cobaltdan
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Everything posted by cobaltdan
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murps, canopies are flexible and stretchable membrane surfaces. a canopy at extremely high wingloadings will tension diferently and form a different shape than one at normal loadings. unless you design the canopy specifically to take advantage of this effect the result is typically more negative than positive. dan Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military)
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im guessing the 120 canopy 500# story was about us. it was a comp cobalt 120 with continuous lines, not a stilletto. exit weight was 535 pounds and the pilot on all the jumps was john heady and yes the glide ratio did increase however im not sure about your deduction listed. without going into a lengthy discussion, i can tell you the the inflated shape of the cobalt 120 at 5:1 wing loading is different from the canopy at 0-3:1. the is much less spanwise distortion which is the reason for the increased L/D. the reason for the reduced distortion is in brief how the canopy tensioned at such a high wing loading. these tests formed the basis for our understanding and design techniques of canopies we produce for the u.s. army which fly at wingloadings from 4 to 20 pounds per square foot with glide ratios up to 6.2:1 sincerely, daniel preston atairaerospace.com atairaerodynamics.com Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military)
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Is more weight benefical throughout the swoop?
cobaltdan replied to SkiD_PL8's topic in Swooping and Canopy Control
eric butts and i hatched an idea a few years ago to build him pants with water bladders. The bladders would put an extra 50# on him. the intention was coming out of the corner he would pull the plug on the bladders and the port would be sized to drop all the water in the time of a full swoop.... akin to being in a glider and dropping water ballast. it would definitely give a swooping advantage...but is it worth the trouble. dan Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military) -
Here are some pictures from the Smithsonian Museum opening last night. It was a brilliant affair and the exhibition is stunning ! Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military)
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line charts are posted on our web site and line sets are typically in stock. relines are done in house by atair or if we are too busy by pierre ponson our authorized reline center. note: most vipers have exactly the same line set as a cobalt, but if your viper was privately labled for winchester technologies it may have a modified line set. best thing is to fax us the information on the placard so we can look up the canopy. sincerely, daniel preston atair aerodynamics 718-923-1709 ph 718-923-1733 fx www.atairaerodynamics.com Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military)
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we have developed "disappearing canopies" for sensor delivery. contact me offline for more info. daniel preston www.atairaerospace.com Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military)
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far from fading away... just the opposite in fact. we have increased in size three times over and are extremely busy with military contracts (dod/army, darpa, nasa)and defense industry partnerships.... see you at pia. sincerely, daniel preston atair Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military)
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The canopy is a prototype and is not being marketed yet. we will release details when ready. sincerely, daniel preston atair www.atairaerospace.com Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military)
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if your canopy flies perfectly straight without any control inputs (brakes stowed and brakes unstowed). than your twists have to be caused by: body position, packing, or possibly a faulty pilot chute. when a pilot chute gets ragged out it can slip air uneavenly and rotate. in all probablilty it is your body position. have someone video your opening and you should be able to diagnose. sincerely, dan atair Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military)
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we designed and manufactured the viper and privately labeled for skydepot/winchester technologies. the viper was improved into the alpha(also called the space or impulse), which was improved into the cobalt. we will be glad to support your viper with new line sets should you need. sincerely, dan atair www.extremefly.com Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military)
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tree, if anyone says anything about atair there going to say we are original. there is no copying canopies here. the stilletto and cobalt have nothing in common. in fact the cobalt is one of the only canopies that does not use the same airfoil as a stilletto. as to eric placing 9th, there was no luck involved, this was averaged out across a year of competition, pure pilot skill and canopy design. If he was doing the circuit this year with the same canopy he would still place top ten. And yes the onyx was advertised last season and yes hit the streets this season. we are nothing if not overly diligent and cautious in our testing. something i think no one will complain about. sincerely, daniel preston atair www.extremefly.com Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military)
