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Difference Between Flaps And Slats?  
User currently offlineJAM747 From United States of America, joined Feb 2005, 550 posts, RR: 1
Posted (9 years 4 months 3 days ago) and read 32767 times:

What is the difference between flaps and slats. Does it depend on the size or type of aircraft or do all aircrafts have both.

22 replies: All unread, jump to last
 
User currently offlineFredT From United Kingdom, joined Feb 2002, 2185 posts, RR: 26
Reply 1, posted (9 years 4 months 3 days ago) and read 32767 times:

Do a search. The subject has come up in several incarnations here over the last few weeks.

The terminology is somewhat confused. My definition is that slats (and slots) are leading edge devices while flaps are trailing edge devices.

Cheers,
Fred



I thought I was doing good trying to avoid those airport hotels... and look at me now.
User currently offlineOPNLguy From , joined Dec 1969, posts, RR:
Reply 2, posted (9 years 4 months 3 days ago) and read 32767 times:

Quoting FredT (Reply 1):
The terminology is somewhat confused. My definition is that slats (and slots) are leading edge devices while flaps are trailing edge devices.

It gets more confusing because Boeing uses leading edge Krueger flaps. MEL deferrals on L/E indication systems can get challenging sometimes because of the phonetic similarity between flaps (not deferrable) and slats (deferrable, with exceptions), and one has to annunciate very clearly.


User currently offlineStarlionblue From Greenland, joined Feb 2004, 17002 posts, RR: 67
Reply 3, posted (9 years 4 months 3 days ago) and read 32767 times:

Slats are usually mounted on the leading edge. Slats extend the edge and sit like a glove on the edge.

Flaps are usually mounted on the trailing edge but can be mounted on the leading edge. They extend the edge but are not mounted like a glove. They either pivot only (simple and split flaps), extend and come down (complex and slotted flaps) or extend and camber (Krueger flaps). There are other types as well.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offline411A From United States of America, joined Nov 2001, 1826 posts, RR: 8
Reply 4, posted (9 years 4 months 2 days 19 hours ago) and read 32767 times:

Not forgetting 'droops'...as on the first civil jet transport aircraft to achieve complete automatic approach/land certification...the HS.121 Trident.

A superb achievement, at the time.
Left the yanks FAR behind in automation.

And, I admire 'em greatly...even as a yank. Smile


User currently offlineUAcsOKC From United States of America, joined Dec 2004, 107 posts, RR: 1
Reply 5, posted (9 years 4 months 1 day 4 hours ago) and read 32767 times:

Quoting 411A (Reply 4):
superb achievement, at the time.
Left the yanks FAR behind in automation.

Also had problems with deep stall, associated with the droops. guess nobody's perfect....



I love the rumble of a 727 takeoff in the morning!
User currently offline411A From United States of America, joined Nov 2001, 1826 posts, RR: 8
Reply 6, posted (9 years 4 months 20 hours ago) and read 32767 times:

Yes, nobodys perfect, UAcsOKC, especially the First Officer, who altho confused, nonetheless, retracted the droops far too soon.
Gotta watch these contrary co-pilots.  Wink


User currently offlineDubliftment From Germany, joined Sep 2007, 56 posts, RR: 0
Reply 7, posted (6 years 2 weeks 1 day 11 hours ago) and read 32767 times:

as far as I know, "slats" is an abbrevation for "slotted flaps", meaning they have a nozzle like slot between the high-lift device and the wing. on the contrary, krueger flaps do not have this slot.

User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 8, posted (6 years 2 weeks 1 day 5 hours ago) and read 32767 times:



Quoting JAM747 (Thread starter):
What is the difference between flaps and slats. Does it depend on the size or type of aircraft or do all aircrafts have both.


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retracted slats

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extended slats

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flaps retracted

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flaps extended


User currently offlineAvioniker From United States of America, joined Dec 2001, 1109 posts, RR: 11
Reply 9, posted (6 years 2 weeks 1 day 5 hours ago) and read 32767 times:

Very simply put (and there are exceptions) Flaps are an extension of the wing and may or may not affect the aerodynamic chord length and angle.
Slats are more akin to an additional wing, forward of the wing, and act more to add lift than drag. Of course many aircraft have slats with more than one selectable position that may or may not be sealed to the wing in partial extension. So they act as flaps or slats depending on position.
Both flaps and slats act to lower the stall speed of the aircraft and provide enhanced low speed maneuverability.
I personally like the "slotted flap" explanation/definition. It makes sense and is easy to visualize.
 Smile



One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
User currently offlineTdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 10, posted (6 years 2 weeks 1 day ago) and read 32767 times:



Quoting Avioniker (Reply 9):
Slats are more akin to an additional wing, forward of the wing, and act more to add lift than drag.

Slats do very little to add lift directly. Their main contribution is to allow an increases angle of attack prior to stall. It's the increased AoA, not the slat itself, that generates the extra lift.

Tom.


User currently offlineWPIAeroGuy From United States of America, joined Aug 2007, 240 posts, RR: 0
Reply 11, posted (6 years 2 weeks 1 day ago) and read 32767 times:

Flaps, slats, kreuger flaps, etc. all work by increasing the camber of the wing, which allows for a higher AoA and increased drag. Some flaps also increase the chord.

Slats have a gap between the slat and the LE, airflow through the slot is redirected over the top surface of the wing, increasing airflow over the wing which increases lift. Slotted flaps work on the same princicple, the slots in the flaps allows for the airflow to remain stay attached through higher angles of attack, ergo creating more lift.

