Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: the4ork on July 19, 2007, 10:44:10 PM
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i've looked around on google and such but i cant really figure out HOW they are pushed in and out all the time mechanically...
somone told me the wind pushes them back into the wing but when the chord line or 'aoa' reaches a sertain amount they pop out
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How the slots work, and the benefits, and testimonies.
http://www.virtualpilots.fi/feature/articles/109myths/#slats
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they're actually very simple.............when the plane accelerates, and positive airflow is achieved over the wing, the presure forces them back into their slots...this is where they stay, as long as the pilot doesn't stall a wing. once a wing stalls, there's actually negative airpressure at the leading edge, thus allowing the slats to drop out. if you noticed the curverature to them, they actually increas the wing's camber, and i think they also slightly increase the wing'sarea too.....both of which help that wing to produce lift. :D :aok
pretty ingenious bastages they had back then, eh??:aok
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john
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Yes the Handley-Page slats on the 109 were ingenious.
The Faery Swordfish had them as well, for some reason.
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Originally posted by MiloMorai
Yes the Handley-Page slats on the 109 were ingenious.
The Faery Swordfish had them as well, for some reason.
REALLY????:O
i didn't know that...i really thought only the german aircraft had them........ya learn something every day!:aok
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john
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Originally posted by MiloMorai
Yes the Handley-Page slats on the 109 were ingenious.
The Faery Swordfish had them as well, for some reason.
Never heard that before, so Im forced to ask: Documents please?
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Originally posted by CAP1
REALLY????:O
i didn't know that...i really thought only the german aircraft had them........ya learn something every day!:aok
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john
La's have them too (in game, at least).
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Me-262 has them too, :) and i think the 163's do too,but im not sure. :aok
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Originally posted by CAP1
REALLY????:O
i didn't know that...i really thought only the german aircraft had them........ya learn something every day!:aok
The slats on the 109 and other German types were Handley-Page style slats. Guess why? Because they were Handley Page patent and the British company was paid royalties for every single fighter and other plane Germany built that used the slats.
Of course, British planes used the slats too. And Russian. La-5 series for example. And Japanese. Surely in many US types too, for example F-86 Sabre had identical slats to 109. Who knows, maybe even Italians too. And slats are used in every modern airliner and fighter, though these days automatically.
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doesn't the La7 and La5FN have slats?
and the 163 has slats, Germans loved their slats!
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They don't actually always come out all at once with a loud sound but it is also possible that they move slightly out and in in slow level flight. I didn't know this until I saw it in in-flight video of Black 6. So their operation does not rely only on AoA but also of speed.
-C+
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Originally posted by Serenity
Never heard that before, so Im forced to ask: Documents please?
Documentation on what?
The 163 had a fixed slot.
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Originally posted by CAP1
they're actually very simple.............when the plane accelerates, and positive airflow is achieved over the wing, the presure forces them back into their slots...this is where they stay, as long as the pilot doesn't stall a wing. once a wing stalls, there's actually negative airpressure at the leading edge, thus allowing the slats to drop out.
This has bothered me for a long time. There are several photos where the slats are shown open while the plane is on ground and people tend to believe that "open" is some kind of neutral position and only speed forces the shut.
AFAIK, the slats have no springs or such, but they move freely. Therefore they could just as well be in shut position already before take-off. It is the airflow and AoA that forces them open. The photos with open slat on ground are, I believe, because of mechanicians just checking their movement or something after landing.
It seems a bit funny that in game the slat are always open when the plane is on ground....
Someone, please correct or verify this :)
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Originally posted by Serenity
Never heard that before, so Im forced to ask: Documents please?
The slats on the swordfish upper wing are easy to see - just google some pictures of the swordfish. I do believe (remember reading it someplace) that the swordfish slats were different than the 109s in that the pilot could lock them in position - perhaps necessary when the wings were folded for storage?
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http://109lair.hobbyvista.com/techref/systems/control/slats/slats.htm
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De Haviland initially planned them for the Mosquito, but then removed them after initial flight tests. They felt the Mosquito was manuverable enough without them.
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"They felt the Mosquito was manuverable enough without them."
Sure. Do you know this or just think that that was the reason?
-C+
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Originally posted by Grendel
The slats on the 109 and other German types were Handley-Page style slats. Guess why? Because they were Handley Page patent and the British company was paid royalties for every single fighter and other plane Germany built that used the slats.
