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Lowenherz
06-27-2006, 01:51 AM
OK, can someone define for me how an aircraft stalls, please? I am (obviously) a n00b, and all those amazing aerobatic manouvers I had planned in my head don't actually work! http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif

Siwarrior
06-27-2006, 02:03 AM
ok i don't know much on the subject and i could be wrong

basically the wing of the aircraft is not producing enough lift to keep the aircraft flying, this can be due to not enough air flowing over and under the wing due to possibly loss of speed or the wing can have such a high angle of attack (the angle between the chord and the relative airflow) that it is not producing lift.........

Waldo.Pepper
06-27-2006, 02:37 AM
You go boom!

slipBall
06-27-2006, 02:48 AM
You really should read about flight theory. Once you have a understanding of lift/gravity/drag/thrust/wing angle of attack, you will be able to be more in control of your aircraft

Lowenherz
06-27-2006, 03:02 AM
Originally posted by slipBall:
You really should read about flight theory. Once you have a understanding of lift/gravity/drag/thrust/wing angle of attack, you will be able to be more in control of your aircraft

Right... any pointers to a concise and accurate source??

Originally posted by Siwarrior:
ok i don't know much on the subject and i could be wrong

basically the wing of the aircraft is not producing enough lift to keep the aircraft flying, this can be due to not enough air flowing over and under the wing due to possibly loss of speed or the wing can have such a high angle of attack (the angle between the chord and the relative airflow) that it is not producing lift.........

Hmm... yes... the high angle of attack producing more drag?

Originally posted by Waldo.Pepper:
You go boom!

I frequently do, mate!

slipBall
06-27-2006, 03:14 AM
I quess that it depends on how much reading you want to do http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif. I got this site from a google search, probably alot more info than you need for this sim, but it covers the basic's

http://www.auf.asn.au/groundschool/contents.html

Lowenherz
06-27-2006, 03:19 AM
Originally posted by slipBall:
I quess that it depends on how much reading you want to do http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif. I got this site from a google search, probably alot more info than you need for this sim, but it covers the basic's

http://www.auf.asn.au/groundschool/contents.html

Thanks a lot - better than the site I was looking at.

PikeBishop
06-27-2006, 07:02 AM
dear Noob,
To execute any manoeuver safely you must be doing about 2.5 times your level flight stall speed........about 80 - 120mph X 2.5 for most fighters.
For anything going vertically upwards about 3 times your stall speed is required.

Best regards,
SLP

Lowenherz
06-27-2006, 07:57 AM
The 'stall' is the breakdown in the smooth airflow over the upper wing surface, that starts to occur when the wing nears a particular angle of attack ââ‚¬" for light aircraft, without high-lift devices, usually around 16â?. This critical angle of attack has no relationship either with the aircraft attitude relative to the horizon or the aircraft velocity
According to this, it is not just about speed...

TgD Thunderbolt56
06-27-2006, 08:12 AM
Originally posted by Lowenherz:
According to this, it is not just about speed...

No, it's not. You can 'stall' an aircraft at relatively high speed if the angle of attack is too high relative to your inertia.

For example, if you take a P-51 (or Spit or whatever) and go into a shallow dive, gaining airspeed, and suddenly pull the stick, you'll hear the buffeting and if you continue increasing the AOA your wing will drop, thus a stall at high speed.

The basic aerodynamics of a stall are much more involved and possibly you've already realized that. Those aerobatic performances you dreamed about can certainly be performed in this sim. Chances are you're not keeping your airspeed up and/or you're your using too much deflection on your control surfaces.

Hope this helps, but remember there's no substitute for practice.

TB

OD_79
06-27-2006, 08:23 AM
A stall is down to the airflow notbeing able to flow smoothly over the wings anymore, you get 'buffet' from the vortexs that pass over the wing as a result of trying to fill the gap where smooth airflow should be, so if you have a FFB stick you will feel it shake, you can see it happen in most of the planes in game. As a result your wings stop producing enough lift and the plane drops until airflow is restored. You might only stall one wing, or stall one wing more than the other which is why you get a wing drop. The only time you can't stall an aircraft is when you are pushing the stick forwards.
Generally with civil aircraft the maximum angle of attack before you get aproach a stall is about 15 degrees, having said that the aircraft in game are a hell of a lot more powerful than your average cessna and so can climb a lot steeper before they will stall.
It's not like your car where you stall the engine, though this wouldn't help if you were climbing at the time!

