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-   -   109 slots (http://forum.fulqrumpublishing.com/showthread.php?t=18863)

Strike 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

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.

robtek 02-23-2011 09:11 PM

Sorry for OT, but the problem of the p-38 was the turbulence from the center fuselage which rendered the elevator useless at high speeds.

Strike 02-23-2011 09:53 PM

Quote:

Originally Posted by robtek (Post 227561)
Sorry for OT, but the problem of the p-38 was the turbulence from the center fuselage which rendered the elevator useless at high speeds.

hey you're absolutely right.. I forgot about that! But nevertheless, the tuck-under effect applies for nearly all planes with relaxed stability going too fast.

WTE_Galway 02-23-2011 09:58 PM

Quote:

Originally Posted by melkarth (Post 227352)
So it does not matter if they are in or out, they are free and independent the one from the other.

Absolutely and asymmetric deployment of slats did occur and even in some cases caused fatalities.

Khamsin 02-24-2011 06:41 AM

Quote:

Originally Posted by Strike (Post 227546)
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. .................................................. .

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.

Sorry, but no springs on the Bf-109 slat design .... purely air pressure driven.

Which is why you'll see some photos of 109's on the ground with slats retracted, and some with slats extended. If they were spring driven, the slats would always be extended on the ground, wouldn't they?

*Buzzsaw* 02-24-2011 06:48 AM

Salute

To suggest the 109's in CoD are not going to have slats is nonsense.

IL-2 is ten years old and Oleg modelled slats on the 109's in it.

Why should he suddenly decide to go ahistorical and not include them?

Silly thread.

JG52Krupi 02-24-2011 07:11 AM

I'm surprised it's on page 3 but to be fair it's no longer discussing the OP questions any more :)

Strike 02-24-2011 07:41 AM

Quote:

Originally Posted by Khamsin (Post 227702)
Sorry, but no springs on the Bf-109 slat design .... purely air pressure driven.

Which is why you'll see some photos of 109's on the ground with slats retracted, and some with slats extended. If they were spring driven, the slats would always be extended on the ground, wouldn't they?

I agree with your theory, like I said, I'm no 109 expert. However I am familiar with pure aerodynamic slats. I saw a french design during my training that was easily pushable to either retracted or open, like you say about the 109.

I just believe that, for maintenance purposes and wearing, there should be some spring to "dampen" the movement of the slats so that they don't violently slam open or shut. Anyone could tell you that this will fatigue the design unless there was some buffer or spring to soften the movement. Anyways, there seems to be no springs forcing the slats to open.

WTE_Galway 02-24-2011 09:35 AM

Quote:

Originally Posted by Strike (Post 227719)
I agree with your theory, like I said, I'm no 109 expert. However I am familiar with pure aerodynamic slats. I saw a french design during my training that was easily pushable to either retracted or open, like you say about the 109.

I just believe that, for maintenance purposes and wearing, there should be some spring to "dampen" the movement of the slats so that they don't violently slam open or shut. Anyone could tell you that this will fatigue the design unless there was some buffer or spring to soften the movement. Anyways, there seems to be no springs forcing the slats to open.

By all accounts the109 slats actually did, on occasion, violently slam open and shut.

Kwiatek 02-24-2011 06:16 PM

Well it is really funny but i didnt see in any screenshot or videos from BoB slats in 109 or 110. I watched all screenshots from 2008 until now and i didnt saw any open slats in these planes even in turns, take off etc.

It start to be funny :)


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