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Hi,
I heard they were a bit of a problem in dog-fights.
Over the years, all manner of explanations have been offered about the slats on the Messerschmitt 109 family, some of them fairly accurate and some of them downright ludicrous. This article should help to clarify the operation of the slats, their mounting, and their operation.
First, let's discuss what they are NOT:
- They are not motor-operated.
- The port and starboard slats are not connected to each other.
- They are not fixed in one position.
- When extended from the wing surface, they are not "dropped"- they are extended.
This slat design was first proposed by Sir Frederick Handley Page around 1919 as a way to maintain airfoil efficiency at high angles of attack. As the airfoil pivots at a greater angle from the direction of airflow, the point at which the flow detaches from the upper wing surface moves further and further forward. Eventually, if this condition continues, the airflow "unsticks" completely from the upper surface, and the wing stalls. In order to delay this action, the slat on the 109 extends outwards under aerodynamic pressure, channeling airflow back up and over the wing upper surface, thereby maintaining airfoil effectiveness.
A common question asked regarding the 109 is "Should the slats be in or out when the aircraft is parked?" The answer is "yes". The slats are free-moving devices, and are commonly seen extended in many wartime and contemporary photos; however, if manually pushed back into the wing, the slats would remain there until the aircraft moved, at which time they would extend of their own volition. This action was confirmed by Günther Rall when questioned by Lair visitor Erik Whipple some time back; according to Gen. Rall, it was common practice at their field to push the slats in once the aircraft were secured so that no dust or debris would accumulate in the traveling tracks. Evidently at least one new pilot was lost due to faulty operation of the slats when taking off, which led to this practice. However, as with almost everything else 109-related, if the position of the slats is of serious concern to you when building a static model, consult your references to determine the best configuration.
So, now that we've very briefly covered what they are and what they do, let's take a detailed look at the slat systems of the Bf 109. The manual illustrations below are taken from an official factory manual for the Bf 109E; however, the Friedrich retained a similar design for slat operation as the diagram below will show. It should be noted that two major differences introduced on the F version were a reduction in slat span from 2292.5mm to 1800mm, and the elimination of the inboard to outboard connecting linkage . The basic swing-arm movement, function and operation of the slats remained the same, however.
The Bf109 "E" through "F" used the swing arm parallelogram mechanism to agitate the slats. From the "G" onwards the Me 109's used the roller-track mechanism to guide the slats in and out. It all follows a patent bought by Messerschmitt from DeHavilland just prior to the war. The slats are driven out by means of low air-pressure if the AOA gets higher ( slow flight ) and retract by means of air-pressure when accelerating...
The most interesting thing about this is that there are clearly several significant differences between the Friedrich and Gustav wings, despite their outwardly identical appearance. The radiator ducting and the slat mechanism are both different
Most modern fighter aircraft like the F-22 and Eurofighter Typhoon utilize leading edge slats. That tells me leading edge slats are a good feature on fighter aircraft. They were probably cutting edge technology when introduced on the mass production Me-109.
The F-86 had L/E as did the Lysander...
To claim patent rights I believe the system has to be built exactly like the patent holder. If there are different components and the basis of operation of slightly different, there's no basis for patent infringement.
The F-86 had L/E as did the Lysander...
To claim patent rights I believe the system has to be built exactly like the patent holder. If there are different components and the basis of operation of slightly different, there's no basis for patent infringement.
Were not the slats eliminated with the 6-3 wing?