Difference between 'slotted wing' and 'fixed slat'
or between trailing edge flap segments on a multi-segment trailing edge flap system such as Fowler flaps
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Grumman HU-16A outer wing slots.
Each wing contains a slot from the tip float out to the wing tip. At high angles of attack, these slots help to keep the airflow attached to the outer portions of the wing so that the inboard portion of the wing will stall first. The benefit of this arrangement is that the ailerons should remain effective up to stall.
The slot is located such that at high angles of attack, high pressure air will be driven into the front of the slot, as shown by the arrows. The cross sectional area of the slot decreases as the air passes through it, additionally accelerating the flow through the slot.
The slot is located such that at high angles of attack, high pressure air will be driven into the front of the slot, as shown by the arrows. The cross sectional area of the slot decreases as the air passes through it, additionally accelerating the flow through the slot.
FWIW, the DH-82 had H.P. automatic slats on some versions, and many also had a separate modification of a tail strake. The slats are similar to the A-4's design, popping out when the resultant force from the element gives a forward force relative to the tracks, and thereby driving the slat outboard. The Fieseler Fi-156 Storch had a fixed geometry LE slat AKA a slotted wing.
Or, in the most basic form of (single-segment) Fowler flap
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Check out the wing of a Helio Courier for all the goodies - AoA controlled slats (the inboard right hand slat quite often pops in at high power - high AoA flight, like take-off) spoilers for low speed roll control and loooong fowler flaps.
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Some pre-1940 designs w/fixed slots:
Lockheed 14 (optional on this ship), and possibly the Hudson
Lockheed 18 Lodestar
Boeing B-17
Slots were difficult to anti-ice, and some operators closed them up (w/ performance penalty) to avoid this problem.
Lockheed 14 (optional on this ship), and possibly the Hudson
Lockheed 18 Lodestar
Boeing B-17
Slots were difficult to anti-ice, and some operators closed them up (w/ performance penalty) to avoid this problem.
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I learned to fly on a DH82A with automatic slats. It was a source of great mystery and wonder to me when they floated out at different times as the aircraft flew more slowly (with no slip, honest!) and they did so with no effect in roll or yaw as one deployed but not the other. Can current Tiger Moth operators comment on whether that is a common characteristic, or a was it just a sweetness of our particular aeroplane?
I assumed the former and wondered how difficult that was to achieve, and whether it was done using a wind-tunnel or through much tweaking during development flying.
I assumed the former and wondered how difficult that was to achieve, and whether it was done using a wind-tunnel or through much tweaking during development flying.
Also early model NA F86, Canadair and CAC Sabres until they incorporated the famous 6:3 wing.
http://www.pprune.org/tech-log/50116...at-forces.html
D120A, I spent a few years flying a Tiger Moth with slats and I never unlocked them, they just seemed a bit pointless to me and our other Tigers didn't have slats.
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From a conceptual standpoint, I'd say a fixed slat is something separate bolted onto a given airfoil, whereas a slotted wing is an air channel cut within that airfoil.
In other words, take a given airfoil, and bolt something on the front of it to produce a slot, and that is a fixed slat. Take it off, and you are back to your original airfoil.
Conversely, take a given airfoil and cut a slot through it, and the overall external profile of the airfoil is still the same. Remove the slot (and the portion of airfoil ahead of it) and you no longer have the original airfoil.
In other words, take a given airfoil, and bolt something on the front of it to produce a slot, and that is a fixed slat. Take it off, and you are back to your original airfoil.
Conversely, take a given airfoil and cut a slot through it, and the overall external profile of the airfoil is still the same. Remove the slot (and the portion of airfoil ahead of it) and you no longer have the original airfoil.