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a couple years ago Atair did sponsor a pro swoop team. after a full year of competition Eric Butts was ranked 9th overall competing on a 120 comp cobalt ! a 9 cell vs about 160 x-braced pro competitors. we proved our point that we could be highly competitive. why dont we still sponsor a pro-swoop team, basically because the return on the investment does not make enough financial sense and we dont feel we have anything to prove anymore. the onyx has basically only hit the streets for about a month now. give it time and i think you will see them in serious competition next season by competitors looking for an edge. sincerely, daniel preston atair www.extremefly.com Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military)
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there was 1 revision done to the troll canopy based on user feedback: the cross ports were increased in size. if someone had and early canopy the crossports were easily increased in size as a post manufacture modification. sincerely, daniel preston atair www.extremefly.com Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military)
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greg yarbonet was convicted of a serious criminal offense and i believe will be in prision for may years to come. Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military)
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the design was dubbed the V-wing and was a based on a design Greg Yarbonet did for us. Greg Yarbonet btw is the inventor of the slider. Thje canopy was built in a 95 sq foot size and tested. It was a strange animal and was basically designed to test ideas for lower pack volume cargo canopies. I was not thrilled with the degree of spanwise distortion and due to the high camber of the formed airfoil the canopy was very slow and floaty. our development effort took a different direction and the canopy is now one of my snowboarding traction kite toys. sincerely, dan Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military)
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the cobalt planform is 5 center cells completely square with the outer 2 cells on each side having a linear taper. at high wing loadings the cobalt is a fun canopy for experienced pilots and at low wingloadings it is equally suitable for anyone safe flying a sabre or safire. Note: The "space" was a canopy produced with identical planfrom/airfoil/trim and was extremely successful as a canopy for low experienced jumpers. sincerely, daniel preston atair www.atairaerospace.com Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military)
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travis, call me in the office and i will be glad to help remedy what ever your problem is. sincerely, dan preston atair Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military)
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Rear riser landings on heavily loaded canopies
cobaltdan replied to Miami's topic in Swooping and Canopy Control
You might want to ask Eric Butts. I have watched Eric perform rear riser landings on a 95 onyx prototype, and he is about 260 # exit weight. sincerely, dan Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military) -
the center ribs on an onyx are loaded. The nose and tape reinforcement are triangulated to a point on the center rib top skin seam. this effectively loads the central rib to just past the b lines. all top skin seams are loaded in the area where reduction in spanwise distortion translates to the maximum increases aerodynamic efficiency. just look at the pictures.. 9*4=36 sincerely, daniel Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military)
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yes, by the same account a stilletto should be a 18 cell. but the practice is to only label x-braced canopies in this way. Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military)
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dona. it is 7 * 3 . what we are discussing is the number of subdivisions on the top skin between lines. the velocity is a tri-cell, it has 3 divisions. sincerely, dan atair Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military)
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Luigi Cani reportedly landed an Icarus VX 39
cobaltdan replied to mjasantos's topic in Swooping and Canopy Control
actually the comp cobalt 55 and 65 have been standard sport production sizes for 2 years. (we also make a 40 but not intended for sport, even though it has been sport jumped many times for fun. Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military) -
the onyx has 9 * 4 = 36 the velocity has 7 * 3 (not 5) = 21 the vx has 9 * 3 (not 5) = 27 reducing the distortion on the top skin is all that matters. reducing bottom skin distortion does nothing significant to improve efficiency and performance. sincerely, dan atair Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military)
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on the smaller systems the difference in glide ratio with or without the collapsible drogue is very marginal. as a general rule it is best to have all components land together so as not to create a hazard for aircraft . glide ratios vary depending on wingloading and drag of the load. but with reasonable drag cargos at 5# wing laoding, the systems range from 4 to 6.2 :1 Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military)
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we developed a custom rf peer to peer network comunications protocol. it is masterless and supports about 50 uav's . 'fleet' tests will begin late this month. -dan Daniel Preston atairaerodynamics.com (sport) atairaerospace.com (military)