mlefebvre Posted December 16, 2003 Share Posted December 16, 2003 I have been reading about flow fences on Vari-EZ on a website: http://www.glassovercast.com/goc/mainthangar/tefence/tefence.asp, and wondered if this is something any of you builders have considered for the COZY? Do you think this would be a benefit to the design to increase performance? Has anyone added these and what were your results? Marc Quote Tis far easier to ask for forgiveness than for permission. Link to comment Share on other sites More sharing options...
dust Posted December 16, 2003 Share Posted December 16, 2003 i am planning to do what is on lightspeed eng page, is this the same? Quote maker wood dust and shavings - foam and fiberglass dust and one day a cozy will pop out, enjoying the build i can be reached at http://www.canardcommunity.com/ Link to comment Share on other sites More sharing options...
chuckthedog Posted December 16, 2003 Share Posted December 16, 2003 There will be an artical in the next Central States Newsletter. It should answer all your questions. Quote If the phone don't ring. It's me Link to comment Share on other sites More sharing options...
mlefebvre Posted December 16, 2003 Author Share Posted December 16, 2003 How do I access the Central Statest Newsletter? Is it online? Also, is there a webpage link for lightspeed engineering that references this? Thanks! Marc Quote Tis far easier to ask for forgiveness than for permission. Link to comment Share on other sites More sharing options...
dust Posted December 16, 2003 Share Posted December 16, 2003 http://www.lsecorp.com/KlausInfo/Flowfence.htm there you go enjoy the build Mike Quote maker wood dust and shavings - foam and fiberglass dust and one day a cozy will pop out, enjoying the build i can be reached at http://www.canardcommunity.com/ Link to comment Share on other sites More sharing options...
mlefebvre Posted December 16, 2003 Author Share Posted December 16, 2003 Dust, to answer your earlier question, yes, its the same article. From the article it states: "The configuration of the airplane tested had the standard 3 Vortilons on each wing leading edge with three roughly equally spaced flow fences between the outboard end of the aileron and the winglet. The shape of each fence does not appear to be critical but it is believed that it is important that they exist on top of, behind and below the wing surface to completely isolate the section outboard of the fence from any span wise flow that is developed inboard of it. " which seeems to imply their optimal location. If you go to this link, http://www.glassovercast.com/goc/mainthangar/tefence/layout.jpg you will see that the location recomended and angle of fences. This seems like a straight forward improvement which should show some immediate benefits for the COZY design. The article goes on to state the benefits as: "The overall change in low speed performance was remarkable. It was immediately noticed that take- off distance is reduced 10-15% climb rate is improved 20% and most noticeably approaches can be flown at least 10-15% slower resulting in a significantly shorter landing distance, nearly 30% less. There was no measurable decrease in top speed." with one drawback: "The only negative observation is a reduced roll response at the lower speeds, probably due to lower dynamic pressure." Marc Quote Tis far easier to ask for forgiveness than for permission. Link to comment Share on other sites More sharing options...
chuckthedog Posted December 16, 2003 Share Posted December 16, 2003 The vari-EZ has more sweep than the Cozy wings. So the fences are less effective. I had a chance to read the artical that will be in Central States. It was an extencive test involving a Long-EZ. Same sweep as Cozy wings. Central States has been around a long time, and News letters are vary informative. Alot of the Cozy and Long-EZ improvements were first posted there. www.eracer.org Quote If the phone don't ring. It's me Link to comment Share on other sites More sharing options...
John Slade Posted December 17, 2003 Share Posted December 17, 2003 Central States can be found at http://www.canard.com/~csa/ IMHO this newsletter is the most valuable resource, and the most interesting publication we canardians can get. As for fences, I figured I might try them once I have something to compare with. Quote I can be reached on the "other" forum http://canardaviationforum.dmt.net Link to comment Share on other sites More sharing options...
Jim Sower Posted December 17, 2003 Share Posted December 17, 2003 Not sure about fences, but there was a considerable thread on the Velocity forum the past few weeks around Vortex Generators. They will work on just about any airplane, and they do some pretty dramatic things. I reduced my landing speed by about 10 kts and my takeoff speed by 5 when I installed them. There are about as many different layouts as there are application, and I did mine following the "gospel according to Jim Price". Price is IMO the undisputed champion since he has considerable aerodynamic credentials and holds the altitude record (his NA Long Ez got to over 35,000 ft). Another idea I haven't tried is a row of VGs a couple of inches ahead of the aileron hinge to improve low speed roll authority. The Velocity wallows like a pulp wood truck at low speeds - and that's on a GOOD day. Sealing the aileron hinge gaps is what gave me the roll authority I have at the lower approach speeds I achieved by installing VGs. Quote ...Destiny's Plaything... Link to comment Share on other sites More sharing options...
mlefebvre Posted December 17, 2003 Author Share Posted December 17, 2003 Any good links out there regarding vortex generators? Can you tell me more about these? Thanks. Marc Quote Tis far easier to ask for forgiveness than for permission. Link to comment Share on other sites More sharing options...
