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#31
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GOAT ASW20
I have 1000hrs in '20 with zero spins or surprising stalls. Load any glider from same vintage to aft c/g and it will spin, especially if you do not know how to deal with wing drop (excellent example posted on this forum just recently). Any flapped glider will stall and spin more abruptly with positive flaps. ASW20 being "killer" is OWT of all times. Puchacz is a killer, yes. '20, no.
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#32
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GOAT ASW20
On Friday, January 8, 2021 at 7:53:20 PM UTC-5, wrote:
The problem with the initial model of the ASw 20 spinning inadvertently was caused by poor pilot training coupled with this idea that having the CG way aft was the way to go. Pilots would put down the 55 degree flaps and forget or just not, trim for a pattern speed hands off. The flaps are large, and if you put them full down and forget to trim and get distracted and let go of the forward pitch pressure the plane will rapidly slow down and stall. Coupled with low altitude and a full aft CG this situation was a recipe for disaster. And yes, there were several accidents. When I got my ASw 20 check out this issue was beat into me by a couple of sharp cookies. I never had a problem. The fully rear CG thing is interesting, working with Tom Brenza in MoriarityNM I started out at about 50% aft for about 60 hours. Then I went to about 85% aft. Then, I thought anyway, doing alot of high speed cruising at 17+ out west my plane climbed great and ran best at about 60% aft CG. Every thing I have owned easily spins, Except our ASK 21- My Blanik L-13 was a great ship to do as many spins as you wanted in both directions. My Ka6 CR was really good at controllable multiple, long duration spins, as is my LS3a. I spent a Fall living in Fort Collins Co and got checked out in their C-150. I would come over CX house high and spin that thing like crazy, musta done 200+ in that thing and got really comfortable doing them. Nick T I owned 20's for about 15 years. Early experience showed that far aft CG made it much more prone to departure into a spin. Over time I learned: 1- I put the CG at the point where I could turn as tightly as I wanted without running out of elevator at thermalling speed. That turned out to be about 80% aft. Stall spin characteristics were pretty benign. 2- Adding internal and external seals to wing controls meaningfully improved handling and stall/spin characteristic. 3- Good winglets make handling better and stall/spin more benign, up until the glider spins. After a spin is initiated, winglets can make it more abrupt. After I took delivery of my first 20, I test flew it and it spun almost without warning out of a normal stall. Investigation found 15 lb of lead in the tail that was not documented. The previous owner said he only flew it with water and it was fine for him. The lesson I came away with is at least weigh the tail of any ship new to you to see if the weight agrees with your weight and balance. If not, investigate before becoming an involuntary test pilot. UH |
#33
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GOAT ASW20
kinsell wrote on 1/8/2021 10:26 PM:
On 1/8/21 5:53 PM, Nicholas Kennedy wrote: The problem with the initial model of the ASw 20 spinning inadvertently was caused by poor pilot training coupled with this idea that having the CG way aft was the way to go. Pilots would put down the 55 degree flaps and forget or just not, trim for a pattern speed hands off. The flaps are large, and if you put them full down and forget to trim and get distracted and let go of the forward pitch pressure the plane will rapidly slow down and stall.* Coupled with low altitude and a full aft CG this situation was a recipe for disaster. And yes, there were several accidents. When I got my ASw 20 check out this issue was beat into me by a couple of sharp cookies. I never had a problem. The fully rear CG thing is interesting, working with Tom Brenza in MoriarityNM I started out at about 50% aft for about 60 hours. Then I went to about 85% aft. Then, I thought anyway, doing alot of high speed cruising at 17+ out west my plane climbed great and ran best at about 60% aft CG. Every thing I have owned easily spins, Except our* ASK 21- My Blanik L-13 was a great ship to do as many spins as you wanted in both directions. My Ka6 CR was really good at controllable multiple, long duration spins, as is my LS3a. I spent a Fall living in Fort Collins Co and got checked out in their C-150. I would come over CX house high and spin that thing like crazy, musta done 200+ in that thing and got really comfortable doing them. Nick T Found an article that claims the '20 spins like a top with landing gear down and landing flaps selected, but is stable otherwise: http://flsc.org/portals/12/PDF/Spinning.pdf I'm surprised to hear that it will spin readily with the full landing flap, because that also puts the ailerons into negative deflection. That makes it very difficult to stall the tips, a usual condition for spinning. Perhaps the full deflection affects the airflow over the tail, and that is cause? The reason I heard the reason for changing from 60 degree deflection to 40 degrees was to avoid damage to the flap rods in a hard landing, which was often undetected until the next landing. Selecting full deflection would then fully deflect only one flap, giving a strong rolling motion and a very surprised pilot. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 |
