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02-23-2011 08:33 PM |
Quote:
Originally Posted by JG52Krupi
(Post 227359)
Rofl, u give messerchmit too much credit if u thought they were mechanically driven, it's my understanding that they are operated by speed/pressure.
They would need a massive camber/airfoil to have the space to fit a mechanical design found on Boeing or Airbus aircraft
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You are right. Airbus/Boeing designs have "LEF's" (Leading Edge Flaps) that extend mechanically.
The SLATS that are used on many smaller planes today and the Me-109 for instance, are automatically spring-loaded/air-pressure operated. When the angle of attack increases, or the airspeed is low (meaning to sustain level flight you need a higher AoA) the center of lift(or center of pressure) moves towards the leading edge of the wing! This decreases the airpressure around the upper side of the leading edge, and allows the mechanical springs to push the slat out. The wing effectively has two leading edges now, each starting off with a fresh boundry layer (the layer of wind which is closest to the wing, if it's laminar flow you're good, but turbulent flow will increase drag and can induce a stall)
So really, the slats are springloaded to open, but I don't know the exact design of the messerschmitt, nor the springforce they set to the slats to keep them from stowing. Either way it's the combination of speed and airpressure around the leading edge that allows it to deploy or stow.
On the center of lift topic: If your airspeed increases, the center of pressure moves aft and as you approach supersonic the dreaded tuck-under effect occurs. The center of lift moves behind the Center of gravity, causing a violent pitch down which in turn increases airspeed and keeps the pitch-down tendency. This is noticeable with the BI-1 or BI-6 where you approach 700-800km/h and loose control to a massive pitch down.
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