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#1
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deturbulated std cirrus flies against Diana 1
For the latest parallel flight of my deturbulated Standard Cirrus vs. a
modern glider, go to http://sinhatech.com/SinhaFCSD-Progr...08.asp#article . 20 minutes of parallel flying should be enough to make the point. Download and replay the logs in SeeYou, or what have you. Jim Hendrix Oxford Aero Equipment, LLC 417 N. 11th Street Oxford, MS 38655 662-234-0492 voice 662-234-2195 fax www.oxaero.com |
#2
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deturbulated std cirrus flies against Diana 1
On Jun 9, 2:58*pm, Jim Hendrix wrote:
For the latest parallel flight of my deturbulated Standard Cirrus vs. a modern glider, go tohttp://sinhatech.com/SinhaFCSD-Progress-06072008.asp#article. 20 minutes of parallel flying should be enough to make the point. Download and replay the logs in SeeYou, or what have you. Jim Hendrix Oxford Aero Equipment, LLC 417 N. 11th Street Oxford, MS 38655 662-234-0492 voice 662-234-2195 fax Jim, How narrow is the airspeed "sweet spot" for achieving these performance gains? From the looks of the presentations on the website, it seems like it might be rather small. Are there any handling characteristics that are affected by the modifications such as stall, slow speed, thermalling, etc.? Dave |
#3
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deturbulated std cirrus flies against Diana 1
At 20:39 09 June 2008, wrote:
On Jun 9, 2:58=A0pm, Jim Hendrix wrote: For the latest parallel flight of my deturbulated Standard Cirrus vs. a modern glider, go tohttp://sinhatech.com/SinhaFCSD-Progress-06072008.asp#a= rticle. 20 minutes of parallel flying should be enough to make the point. Download and replay the logs in SeeYou, or what have you. Jim Hendrix Oxford Aero Equipment, LLC 417 N. 11th Street Oxford, MS 38655 662-234-0492 voice 662-234-2195 fax Jim, How narrow is the airspeed "sweet spot" for achieving these performance gains? From the looks of the presentations on the website, it seems like it might be rather small. Are there any handling characteristics that are affected by the modifications such as stall, slow speed, thermalling, etc.? Dave Dave, The narrowness of the extreme performance peak near 50 KIA is seen in the third graph on page http://sinhatech.com/SinhaFCSD-Progress-12012007.asp . The two neighboring speed points are 2.5 kts on either side, or 5 kts apart. That I was not accounting for my additional weight and was flying too slow at 50 KIA is seen in the 47.5 point being higher than the 52.5 KIA point. I believe that is the reason that my extreme performance flight on 12/1/07 only reached 70:1 whereas Johnson's a year earlier reached over 100:1. This is confirmed by my second 50 run on 12/1/07 in which excessive pitch momentum arriving at the magic speed made the AOA and deturbulator performance "hunt" each other such that the performance swung between Johnson's performance at the top and baseline at the bottom (Click Extreme Performance powerpoint link and scroll to the bottom for that graph.). It is interesting that if, as it appears, my ship was matching a 45:1 glider, that is about the performance level between the neighboring speed points I used to define the performance peak width. So, the polar from 12/1/08 closely matches the Diana performance I saw last Saturday. Stall speed is not affected significantly. Neither is handline, though there are a number of interesting effects from flying with wings that change moment to moment. Lately I've been experimenting with instantly improving performance by pulling up to nearly a stall and slowly settling down to 51 KIA. It seems that often this gives me a quick performance boost. JEH |
#4
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deturbulated std cirrus flies against Diana 1
On Jun 9, 4:13*pm, Jim Hendrix wrote:
At 20:39 09 June 2008, wrote: On Jun 9, 2:58=A0pm, Jim Hendrix *wrote: For the latest parallel flight of my deturbulated Standard Cirrus vs. a modern glider, go tohttp://sinhatech.com/SinhaFCSD-Progress-06072008.asp#a= rticle. 20 minutes of parallel flying should be enough to make the point. Download and replay the logs in SeeYou, or what have you. Jim Hendrix Oxford Aero Equipment, LLC 417 N. 11th Street Oxford, MS 38655 662-234-0492 voice 662-234-2195 fax Jim, How narrow is the airspeed "sweet spot" for achieving these performance gains? *From the looks of the presentations on the website, it seems like it might be rather small. Are there any handling characteristics that are affected by the modifications such as stall, slow speed, thermalling, etc.? Dave Dave, The narrowness of the extreme performance peak near 50 KIA is seen in the third graph on pagehttp://sinhatech.com/SinhaFCSD-Progress-12012007.asp. *The two neighboring speed points are 2.5 kts on either side, or 5 kts apart. *That I was not accounting for my additional weight and was flying too slow at 50 KIA is seen in the 47.5 point being higher than the 52.5 KIA point. *I believe that is the reason that my extreme performance flight on 12/1/07 only reached 70:1 whereas Johnson's a year earlier reached over 100:1. *This is confirmed by my second 50 run on 12/1/07 in which excessive pitch momentum arriving at the magic speed made the AOA and deturbulator performance "hunt" each other such that the performance swung between Johnson's performance at the top and baseline at the bottom (Click Extreme Performance powerpoint link and scroll to the bottom for that graph.). It is interesting that if, as it appears, my ship was matching a 45:1 glider, that is about the performance level between the neighboring speed points I used to define the performance peak width. *So, the polar from 12/1/08 closely matches the Diana performance I saw last Saturday. Stall speed is not affected significantly. *Neither is handline, though there are a number of interesting effects from flying with wings that change moment to moment. *Lately I've been experimenting with instantly improving performance by pulling up to nearly a stall and slowly settling down to 51 KIA. *It seems that often this gives me a quick performance boost. JEH- Hide quoted text - - Show quoted text - Jim, Thanks for the info. Some additional questions for you. What do you "feel" in the aircraft when this "AOA and deturbulator performance hunt" is going on? Is there some kind of noticable oscillation going on? What are some of the other "interesting effects"? Dave |
#5
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deturbulated std cirrus flies against Diana 1
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#6
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deturbulated std cirrus flies against Diana 1
If both gliders were flying at about 51 kts, doesn't this give the Cirrus
an advantage? 51 kts probably gives best l/d for the Cirrus, but it will be well below best l/d for the diana. |
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