Leading Edge Slats on the Me-109

[Crumpp]

Then why is washout not automatically considered an anti-spin device?

Washout does not energize the boundary layer....

[taildraggernut]

Originally Posted by Crumpp

Washout does not energize the boundary layer....

neither do slats once they have gone beyond maximum angle of attack and stalled........

[Glider]

Originally Posted by Crumpp

Washout does not energize the boundary layer....

Still Wondering

Crumpp
What do you tell your students about leading edge slots? Do you tell them:-

a) That they are devices that delay the stall or
b) That they are anti spin devices

Just wondering

[TomcatViP]

Originally Posted by taildraggernut

neither do slats once they have gone beyond maximum angle of attack and stalled........

The section of the wing close to the wing roots have alrdy stalled at that time (pls refer to the diag that has been alrdy posted on another similar topic). Hence the stall has alrdy occured before the slotted portion of the wing has stalled!!!

It's all abt having such device.

Washout is good but produce a lot of drag. Accetable for a GA aircraft but not good for a fighter! It's one of the raison why the Spitty was so slow!

[Crumpp]

neither do slats once they have gone beyond maximum angle of attack and stalled........

Right, they don't fly to the moon either despite being an anti-spin device.

What that has to do with anything, I don't know. Maybe it is significant in your mind?

What they do is energize the boundary layer by increasing the high energy turbulent portion so that stall is delayed significantly compared to plain airfoil.

Twisting on the otherhand, simply moves the angle of incidence a few degrees.

Go back a few pages and look over the definition of "spin resistant airplane".

Maybe the light bulb will come on for you and maybe not?

[*Buzzsaw*]

Originally Posted by TomcatViP

A-The 109 undercarriage was not build that way to facilitate it's shipping via train (at least not only - but this is the first time I think that I have to read it). It was made to make assembly easier with the wing being plugged onto the fuselage. Remind that Bf (and not Mtt at the time ) did not have the production facilities that would be needed for such a big order by the RLM. Many parts were subcontracted (heinkel etc...) and had to be moved from one facility to another. Having the fuselage "crated" by its own undercarriage as soon as possible facilitate the production and made the wing stronger for a given weight (and Mr Messer was addicted to weight reduction as any good eng shld be!).

I have seen several sources which say the requirement for train transport was listed by RLM in the competition. Yes, Bayerische Flugzeugwerke was compelled to outsource many of its manufacture, but that did not require a design which had the undercarriage mounted as it was.

there was a revolution in 1935. And this flow slowly ard the globe from Germany then USA and all obver the globe after 1945.

Suggesting an aero revolution occurred only in Germany, and spread from there is not accurate. In fact, modern designs were being created in many other countries at the same time as the 109, some of which could be called further advanced, some less.

And further, many of the design elements of the 109 were taken from many other aircraft, i;ncluding those from outside Germany. To suggest these elements originated only in Germany again is inaccurate.

Aircraft design in the early '30's, as it is today, was a process of osmosis, with ideas and innovations rapidly circulating and moving from one location to another.

[*Buzzsaw*]

Originally Posted by TomcatViP

Washout is good but produce a lot of drag. Accetable for a GA aircraft but not good for a fighter! It's one of the raison why the Spitty was so slow!

The drag profile for the Spitfire showed the majority of the drag was a function of its radiator placement, not the washout.

And are you suggesting slats don't produce drag? Any device this size extended into the airstream below the wing is obviously going to produce a very large amount of drag.

Even when the slats are not extended there was drag.

And the 109 wing's tendency to early compressibility was partially a function of the slats being present.

If you haven't seen it, then time to look at the following analysis, by an engineer who was on the Messerschmidt design staff:

http://www.wwiiaircraftperformance.o...ner-Me_109.pdf

[taildraggernut]

Originally Posted by Crumpp

Right, they don't fly to the moon either despite being an anti-spin device.

What that has to do with anything, I don't know. Maybe it is significant in your mind?

What they do is energize the boundary layer by increasing the high energy turbulent portion so that stall is delayed significantly compared to plain airfoil.

Twisting on the otherhand, simply moves the angle of incidence a few degrees.

Go back a few pages and look over the definition of "spin resistant airplane".

Maybe the light bulb will come on for you and maybe not?

when it comes to defining resistant I think you provide the perfect example.

Heres a really nice and simple way to illustrate this for you...you have pitched up in your 109....inboard section of the wing begins to stall and the lovely slats have deployed keeping you nice and safe....you keep pulling and your angle of attack is still increasing (even for the magic outboard section of the wing).....now you have pitched so much that you have stalled the outboard section of the wing because you have gone beyond the maximum angle of attack the slats allow.......please explain from this point what magic force is in place to prevent a spin.

Now if you are sticking with the 109 elevator being unable to provide enough force to pitch beyond that point then you have:

1. eliminated the slats from actually being the main protection.
2. just highlighted exactly why the 109 was inferior in turn performance.

I see that not even NACA managed to educate you on the real mechanics behind boundary layers.....go back a few pages and you will see how they completely contradict your theories.

now what washout does is because of the physical twist in the wing putting the tips at lower incidence, the outboard sections of the wing remain unstalled when the inboards are stalled because the outboard sections are at a lower angle of attack.....which means the boundary layer is still adhereing to outboard section ofthe wing (because they are NOT stalled), airflow is still flowing over the ailerons making them effective...pretty much all the same conditions that are applying to the 109.....now if only there was some way of preventing pitching beyond critical angle of attack my Spit would be unspinnable.......no stall = no spin remember.

Trust me...my lightbulb is on AND I'm home too.

[TomcatViP]

Originally Posted by *Buzzsaw*

The drag profile for the Spitfire showed the majority of the drag was a function of its radiator placement, not the washout.

And are you suggesting slats don't produce drag? Any device this size extended into the airstream below the wing is obviously going to produce a very large amount of drag.

Even when the slats are not extended there was drag.

And the 109 wing's tendency to early compressibility was partially a function of the slats being present.

If you haven't seen it, then time to look at the following analysis, by an engineer who was on the Messerschmidt design staff:

http://www.wwiiaircraftperformance.o...ner-Me_109.pdf

C'mon a lot of modern fighter use slat and are supersonic. I don't see any link.

More over when you hve 1000hp in front of your airplane you don't care that much abt low speed drag (but to weight).
Washout are draggy during cruise (range) and when you attend your max perf range.

Ok enough of this especially after your argument abt going into the stall after your plane is shaking during a fight (but no mention here from you abt stick travel and af Cg huh).

[Al Schlageter]

Originally Posted by TomcatViP

C'mon a lot of modern fighter use slat and are supersonic. I don't see any link.

Don't you mean drooping leading edges.