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#1
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Hello
I have had my glider plans for approximatly 9 years now. My question is, does anyone know the Airfoil used by the Woodstock Glider? NACA ###? Thanks Herbie |
#2
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On Apr 4, 9:35 am, wrote:
NACA ###? More likely Culver ####. Ah, here it is: Culver 18%: http://www.ae.uiuc.edu/m-selig/ads/aircraft.html More than likely, the 18% is the thickness (T/C), nice and deep to keep the spar simple and cheap. Who's Irv Culver? Just the guy who was at the center of the design of some of the hottest airplanes of the 20th century. The guy who gave Kelly Johnson's "Skunk Works (R)" its name. http://www.ssa.org/myhome.asp?mbr=58...chive=9/1/1999 http://www.lockheedmartin.com/aerona...orks/name.html Thanks, Bob K. |
#3
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Irv also did the airfoils and structure analysis for the
record-setting Carbon Dragon and the very unique Windrose (originally called the Extremely Easy). I had plans for both. The WR struck me as a design of near genious for its simplicity of construction (a 13 or 15 meter moldless composite motorglider). Seems to me that any reported handling issues should not be too hard to remedy. I sold my WR plans and am now sorry that I did. -- Regards, Doug -- Posted via a free Usenet account from http://www.teranews.com |
#4
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![]() Thanks Guys Correct me if I'm wrong, but there is no washout in this design is there? |
#5
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On Apr 7, 12:38 pm, wrote:
Thanks Guys Correct me if I'm wrong, but there is no washout in this design is there? Sorry, yet another question, are the Airfoil Data points freely available? |
#6
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On Apr 7, 9:50*am, wrote:
Correct me if I'm wrong, but there is no washout in this design is there? If there is, it will be shown in the plans. It might also be covered in _Fundamentals of Sailplane Design_, but my copy is not handy. Sorry, yet another question, are the Airfoil Data points freely available? Probably not. It's not at the UIUC site, so it's probably not freely available. From what I've heard, it was a one-off profile (OK, two-off if you count the substantial difference between the root and tip shapes) that Irv did on a relatively casual basis. Thanks, Bob K. |
#7
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I believe the Woodstock has an aerodynamic twist that allows the tip
stall later (slower) then the root. I believe the airfoil was derived from the Gother 549 (modified by Erv Culver) then it blends into USA 35B at the tip. I flew the prototype and it didn't have a tip stall. JJ wrote: Thanks Guys Correct me if I'm wrong, but there is no washout in this design is there? |
#8
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On Apr 7, 3:03 pm, JJ Sinclair wrote:
I believe theWoodstockhas an aerodynamic twist that allows the tip stall later (slower) then the root. I believe the airfoil was derived from the Gother 549 (modified by Erv Culver) then it blends into USA 35B at the tip. I flew the prototype and it didn't have a tip stall. JJ wrote: Thanks Guys Correct me if I'm wrong, but there is no washout in this design is there? I'm looking at the plans, and there is no Washout, that I can detect, which is why I'm asking. The spar cutouts are exactly the same relative position on all the foil profiles, with no twisting. I am also an Aerospace Engineer, been working mostly mechanical for the last 8 years so my aerospace brain has cobwebs, but I do know how to read a drawing, my guess is it was this way for ease of construction. I'll re-read the assembly manual again. I scanned sheet one of the 13M drawings and have the foils now in a DWG format. What I'll do is use Pro/E to loft between foil 1 and 20, then insert each foil from 1 to 20 at station, then generate cross sections at each station to see if they all meet up. |
#9
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Sorry, I just clued in on the aerodynamic twist.
The tip foil should stall later, right. I got confused with the %18 vs %13, which is just the thickness and I wouldn't have thought the difference would have been significant, but if what Mr. Sinclair is saying, they are actually different foils then there would be some form of washout. Thanks guys. Herbie. |
#10
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On Apr 7, 4:44 pm, wrote:
Sorry, I just clued in on the aerodynamic twist. The tip foil should stall later, right. I got confused with the %18 vs %13, which is just the thickness and I wouldn't have thought the difference would have been significant, but if what Mr. Sinclair is saying, they are actually different foils then there would be some form of washout. Thanks guys. Yup, that's the way I understand it - there's no angular difference between the chord lines of the root and tip sections, but the profile differences between the root and tip airfoils make the wing act as if there are. Here's a couple of pictures from the Les Sparks site that shows the Woodstock wing profiles: http://members.aol.com/lessparks/clint20.jpg http://members.aol.com/woodglider/clint25t.jpg It's kind of hard to see in the photos, but if you look closely you can see that the profile goes from sort of flat-bottomed at the tip to a deeper-bellied (for lack of a better term) section at the root. Here's the home page for the site those photos are from: http://members.aol.com/woodglider/index.htm I haven't heard from Les for a while, I wonder what's up with his project. I scanned sheet one of the 13M drawings and have the foils now in a DWG format. What I'll do is use Pro/E to loft between foil 1 and 20, then insert each foil from 1 to 20 at station, then generate cross sections at each station to see if they all meet up. That sounds like a good plan, that ought to work great. The main gotcha, and you've probably already thought of this, is that old blueprints tend to shrink and warp a bit as they age. Also, sometimes scanners add their own scaling errors. So its possible to accumulate a bunch of little errors that add up to something substantial. The plans probably have some key dimensions that you can use to correct the scaling of your DWGs; if you keep an eye on them you'll be fine. Thanks, Bob K. http://www.hpaircraft.com/hp-24 |
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