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#1
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JS-1 Exhaust Vent
Gotta hand it to Johan Bosman on this one... look at pg 5 of this pdf:
http://www.streckenflug.at/news/js_c...on_2010_07.pdf Personally I think his take on the exhaust vent is simply ingenious. The opening on that thing is immense and has got to allow much air to pass, but flow is organized by that little louver/wing. Pure genius. I may just be preoccupied on the subject right now since I'm in the middle of making vented ASW-20 hatches (Mandl and Butler styles) for the upcoming 20 gathering at Tehachapi. Pics to follow... -Paul |
#2
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JS-1 Exhaust Vent
Paul,
I am greatly looking forward to seeing your work at the upcoming 20 get together. I was talking to a few pilots I respect at the Region 9 Logan contest last week and mentioned your proposed vent and they said that there will be a problem with the hatch being off to one side and not centered. What do you think? Still count me in for trying one out. Bruno - B4 On Jul 25, 4:33*pm, sisu1a wrote: Gotta hand it to Johan Bosman on this one... look at pg 5 of this pdf:http://www.streckenflug.at/news/js_c...on_2010_07.pdf Personally I think his take on the exhaust vent is simply ingenious. The opening on that thing is immense and has got to allow much air to pass, but flow is organized by that little louver/wing. Pure genius. I may just be preoccupied on the subject right now since I'm in the middle of making vented ASW-20 hatches (Mandl and Butler styles) for the upcoming 20 gathering at Tehachapi. Pics to follow... -Paul |
#3
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JS-1 Exhaust Vent
On Jul 25, 8:52*pm, Bruno wrote:
... there will be a problem with the hatch being off to one side and not centered... You mean, like the DG exit vents ? |
#4
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JS-1 Exhaust Vent
"Dave Nadler" wrote in message You mean, like the DG exit vents ? No, like the Antares 220 volt electrical plug outlet and outboard fire extinguisher bracket. |
#5
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JS-1 Exhaust Vent
On Jul 25, 5:52*pm, Bruno wrote:
Paul, I am greatly looking forward to seeing your work at the upcoming 20 get together. *I was talking to a few pilots I respect at the Region 9 Logan contest last week and mentioned your proposed vent and they said that there will be a problem with the hatch being off to one side and not centered. *What do you think? *Still count me in for trying one out. * Bruno - B4 On Jul 25, 4:33*pm, sisu1a wrote: Gotta hand it to Johan Bosman on this one... look at pg 5 of this pdf:http://www.streckenflug.at/news/js_c...on_2010_07.pdf Personally I think his take on the exhaust vent is simply ingenious. The opening on that thing is immense and has got to allow much air to pass, but flow is organized by that little louver/wing. Pure genius. I may just be preoccupied on the subject right now since I'm in the middle of making vented ASW-20 hatches (Mandl and Butler styles) for the upcoming 20 gathering at Tehachapi. Pics to follow... -Paul Maybe equally impressive to the engineering of the JS1 exhaust vent is the psychological-gamesmanship of emphasizing the performance enhancement effects of this just prior to the 18m Worlds. Love it. Darryl |
#6
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JS-1 Exhaust Vent
On Jul 25, 6:11*pm, Darryl Ramm wrote:
On Jul 25, 5:52*pm, Bruno wrote: Paul, I am greatly looking forward to seeing your work at the upcoming 20 get together. *I was talking to a few pilots I respect at the Region 9 Logan contest last week and mentioned your proposed vent and they said that there will be a problem with the hatch being off to one side and not centered. *What do you think? *Still count me in for trying one out. * Bruno - B4 On Jul 25, 4:33*pm, sisu1a wrote: Gotta hand it to Johan Bosman on this one... look at pg 5 of this pdf:http://www.streckenflug.at/news/js_c...on_2010_07.pdf Personally I think his take on the exhaust vent is simply ingenious. The opening on that thing is immense and has got to allow much air to pass, but flow is organized by that little louver/wing. Pure genius. I may just be preoccupied on the subject right now since I'm in the middle of making vented ASW-20 hatches (Mandl and Butler styles) for the upcoming 20 gathering at Tehachapi. Pics to follow... -Paul Maybe equally impressive to the engineering of the JS1 exhaust vent is the psychological-gamesmanship of emphasizing the performance enhancement effects of this just prior to the 18m Worlds. Love it. Darryl perhaps some will file the trailing edge of their wings to a knife like edge...............no, wait, that's been done before! |