#34
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GOAT ASW20
On Saturday, January 9, 2021 at 8:55:22 AM UTC-5, Eric Greenwell wrote:
kinsell wrote on 1/8/2021 10:26 PM: On 1/8/21 5:53 PM, Nicholas Kennedy wrote: The problem with the initial model of the ASw 20 spinning inadvertently was caused by poor pilot training coupled with this idea that having the CG way aft was the way to go. Pilots would put down the 55 degree flaps and forget or just not, trim for a pattern speed hands off. The flaps are large, and if you put them full down and forget to trim and get distracted and let go of the forward pitch pressure the plane will rapidly slow down and stall. Coupled with low altitude and a full aft CG this situation was a recipe for disaster. And yes, there were several accidents. When I got my ASw 20 check out this issue was beat into me by a couple of sharp cookies. I never had a problem. The fully rear CG thing is interesting, working with Tom Brenza in MoriarityNM I started out at about 50% aft for about 60 hours. Then I went to about 85% aft. Then, I thought anyway, doing alot of high speed cruising at 17+ out west my plane climbed great and ran best at about 60% aft CG. Every thing I have owned easily spins, Except our ASK 21- My Blanik L-13 was a great ship to do as many spins as you wanted in both directions. My Ka6 CR was really good at controllable multiple, long duration spins, as is my LS3a. I spent a Fall living in Fort Collins Co and got checked out in their C-150. I would come over CX house high and spin that thing like crazy, musta done 200+ in that thing and got really comfortable doing them. Nick T Found an article that claims the '20 spins like a top with landing gear down and landing flaps selected, but is stable otherwise: http://flsc.org/portals/12/PDF/Spinning.pdf I'm surprised to hear that it will spin readily with the full landing flap, because that also puts the ailerons into negative deflection. That makes it very difficult to stall the tips, a usual condition for spinning. Perhaps the full deflection affects the airflow over the tail, and that is cause? The reason I heard the reason for changing from 60 degree deflection to 40 degrees was to avoid damage to the flap rods in a hard landing, which was often undetected until the next landing. Selecting full deflection would then fully deflect only one flap, giving a strong rolling motion and a very surprised pilot. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 The biggest reason for reduced flap deflection was to prevent damage to the newly implemented gap seals, originally metal and soon after polyester (Mylar). My experience agrees with Eric in that landing flap makes the ship more docile, not less. UH |
#35
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GOAT ASW20
On Sunday, January 10, 2021 at 6:00:08 AM UTC-8, Hank Nixon wrote:
On Saturday, January 9, 2021 at 8:55:22 AM UTC-5, Eric Greenwell wrote: kinsell wrote on 1/8/2021 10:26 PM: On 1/8/21 5:53 PM, Nicholas Kennedy wrote: The problem with the initial model of the ASw 20 spinning inadvertently was caused by poor pilot training coupled with this idea that having the CG way aft was the way to go. Pilots would put down the 55 degree flaps and forget or just not, trim for a pattern speed hands off. The flaps are large, and if you put them full down and forget to trim and get distracted and let go of the forward pitch pressure the plane will rapidly slow down and stall. Coupled with low altitude and a full aft CG this situation was a recipe for disaster. And yes, there were several accidents. When I got my ASw 20 check out this issue was beat into me by a couple of sharp cookies. I never had a problem. The fully rear CG thing is interesting, working with Tom Brenza in MoriarityNM I started out at about 50% aft for about 60 hours. Then I went to about 85% aft. Then, I thought anyway, doing alot of high speed cruising at 17+ out west my plane climbed great and ran best at about 60% aft CG. Every thing I have owned easily spins, Except our ASK 21- My Blanik L-13 was a great ship to do as many spins as you wanted in both directions. My Ka6 CR was really good at controllable multiple, long duration spins, as is my LS3a. I spent a Fall living in Fort Collins Co and got checked out in their C-150. I would come over CX house high and spin that thing like crazy, musta done 200+ in that thing and got really comfortable doing them. Nick T Found an article that claims the '20 spins like a top with landing gear down and landing flaps selected, but is stable otherwise: http://flsc.org/portals/12/PDF/Spinning.pdf I'm surprised to hear that it will spin readily with the full landing flap, because that also puts the ailerons into negative deflection. That makes it very difficult to stall the tips, a usual condition for spinning. Perhaps the full deflection affects the airflow over the tail, and that is cause? The reason I heard the reason for changing from 60 degree deflection to 40 degrees was to avoid damage to the flap rods in a hard landing, which was often undetected until the next landing. Selecting full deflection would then fully deflect only one flap, giving a strong rolling motion and a very surprised pilot. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 The biggest reason for reduced flap deflection was to prevent damage to the newly implemented gap seals, originally metal and soon after polyester (Mylar). My experience agrees with Eric in that landing flap makes the ship more docile, not less. UH I’ll go out and stall my 20 with full flaps this spring when I get it put back together. |
