Oh I do, pal. ;) What I don't understand is your ego. ;) You ruin every potentially interesting conversation by your aggressive 'fu, I know it all' attitude. :-P:-P

Let's try again - you can control the AoA, you can control the speed, but you can't actualy control the bloody slats. They pop in or out as a result of the above and you can predict it if you're not diff - just as you can predict that the aerial on your car will bend when you reach say 120mph - but you don't bend your aerial, it bends because you drive fast. :o You can make a video of yourself driving a car on the motorway with your foot on the pedal and the aerial bending but that's its design and general physics. Look - aerial control. As you can predict its behaviour you can take advantage of it, shall it come to that. Please don't ask me why have I come with bizarre example like this :D

And yes I know what you ment, we're not retarded here dude.

Oh yeah and tell us how you control your altimeter as you move the nose of your aircraft up and down.

Need video of slats at an intermediate position.

As a dedicated piloting task controlling slat position with fine stick (AOA) control is a straight forward and good experiment. however in the hussle and Bustle of combat I suggest AOA changes would generally result in the slats being either in or out ... hence the pilots description of them "banging" in or out.

Crummp I too am confused by your "Wannka Wannka Wannnka" bit... can I assume you have spelt it correctly ? Is it a US term or are you referring to some basic Brit slang ?

Look at the Bf-109E polar I posted, it is only ~2.5 degrees of AoA between the slats beginning to open and fully deployed. That is not much to work with.

I did not say it was easy or did not take practice to control them. You are right in that it is not something a pilot is likely to master in his first few hours. They take some getting used too. The airplane will shift when they deploy. If you watch the video, you can see some of the changes in radius in that turn. The slats can make loud startling noises.

In a fighter equipped with them, that shifting would make aiming more difficult. Once you learn what they can do though, the low speed maneuvering is fantastic. I won an ultralight Short Landing contest with a 4000lb airplane because of those slats. I could hang that airplane on the propeller all day long. In fact, clean, it would not break in the stall. With full length LE slats, the plane would nose up, hang on the propeller, and gradually enter a 900 fpm descent. You were stalled when the airplane was nose up and descending. The stall angle was so steep, I used to put a pencil on the glare shield to impress FAA examiners and it would fall straight back to the luggage compartment over the top of all the seats without hitting them.

The real maneuvering fight would not begin for a Bf-109 pilot until those slats where out. That is exactly how I felt about my aircraft. Once those slats deployed, it was time get busy if I wanted to maneuver.

http://www.virtualpilots.fi/feature/...09myths/#slats

As I see it based on my experience and knowledge:

Slats Pro's

- Low speed handling / maneuvering improvement
- very benign stall
- immune to spinning (read the RAE trials)

http://kurfurst.org/Tactical_trials/...ls/Morgan.html

Slat Con's
- Opening moment reduces effectiveness as a gun platform.
- Asymmetric deployment is normal. A mechanical malfunction is not. If a slat becomes stuck due to mechanism failure, the pilot has a real control problem if the other deploys.
- noise form a hard opening is startling.

Much of what you are asking depends on the specific stability and control of the aircraft in question. I will try to convey the general effect of the slats outside of specific stability and control.

You can definitely feel when the slats deploy. It moves the trim point and the stick pushes back against your hand trying get to that point.

The slats energize the boundary layer. What does that mean? They create turbulent flow over the wing. Turbulent flow is high energy flow and that means it has energy to convert that flow to lift. That is not turbulence as in buffeting. Buffeting is caused by flow reversal which means the boundary layer separates from the wing stalling that portion.

A boundary layer has two types of flow, Laminar and turbulent. Watch a cigarette in an ashtray sometime as it burns. The straight smoke is laminar and where it becomes wavy is turbulent. Laminar is low drag and low energy. Turbulent flow has more energy and more drag. The higher energy means it can meet the lift force required at a lower dynamic pressure.

The effect is best described as the airplane responds like it is flying at a much higher speed. It does not feel mushy or like it is struggling in slow flight. You can maneuver more precisely than you could when the slats were not out. As you get closer to CLmax and the dynamic pressure drops in 1G level flight, that feeling will diminish.

