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#131
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Another stall spin
I guess we were reading different posts, Bob, or, at least coming from
different mindsets. Having directly witnessed a low altitude departure and the results, I'm just hard core about maintaining airspeed and NEVER getting low enough that I need to claw my way out or crash. Learn to recognize low airspeed by sound and control pressures and high AoA by control feedback, buffeting, reversal, etc. Learn to extract the maximum from your glider at altitude and learn to regain control with a simple flick of the wrist at the first indication of a departure. Of course you should also know how to recover from an incipient spin. You should learn none of these things at low altitude because you most likely won't get the chance to try a second time. That's my whole point - don't put yourself in a position to kill yourself. "BobW" wrote in message ... On 9/5/2012 6:34 PM, Dan Marotta wrote: In my last post I talked about making an early decision to land out and never attempting low saves ala 300' AGL. The many following posts are all about low altitude departures from controlled flight. Nobody thinks he'll die on this flight but, if I was an insurance underwriter, I'd give lower premiums to those who commit to safe field landings over those who attempt low saves. I have a hard time accepting "safety lectures" which espouse safely pulling your fat out of the fire rather than not letting it get there in the first place. Lordy. Are we reading the same posts? *I'm* certainly not espousing safely pulling my - or anyone else's - fat out of the fire (by attempting low saves in Russian roulette territory) vs. "not going there in the first place". Just to be clear, I think attempted thermalling at Russian roulette height agl (and each pilot gets to determine what that height is for them) is (choose what you'd like): asinine; foolish; irresponsible (at many levels); playing with fire; etc., etc., etc. That said, no "safety lecture" anyone thinks I may be indulging in applies *only* to low thermalling. Minor messing about in the NTSB database, paying attention to what one reads over the years, etc., reveals lots of pattern-based, fatal, departures from controlled flight that may easily have been avoidable had the pilots' involved not been "surprised". Remember the Questair Venture? Designed by two highly experienced professional aeronautical types, one of whom eventually died in a Venture after a (very) high-altitude (meaning, lots of time to get things sorted out and develop a plan) engine failure that resulted in a base-to-final departure-from-controlled flight when they easily had the Des Moines International Airport made. That crunch merely springs to mind...there're lots more, including "benign spam can" crunches. Nor are pattern departure fatalities limited to power planes. FWIW, Bob W. |
#132
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Another stall spin
On Thursday, September 6, 2012 12:59:10 AM UTC-7, BruceGreeff wrote:
Hi Eric Standard recovery is good - as long as the PIC knows the necessary numbers, and has the presence of mind to apply it. I have seen 2 fatalities where a spin recovery included the pilot achieving a recovery attitude so steep that Vne was exceeded for the flap setting. Predictable results of flutter and catastrophic failure ensue quite rapidly. In the one case the pilot achieved 2x Vne. In my opinion the most important thing is to aviate first, as soon as you are no longer spinning, fly the aeroplane. Don't follow a procedute to it's end when you have achieved the object already, lest you make things worse. Most flapped gliders have multiple flap limiting speeds and accelerate rapidly with nose down attitude. So - by the time you have gone flaps neutral, you are probably already no longer stalled. Bruce On 2012/09/06 7:44 AM, Eric Greenwell wrote: On 8/30/2012 1:13 PM, wrote: The dumping of flaps seems to be well practiced in recovering from this maneuver- I wonder who taught him this. Bruno seems more worried about staying in the thermal than getting control of the glider. Maybe these techniques were why he spun it so much. Luckily not at low altitude. From the flight manual spin recovery section for my ASH 26 E, which has the same interconnected flap and aileron system as the ASW 20. "Furthermore, spin recovery will be achieved more quickly if the flap deflection is reduced. It is advisable to reduce circling flap to the neutral flap setting." I believe my ASW 20 B flight manual had similar advice. In any case, I found reducing the flap deflection effective in the incipient or just departed stage. I have not practiced spins beyond a quarter turn in either the 20 or the 26. Even though reducing flap deflection is effective, I always used the standard recovery in addition, and I recommend Bruno learn to do that, also. It is what gliders are certified to do, and the flap reduction might not work well enough on all ships in all conditions, and certainly won't work on a standard class glider. -- Bruce Greeff T59D #1771 Bruce, can you elaborate more on those accidents? I dont recall hearing about accidents attributed to exceeding VNE after spin recovery, in particular flap setting lower VNE. As far as I know the risk of exceeding flap VNE is flaps damage, not flutter, but I could be wrong. I can imagine spin turning to spiral resulting in exceeding VNE, but normal recovery, even if pointing straight down, should not exceed VNE unless held too long, since the entry speed is low. Ramy |