Of course, British planes used the slats too. And Russian. La-5 series for example. And Japanese. Surely in many US types too, for example F-86 Sabre had identical slats to 109. Who knows, maybe even Italians too. And slats are used in every modern airliner and fighter, though these days automatically.
i knew later models of most major nations had them....and i know they're on airliners........i was talking bout ww2 planes.......
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john
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Originally posted by Charge
They don't actually always come out all at once with a loud sound but it is also possible that they move slightly out and in in slow level flight. I didn't know this until I saw it in in-flight video of Black 6. So their operation does not rely only on AoA but also of speed.
-C+
right........they rely on negative pressure on the wing.......when the wing is about to stall for ANY reason, there's negative air presure there.......because it's not producing lift for what ever reason......but since the wing has to exceed the aircraft's critical angle of attack to stall, yes......AOA still does play a part. when you slow down in level flight, what do you do to maintain your alt? you lift the nose. the slower you go, the higher you pitch the nose.....untill critical AOA is reached, then ya stall. a stall can also happen at hi speed though as we all know, because AGAIN, when we try to turn inside that spit9, we're pulling the wing up to the critical AOA. remember....the plane doesn't know which way is up.....you can be banked 60 degrees, and pulling, and the plane can exceed its critical AOA to the oncomming wind. to the plane, the oncomming wind is obvioulsy from its front.assume 109 AOA in normal flight is 10 degrees(i don't know, just using a for instance) and its critical aoa is 17 degrees. now, you roll and pull into turn, smoothly and coordinated, you bring it around nicely never pulling the wing up past 13 degrees. but now ya get bounced...you pull hard, and the wing hits 17-18 degrees......now the air cannot flow properly over it, so it stops producing lift, creating the negative air pressure on the wing, and the slats drop, increasing the wing's camber, allowing it to produce some lift till you get back into normal flight.
if i'm wrong on this then someone please correct me?
now.....i'm gonna get flamed for this, aren't i?:noid :noid
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john
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Originally posted by BlauK
This has bothered me for a long time. There are several photos where the slats are shown open while the plane is on ground and people tend to believe that "open" is some kind of neutral position and only speed forces the shut.
1)it's the airflow over the wing that forces them in......so sitting on the ramp, shut down, they'll fall out to open position.
AFAIK, the slats have no springs or such, but they move freely. Therefore they could just as well be in shut position already before take-off. It is the airflow and AoA that forces them open. The photos with open slat on ground are, I believe, because of mechanicians just checking their movement or something after landing.
2)it's not airflow that forces them open.....it's LACK of airflow over the wing...as it stalls...
It seems a bit funny that in game the slat are always open when the plane is on ground....
3)see 1 and 2:D
Someone, please correct or verify this :)
:D
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john
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There is test data from Mtt on slats and above certain speed they stay in despite needed AoA is reached because the pressure caused by speed prevents the opening. So if there is enough AoA and the speed decreases from high speed to below that certain speed, the slats open with loud bang. Otherwise the pilot don't usually really notice the movements of the slats; when the AoA increase they slowly come out and so on.
Regarding the rest; principal wise the slats are boundary layer devices so these do not increase lift directly but increase reachable AoA. In the Bf 109 the slats were to prevent tip stall and in practice there was only small increase in the Clmax because the rest of the wing stalls at given AoA regardless the slats.
And the slats are quite rare nowadays in the fighter aircraft; IIRC the F-14 and Eurofighter utilize them. The most other planes (F-22, F-16, F-18, Mirage 2000, Gripen, Mig-29, Su-27...) utilize leading edge flaps which are principal wise true camber changing devices.
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Originally posted by Charge
"They felt the Mosquito was manuverable enough without them."
Sure. Do you know this or just think that that was the reason?
-C+
That is De Haviland's claim. Whether or not they are telling the truth I can't say, but I don't see why they would lie.
I certainly don't think it was as manuverable as a single engined fighter. I think it just met their target manuverability without the slats. It did a little better than expected is all.
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Originally posted by CAP1
1)it's the airflow over the wing that forces them in......so sitting on the ramp, shut down, they'll fall out to open position.
john
Like I said, there are also pics of landed or taxi'ing planes with slats closed. Would they then just be rusty or lack lubricants or something??? :)
In the museum this slat was closed before it was pulled out for the photo.
Notice the angle it moves.. almost sideways when the plane sits tail down.
