Wings

Please forgive my ignorance, But what is the difference between a Warren Truss wing and a Geodetic wing??

>Please forgive my ignorance, But what is the difference
>between a Warren Truss wing and a Geodetic wing??
>
>Larry, NorCal Circle Jerks

Well... the geodetic wing is related to the determination of of the size and shape of the earth and the warren truss is would be a place legally authorized for keeping small game to reduce a hernia by pressure...

Isn't English great?
I wish I could speak and write it...

Good reply, wise-#####. Are you by any chance related to Brett?????????

The Warren Truss has additional (straight) ribs between the diagonal ones, essentially. It is a classic bridge structure.

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"I don't know the key to success, but the key to failure is trying to please everybody." -Bill Cosby

>
>"I don't know the key to success, but the key to failure is
>trying to please everybody." -Bill Cosby

"Give me 200 active 2 year olders and I'll conquer the world"

Bill Cosby

>Please forgive my ignorance, But what is the difference
>between a Warren Truss wing and a Geodetic wing??
>
>Larry, NorCal Circle Jerks

Ron B.
F4Fguy

Like so many of our(modelers)terms there is no difference as we use the terms.Actually none of our wings is of "geodetic" construction.

A geodetic* structure consists of a number of modular equilateral geometric shapes which,when assembled,form a spherical or semi-spherical surface,which is self supporting by transferring local loads throughout the structure.
*The term should be "geodesic".

A "warren truss" is a triangulated plane (in the geometric sense) surface in which the triangulation produces both stiffness and resistance to warping as all* parts are in tension under load.This is actually closest to a wing structure consisting of angled ribs as opposed to the traditional parallel rib placement.In actual fact even most so called "trussed" CL Stunt wings aren't.To be a true truss,the ribs and leading and trailing edges must intersect to form triangles.Most of the ones I've seen form trapeziods,or truncated triangles.
*Not always exactly true,but that's the aim.

>A "warren truss" is a triangulated plane (in the geometric sense)

I've flinched a little at the use of "Warren truss" to describe
a wing because a wing is a 3D structure and a truss is a 2D structure
(as Ron notes, above). To resist all the bending, twisting,
warping, etc. in a wing, you want some sort of 3D structure like
a space frame, or stressed skin, etc. (which we tend to have,
one way or another).

Following Hank Cole's lead, I've build a couple of space frames
out of CF pulltrusions. Pretty tedious to build,
but remarkably stiff.

>>A "warren truss" is a triangulated plane (in the geometric sense)
>
>I've flinched a little at the use of "Warren truss" to
>describe
>a wing because a wing is a 3D structure and a truss is a 2D
>structure
>(as Ron notes, above). To resist all the bending, twisting,
>warping, etc. in a wing, you want some sort of 3D structure
>like
>a space frame, or stressed skin, etc. (which we tend to
>have,
>one way or another).
>
>Following Hank Cole's lead, I've build a couple of space
>frames
>out of CF pulltrusions. Pretty tedious to build,
>but remarkably stiff.
>
>Preston

Ron B.
F4Fguy

Preston:

A space frame is ,when you analyze it,a series of trussed members tied together in a three dimensional structure.The aim is the same,an indeterminate structure in which all members are in tension.

Also,a true truss is highly resistant to twisting,or warping,even if it is a single plane plane.Placing the ribs in a "trussed" configuration in fact,does give a high degree of three dimensionality to a wing as the wing is not a true plane.It has depth.The true structural nature (fore and aft) is a series of lines from the LE to the top spar to the TE repeated on the bottom with the shear web in compression between the spars.If you consider it,tying the ribs together in a horizontal truss makes it into a (sort of) space frame.

>A space frame is ,when you analyze it,a series of trussed
>members tied together in a three dimensional structure.

Sure.

>Placing the ribs
>in a "trussed" configuration in fact,does give a high degree
>of three dimensionality to a wing as the wing is not a true
>plane. It has depth.

Again, sure. I agree. That's why our wings work.

But you also wrote:
>Also,a true truss is highly resistant to twisting,or
>warping,even if it is a single plane.