chuckthedog Posted December 17, 2003 Share Posted December 17, 2003 I put a set from CCI on my Long-EZ stock canard. They work great! No change of trim in rain. Take 10 mph off landing speed. No loss of airspeed in flight. EZ to install. Tom Staggs, a long time Long-EZ air show performer. Is the man who will be submitting his test results on TE fences In Central States news letter. Quote If the phone don't ring. It's me Link to comment Share on other sites More sharing options...
dust Posted December 17, 2003 Share Posted December 17, 2003 Jim is our tech advisor, great guy, and he also likes our workmanship. his record is 35,027 feet and when he did it he didn't realize that gas freezes at -64, but not to worry, it was only -60 at his altitude he figured he had 30 hp at that height to "cruise" on enjoy the build Mike Quote maker wood dust and shavings - foam and fiberglass dust and one day a cozy will pop out, enjoying the build i can be reached at http://www.canardcommunity.com/ Link to comment Share on other sites More sharing options...
Jim Sower Posted December 18, 2003 Share Posted December 18, 2003 Any good links out there regarding vortex generators None that I know of. I put them on the canard and main wing both along the 25% chord line, 1" long wedges, in pairs about 1" apart splayed about 20 deg (total), about 7" between pairs. As I said, I got excellent results. I made them out of plastic moulding available at Home Depot for $1.74 for eight feet and stuck them on with RTV. Whole operation took the wife and I a couple of hours. On Price's advice, I moved them from 25% to 20% chord and changed from wedge shaped to rectangular. I thought it was a trivial change, but was very much surprised at how much more effective they were done his way. At some point, I aim to put a row a few inches forward of the aileron hinge line to improve roll authority at the new lower speeds I have achieved. Jim Price is in CSA and his email would be in the CSA directory. He could advise you best and maybe point you to the sites you want to browse. Hope this helps ... Jim S. Quote ...Destiny's Plaything... Link to comment Share on other sites More sharing options...
Spodman Posted January 3, 2004 Share Posted January 3, 2004 I don't have any first hand knowledge here, but I thought I understood that the first thing to stall is the canard. How does increasing the efficiency of the wing help this, or is it a bit more complicated than that? Possible alternative view, nobody really understands how canards fly, so stick stuff on and EXPERIMENT. Also, request translation please, what is RTV? Silicon? Quote Mark Spedding - SpodmanDarraweit Guim - AustraliaCozy IV #1331 - Chapter 09www.mykitlog.com/Spodmanwww.sites.google.com/site/thespodplane/the-spodplane Link to comment Share on other sites More sharing options...
Jim Sower Posted January 3, 2004 Share Posted January 3, 2004 <... the first thing to stall is the canard ...> That's true. But we're not trying to stall anything. We're trying to make it work better when it's NOT stalled <... How does increasing the efficiency of the wing help this ...> VGs provide more/better attached flow on a flying surface. If you have more attached flow on a flying surface it increases the slope of the lift curve (Cl v. AoA) which means that you get more lift at a given AoA. This translates to slower takeoff / landing speeds and therefore shorter takeoff / stopping distances. Additionally VGs might raise the AoA at which stall occurs, further enhancing lift performance. Fences (and to a lesser extent VGs) reduce spanwise flow on swept wings and therefore enhance wing lift performance (Cozy/EZ wings don't have enough sweep to gain really dramatic improvements here, but it is measurable and every little bit helps). <... nobody really understands how canards fly, so stick stuff on ...> The aerodynamics of a canard airplane is more complex than that of a conventional planform, but it's not terribly difficult until you get waaaaay into design aspects (which Burt has done for us). Everyone in the canard community knows enough beyond what you need to get a private license to build and fly the airplane. You go beyond that as your interest, math/physics background and time permit. RTV stands for "Room Temperature Vulcanize". Basically, it's the silicone caulking you buy at Home Depot and Lowes. High Temperature RTV is the silicone gasket goo you get at auto parts houses (it goes up to about 700F or so). Quote ...Destiny's Plaything... Link to comment Share on other sites More sharing options...
Spodman Posted January 4, 2004 Share Posted January 4, 2004 Thanks for the info Jim. I think I need to find somebody local with such a machine and ask questions face-to-face until they get corns on their ears... Quote Mark Spedding - SpodmanDarraweit Guim - AustraliaCozy IV #1331 - Chapter 09www.mykitlog.com/Spodmanwww.sites.google.com/site/thespodplane/the-spodplane Link to comment Share on other sites More sharing options...
No4 Posted January 10, 2004 Share Posted January 10, 2004 Links for Vortex Generators http://www.nar-associates.com/technical-flying/vortex/Vgs_stall_wide.pdf http://www.nar-associates.com/technical-flying/vortex/Vgs_cruise_wide.pdf http://www.smartcockpit.com/operations/Vortex%20Generators.PDF and links for winglets http://www.boeing.com/commercial/aeromagazine/aero_17/winglet_story.html http://www.mandhsoaring.com/articles/WL-Soaring.pdf Quote The Coconut King Link to comment Share on other sites More sharing options...
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