(http://koti.welho.com/skukkone/kuvia/slats/Bf109G6_slat.jpg)
109G6 landing with flaps open, but slats stay closed.
(http://koti.welho.com/skukkone/kuvia/slats/Bf109G6_landing_slat.jpg)
Same plane parked with slats closed.
(http://koti.welho.com/skukkone/kuvia/slats/Bf109G6_parked_slat.jpg)
Three museum planes with slats closed.
Two of them lie on their bellies, but do they have moving slats?
(http://koti.welho.com/skukkone/kuvia/slats/Bf109G2_slat.jpg)
(http://koti.welho.com/skukkone/kuvia/slats/Bf109E_slat.jpg)
(http://koti.welho.com/skukkone/kuvia/slats/BF-109E-3.jpg)
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Me262 taxi'ing after landing. Slats open, but it is no tail dragger like 109.
Are these original slats or does this newly built replica have leading edge "flaps"?
(http://koti.welho.com/skukkone/kuvia/slats/Me262_landed_slat.jpg)
109G-2 taxi'ing with slat slightly open. Was it pulled open while the plane was still parked?
(http://koti.welho.com/skukkone/kuvia/slats/BF-109G2-Taxi_slat.jpg)
109 in a museum with other side's slat open and other side's closed.
(I think it is he same plane)
(http://koti.welho.com/skukkone/kuvia/slats/BF-109-slat.jpg)
(http://koti.welho.com/skukkone/kuvia/slats/Me109-G-10-slat.jpg)
So... I am not yet convinced that the "neutral position" of the slat would be "open".
The airflow forces them shut and getting close to a stall with high AoA opens them. Yes. But otherwise I am still lacking the evidence to believe they would open themselves because of gravity while parked or taxi'ing. :rolleyes:
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La7 slat is the same motion via a swing arm......
Here is white 77 at Kebly in its Default position.......... However the rear wheel is lifted on a concrete block. I suspect that when in its normal taxiing position the slat would fall fully closed.
(http://www.tilt.clara.net/White77/prtslat.jpg)
here I am pulling it out
(http://www.tilt.clara.net/White77/prtslatx.jpg)
this gives some insight into the slat angle and extent of deployment
(http://www.btinternet.com/~fulltilt/la7topbot2.GIF)
I have more detailed pictures but need FTP stuff to check their URL's which is at home.
As above basically at a certain AoA the slat is sucked out due to its aerofoil shape, the mechanical advantage obtained from its linkage and the differential pressures about it.
Slats had to be "trimmed" by checking the bearing pins and their "fit" into the wing profile.
I have one set La7 test reports where the pilot reports the slats to be out of trim one side staying open longer/shorter than the other as he conducted a climbing trial.
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"I certainly don't think it was as manuverable as a single engined fighter. I think it just met their target manuverability without the slats. It did a little better than expected is all."
I read a book of the Hurricane pilots at Malta and the writer flew a mock dogfight against Mossie in his Hurricane. He told that the Hurri's turn radius had little use because the Mossie flew circles around him so fast he couldn't take a shot at it even if he wanted to... So in that light the slats really would have been quite useless.
-C+
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Sigh... wishing for a properly coded mossie:)
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Originally posted by Souless
Sigh... wishing for a properly coded mossie:)
There's still hope for ya Souless. I was really worried you were going to be talking 109Ks.
Thank goodness the Mossie is keeping you from being completely assimilated into the leather underwear crowd :)
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Originally posted by Guppy35
There's still hope for ya Souless. I was really worried you were going to be talking 109Ks.
Thank goodness the Mossie is keeping you from being completely assimilated into the leather underwear crowd :)
I prefer pleather Dan, the leather chaffs and is quite itchy:D
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Originally posted by BlauK
Like I said, there are also pics of landed or taxi'ing planes with slats closed. Would they then just be rusty or lack lubricants or something??? :)
1)yes, you are right....if i recall, i did read about them sticking sometimes...
In the museum this slat was closed before it was pulled out for the photo.
Notice the angle it moves.. almost sideways when the plane sits tail down.
(http://koti.welho.com/skukkone/kuvia/slats/Bf109G6_slat.jpg)
109G6 landing with flaps open, but slats stay closed.
(http://koti.welho.com/skukkone/kuvia/slats/Bf109G6_landing_slat.jpg)
Same plane parked with slats closed.
(http://koti.welho.com/skukkone/kuvia/slats/Bf109G6_parked_slat.jpg)
Three museum planes with slats closed.