#36
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GOAT ASW20
wrote on 1/10/2021 6:35 AM:
On Sunday, January 10, 2021 at 6:00:08 AM UTC-8, Hank Nixon wrote: .... Found an article that claims the '20 spins like a top with landing gear down and landing flaps selected, but is stable otherwise: http://flsc.org/portals/12/PDF/Spinning.pdf I'm surprised to hear that it will spin readily with the full landing flap, because that also puts the ailerons into negative deflection. That makes it very difficult to stall the tips, a usual condition for spinning. Perhaps the full deflection affects the airflow over the tail, and that is cause? The reason I heard the reason for changing from 60 degree deflection to 40 degrees was to avoid damage to the flap rods in a hard landing, which was often undetected until the next landing. Selecting full deflection would then fully deflect only one flap, giving a strong rolling motion and a very surprised pilot. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 The biggest reason for reduced flap deflection was to prevent damage to the newly implemented gap seals, originally metal and soon after polyester (Mylar). My experience agrees with Eric in that landing flap makes the ship more docile, not less. UH Ill go out and stall my 20 with full flaps this spring when I get it put back together. I hope you have the original 20 with the 60 degree flaps and are willing to try turning stalls. My 20C, with 40 degree flaps, was hard to stall straight ahead, and remained controllable. I don't recall trying any turning stalls in landing configuration, so I'd like to know how the "A" model compares to the B or C model. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 |
#37
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GOAT ASW20
Just remember that spins in landing flap are prohibited - all explained in the manual.
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#38
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GOAT ASW20
George Haeh wrote on 1/10/2021 9:33 AM:
Just remember that spins in landing flap are prohibited - all explained in the manual. I'm not expecting anyone to try to intentionally spin, but just fly as you normally would, and "mishandle" it like a person might inadvertently do; eg, a steady, coordinated 20 deg banked turn while you slow down, or perhaps a shallow skidded turn at slower and slower speeds. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 |
#39
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GOAT ASW20
On Sunday, January 10, 2021 at 12:33:58 PM UTC-5, wrote:
Just remember that spins in landing flap are prohibited - all explained in the manual. Tell that to the few that were killed, I don't think that they did it on purpose, and the manual would not have made any difference. |
#40
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GOAT ASW20
On Sunday, January 10, 2021 at 7:37:11 AM UTC-8, Eric Greenwell wrote:
wrote on 1/10/2021 6:35 AM: On Sunday, January 10, 2021 at 6:00:08 AM UTC-8, Hank Nixon wrote: .... Found an article that claims the '20 spins like a top with landing gear down and landing flaps selected, but is stable otherwise: http://flsc.org/portals/12/PDF/Spinning.pdf I'm surprised to hear that it will spin readily with the full landing flap, because that also puts the ailerons into negative deflection. That makes it very difficult to stall the tips, a usual condition for spinning. Perhaps the full deflection affects the airflow over the tail, and that is cause? The reason I heard the reason for changing from 60 degree deflection to 40 degrees was to avoid damage to the flap rods in a hard landing, which was often undetected until the next landing. Selecting full deflection would then fully deflect only one flap, giving a strong rolling motion and a very surprised pilot. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 The biggest reason for reduced flap deflection was to prevent damage to the newly implemented gap seals, originally metal and soon after polyester (Mylar). My experience agrees with Eric in that landing flap makes the ship more docile, not less. UH I’ll go out and stall my 20 with full flaps this spring when I get it put back together. I hope you have the original 20 with the 60 degree flaps and are willing to try turning stalls. My 20C, with 40 degree flaps, was hard to stall straight ahead, and remained controllable. I don't recall trying any turning stalls in landing configuration, so I'd like to know how the "A" model compares to the B or C model. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 Yep I have an early “A” model. I’ll get up high this spring and see how it goes. I don’t recall if I did a full flap stall when I initially checked myself out. |
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