Are slats shy ?

[JtD]

Originally Posted by IvanK

Here are the values the RAE determined in Flight test Source AVIA 6/2394 BF109E Evaluation...

A pretty good match with the simple statement in the 109E description, all things considered.

Regardings Crumpps chart, "Spaltklappen" and "Spreizklappen" are two different types of flaps, not leading edge slats. The slats don't open gradually. But from that polar and the RAF test, it should be easy to derive the AoA of ~ 8° at which they bang open.

[Crumpp]

"Spaltklappen" and "Spreizklappen" are two different types of flaps, not leading edge slats

Who cares and totally irrelevant to anything I posted. I know that and anyone who reads German knows it as well.

Neither of those polars is even in the discussion nor included in the values presented.

The slats don't open gradually

Baloney.

The slats open as required and the amount can be precisely controlled by the pilot. From open to close in the Bf-109 is ~2.5 degrees of angle of attack. A pilot can move through than little amount of angle so fast it would seem that they either open or closed. The reality is a pilot can control them and they will only open the amount required. If you knew how to read a polar, you would know that as the shape of the curve would depict it if the slats could only be fully open or fully closed. Simply put, there would be a shift in the polar and not a smooth transition.

Just how many hours do you have flying an aircraft equipped with slats? I can tell you, you have NONE as you don't know how they work at all. You have never been up in an airplane equipped with them either. Stop presenting erroneous information as fact.

I have about 400 hours flying a plane equipped with slats that work just like the Bf-109's.

It is called a "stick" and it is there for the pilot to command the airplane. This is me piloting my airplane a few years ago.

http://www.youtube.com/watch?v=-vbqgfjyW2Q

[Crumpp]

"Spaltklappen" and "Spreizklappen"

Is the radiator and intake flaps, btw....

Polar represents landing flaps at 60 degrees and the influence of the radiator and intake flap settings.

[CaptainDoggles]

Originally Posted by Crumpp

Is the radiator and intake flaps, btw....

Are you sure? I think Spreizklappen are slotted trailing edge flaps whereas spaltklappen are split flaps. I understood these polars to be from tests of an E-3 for evaluating different alternatives to be included on the F-series as components (in this case different flap designs).

Image for those not familiar with different types of flaps

[JtD]

Originally Posted by Crumpp

Is the radiator and intake flaps, btw....

Polar represents landing flaps at 60 degrees and the influence of the radiator and intake flap settings.

No, in addition to what CaptainDoggles wrote, the cooler flap is set at 60°.

[Friedric]

And there should be a bang nose isn it ?

[CaptainDoggles]

Originally Posted by Friedric

And there should be a bang nose isn it ?

Only if they open violently, i.e you go from low to very high AOA in a short amount of time. It's basically just like a drawer in your kitchen. If you yank it open it'll slam into the end of its track. If you open it smoothly it won't.

[CaptainDoggles]

Originally Posted by cheesehawk

Unless it was very very drastic, I doubt you'd hear it over an engine anyways.

Agree. It'd probably be more like a tactile sensation through the controls.

[TomcatViP]

In that case the noise of the shock will travel inside the wing just to be amplified by the vast empty space of the fuselage (resonance) where there is the pilot. I think that the Bang (if there was one ever) wld be audible above the eng noise (just like AP bullets impact etc...).

Reading modern account of private pilot flying the 109 E shld give the answer.

[JtD]

Not everyone around here speaks German, and given that the chart is labelled with Spalt- und Spreizklappe, and the legend contains it as well, it is useful information for everyone to understand the chart.

You presented a value from flaps extended polars, as you say the stall happens at ~17.5°, which is only the case with flaps extended. Good to know it wasn't intentional.

Slats open as chosen by the designer. It is absolutely possible to give them progressive characteristics so that they indeed bang open. This is reported by many pilots in case of the 109, and while I haven't flown one, I trust their word over yours.

I also have no clue how much simplified the polar is, it can contain everything or nothing. The information that can definitely be taken out is the one you and I agree on, the AoA the slats open at.

You're welcome to educate everyone on how you extract the other information.