Two of them lie on their bellies, but do they have moving slats?
(http://koti.welho.com/skukkone/kuvia/slats/Bf109G2_slat.jpg)
(http://koti.welho.com/skukkone/kuvia/slats/Bf109E_slat.jpg)
(http://koti.welho.com/skukkone/kuvia/slats/BF-109E-3.jpg)
>
john
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Originally posted by Guppy35
There's still hope for ya Souless. I was really worried you were going to be talking 109Ks.
Thank goodness the Mossie is keeping you from being completely assimilated into the leather underwear crowd :)
Vat is zat zuppozed to mean?
:D
Anyway, there was another slat thread thatturned into a flamefest. Because of some issues I called Gunther Rall and directly asked him about the good and bad sides.
Tha bad sides are mentioned on the website linked in the beginning of this thread, - how he put it was simply that "in a rough turn a slat would come out and the aircraft would snap-stall" It was the outboard slat.
He said he did not prefer them in combat, but without them as a contrary, landing speed would have been unacceptably high.
I asked a former LW wingco about them. He told me that the F4's (Phantom) did have some problems with them, and they had caused some disintergrations (!). Now the tendency was more to use manually controlled slats in the new designs, if any at all.
Thoughts?
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Originally posted by MiloMorai
Documentation on what?
The 163 had a fixed slot.
you wasnt talking about 163s....
Originally posted by MiloMorai
The Faery Swordfish had them as well, for some reason.
Hence serenity's question.
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(http://img.villagephotos.com/p/2005-12/1114844/slat1.jpg)
(http://img.villagephotos.com/p/2005-12/1114844/slat2.jpg)
(http://img.villagephotos.com/p/2005-12/1114844/slat3.jpg)
(http://img.villagephotos.com/p/2005-12/1114844/slat4.jpg)
(http://img.villagephotos.com/p/2005-12/1114844/slat5.jpg)
(http://img.villagephotos.com/p/2005-12/1114844/slat6.jpg)
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Originally posted by Anyone
you wasnt talking about 163s....
Hence serenity's question.
Agh? PanzerIV and Wes14 thought the 163 had slats but then if you don't read the whole thread...... Oh well.
I didn't answer Serenity because he would get more info by using Google.
Anyways, the slats were used by the Swordfish to get the slowest landing speed, from an already slow a/c, hense the comment 'for some reason'. Doesn't take a genious to understand the comment.
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Originally posted by MiloMorai
Agh? PanzerIV and Wes14 thought the 163 had slats but then if you don't read the whole thread...... Oh well.
I didn't answer Serenity because he would get more info by using Google.
Anyways, the slats were used by the Swordfish to get the slowest landing speed, from an already slow a/c, hense the comment 'for some reason'. Doesn't take a genious to understand the comment.
I was asking for documentation as to the German slats being copies of handley-paige slats. Now, how would one type that into google? It makes more sense to simply ask you for your documentation. Its not that I dont believe you, I just dont recall having heard that before.
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Gee Serenity, the first link when I Googled came up with a reference to H-P slats on the 109.:eek:
http://freespace.virgin.net/john.dell/bf109/Bf109Story.htm
Here is another link, http://www.virtualpilots.fi/feature/articles/109myths/
You needed to be more specific for it is common knowledge that the 109 used H-P slats so thought you were asking about the Swordfish.
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Originally posted by MiloMorai
Gee Serenity, the first link when I Googled came up with a reference to H-P slats on the 109.:eek:
http://freespace.virgin.net/john.dell/bf109/Bf109Story.htm
Here is another link, http://www.virtualpilots.fi/feature/articles/109myths/
You needed to be more specific for it is common knowledge that the 109 used H-P slats so thought you were asking about the Swordfish.
lol. I feel like an idiot. Reading that I realised "OMFG! I already KNOW THIS!" lol. Guess I was just having a major brain-fart that day! lol
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Wait till you get older for they happen more often.;)
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"He told me that the F4's (Phantom) did have some problems with them, and they had caused some disintergrations (!). Now the tendency was more to use manually controlled slats in the new designs, if any at all. Thoughts?"
I think there are no manually controlled slats nowadays. They are all computer controlled in faster or fixed in slow aircrafts.
Although hogging quite a bit of top speed many countries where F4 was exported preferred the slats because F4 had a tendency for nasty uncontrolled departures in high Gs without slats.