#133
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Another stall spin
On 9/6/2012 7:56 AM, Dan Marotta wrote:
I guess we were reading different posts, Bob, or, at least coming from different mindsets. Having directly witnessed a low altitude departure and the results, I'm just hard core about maintaining airspeed and NEVER getting low enough that I need to claw my way out or crash. Learn to recognize low airspeed by sound and control pressures and high AoA by control feedback, buffeting, reversal, etc. Learn to extract the maximum from your glider at altitude and learn to regain control with a simple flick of the wrist at the first indication of a departure. Of course you should also know how to recover from an incipient spin. You should learn none of these things at low altitude because you most likely won't get the chance to try a second time. That's my whole point - don't put yourself in a position to kill yourself. Whew! Color me mildly perplexed there, for a bit. :-) I'm in 100% agreement with everything you say above, and it's not a recent mindset. If I could find it - which I can't - I'd include a link to an old bit on my soaring club's website from a pre-web newsletter proving my "not a recent mindset" claim. Back when Rick Kohler had recently started Sundance Aviation in Moriarty (a glider FBO, for those unfamiliar with S.A., and, in the early '90s?), on the drive down to attend a soaring camp, I'd been pondering various aspects of landing-pattern-departure accidents then known to me. Sought (very experienced CFIG) Rick's input/take on things, because I - generally a believer in "never say 'never'" when it comes to airplane/pilot possibilities - had come to the conclusion that Joe Pilot should NEVER put himself into the position of an inadvertent departure from controlled flight in the landing pattern. So I asked Rick, "What do you teach your students about pattern stalls?" His reply was, "Don't DO them!" (He/we went on to elaborate, natch, but his pithy point was immediately clear to any reasonably experienced pilot.) Yeah, it's a "Duh!" conclusion...if a person has ever actively thought about it. But no licensed pilot is born "wise in the ways of aviation"... Bob - no harm no foul - W. |
#134
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Another stall spin
I tried a stall while thermalling, with a couple notches of positive flaps, in my last outing and find I am instinctively doing the same by moving flaps to neutral also, while moving stick forward to increase airspeed and re-attach flow. The main reason is because it is easier and requires less force to move the stick forward with the flaps moved forward to neutral at the same time. Since they are lightly mechanically coupled in my ship. |
#135
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Another stall spin
I was just discussing this thread with Rick this morning and we both agree
with what you say. I tow for Rick a couple of days a week (today being one). It helps pay for my gliding. "Bob Whelan" wrote in message ... On 9/6/2012 7:56 AM, Dan Marotta wrote: I guess we were reading different posts, Bob, or, at least coming from different mindsets. Having directly witnessed a low altitude departure and the results, I'm just hard core about maintaining airspeed and NEVER getting low enough that I need to claw my way out or crash. Learn to recognize low airspeed by sound and control pressures and high AoA by control feedback, buffeting, reversal, etc. Learn to extract the maximum from your glider at altitude and learn to regain control with a simple flick of the wrist at the first indication of a departure. Of course you should also know how to recover from an incipient spin. You should learn none of these things at low altitude because you most likely won't get the chance to try a second time. That's my whole point - don't put yourself in a position to kill yourself. Whew! Color me mildly perplexed there, for a bit. :-) I'm in 100% agreement with everything you say above, and it's not a recent mindset. If I could find it - which I can't - I'd include a link to an old bit on my soaring club's website from a pre-web newsletter proving my "not a recent mindset" claim. Back when Rick Kohler had recently started Sundance Aviation in Moriarty (a glider FBO, for those unfamiliar with S.A., and, in the early '90s?), on the drive down to attend a soaring camp, I'd been pondering various aspects of landing-pattern-departure accidents then known to me. Sought (very experienced CFIG) Rick's input/take on things, because I - generally a believer in "never say 'never'" when it comes to airplane/pilot possibilities - had come to the conclusion that Joe Pilot should NEVER put himself into the position of an inadvertent departure from controlled flight in the landing pattern. So I asked Rick, "What do you teach your students about pattern stalls?" His reply was, "Don't DO them!" (He/we went on to elaborate, natch, but his pithy point was immediately clear to any reasonably experienced pilot.) Yeah, it's a "Duh!" conclusion...if a person has ever actively thought about it. But no licensed pilot is born "wise in the ways of aviation"... Bob - no harm no foul - W. |
#136
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Another stall spin
Hi Bruce - I don't think I understand your points(s).