Is that clear or confusing?

That makes a little bit of sense, as the chart explicitly states "Spreizklappen innen" - "slotted flaps inwards". Which probably means they only changed the part around the radiator.

I'd think they move to the left, i.e. proving more lift for the same AoA...but I don't see how the trailing edge flaps suddenly became the issue.

That's interesting and impossible to know from just looking at the chart - these dots carry no designation and could be anything, in particular as the same dots cannot be distinguished in the flaps extended polars. So thanks for telling.

Of course not....that would mean you spouted off without knowing the context or details, posting something to discredit whatever I said.
:rolleyes:

It does move to the left when TE flaps deploy. A camber change shifts the lift curve reducing the AoA CLmax for the airfoil occurs.

In this case though you claimed that the top polars were different designs of TE flaps deployed and their effect. They were different designs of radiator flaps as I stated in my first reply of too many to you.

Therefore, the curve in question on the bottom would be shifted to the right if that was the case. You started posting about the language used on the polar out of context and without the details.

JtD your focus is never on the topic at hand. It is only to discredit anything I say in any way that you can.

I have nothing further on this topic or any other topic for you. You can work whatever angle you dream up to claw at this conversation but I wish you good luck in your life.

For the readers, asymmetric deployment is normal. As the slat works as required, it does not effect the flight of the aircraft at all compared to symmetrical deployment.

It only becomes a problem when if the slats experience a mechanical malfunction and one slat cannot meet the force required.

Hi IvanK,

I hve been thinking at the solution you wrote over the night and I hve some doubt of the solution proposed: V_SlatOut = VstallxSQR(G)

At first I understand that this is similar to old IL2 and thus is a satisfactory solution for all. However my point here is that it cld be improved.

Slat deployment on the 109 was governed by the air pressure on the leading edge (LE) and the hinged mechanism weight and frictions forces.

a. Frictions forces are cte (K)
b. Weight effect is dependent on G (P=mg)
c. Dyn Pressue acting on the slat is a function of the speed of the plane (V) and the AoA (alpha) with Pdyn = 0.5roV²S*cos(alpha)

Hence we have V_SlatOut = f(G, Pdyn) + K

At 1G, the speed being known, as is the AoA we have the resulting value of the Weight and friction of the mechanism given that we make the calculation of the projected surface of the slat

We can now choose to consider the friction of the mechanism negligible given tht the slat were known to be retractable only by the application of one finger (and much attention were required to keep the slat close on the ground to protect the mechanism from ingesting dust, sand and small objects).

So basically we will hve V_SlatOut = f(G, Pdyn) tht result in the programmed law :

If V<= V_Stall*SQR(G) and If Pdyn>=mg (m being the resulting balancing mass calculated at the 1G condition) Then Slats Out.

The good thing is that by this way you hve an independent behaviour for both slat that can result in asymmetric deployment ;)

Pls note tht the Weight I am talking abt is not really a mass per G. It's the seen mass by the system combining all efforts in the mechanism that result in the deployment of the slat minus the friction. I am pulling away the frictions forces as they are not dependent of the G and are basically negligible if the system is functioning optimally.

EDIT:

Sry Crumpp I did delete my post as I needed to check my info. Here it is right as before.

I checked the deployment principles here http://109lair.hobbyvista.com/index1024.htm

just a small vid i just made to spice this interesting thread up..

http://www.youtube.com/watch?v=cewk7t_gN-w

Then why do you say the opposite, first?
The Messerschmitt engineers referred to them as trailing edge flaps, but since the radiator flap was part of the trailing edge flap, I don't even understand what point you're trying to make now?
The curve on the bottom would shift to the right if wing camber increased? It wouldn't. In case I misread you, can you please post a little bit more coherent (leaving out the "u suck I rule" stuff would help)?

You could still explain how you see that the slats deploy within the 2.5° between 8 and 11.5° AoA as you said. From where I am standing, it is not on the chart.