-C+
PS. Thanks for nice pictures Milo. I've never seen those before.
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Originally posted by Charge
I think there are no manually controlled slats nowadays. They are all computer controlled in faster or fixed in slow aircrafts.
What gives you that idea? There are several light STOL aircraft with aerodynamically actuated slats. Like this CH 701 (also note the Junker-type flaperons):
(http://www.zenithair.com/stolch701/pic06/zu-dok.jpg)
American Hombuilts:
(http://www.ultralightflyer.com/images/johndoe2.jpg)
Savannah:
(http://www.stolspeed.com/uploads/images/Slats.jpg)
Yuma:
(http://www.alisport.com/eu/images/yuma/yuma_gg.jpg)
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Originally posted by Serenity
I was asking for documentation as to the German slats being copies of handley-paige slats.
German slats were not COPIES of Handley-Page slats. They WERE Handley-Page slats. That the beauty of licences :)
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Originally posted by Viking
What gives you that idea? There are several light STOL aircraft with aerodynamically actuated slats. Like this CH 701 (also note the Junker-type flaperons)
CH 701 and its "copies" have fixed slats (very clearly seen from the picture of the Savannah you posted). Mr. Heinz has a very nice (allthough not pretty) design in the CH 701 which *influence* can be clearly seen in planes like the Savannah and Yuma.
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Ok, my bad.
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Originally posted by Grendel
German slats were not COPIES of Handley-Page slats. They WERE Handley-Page slats. That the beauty of licences :)
Ah funny coincidence. I was working on some stuff by an Italian Messerschmitt 109 pilot and heh, of his impressions about the 109...
"Another important aspect of the German plane was the Handley-Page slats which allowed very tight turns."
Summer 1943 ;-)
Oddone Colonna, 150° Gruppo CT and 1°Gruppo Caccia
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Made in Germany I bet, and no fees payed.
I think it was originally a German invention that Handley-page however put to used and got a license for.
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Originally posted by Angus
Made in Germany I bet, and no fees payed.
Of course made in Germany ... that's the whole point of license production. I believe Messerschmitt actually payed license-fees to Handley-Page until Britain declared war on Germany.
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Actually, I recall hearing somewhere that Messerschmitt payed the fees all the way through the war. However, I dont remember just where I saw that, so dont hold me to it. Ill go look through my books right now though, lol.
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Originally posted by Viking
Of course made in Germany ... that's the whole point of license production. I believe Messerschmitt actually payed license-fees to Handley-Page until Britain declared war on Germany.
And paid the licenses after war was declared, too. Just like British and US companies were paying royalties for German patents and licenses during the war. Even for the military production.
War? Pfft. Business is business and license/patent payments are done. The money just waits in the bank until the war ends, so the transfer can then be done normally.
All the western countries paid full license fees/patent fees/royalties to the "enemy" country for every single thing manufactured during wartime.
You overestimate the effect of war to business sector :)
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Hehe, a sidenote to this.
There was a spy, working for the Germans. He was brought to Iceland in a U-Boat.
He was supposed to be paid into a Copenhagen bank account, and he did check it out after the war, but had never received a penny.
Anyway, he had got back to them before, because he became a double agent and worked the whole war for the British.
:D
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The Slats were an invention of the handley Page company Fact.;)
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"STOL"
Reminiscent of the Fieseler Storch, which had huge leading edge slats. There are some interesting shots of a model Storch here (http://www.modelflight.com.au/lxmodel/lx_model_fieseler_storch.htm). Wouldn't it be great if the company that's making those replica 262s could churn out some Storches. Looks like there was an original for sale recently here (http://www.aero-auktion.com/angebotdetails.php?selectlotid=56). 185,000 Euros, which is £125,000, and going by the current pound/dollar exchange rate that would be ninety million US dollars.
There's a shot of a Fairey Swordfish, with its slats, here (http://avions.legendaires.free.fr/Images/imagesep03.jpg), although they are retracted. You can barely see the faces of the passengers, but they don't look comfortable. Did they have some kind of bulletproof tub around them? If not, burly.
Also, the 110s in the game have slats.
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Originally posted by Wmaker
CH 701 and its "copies" have fixed slats (very clearly seen from the picture of the Savannah you posted).
Not anymore, Wmaker, at least on not all the model: Savannah ADV (http://www.icp.it/nuovo_savannah.htm) has electrical operated slats