Are you suggesting the flap movement not be done, or the standard recovery be done only if the flap movement doesn't stop the spin? In other words, what would "aviate first" be for my ASH 26 E? My understanding of the manual is the flap movement to a more negative setting is initiated at the same time as the standard recovery. The manual does not indicate you should follow the procedure to "it's end", but to recover normally as soon as the spin is halted (in fact, I think that is part of the standard procedure). On 9/6/2012 12:59 AM, BruceGreeff wrote: Hi Eric Standard recovery is good - as long as the PIC knows the necessary numbers, and has the presence of mind to apply it. I have seen 2 fatalities where a spin recovery included the pilot achieving a recovery attitude so steep that Vne was exceeded for the flap setting. Predictable results of flutter and catastrophic failure ensue quite rapidly. In the one case the pilot achieved 2x Vne. In my opinion the most important thing is to aviate first, as soon as you are no longer spinning, fly the aeroplane. Don't follow a procedute to it's end when you have achieved the object already, lest you make things worse. Most flapped gliders have multiple flap limiting speeds and accelerate rapidly with nose down attitude. So - by the time you have gone flaps neutral, you are probably already no longer stalled. Bruce On 2012/09/06 7:44 AM, Eric Greenwell wrote: On 8/30/2012 1:13 PM, wrote: The dumping of flaps seems to be well practiced in recovering from this maneuver- I wonder who taught him this. Bruno seems more worried about staying in the thermal than getting control of the glider. Maybe these techniques were why he spun it so much. Luckily not at low altitude. From the flight manual spin recovery section for my ASH 26 E, which has the same interconnected flap and aileron system as the ASW 20. "Furthermore, spin recovery will be achieved more quickly if the flap deflection is reduced. It is advisable to reduce circling flap to the neutral flap setting." I believe my ASW 20 B flight manual had similar advice. In any case, I found reducing the flap deflection effective in the incipient or just departed stage. I have not practiced spins beyond a quarter turn in either the 20 or the 26. Even though reducing flap deflection is effective, I always used the standard recovery in addition, and I recommend Bruno learn to do that, also. It is what gliders are certified to do, and the flap reduction might not work well enough on all ships in all conditions, and certainly won't work on a standard class glider. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm http://tinyurl.com/yb3xywl - "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz |
#137
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Another stall spin
On 8/30/2012 1:15 PM, Bob Whelan wrote:
Indeed, assuming no other changes/inputs, reducing flap deflection reduces lift, the glider will settle (increasing the AoA, as - thanks to gravity and trim forces - the plane/wing tries to regenerate the lost lift and return to a non-changing-acceleration state), and the stall speed (assuming no change in G load) increases. Kinda makes for a strong argument to not put oneself in the position of NEEDing to dump flaps (reducing the wing's camber and effective AoA) to prevent a spin when close to the ground, eh? "Settling" is more of an issue at 50 feet on final, than at spin starting at pattern altitude. When thermalling or on final, I can change from positive to neutral or some negative flap, and the settling is minimal. Because it is effective, quick to do, and loses less altitude, I think doing near the ground is safer than the standard procedure. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) |
#138
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Another stall spin
I see the sailplane spin recovery procedure in the EASA
certification specs is ailerons neutral full opposite rudder stick forward until rotation stops centralise rudder and ease out of the dive I'd guess any flap change that manufacturers recommend is more in preparation for the likely high speeds in the dive. http://www.easa.europa.eu/agency-mea...certification- specifications/CS-22/Consolidated%20version%20CS- 22%20Amdt%202.pdf At 02:54 10 September 2012, Eric Greenwell wrote: On 8/30/2012 1:15 PM, Bob Whelan wrote: Indeed, assuming no other changes/inputs, reducing flap deflection reduces lift, the glider will settle (increasing the AoA, as - thanks to gravity and trim forces - the plane/wing tries to regenerate the lost lift and return to a non-changing-acceleration state), and the stall speed (assuming no change in G load) increases. Kinda makes for a strong argument to not put oneself in the position of NEEDing to dump flaps (reducing the wing's camber and effective AoA) to prevent a spin when close to the ground, eh? "Settling" is more of an issue at 50 feet on final, than at spin starting at pattern altitude. When thermalling or on final, I can change from positive to neutral or some negative flap, and the settling is minimal. Because it is effective, quick to do, and loses less altitude, I think doing near the ground is safer than the standard procedure. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) |
#139
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Another stall spin
On 9/4/2012 6:49 PM, Greg Arnold wrote:
What glider were you flying?: We tried that with an Blanik L13, and couldn't get it to spin without using the normal highly exaggerated control inputs - stick all the way back and full rudder. Our Blanik would depart and spin from a smoothly flown, coordinated turn. I'd have the student do a shallow (10-15 degrees) turn, keeping the yaw string centered, and have them slowly reduce speed. At some point, the inner wing would fall and begin a spin. A common response was out-spin aileron, even though I'd briefed them and demonstrated the maneuver earlier. With one student (the lightest one), the out-spin aileron was enough to maintain the spin, even though the stick was a bit forward of neutral. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) |
#140
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Another stall spin
On 9/9/2012 8:18 PM, Andrew wrote:
I see the sailplane spin recovery procedure in the EASA certification specs is ailerons neutral full opposite rudder stick forward until rotation stops centralise rudder and ease out of the dive I'd guess any flap change that manufacturers recommend is more in preparation for the likely high speeds in the dive. No need to guess, as the flight manual for my ASH 26 E (and my ASW 20 B before) is clear: "Furthermore, spin recovery will be achieved more quickly if the flap deflection is reduced. It is advisable to reduce circling flap to the neutral flap setting." -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) |
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