OD.

p-11.cAce
06-27-2006, 09:18 AM
Another interesting aspect of a stall from low-speed flight is that you MUST use your RUDDER to pick up a dropping wing and not the ailerons. This was made painfully clear to me while learning to fly sailplanes. If you are slow and a wing starts to drop using the ailerons will only deepen the stall on that wing (the aileron increases the lift - and consequently drag - on the wing you are trying to pick up). In real life this rapidly accelerates the roll into the stalled wing while at the same time the added drag yaws you in that direction - the result is a perfectly (and often unintentionaly) entered spin. Great fun when you are high up (and always a laugh for the instructor) http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

Bremspropeller
06-27-2006, 09:23 AM
You CAN stall a plane by pushing too hard in both, game and RL. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

PikeBishop
06-27-2006, 10:02 AM
Dear All,
Yes, it IS related directly to speed!
The point is that your speed governs how much 'g' you can pull at that speed. As soon as you attempt a manoeuver the induced drag causes your speed to drop off. If your speed drops below the speed that you can pull the required 'g' at, you will stall. This is why you need speed in hand so that the speed does not drop too low. What you have to remember also is that as the 'g' required is pulled the stall speed rises, so your flight envelope is eroded at both ends.
So, again, due to drag your max speed is falling and due to load rising, ('g') your stall speed is rising. When they meet.......a high speed stall results.

Best regards,
SLP

Lowenherz
06-27-2006, 10:39 AM
Dude, it was, like... on the internet!! http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

dbillo
06-27-2006, 11:51 AM
Originally posted by PikeBishop:
Dear All,
Yes, it IS related directly to speed!...

No, it's only related indirectly to speed. It's related directly to angle of attack. The wing will stall at a certain angle of attack. The speed at which that angle of attack can occur will vary with things like: wing loading, control inputs, etc.

WWMaxGunz
06-27-2006, 01:16 PM
First:

Stall is about Lift versus Speed, not speed alone. Stall at high speed can be worse trouble.
EDIT: That is WRONG! As pointed out on page 3, effects are not causes! My mistake. Sorry.

Here: http://www.av8n.com/how/htm/vdamp.htm#sec-stall-intro

Really best to start at: http://www.av8n.com/how and work through from there.

EDIT: lines deleted due to misinterpretation of diagram by myself. The point X labelled
stall on the curve is not the point of stall, it is AT the critical AOA.

Treetop64
06-27-2006, 01:56 PM
Well, it's always nice to bury your nose in a book and study theory, as there are lots of "nice to know" stuff to learn. However, there is no replacement for practice, practice, and more practice, whether you studied the theory or not.

06-27-2006, 02:07 PM
Originally posted by TgD Thunderbolt56:
You can 'stall' an aircraft at relatively high speed if the angle of attack is too high

And the winner is... Mr Thunderbolt! http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

A wing stalls when flown at excessive angle of attack. The stall is indeed independent of the speed. In Il2 this is beautifully simualted in tigh turns, when at any speed you can stall a wing if you pull too hard.

Highly recommended book on the subject:
Stick and Rudder: An Explanation of the Art of Flying, Wolfgang Langewiesche.
http://www.amazon.co.uk/gp/product/0070362408/202-56039...22?v=glance&n=266239 (http://www.amazon.co.uk/gp/product/0070362408/202-5603905-3774222?v=glance&n=266239)

http://www.f19vs.se/fokker_now.jpg

WWMaxGunz
06-27-2006, 03:56 PM
Originally posted by Treetop64:
Well, it's always nice to bury your nose in a book and study theory, as there are lots of "nice to know" stuff to learn. However, there is no replacement for practice, practice, and more practice, whether you studied the theory or not.

People ignorant of the time tested 'theory' (is it theory only when you can demonstrate the
facts in many ways?) will go out and cook up their own ideas which many times fail. REAL
pilots go through ground school and are tested on understanding for more than just to slow
them down and justify having instructors.

It is far more than 'nice to know'. Sites like See How It Flies will make you a better pilot
in sims and for actual real flying. Consider the order of topics there, it starts with energy
management.

Also over half the whines posted on forums are from sim players with little or no grounding
in 'theory' (hell, they build working airplanes from that!) who can't understand how or even
-that- they have blown speed or presented an nme with a more efficient approach, they just
come up and post about impossible moves or other nonsense. The less they know about how
planes actually fly and the geometry or relative geometries of flight the more they insist
that what they think they observed is wrong.

