Woodstock Glider

[[email protected]]

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

[Bob Kuykendall]

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=5811273455&show=blog&archive=9/1/1999

http://www.lockheedmartin.com/aeronautics/skunkworks/name.html

Thanks, Bob K.

[Doug Hoffman]

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

[[email protected]]

Thanks Guys

Correct me if I'm wrong, but there is no washout in this design is
there?

[[email protected]]

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?

[Bob Kuykendall]

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.

[JJ Sinclair]

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?

[[email protected]]

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.

[[email protected]]

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.

[Bob Kuykendall]

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

[[email protected]]

And I might add that the Woodstock is an amazing sailplane or at least
a simple one that handles well with an amazing wing for a lightweight
glider. It's remarkably fast and surprises me almost everytime I go
somewhere with it. Gary Osoba called it the best kept secret in
soaring.
MM

[[email protected]]

On Apr 7, 7:36 pm, wrote:
> 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.

The original 12-meter Woodstock wing has no twist. Irv Culver
(Lockheed Skunkworks) did the airfoils at the request of designer Jim
Maupin (both now no longer with us, regrettably). Wingtip/aileron
stall protection was secured via reducing the percent section near the
wingtip. It's in the manual. Woodstock wing stall characteristics (at
least for the original 12 meter wing, which I built and flew) were
absolutely delightful: first time I stalled my n20609, on her maiden
flight, I broke out loud laughing. Perfect stall behavior; as mannerly
as it is possible to be. Despite low wing loading, the Woodstock
feels as much like Libelle as it does a SGS1-26. Easier to keep
rightside up in turbulence than a 1-26 in turbulence to boot,
particularly on aerotow.
Safe soaring,
Bob Wander

[[email protected]]

On Apr 7, 8:51 pm, Bob Kuykendall > wrote:
> 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

>
> 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.

Yes, Hence me looking for data points. The chord at root and tip are
known and have hard dimensions for.
I can check that with % chord at root and tip for scaling in that
direction, print off and check over the actual prints I have.
I can also CNC Route some "test ribs" using my CNC router.

[[email protected]]

On Friday, April 4, 2008 12:35:37 PM UTC-4, wrote:
> 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

Dear Sir:
Is there any way I could buy a copy of your complete set to build woodstock glider?

Thanks Theodore R. Hansen

[[email protected]]

I have one of the earliest set of plans; the airfoil sheet is a full size template that you glue (contact cement)to a piece of 3/4" plywood. Each rib has its own profile printed inside the previous one as it tapers toward the tip. From this template you trace and sand the root rib first then sand the template to the next line and trace the next rib and so on. You keep sanding and tracing all the way out to the tip rib profile. THERE ASRE NO COORDINATES given or in anyway documented for any of the rib profiles. I recall a conversation I had with Jim in the late 1980's, I remember him telling me that when it came to the airfoil development, he said that Irv said "let me run the numbers". He came up with this design/method and Jim did as above to build the prototype.

The only parts I ever made for the airplane are the root ribs and the template itself. The original prints including the full size rib template drawing are the old style diazo prints and not accurately copyable; further, my print is used up to make the template. I suppose I could resurrect my project and make all the ribs, digitizing as I go. I estimate I could do this with an accuracy of approximately .05" which should be good enough for an airfoil working at these reynold's numbers as long as everything is "nice and smooth", as professor Alex Strojnik once told me; (see Low Power Laminar Aircraft Design/Structures/Technologies) Recognize that this will be quite time consuming. If anyone wants to seriously pursue this, contact me @ bpkuenen(at)gmail; I don't read these threads often

[[email protected]]

Hi. Did you ever follow through with the wing rib patterns or templates. I'm looking to start a build this summer. Any time savings on templates would be greatly appreciated and worth a financial fee to me. Turns out my plans are a copy from years ago so I dont really trust their accuracy. Either way, thanks for your time. Mark

[son_of_flubber]

On Thursday, May 10, 2018 at 8:36:39 PM UTC-4, wrote:
>I'm looking to start a build this summer. Any time savings on templates would be greatly appreciated and worth a financial fee to me.

Something to think about. People who're building boats out of marine plywood often have their plywood cut out by laser. You can get your Woodstock paper pattern for ribs professionally scanned, then send the file to a job shop to be cut out. This is quite common for boat builders who're building from both traditional and new designs. It is cost effective because of the time savings and precision. The laser cutter can insure that the ribs for the left and right wings are identical, and symmetry is important.

Google for 'custom laser cutting plywood'. You can send your file to multiple shops for competitive bid.

[Bob Kuykendall]

On Thursday, May 10, 2018 at 7:16:17 PM UTC-7, son_of_flubber wrote:
> symmetry is important.

Balance is important. Symmetry is way overrated, and I have the check templates to prove it.