#7
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JS-1 Exhaust Vent
On Jul 25, 4:33*pm, sisu1a wrote:
Gotta hand it to Johan Bosman on this one... look at pg 5 of this pdf:http://www.streckenflug.at/news/js_c...on_2010_07.pdf Personally I think his take on the exhaust vent is simply ingenious. The opening on that thing is immense and has got to allow much air to pass, but flow is organized by that little louver/wing. Pure genius. I may just be preoccupied on the subject right now since I'm in the middle of making vented ASW-20 hatches (Mandl and Butler styles) for the upcoming 20 gathering at Tehachapi. Pics to follow... -Paul I still think a reversed NACA duct will work better than the Butler and much better than the Mandl. The Mandl throws the low speed air out into the faster air stream. The JS design accelerates half the air over the airfoil but what happens to the air under the airfoil? |
#8
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JS-1 Exhaust Vent
On Jul 25, 9:54*pm, Tim Taylor wrote:
I still think a reversed NACA duct will work better than the Butler and much better than the Mandl. *The Mandl throws the low speed air out into the faster air stream. *The JS design accelerates half the air over the airfoil but what happens to the air under the airfoil? All good points, but I have an even bigger question: What happens when the cockpit air intakes are closed (say on a cold day or at high/cold altitudes)? It seems to me that there would be an ideal extractor position & size (or louver camber/AOA) for each particular air intake position... You're looking for a balance in order to keep the fuselage airflow from being unnecessarily disturbed at one end or the other, right? I mean, with a tight canopy seal and closed intakes isn't your fixed-size extractor going to be starved for airflow once the cockpit pressure reaches its minimum, and that is going to in turn wind up disturbing the airflow over the extractor itself? --Noel |
#9
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JS-1 Exhaust Vent
On Jul 26, 12:02*am, "noel.wade" wrote:
On Jul 25, 9:54*pm, Tim Taylor wrote: I still think a reversed NACA duct will work better than the Butler and much better than the Mandl. *The Mandl throws the low speed air out into the faster air stream. *The JS design accelerates half the air over the airfoil but what happens to the air under the airfoil? All good points, but I have an even bigger question: What happens when the cockpit air intakes are closed (say on a cold day or at high/cold altitudes)? *It seems to me that there would be an ideal extractor position & size (or louver camber/AOA) for each particular air intake position... You're looking for a balance in order to keep the fuselage airflow from being unnecessarily disturbed at one end or the other, right? *I mean, with a tight canopy seal and closed intakes isn't your fixed-size extractor going to be starved for airflow once the cockpit pressure reaches its minimum, and that is going to in turn wind up disturbing the airflow over the extractor itself? --Noel EXACTLY!! No extractor design optimized for a given airspeed and vent opening will be optimal for all speeds and vent openings. When might I close my vents (mostly)? Likely running near redline near cloudbase or the PCA. (though that doesn't happen as often as I'd like!). I made one for my Speed Astir (aka - the Grob solar sauna) right after seeing the DG article. I have no idea how it changes the glider performance, but it keeps ME from roasting quite so much, and that's gotta' help! |
#10
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JS-1 Exhaust Vent
On Jul 25, 8:54*pm, Tim Taylor wrote:
I still think a reversed NACA duct will work better than the Butler and much better than the Mandl. *The Mandl throws the low speed air out into the faster air stream. *The JS design accelerates half the air over the airfoil but what happens to the air under the airfoil? The NACA duct was designed such that the edges create vortices which force the air into the duct. Reversing the flow through a NACA duct is an inefficient way to exit fluid from a body. |
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