J_Weaver
06-27-2006, 04:39 PM
Originally posted by p-11.cAce:
Another interesting aspect of a stall from low-speed flight is that you MUST use your RUDDER to pick up a dropping wing and not the ailerons. This was made painfully clear to me while learning to fly sailplanes. If you are slow and a wing starts to drop using the ailerons will only deepen the stall on that wing (the aileron increases the lift - and consequently drag - on the wing you are trying to pick up). In real life this rapidly accelerates the roll into the stalled wing while at the same time the added drag yaws you in that direction - the result is a perfectly (and often unintentionaly) entered spin. Great fun when you are high up (and always a laugh for the instructor) http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

Thanks for posting that! Could you go into more detail on how to use the rudder to counter this?

WWMaxGunz
06-28-2006, 01:52 AM
Rudder away from the wing that has started to drop.
Also and more important, loosen up on the stick!

PikeBishop
06-28-2006, 02:08 AM
Dear dbillo,
YES it IS directly related to speed. The max AoA of the wing (15deg) is directly dependent on speed. The higher the wing loading the faster you must go to be able to reach the max AoA. A Zero can do it at a much lower speed than a P47 because the stall speed is lower as the wing loading is lower. This means that e.g. at twice its stall speed the Zero can pull 4 'g' before stalling which means it is at 15deg AoA at around 120mph. Note that at 4'g' the stall speed is twice what it was which is why you need to be doing more that twice your stall speed to do it.
A P47 can only pull 4 'g' at 220mph i.e. it can only reach the 15deg AoA at this speed, in fact the P47 stall is about 110mph where the Zero is still able to pull over 3'g' at max AoA.
Also, because the Zero's power loading is around 5 pounds per HP and the P47's is around 9 pounds per HP, the zero can hold it's speed in a turn much better and counter the drag. Thus the P47 pilot must NEVER try to dogfight with a Zero because of this. Hope this is more understandable.
Best regards,
SLP

IL2-chuter
06-28-2006, 03:06 AM
Stall is dependant only on AOA. Speed at which this happens is dependant on wing loading. Gs are not a factor but a result of AOA and Speed. (Don't confuse factors with results, it's commonly done.) Stall performance (all parameters) is dependant on airfoil design.

Note: There are other variables.

http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

Oh, and when the stall occurs at greater than one G it is called an accellerated stall.

WWMaxGunz
06-28-2006, 03:14 AM
Completely wrong Pike. P-47 stall speed can be reached at as you freaking say 110 mph.
Is that the clean or dirty stall speed? Is that stall speed power on, off or idle?

You just keep flying level while nosing up and adding power, you get to critical AOA and
beyond at which point you get control-reversal as you are flying the back side of the
level power curve. It's required training AFAIK to prevent pilots in landing approach
from getting in serious trouble, there are many real aviation pages covering that as so
much is not learn and you have it forever but needs refreshing in such a life-critical
pusuit as piloting.

AOA is not speed dependant whatsoever. Stall is about AOA. I made a bad line in my
post yesterday, I was tired and rushed it and didn't edit out enough. My mistake.

PikeBishop
06-28-2006, 04:04 AM
Dear Chuter,
Yes that is correct.....stall is dependent on AoA but wing loading directly affects at what minimum speed max AoA can be achieved which in turn affects the minimum radius of the turn because of the speed. If one yanks the stick back to try to exceed Max AoA you will stall because you are manually forcing the wing beyond the 15deg mark but if you hold it at the point of stall this will be the minimum speed at which a stall will occur. As the aircraft turns the load exerted will increase as the speed is increased.
So, if a Zero is diving at 450mph and the pilot could pull back and hold the AoA at 15deg he should theoretically be able to pull 67'g'equalling a radius of 6,500' except that blackout is around 6 'g' for the average pilot and structural failure at around 9'g' for the aircraft.
Best regards,
SLP