I know the Bf-109 and F-86 had leading edge devices that responded automatically to prevent loss of lift in high AoA situations. I believe the F-22 has similar devices though I may be very wrong.



-WPIAeroGuy
User currently offlineWingscrubber From UK - England, joined Sep 2001, 845 posts, RR: 0
Reply 12, posted (6 years 2 weeks 23 hours ago) and read 32767 times:

JAM747, Flaps are trailing edge lift aids/drag inducers, slats are leading edge lift aids/drag inducers. Flaps are on most anything that flies with some exceptions, but slats are generally only prevalent on bigger aircraft, but there's exceptions to that too.

This is my favourite wing design ever - achieves fantastic STOL. Big fat camber with fixed slat and flaperon. Brilliant.



Resident TechOps Troll
User currently offlineZuluAviator994 From Australia, joined Mar 2008, 510 posts, RR: 0
Reply 13, posted (6 years 1 week 5 days 1 hour ago) and read 32767 times:



Quoting Wingscrubber (Reply 12):
Wingscrubber

What plane is that?



If Speed is life, Altitude is life insurance. No one has ever collided with the sky.
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17002 posts, RR: 67
Reply 14, posted (6 years 1 week 5 days 1 hour ago) and read 32767 times:



Quoting Wingscrubber (Reply 12):
JAM747, Flaps are trailing edge lift aids/drag inducers, slats are leading edge lift aids/drag inducers.

I disagree. There are plenty of flaps on leading edges, for example on the 747 and the 737.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineBoeing767mech From United States of America, joined Dec 2000, 1025 posts, RR: 3
Reply 15, posted (6 years 1 week 5 days 1 hour ago) and read 32767 times:



Quoting Starlionblue (Reply 14):
There are plenty of flaps on leading edges, for example on the 747 and the 737.

Don't forget the CV-990A

David



Never under-estimate the predictably of stupidty
User currently offlineWingscrubber From UK - England, joined Sep 2001, 845 posts, RR: 0
Reply 16, posted (6 years 1 week 4 days 21 hours ago) and read 32767 times:

Thats the Zenith CH701/801 wing. Sorry should have said what it was...


Resident TechOps Troll
User currently offlinePihero From France, joined Jan 2005, 4392 posts, RR: 76
Reply 17, posted (6 years 1 week 4 days 15 hours ago) and read 32767 times:
Support Airliners.net - become a First Class Member!



Quoting Wingscrubber (Reply 12):
This is my favourite wing design ever - achieves fantastic STOL. Big fat camber with fixed slat and flaperon. Brilliant.

....and really nothing new since the Fieseler Storch .

From Wiki :
" Penned by chief designer Reinhold Mews and technical director Erich Bachen, Fieseler's entry was the most advanced in terms of STOL performance, by far. A fixed slat ran along the entire leading edge of the long wings, while the trailing edge, inspired by earlier 1930s Junkers aircraft wing control surface designs, including the ailerons, was a hinged and slotted flap. The wings could be folded back along the fuselage, allowing it to be carried on a trailer or even towed slowly behind a vehicle. "...
"The first Fi 156 V1 prototype flew in the spring of 1936. It was powered by a 180 kW (240 hp) inverted-vee Argus As 10C V8 engine, which gave the plane a top speed of only 175 km/h (109 mph), enabling the Storch to fly as slow as 50 km/h (32 mph), take off into a light wind in less than 45 m (150 ft), and land in 18 m (60 ft). "



Contrail designer
User currently offlineMD-90 From United States of America, joined Jan 2000, 8502 posts, RR: 12
Reply 18, posted (6 years 1 week 4 days 15 hours ago) and read 32767 times:



Quoting Wingscrubber (Reply 12):
This is my favourite wing design ever - achieves fantastic STOL. Big fat camber with fixed slat and flaperon. Brilliant.

Never going to win any races, however.


User currently offlineStarlionblue From Greenland, joined Feb 2004, 17002 posts, RR: 67
Reply 19, posted (6 years 1 week 4 days 11 hours ago) and read 32767 times:



Quoting MD-90 (Reply 18):
Never going to win any races, however.

If they had a STOL competition.  Wink



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineNicoEDDF From Germany, joined Jan 2008, 1099 posts, RR: 1
Reply 20, posted (6 years 1 week 4 days 9 hours ago) and read 32767 times:



Quoting MD-90 (Reply 18):
Never going to win any races, however.

And speed is not always your friend...lift is...in the air...and in the bed... Big grin


User currently offlineTristarSteve From Sweden, joined Nov 2005, 3982 posts, RR: 34
Reply 21, posted (6 years 1 week 4 days 6 hours ago) and read 32767 times:



Quoting 411A (Reply 4):
Not forgetting 'droops'...as on the first civil jet transport aircraft to achieve complete automatic approach/land certification...the HS.121 Trident.



Quoting Tdscanuck (Reply 10):
Slats do very little to add lift directly

My recollection is that the droop leading edge on the Trident 1 increased the lift by 40pc. When the pilot retracted the droops the plane stopped flying.
The original Trident design had two levers, a droop lever and a flap lever. After this accident they were interconnected with a baulk system, and from that day (1968) all aircraft had a single lever.
Later Tridents had slats instead.


User currently offlineMD-90 From United States of America, joined Jan 2000, 8502 posts, RR: 12
Reply 22, posted (6 years 1 week 3 days 23 hours ago) and read 32767 times:



Quoting NicoEDDF (Reply 20):
And speed is not always your friend...lift is...in the air...and in the bed... Big grin

haha good one. I hear that the Zenith 701/801 series fly well. They certainly seem to be popular with homebuilders.


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