are the rule is POW's resist.  The exception is that they cooperate.

[Simaril]

But the real question, Crumpp, is whether you would have dismissed them if they said something you liked. That lies at the root of intellectual honesty, and separates the partisan from the investigator.

So while you feel safe in saying POWs as a rule resist, we can also say that interrogators as a rule understand that their subjects are unwilling and may be actively deceptive. Interrogators carefully seek corroboration and independent sources of information before reaching conclusions.

Why are you eager to trust the nature of german POWs but not the nature of their interrogators?

I have my suspicions.

[Crumpp]

I think you are speculating quite a bit there.  I did not make a snap judgement based on feelings or desires.

I think it is much more plausible to believe the BMW, Rechlin, and Focke Wulf reports on the technical aspects of the aircraft.

So it has nothing to do with speculation on the part of a POW's testimony.  

Since the technical qualities discussed are not the technical qualities exhibited by the motor when set up properly.  The engine did not vibrate excessively.  In fact the Lufterrad was designed to uncouple from the shaft if it vibrated out of specified range.

All the best,

Crumpp

[Simaril]

Speculating that interrogators know their subjects are enemy combatants? That their loyalties likely lie with their homeland?

Seems a pretty safe bet....safer than, say, assuming that the interrogators would take eveything at face value...

[Glasses]

Well NASA had to reverse engineer the Kommandogeraet in the Fw 190 to see how it went together