PikeBishop
06-28-2006, 04:28 AM
Dear MaxG,
I think we are confusing each other over this. All my understanding of this comes from a physics course on the mchanics of flight I did back in the mid 70's. I was doing a thesis on bird and insect flight. This meant that I had to understand the mechanics of aircraft flight as well. All the data can be worked out mathematically on paper and there is a set formulae for each of the parameters you require. I am sure that you are aware of this anyway, but one can run into problems in terms of 'the chicken before the egg' situation. So, AoA affects 'g' which affects speed which affects load which affects drag which affects speed which affects AoA and so on. But the prime denominator in all of this is speed which affects lift and therefore 'g'.
I think that one of the problems on these forums is that we all understand from a certain point of view but our individual experiences influence HOW we understand it. I am no pilot but I'm in science so look at it purely from a mathematical point of view.
Best regards,
SLP

dbillo
06-28-2006, 12:00 PM
Originally posted by PikeBishop:
Dear dbillo,
YES it IS directly related to speed. The max AoA of the wing (15deg) is directly dependent on speed. The higher the wing loading the faster you must go to be able to reach the max AoA.

I think it makes more sense to say, "You'll reach the max AoA at a higher airspeed when you have a higher wing loading". You can increase the wing loading simply by piling more payload into the aircraft. In that situation, the aircraft will stall at a higher airspeed.

That's because the coefficient of lift has a maximum, and you need to generate enough lift to equal the weight of the aircraft. So, yeah, in a sense, for a particular airplane, a level flight, low speed stall, will occur at a particular speed, for a certain wing loading or aircraft weight. Increase the weight (wing loading) and, for a given airspeed, you need a higher angle of attack to get enough lift to balance out the higher weight. But would we be correct in saying that "the stall is directly related to wing loading"? No, but the stall SPEED is directly related to wing loading.

There are all these factors which affect the angle of attack required to get enough lift to balance the aircraft weight: Pulling g's increases the wing loading requiring a higher angle of attack to generate enough lift to counter the added g's. Flying slower generates less lift, so a higher AoA is required to increase the lift. At the end of the day, though, the wing stalls at the critical AoA, regardless of speed, or wing loading, or anything else.

If we put an airfoil in a wind tunnel, we can move air across it at ANY speed, even ridiculously low speeds at which a flying airplane with that airfoil would stall, and the wind tunnel airfoil won't stall as long as the AoA remains less than the critical 15 or 16 degrees. Rotate the airfoil beyond that angle, and it will stall, again, regardless of the speed of the airflow. Of course, an airfoil in a wind tunnel doesn't have to worry about wing loading and payload like an airplane in flight does.

Anyhow, I reread everything you wrote, and I agree that we are probably all confusing each other to some extent. What happens to an airplane in flight is determined by a multitude of forces and factors. I'm trying to isolate the stall phenomenon from everything else, so that's why I'm saying the stall is directly related to angle of attack...not speed... a la wind tunnel.

WWMaxGunz
06-28-2006, 02:10 PM
There are many and varied Stall Speeds.

The most common is the 1G power off clean stall. Next is the 1G power off dirty stall.
Dirty is with flaps and gear down, clean is with the same up. They are Reference Stall
Speeds at some nominal load for every AC manufactured before it can be sold. The FAA
and EAA have very strictly defined regulations governing how to determine those since
manufacturers like to play the definitions game (and others) for profit.

15 degrees critical AOA? Many wings run critical at less, like 10 to 12, some less.
It's a matter of design.

You can vary the ability to hold 1G or even higher by using enough power and fly stalled,
even climb while stalled. Up to some point into the stall you still have lift, just not
as much as when the AOA was less. Your drag will be extrememly high but that's what the
power is for. That's where control reversal comes in, nose down to rise and up to sink.
There's the old rule of pull the stick back and the houses get smaller, keep it back and
the houses get bigger again. If you can keep adding power then they don't.

How can stall be G dependant and there be such a thing as 1G power off Stall Speed?

And yeah there are GA planes made that cannot stall or at least I have read of those.
They still drop depending on power but you'll never see one ride the backside of the
level power curve, ever.

My old favorite to link to aero site with simple stepped explanations and lots of graphs,
diagrams and pictures seems to be gone. In the meantime someone else pointed out John
Denker's See How It Flies which is correct and enormously practical but then given his
history and credentials it's no surprise he has these things so well and completely
ordered.

The link to that is in one of my posts on page 1 of this thread. Right from the start it
is about energy management which for combat sim pilots is of extreme importance especially
if you are playing on sim experience, guesswork, short advice, and snips from books.

