AirTalk.org Aviation discussions newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Dynamic Stalls          AirTalk.org Forum Index -> Planes, gliders and flying in Australia View previous topic :: View next topic   Author Message M. Guest Posted: Mon Jun 21, 2004 8:55 am    Post subject: Dynamic Stalls G'day all Just a quick query to all the aerobatic pilots out there, what is dynamic stalling?. Any site references would be greatly appreciated Regards Mike Back to top Stealth Pilot Guest Posted: Mon Jun 21, 2004 10:05 am    Post subject: Re: Dynamic Stalls On Mon, 21 Jun 2004 20:55:42 +1200, "M." <mkarsten.nospam (AT) xtra (DOT) co.nz> wrote: Quote: G'day all Just a quick query to all the aerobatic pilots out there, what is dynamic stalling?. Any site references would be greatly appreciated Regards Mike simple really. pilots get accustomed to the stall at minimum speed so end up equating the two as being linked. in actuality the stall occurs at an angle of attack regardless of the speed. so if you are hauling arse around the sky and with huge amounts of elevator input or elevator plus some momentum dynamics and you happen to poke the nose past the stalling angle of attack you get the surprise of your life and a dynamic stall occurs. one area where this can occur is in the recovery from a deliberate stall when downward sink is high. haul on a lot of up elevator and you can stall again regardless of your speed. references ??? Stealth Pilot Back to top Centurion Guest Posted: Mon Jun 21, 2004 11:31 am    Post subject: Re: Dynamic Stalls On Mon, 21 Jun 2004 20:55:42 +1200, M. wrote: Quote: G'day all Just a quick query to all the aerobatic pilots out there, what is dynamic stalling?. Any site references would be greatly appreciated Regards Mike Stealth Pilot has done a good job of explaining. I'll just add that stalling the tail is also possible (usually when inverted) and leads to a pretty radical departure from controlled flight. First time it happens it scares the bejeesus out of you, after a few you get accustomed to it, and dare I say it, enjoy it :) Long story short - any airfoil will stall at a certain angle of attack. Wings, stabilsers, rudders...all of them can stall. Actually *getting* them to stall is another matter all together. James -- You cannot see the wood for the trees. -- John Heywood Back to top Ted Harrison Guest Posted: Mon Jun 21, 2004 11:51 am    Post subject: Re: Dynamic Stalls "M." <mkarsten.nospam (AT) xtra (DOT) co.nz> wrote Quote: Just a quick query to all the aerobatic pilots out there, what is dynamic stalling?. Any site references would be greatly appreciated A dynamic stall is one where the angle of attack is increased beyond the stalling angle suddenly. This is how you enter a snap roll. Stick back sharply to stall, then full rudder in the direction you want to roll. The aircraft is stalled during the roll. Strong upgusts in turbulence can cause dynamic stalls. That's a simple answer. But you can find plenty on the web like this http://aerodyn.org/Dstall/dstall.html Back to top Qansett Guest Posted: Tue Jun 22, 2004 2:50 am    Post subject: Re: Dynamic Stalls "Centurion" <spam_this (AT) nowhere (DOT) tld> wrote Quote: On Mon, 21 Jun 2004 20:55:42 +1200, M. wrote: G'day all Just a quick query to all the aerobatic pilots out there, what is dynamic stalling?. Any site references would be greatly appreciated Regards Mike Stealth Pilot has done a good job of explaining. I'll just add that stalling the tail is also possible (usually when inverted) and leads to a pretty radical departure from controlled flight. First time it happens it scares the bejeesus out of you, after a few you get accustomed to it, and dare I say it, enjoy it :) Long story short - any airfoil will stall at a certain angle of attack. Wings, stabilsers, rudders...all of them can stall. Actually *getting* them to stall is another matter all together. James -- You cannot see the wood for the trees. I remember in 1985 a Mooney MU2 went into a high speed stall while cruising over West Aust at 18,000ft Can any of you guys explain to me how that would happen. I realize that the MU2 was not gifted with a large wing span. Quote: -- John Heywood Back to top Centurion Guest Posted: Tue Jun 22, 2004 3:53 am    Post subject: Re: Dynamic Stalls Qansett wrote: Quote: "Centurion" <spam_this (AT) nowhere (DOT) tld> wrote in message news:pan.2004.06.21.11.31.48.244448 (AT) nowhere (DOT) tld... On Mon, 21 Jun 2004 20:55:42 +1200, M. wrote: G'day all Just a quick query to all the aerobatic pilots out there, what is dynamic stalling?. Any site references would be greatly appreciated Regards Mike Stealth Pilot has done a good job of explaining. I'll just add that stalling the tail is also possible (usually when inverted) and leads to a pretty radical departure from controlled flight. First time it happens it scares the bejeesus out of you, after a few you get accustomed to it, and dare I say it, enjoy it :) Long story short - any airfoil will stall at a certain angle of