--Bob K.

[[email protected]]

On Thursday, May 10, 2018 at 11:35:16 PM UTC-4, Bob Kuykendall wrote:
> On Thursday, May 10, 2018 at 7:16:17 PM UTC-7, son_of_flubber wrote:
> > symmetry is important.
>
> Balance is important. Symmetry is way overrated, and I have the check templates to prove it.
>
> --Bob K.

If I might suggest, have them cut on a CNC machine, not burned on a laser cutting machine. Adhesives don't stick well to charred wood. I have a set of Wood stock parts, even completed spares that I cut by hand on a bandsaw, maybe 30 years ago...other ships got in the way and I never got around to assembly...plans are sometimes procrastinated by life. However it is a very straight forward process, tack the drawing to a piece of HARD masonite. Cut to almost the line then sand to the line. Tack two sheets of the 1/4 inch Marine ply together and trace the master pattern onto the stacked plywood. Rough cut (within an 1/4 or a 1/2 with a hand jigsaw)then cut and sand to the line. Trim the master pattern to the next rib and do the same for all the ribs. You can make a second set of master patterns by making a second master pattern with the sacrificial pattern each time. Please feel free to contact me should you like.
Jeff

[son_of_flubber]

On Thursday, May 10, 2018 at 11:35:16 PM UTC-4, Bob Kuykendall wrote:
> On Thursday, May 10, 2018 at 7:16:17 PM UTC-7, son_of_flubber wrote:
> > symmetry is important.
>
> Balance is important. Symmetry is way overrated, and I have the check templates to prove it.
>
> --Bob K.

Please say a little more about how this works. I was thinking that precision and symmetry affects the left right balance in an aircraft.

[[email protected]]

Guys, we're talking about a wooden glider that is covered with plywood and fabric. Space age technology is not required. Your precision cut ribs will be cut in half, then glued to the spar........I'd be more concerned about maintaining a true cord line in the vertical assembly process. Jim's instructions were to glue the master rib sheet to 1/8 birch, then nail two blank rib pieces of 1/4 plywood, then cut to within 1/16 with a band saw, followed by disc sanding down to final size. Then nail two more blanks to the master and repeat the process. After all ribs have been glued to the spar, I like to level everything with a 36" sanding board running it fore and aft as I slowly move down the wing.
Hope this helps,
JJ

[Bob Kuykendall]

On Thursday, May 10, 2018 at 9:33:49 PM UTC-7, son_of_flubber wrote:

> Please say a little more about how this works. I was thinking that precision and symmetry affects the left right balance in an aircraft.

The gist of it is in Eric Stewart's article in the March 2018 issue of Soaring.

--Bob K.

[[email protected]]

On Friday, April 4, 2008 at 4:35:37 PM UTC, wrote:
> 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

How could I join this group?

[[email protected]]

Does anyone have available the drawings for the long wings. I bought an original set of drawings from
Jim in the mid '80,s (#58). The only thing I ever started on the project is the wing rib template , before I got side
tracked on a Wittman Tailwind (very fast) and a Buttercup . Since retiring and having sold both my interest is again
peaked in this glider, but if it makes a difference I'ld like a higher performance wing.

Tailwind888WT

[Frank Whiteley]

On Sunday, December 29, 2019 at 9:07:01 PM UTC-7, wrote:
> Does anyone have available the drawings for the long wings. I bought an original set of drawings from
> Jim in the mid '80,s (#58). The only thing I ever started on the project is the wing rib template , before I got side
> tracked on a Wittman Tailwind (very fast) and a Buttercup . Since retiring and having sold both my interest is again
> peaked in this glider, but if it makes a difference I'ld like a higher performance wing.
>
> Tailwind888WT

Have you tried ESA?
http://esoaring.com/contact-us.shtml

or
VSA?
https://www.vintagesailplane.org/

Good luck

Frank W

[[email protected]]

On Friday, April 4, 2008 at 11:35:37 AM UTC-5, wrote:
> 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

I am helping the estate of one of our dearly departed soaring buddies sell off all of his soaring artifacts. I stumbled into a pile of wing ribs and a portion of a vertical stabilizer that I believe may be parts for a Woodstock. Anyone interested?

Thanks,

Paul

[[email protected]]

On Monday, January 6, 2020 at 12:36:05 AM UTC, wrote:
> On Friday, April 4, 2008 at 11:35:37 AM UTC-5, wrote:
> > 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 ###?
> >

I'm interested possibly...



> > Thanks
> > Herbie
>
> I am helping the estate of one of our dearly departed soaring buddies sell off all of his soaring artifacts. I stumbled into a pile of wing ribs and a portion of a vertical stabilizer that I believe may be parts for a Woodstock. Anyone interested?
>
> Thanks,
>
> Paul