Want things simpler? Get a copy of Barnaby's How To make And Fly Paper Airplanes which
covers very basic unpowered aerodynamics -- available used at Amazon for under US\$5.
His designs go back to 1910 and include lifting wings with camber, dihedral and vortex
defeating measures. He was from a kid a close friend of both the Wrights and shows his
pilots license which is number 2. Read up on him, Ralph Barnaby and his career as a
Navy Aviator. He is more than qualified. It's not a book about making paper darts.

Lowenherz
06-28-2006, 04:13 PM
Originally posted by WWMaxGunz:
There are many and varied Stall Speeds.

The most common is the 1G power off clean stall. Next is the 1G power off dirty stall.
Dirty is with flaps and gear down, clean is with the same up. They are Reference Stall
Speeds at some nominal load for every AC manufactured before it can be sold. The FAA
and EAA have very strictly defined regulations governing how to determine those since
manufacturers like to play the definitions game (and others) for profit.

15 degrees critical AOA? Many wings run critical at less, like 10 to 12, some less.
It's a matter of design.

You can vary the ability to hold 1G or even higher by using enough power and fly stalled,
even climb while stalled. Up to some point into the stall you still have lift, just not
as much as when the AOA was less. Your drag will be extrememly high but that's what the
power is for. That's where control reversal comes in, nose down to rise and up to sink.
There's the old rule of pull the stick back and the houses get smaller, keep it back and
the houses get bigger again. If you can keep adding power then they don't.

How can stall be G dependant and there be such a thing as 1G power off Stall Speed?

And yeah there are GA planes made that cannot stall or at least I have read of those.
They still drop depending on power but you'll never see one ride the backside of the
level power curve, ever.

My old favorite to link to aero site with simple stepped explanations and lots of graphs,
diagrams and pictures seems to be gone. In the meantime someone else pointed out John
Denker's See How It Flies which is correct and enormously practical but then given his
history and credentials it's no surprise he has these things so well and completely
ordered.

The link to that is in one of my posts on page 1 of this thread. Right from the start it
is about energy management which for combat sim pilots is of extreme importance especially
if you are playing on sim experience, guesswork, short advice, and snips from books.

Want things simpler? Get a copy of Barnaby's How To make And Fly Paper Airplanes which
covers very basic unpowered aerodynamics -- available used at Amazon for under US\$5.
His designs go back to 1910 and include lifting wings with camber, dihedral and vortex
defeating measures. He was from a kid a close friend of both the Wrights and shows his
pilots license which is number 2. Read up on him, Ralph Barnaby and his career as a
Navy Aviator. He is more than qualified. It's not a book about making paper darts.

OK, here's my argument..... stalling sucks! http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif

p-11.cAce
06-28-2006, 05:10 PM
Could you go into more detail on how to use the rudder to counter this?
WWMaxgunns called it right - rudder away from the dropping wing and it will pick it up...can be as useful in a tight turning fight on the deck as in a tight scratching climb in a thermal http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

How can stall be G dependant and there be such a thing as 1G power off Stall Speed?
stall speed is "G" dependant indirectly as countering "G" requires additional AOA than flying straight and level. Aircraft "feel" G loading as additional weight that has to be countered by additional lift. In order to gain additional lift the AOA must be increased bringing you closer to the critical AOA. The key to this whole thing is understanding how to "fly the wing" as the old-timers called it...speed, G loading, aircraft weight, etc. all effect the required AOA.

J_Weaver
06-28-2006, 05:21 PM
Originally posted by p-11.cAce:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> Could you go into more detail on how to use the rudder to counter this?
WWMaxgunns called it right - rudder away from the dropping wing and it will pick it up...can be as useful in a tight turning fight on the deck as in a tight scratching climb in a thermal http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif
</div></BLOCKQUOTE>

Its also very handy in keeping an over loaded Corsair from rolling into the drink. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif Thanks guys!

RCAF_Irish_403
06-28-2006, 07:09 PM
rudder away from dropping wing plus lowering the throttle should get you out of the stall/spin

WWMaxGunz
06-28-2006, 08:22 PM
Originally posted by p-11.cAce:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> How can stall be G dependant and there be such a thing as 1G power off Stall Speed?
stall speed is "G" dependant indirectly as countering "G" requires additional AOA than flying straight and level. Aircraft "feel" G loading as additional weight that has to be countered by additional lift. In order to gain additional lift the AOA must be increased bringing you closer to the critical AOA. The key to this whole thing is understanding how to "fly the wing" as the old-timers called it...speed, G loading, aircraft weight, etc. all effect the required AOA. </div></BLOCKQUOTE>

I was trying to get him to think a bit more. Of course 1G stall speed is G dependant. It HAS
to be done at 1 G. However _stall_ alone is not G dependant. There is a 2G stall speed, a 3G
stall speed and even a 1.41G stall speed, such as stall _speed_ in turns.

