Leading Edge Slats on the Me-109

[Kurfürst]

Originally Posted by lonewulf

The slats were spring loaded and extended or retracted depending on the amount of air pressure being exerted on the leading edge. If you suddenly stalled one wing the slat on that wing might extend suddenly but typically they would extend gradually as airspeed dropped below 200k.

Because the slats could extend asymmetrically, this could result in an uneven airflow over the wings.

Hi,

There is no spring in the Me 109 slats, they are sucked out by air pressure. AFAIK they are more actuated by the angle of attack of the wing and designed that if it reaches crticial angle, they would deploy. That's why they are working independent, i.e. if they deploy assimetrically, it means that one of the wings have reached a critical angle of attack, the other did not. The uneven airflow is a cause and not an effect of their deployment (if they would not deploy on that wing, the wing would detach the airflow stall).

The very reason of their employment is to make sure that once the wing is near stalling, the slats, by their deployment would keep the outer portion of the wing from stalling, so that ailerons would be still effective.

[Flanker35M]

S!

As Kurfürst said, the slats on Bf109 have no springs. They are on rails sliding forth and back depending on AoA. Moved them on the Finnish Bf109G-6 in Tikkakoski.

[Redroach]

Mh there still seem to be doubts... optically, some confirm that they work, but functionally?
My personal, albeit not extensive, experience, is that the Me-109s are VERY flimsy at slow speeds, when compared to its IL-2 1946 incarnations. Every remotely hard aileron/rudder input could lead into a spin imho - that's why I was asking.

[bongodriver]

slats don't prevent spins

[lonewulf]

I clipped the following info from the wikipedia on the subject of leading edge slats to back up my comments:

Leading Edge Slats
"Types include:
Automatic - the slat lies flush with the wing leading edge until reduced aerodynamic forces allow it to extend by way of springs when needed.
Fixed - the slat is permanently extended. This is sometimes used on specialist low-speed aircraft (these are referred to as slots) or when simplicity takes precedence over speed.
Powered - the slat extension can be controlled by the pilot. This is commonly used on airliners."

"During World War II German aircraft commonly fitted a more advanced version that pushed back flush against the wing by air pressure to reduce drag, popping out when the airflow decreased during slower flight. Notable slats of that time belonged to the German Fieseler Fi 156 Storch. These were similar in design to retractable slats, but were fixed non-retractable slots. The slotted wing allowed this aircraft to take off into a light wind in less than 45 m (150 ft), and land in 18 m (60 ft). Aircraft designed by the Messerschmitt company employed leading-edge slats as a general rule."

If someone has some conflicting information to backup their views that the 109s LES weren't spring actuated, I'd be interested to see it.

[Al Schlageter]

Originally Posted by lonewulf

If someone has some conflicting information to backup their views that the 109s LES weren't spring actuated, I'd be interested to see it.

http://109lair.hobbyvista.com/techre...lats/slats.htm

[Random_Nonsense]

Originally Posted by lonewulf

If someone has some conflicting information to backup their views that the 109s LES weren't spring actuated, I'd be interested to see it.

I've pushed the slats in and out on a Buchon . No springs on them and they are pretty similar to a 109

[lonewulf]

Well, on the basis of the info supplied by Schlageter and Random Nonsense it appears that I was wrong about the slats. I withdraw and apologize.

[5./JG27.Farber]

Originally Posted by lonewulf

I clipped the following info from the wikipedia

Wikipedia is by far the worst source for any information. You might as well ask a stranger in the street. You can actually find contradictions on the same page on most things on wiki if you look hard enough.... Sometimes not even that hard.

Like you, I also found this out the hard way.

[JtD]

Originally Posted by 5./JG27.Farber

Wikipedia is by far the worst source for any information.

That's just not true, on average it's a great free source of accurate information. It is, as with any other source, still advisable to double check against another source.

WRT the slats, the flight model and the slat animation are not necessarily linked. You can have the full benefit of the slats in terms of stall speed and handling, without ever seeing them move. Other way round is also possible. You can most easily check if they are in the FM by determining the maximum power off lift coefficient.