attack. Wings, stabilsers, rudders...all of them can stall. Actually *getting* them to stall is another matter all together. James -- You cannot see the wood for the trees. I remember in 1985 a Mooney MU2 went into a high speed stall while cruising over West Aust at 18,000ft Can any of you guys explain to me how that would happen. I realize that the MU2 was not gifted with a large wing span. -- John Heywood Firstly it's a Mitsubishi MU-2, and secondly that was an icing incident. Basically the MU2 involved encountered icing conditions which altered the shape of the wing due to ice accumulation. The airflow over the wing then became disturbed and ultimately the pilot was unable to maintain control when the wing eventually stalled (due to ice). Ice accumulation can dramatically increase the stall speed in level flight and has caught out many pilots...including a recent incident involving a Saab 340: http://www.atsb.gov.au/atsb/media/mrel046.cfm James -- Q: How did you get into artificial intelligence? A: Seemed logical -- I didn't have any real intelligence. Back to top Paul Repacholi Guest Posted: Tue Jun 22, 2004 9:26 am    Post subject: Re: Dynamic Stalls Centurion <spam_this (AT) nowhere (DOT) com> writes: Quote: I remember in 1985 a Mooney MU2 went into a high speed stall while cruising over West Aust at 18,000ft Can any of you guys explain to me how that would happen. I realize that the MU2 was not gifted with a large wing span. Firstly it's a Mitsubishi MU-2, and secondly that was an icing incident. Basically the MU2 involved encountered icing conditions which altered the shape of the wing due to ice accumulation. The airflow over the wing then became disturbed and ultimately the pilot was unable to maintain control when the wing eventually stalled (due to ice). A MU-2 also has the added wrinkle of the spoilers. Ice film forms, spoiler shoves it up a bit, added ice reinforces the arched ice, spoiler shoves it all a bit highter... Quote: Ice accumulation can dramatically increase the stall speed in level flight and has caught out many pilots...including a recent incident involving a Saab 340: http://www.atsb.gov.au/atsb/media/mrel046.cfm And the MU-2 has a pretty high wingloading to start with. The high speed stall also is very good at starting an inverted spin :( Quote: Q: How did you get into artificial intelligence? A: Seemed logical -- I didn't have any real intelligence. We will know that Artificial Intelligence has succeded when it is indistinguishable from NAtural Stupidity. -- Paul Repacholi 1 Crescent Rd., +61 (0 9257-1001 Kalamunda. West Australia 6076 comp.os.vms,- The Older, Grumpier Slashdot Raw, Cooked or Well-done, it's all half baked. EPIC, The Architecture of the future, always has been, always will be. Back to top viz Guest Posted: Tue Jun 22, 2004 9:37 am    Post subject: Re: Dynamic Stalls "Centurion" <spam_this (AT) nowhere (DOT) com> wrote Quote: Firstly it's a Mitsubishi MU-2, and secondly that was an icing incident. I think that it may have been initially marketed in the States as a Mooney - I stand to be corrected... /viz Back to top Qansett Guest Posted: Wed Jun 23, 2004 11:09 am    Post subject: Re: Dynamic Stalls "viz" <viz@NOSPAM*.pacific.net.au> wrote Quote: "Centurion" <spam_this (AT) nowhere (DOT) com> wrote in message news:k2nkq1-i9m.ln1 (AT) news (DOT) grayonline.id.au... Firstly it's a Mitsubishi MU-2, and secondly that was an icing incident. I think that it may have been initially marketed in the States as a Mooney - I stand to be corrected... You are both right. Quote: /viz Back to top Centurion Guest Posted: Thu Jun 24, 2004 4:15 am    Post subject: Re: Dynamic Stalls Paul Repacholi wrote: Quote: Centurion <spam_this (AT) nowhere (DOT) com> writes: I remember in 1985 a Mooney MU2 went into a high speed stall while cruising over West Aust at 18,000ft Can any of you guys explain to me how that would happen. I realize that the MU2 was not gifted with a large wing span. Firstly it's a Mitsubishi MU-2, and secondly that was an icing incident. Basically the MU2 involved encountered icing conditions which altered the shape of the wing due to ice accumulation. The airflow over the wing then became disturbed and ultimately the pilot was unable to maintain control when the wing eventually stalled (due to ice). A MU-2 also has the added wrinkle of the spoilers. Ice film forms, spoiler shoves it up a bit, added ice reinforces the arched ice, spoiler shoves it all a bit highter... Funny - I used to refuel the MU-2's that operated out of YSBK...but never noticed the spoilers :-/ Goes to show how alert refuellers are at 2am after being roused from their blissful slumber :P Makes sense though - with such a short wing, by the time you've jammed big enough flap on there, to make take-off & landing possible on anything less than endless salt flat, there wouldn't be a lot of room for ailerons. So I guess it would need some "roll augmentation". James -- Serenity through viciousness. 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