Stall _speed_ increases in many different instances which is why the regs for determining the
reference stall speed are so tight.

Stall happens at and above critical AOA regardless of how you get there. I got confused on
page one because I was tired and a bit dizzy and looked at too many danged related graphs BUT
I was still wrong about something I knew better about. Oh well.

WTE_Galway
06-28-2006, 08:35 PM
Originally posted by WWMaxGunz:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by p-11.cAce:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> How can stall be G dependant and there be such a thing as 1G power off Stall Speed?
stall speed is "G" dependant indirectly as countering "G" requires additional AOA than flying straight and level. Aircraft "feel" G loading as additional weight that has to be countered by additional lift. In order to gain additional lift the AOA must be increased bringing you closer to the critical AOA. The key to this whole thing is understanding how to "fly the wing" as the old-timers called it...speed, G loading, aircraft weight, etc. all effect the required AOA. </div></BLOCKQUOTE>

I was trying to get him to think a bit more. Of course 1G stall speed is G dependant. It HAS
to be done at 1 G. However _stall_ alone is not G dependant. There is a 2G stall speed, a 3G
stall speed and even a 1.41G stall speed, such as stall _speed_ in turns.

Stall _speed_ increases in many different instances which is why the regs for determining the
reference stall speed are so tight.

Stall happens at and above critical AOA regardless of how you get there. I got confused on
page one because I was tired and a bit dizzy and looked at too many danged related graphs BUT
I was still wrong about something I knew better about. Oh well. </div></BLOCKQUOTE>

lets not forget dynamic and accelerated stalls just to confuse matters http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

what the heck spiral dives are way more fun anyway

Targ
06-28-2006, 09:58 PM
I second the recomendation to purchase stick and rudder, great entry level book for the new pilot. The book was written in the day's of tail draggers so very relavent to the game we fly.

PikeBishop
06-29-2006, 02:17 AM
Dear All,

Yep! - I/We are in complete agreement now....it all makes sense. Now all I need to do is remember it all. I think my weak area is when people talk about energy management. I do realise that I probably do it all the time but am not aware of it....you know.....speed means life........keep your speed up or you cannot manoeuver. By the way the figures I quoted about speeds to enter manoeuvers at, were from a book written by one of our aerobatics champions which I no longer have as I lent it to someone some time ago. I believe the author was killed several years ago doing aerobatics at an airshow??
Best regards,
SLP

Bearcat99
06-29-2006, 12:22 PM
Once the angle of the wing in relation to the air becomes less like a wing ands more like a sail..... you stall.....

SeaFireLIV
06-29-2006, 12:38 PM
It`s funny to think that IL2 actually got me interested into learning how air acts on an aircraft, the fact that lighter air flows over the wing and their`s heavier air under it, therefore lift is created and it flies.

I still dunno that much, but I certainly think of air as more of a substance than some ethereal thing I used to think of it.

DuxCorvan
06-29-2006, 01:16 PM
Originally posted by SeaFireLIV:
It`s funny to think that IL2 actually got me interested into learning how air acts on an aircraft, the fact that lighter air flows over the wing and their`s heavier air under it, therefore lift is created and it flies.

Mmmm, sorry SeaFire, but it's not that. Air isn't heavier or lighter, above or below wings. Air on wings is forced to run faster than air under them, because of the longer way it has to 'run' to reach the aft edge at the same time.

Due to this, pressure under wings increases, for that air under wings tries to 'fill' the vacuum the fleeing upper air makes, this is, wings are 'sucked' and 'pushed' upwards, like a liquid into a syringe.

That's why, the thicker the wing profile, the longer the difference between upper and lower side of that profile, the higher the difference of the air speeds and the higher the lift... but with much higher drag as a result.

If the airspeed decreases, then there's not enough lift to counter gravity, and the plane falls more or less gently. This is a stall due to low speed.

