Leading Edge Slats on the Me-109

[Crumpp]

I really can't believe you typed this publically, slats are NOT I repeat NOT anti spin devices, slats are not anti-anything devices, they simply allow you to hang on to laminar flow air at slightly higher angles of attack but if you exceed that angle a slatted wing is stalled just like any other and subject to the same pitfalls.

While we're discussing this so civilly

You are not discussing anything civilly...you are just making insults.

So.....how exactly does the fact that the venturi effect caused by the 'slot' created by an open slat which re-energises the boundary layer of air over the wing maintaining smooth flow

First of all, you do not understand the fundamentals of LE slat aerodynamics.

Quit using wikipedia as your source. It is not credible and in this case is just plain wrong as the author does not understand boundary layer mechanics.

In boundary layer mechanics, we have two portions, laminar and turbulent.

Laminar flow is the last thing you want on the outboard portion in a stall. Laminar flow is low energy. That is why it is low drag AND subsequently, low lift.

Slats work by increasing turbulent flow not laminar flow. Turbulent flow portion of the boundary layer is high energy and high lift!

Flow separation from the top of the airfoil, i.e., stall, results from the loss of the kinetic energy in the boundary layer due to viscous shear and an adverse pressure gradient. A turbulent boundary layer is better able to delay flow separation than a laminar boundary layer because of the higher energy associated with the turbulence. For this reason it is better to have a turbulent boundary layer over the airfoil. Vortex generator are put on the top surface of a wing for the purpose of forcing the early transition of the boudary layer to turbulent.

optfly.iaa.ncku.edu.tw/aftdesgn/lect16.pdf

The laminar flow is not the purpose of the slats, it is the increase in turbulent flow boundary layer which delays the onset of the stall.

No stall = NO SPIN! Hence, the spin resistance found in slats and the reason engineers used them as an early anti-spin device.






They are spin resistant because they allow for control inputs that would normally result in a spin. One can easily see this in the RAE report.