Originally Posted by Stuart annat

I'd be very interested to know what started such a profusion of wing building in Europe.Any of you guys on the continent know the history behind it?

It's the result of historical coincidence and language barriers.

The story begins in the late 1800s when a German (or maybe Austrian) naturalist, Frederick Ahlborn, described the flight of the Javanese cucurbit "Zanonia macrocarpa". Really, a flying cucumber seed! Igo Etrich, a Bohemian textile manufacturer with an interest in aviation, got Dr Ahlborn to send him some seeds for study. Etrich built several small gliders and by 1906 had a man carrying glider. Etrich never did get his flying wing to work with an engine but my frind, Carlo Godel, did. Etrich finaly gave up on 'wings but the Zanonia shape lived on in his latter conventional design the Taube. IIRC there were about 70 manufacturers of tauben so by WWI everybody in and around the Austro-Hungarian empire knew something about that wing. Alexander Lippisch was one of those people but he seems to have been the first to realize that the trimming effect could be achieved with simple sweep thus making design and construction much simpler. About the same time that Etrich was giving up on flying wings an Irishman named John Dunne succeeded not only in achieving powered tailless flight but also the first documented inherently stable airplane. This was all before WWI and as one might expect the Wright brothers had a fairly strong influence on aircraft design in America at that time. So we got off to a late start over here and most of the older flying wing literature is in "foreign" languages.

--Norm

Thanks Norm,just what I was hoping for.Truly the seed of an idea.
Regards Stuart

Nurflügel "WS 14" by Horst Wildhack. From "Mechanikus" 2/1951

Heinz

(Soon you are redeemed, then my archive is empty.)

I remember building gliders as far back as the late 60's
and they had PLYWOOD tongues for wing connectors , like the ws14/3.

How did we ever survive without Carbon Fiber ?

he said , tongue in cheek, full well knowing the answer.

Originally Posted by hastf1b

Nurflügel "WS 14" by Horst Wildhack. From "Mechanikus" 2/1951

Heinz

(Soon you are redeemed, then my archive is empty.)

Well, if that were posted as a modern design you'd not argue. Great stuff!

Came across this one today looking over Outerzone. It's a 111" plank and uses what they call an S-1 airfoil. I've been thinking that this might be interesting to plug into XFLR5 and see what it looked like and how it compared with other airfoils, But can't seem to find any converter or directions on how to convert the ordinates to a .dat file that XFLR, (or any other program) could read. I'll keep looking, but if any of you all have any hints or tricks to convert the data...

At any rate, Here's the link to the PDF - http://www.outerzone.co.uk/plan_details.asp?ID=1246

Mark

Thought I'd do a 3D of the WS-14 to better visualize what It could look like.

Bob

Originally Posted by Quick61

can't seem to find any converter or directions on how to convert the ordinates to a .dat file that XFLR, (or any other program) could read. I'll keep looking, but if any of you all have any hints or tricks to convert the data...

At any rate, Here's the link to the PDF - http://www.outerzone.co.uk/plan_details.asp?ID=1246

Mark

It's just the standard NACA format turned sideways. Very course and there's a bad point on the upper surface. It's not a very efficient airfoil. The Cm is way more positive than it needs to be and that robs performance. Here's a comparison of the original coords and two smoothed versions. For the "sm" version I only removed the bad vertex on top. The original coords also has a flat spot on the bottom that didn't look good so I also made a version with the midpoint of the flat removed to get a fair curve through that area. No improvement so I'm sending you the .DAT file with the flat spot.

--Norm

OK here ya go !

I used Profili Pro to import the Dat file then exported it as a DXF.

Then I rebuilt it in Rhino to reduce the huge amount of points that
Profili created.

any way here it is.

The DXF is in the ZIP since RCG wont let me upload the dxf directly.

Bob

PS it appears that there is a flaw in the Forward bottom portion of the foil that I created from the dat file
and I'm not crazy about the smoothness on the top either.

I could do some WAG smoothing if you'd rather.

Thanks guys. It's told me what I wanted to know.

Norm, you said "It's just the standard NACA format turned sideways." Could I talk you into explaining just what you meant by that? I have several old plans that have this type of data for the airfoil and I would like to know just how the conversion works. You know the saying - Teach a man to fish...

Mark

these are some of my older flying wings - and I like them all.

Thomas

Hi Thomas,

Welcome to the American version of Nurflügel. Maybe someday we can move to a more prominent location.

Those old drawings are great. I started life as a draftsman when it was "lead on paper" and nothing more. I had always thought that my German counterparts were very good at this. Your drawings prove it.

The AERIUS I is an amazing design. A thin highly reflexed airfoil with lots of twist. I wonder where these designers got their education back then?

Thanks for posting.

Kent

Originally Posted by Quick61

Norm, you said "It's just the standard NACA format turned sideways." Could I talk you into explaining just what you meant by that?

Sure, Mark--

Let's see if I can recycle an old attachment. Back in the '30s the NACA gathered airfoil data from several different labs in America and Europe and replotted it into a standardized format. I find it easier to read than modern polars but that's probably just because I'm a dinosaur. Anyway what we're interested in here is the columns of numbers in the top left corner. They're just X,Y coordinates. The column labeled "%" is X axis values and the other two are Y axis values. Back in the days when we plotted airfoils by hand we would draw a line the length of the chord we wanted on graph paper and mark the X axis percentages on it by multiplying the length by the percentage. A compass is handy for this. Just set the radius to the length*X and put the point of the compass on the leading edge (that way you can use the same pin hole for all X axis stations) Then you take the absolute of the Y axis values that correspond to an X axis station and multiply them by the chord length to get the height above the reference line (note most tables will have negative numbers for the lower surface but some have both surfaces above the reference line (drop the +/- sign to get the absolute value [[EDIT] and just remember that it's under the line]])). After you've got all the X,Y points (AKA "vertices" if you want to be geeky) you just connect the dots. Some guys do it free hand but I always used a french curve for small stuff and a flexible stick with weights called a spline for bigger stuff.


The modern way is to type the numbers into a plotting program and hope the programmer did things the way you want it done. Here's a screen shot of Profili with the airfoil editing window open. Type in your X,Y values and you're ready to print it out to any scale you want. I'm not sure if this editor expects the leading edge to be at the top of the column but since o,o is already filled in by default (and that's the way the NACA did it) I start there. There is a problem with these really old oordinates though. If you plot the airfoil from just those numbers the result will be a few straight line segments. To get it to draw a smooth shape you need to spline it, just like in the old days In Profili there are two splining options, <Smooth> and <interpolate>. They're both under the <Airfoils management> <process> <Process with Xfoil> menu. They both alter the contour a bit in the process but probably less than normal building errors. Use <interpolate> first because it alters the profile less. <Smooth> is for modifying the spline if it turns out to have bumps and waves.

--Norm

Now that explains a few things. I was getting confused with looking at the modern .dat files and seeing the negative numbers and thinking that they HAD to be negative numbers to work. The use of the negative numbers only notes as to where the foil is plotted in reference to the zero line. Shiny. Your explanation between the two splining options is a big help as well. I was not expecting as much info as you took the time to share and I very much appreciate it. Thank you!

Mark

Addendum: Schlauchkurbler

Heinz