If the AOA increases too suddenly, and because of inertia the plane direction doesn't match that of the wing profile, then the air flow on the wings is broken, and the plane stalls, independently of speed. If it is a very assymetric stall, then your plane gets into a spin, and you're in trouble.

You can make it more complex, but this is just the basics.

justflyin
06-29-2006, 01:55 PM
Stalls suck when you're in a tight dogfight, and you are flying against a very similarly-skilled opponent or better, because you know that's the mistake that will lead to your demise. Or at least usually does. http://forums.ubi.com/images/smilies/winky.gif

Those are my favorite dogfights by the way. The one where the two opponents are so closely matched in skills and brains, that it almost always boils down to who makes the first mistake.

As long as you have enough altitude, the best way I've found to recover from stalls and the not-far-behind impending flat spin, is to apply full opposite rudder to the direction of the spin and hold the stick fully forward, while chopping throttle to zero.

As long as I have near 1000m of altitude, I've been able to recover most planes with room to spare. Well, the P-39 is a tad more difficult to recover from a flat-spin, but it's nowhere near what it was in this game nor does it have the "Widow Maker" qualities it had when this series first started. Back then, if you looked at a turn funny, it went into a mutha of a flat-spin. lol

slipBall
06-29-2006, 02:47 PM
I expect that in BOB we might be seeing more stalling due to the new weather engine, some will possibly fall victim to a increase of
downwind stalls occuring, or very gusty head wind landing attemps
"For instance, a powered plane flying north with airspeed of 180 knots against a
30 knots headwind has 150 ground speed.
If you turn 90 deg. left (west), the plane's airspeed still is 180 knots but is now
drifting 30 knots to the south resulting in approx 195 knots ground speed to the southwest.
If the plane keeps turning south, the drift due to the wind is still 30 knots but now
the ground speed becomes 180+30 = 210 knots, while the airspeed still is 180 knots.

The pilot on the ground will see the ground speed but not the airspeed, and since
the plane seems to move much faster flying downwind, the pilot may instinctively
slow down the plane below the stall speed.
This results in a pilot-induced stall due to the optical illusion of the plane's higher
ground speed when flying downwind. In order to recover from a stall, the pilot has to reduce the angle of attack
back to a low value. Despite the aircraft is already falling toward the ground,
the pilot has to push the stick forward to get the nose even further down. This reduces the angle of attack and the drag, which increases the speed. After the aircraft gained speed and the airflow incidence on the wing becomes favourable, the pilot may pull back on his stick to increase the angle of attack again (within allowable range) restoring the lift. Since recovering from a stall involves some loss of height, the stall is most
dangerous at low altitudes. Engine power can help reduce the loss of height, by increasing the velocity more quickly and also by helping to reattach the flow over the wing.
How difficult it is to recover from a stall depends on the plane"

SeaFireLIV
06-29-2006, 03:06 PM
Originally posted by DuxCorvan:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by SeaFireLIV:
It`s funny to think that IL2 actually got me interested into learning how air acts on an aircraft, the fact that lighter air flows over the wing and their`s heavier air under it, therefore lift is created and it flies.

AH. Thankyou, Dux... http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif
Mmmm, sorry SeaFire, but it's not that. Air isn't heavier or lighter, above or below wings. Air on wings is forced to run faster than air under them, because of the longer way it has to 'run' to reach the aft edge at the same time.

Due to this, pressure under wings increases, for that air under wings tries to 'fill' the vacuum the fleeing upper air makes, this is, wings are 'sucked' and 'pushed' upwards, like a liquid into a syringe.

That's why, the thicker the wing profile, the longer the difference between upper and lower side of that profile, the higher the difference of the air speeds and the higher the lift... but with much higher drag as a result.

If the airspeed decreases, then there's not enough lift to counter gravity, and the plane falls more or less gently. This is a stall due to low speed.

If the AOA increases too suddenly, and because of inertia the plane direction doesn't match that of the wing profile, then the air flow on the wings is broken, and the plane stalls, independently of speed. If it is a very assymetric stall, then your plane gets into a spin, and you're in trouble.

You can make it more complex, but this is just the basics. </div></BLOCKQUOTE>

Snow_Wolf_
06-29-2006, 05:06 PM
http://www.stupidvideos.com/video/just_plain_stupid/Airplane_Nap/

Snow_Wolf_
06-29-2006, 05:11 PM
that video is Quick time and it suppose to be a spin but it got a stall in it