That doesn't seem right. And certainly doesn't agree with
my experience. I wish we could get togther at a workbench,
because I expect the language is going to let us down.
When I build my space frames, they are basically 4 Warren trusses
stuck together. Individually, they are quite floppy, since only
the stiffness of the rods prevents bending. After assembly,
the complete frame is really stiff, since the rods are no longer
required to resist bending; instead, they must resist tension and
compression.

>>A space frame is ,when you analyze it,a series of trussed
>>members tied together in a three dimensional structure.
>
>Sure.
>
>>Placing the ribs
>>in a "trussed" configuration in fact,does give a high degree
>>of three dimensionality to a wing as the wing is not a true
>>plane. It has depth.
>
>Again, sure. I agree. That's why our wings work.
>
>But you also wrote:
>>Also,a true truss is highly resistant to twisting,or
>>warping,even if it is a single plane.
>
>That doesn't seem right. And certainly doesn't agree with
>my experience. I wish we could get togther at a workbench,
>because I expect the language is going to let us down.
>When I build my space frames, they are basically 4 Warren
>trusses
>stuck together. Individually, they are quite floppy, since
>only
>the stiffness of the rods prevents bending. After assembly,
>the complete frame is really stiff, since the rods are no
>longer
>required to resist bending; instead, they must resist
>tension and
>compression.
>
>Preston

Ron B.
F4Fguy

Preston:

I think you're right,it's a language problem.What I meant was that a single plane truss is more resistant to torsion than a simple,longeron-vertical rib structure.Please note that I'm talking torsion only,if you allow it to bend in the plane of the truss,all bets are off.The triangular configuration resists torsion because torsion stresses all the elements.A simple "box" does't.It's why the Delta Dart is so good for beginner free flight.You simply cant warp it once it's glued together,as long as it's built on a flat surface.Even if they overshrink the tissue,it will bow upward,but it won't warp torsionally.To demonstrate what I'm saying,make two simple two bay trusses about 6"x 2" from 1/16"sq.balsa,one with 6 intersecting diagonal ribs and one with ribs normal to the longerons.Hold one end rib and one longeron of each to the bench and try lifting the free corner of each.It will take significantly more force to twist the truss.

>Ron B.
>F4Fguy
>
>Like so many of our(modelers)terms there is no difference as
>we use the terms.Actually none of our wings is of
>"geodetic" construction....
>A "warren truss" is a triangulated plane (in the geometric
>sense) surface in which the triangulation produces both
>stiffness and resistance to warping as all* parts are in
>tension under load.This is actually closest to a wing
>structure consisting of angled ribs as opposed to the
>traditional parallel rib placement.In actual fact even most
>so called "trussed" CL Stunt wings aren't....
>Ron B.

I believe our wings are semimonoque in construction and therefore
the function of the tension/compression members is actually secondary to the function of the "skin" for torsional strength. This is why my silked wings shrunk with SIG butyrate dope always warp. It seems that no matter what secondary truss structure is underneath ("C" tube, I Beaam, diagonal ribs with or without the third rib), the wing always warps when I shrink the covering.

A true Geodetic wings ribs intersect in two places. Free flight guys use them alot.

>A true Geodetic wings ribs intersect in two places. Free
>flight guys use them alot.

Ron B.
F4Fguy

A true geodetic(sic) wing would be round with a semi-spherical airfoil.

Here is a warren truss flap from my Juno. I have built I Beam geodesic wings but they were a lot of trouble Over 900 glue joints.All my free flights in the 60-70's were that way.
Ed

Very nice!

Airfoiled, no less. Just lovely work. Free flighters know how to build.

The structure! The structure!

(Oh yeah, here's a true Warren Truss, a true 3D structure: )

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"Life is like playing a violin solo in public and learning the instrument as one goes on." -Samuel Butler

Looks like a bridge to me, with a deck and 3 trusses
(one on each side and one on the top).

>Looks like a bridge to me, with a deck and 3 trusses
>(one on each side and one on the top).
>
>Preston

Ron B.
F4Fguy

It is! And it also demonstrates my point;note,there are no diagonals "inside" the bridge.The torsional resistance of the trusses on the sides and top(and one supposes the bottom)distrubutes the loads to the entire structure.The trusses on the top of the end openings extending a short way down from the top are the only additional torsion members used to hold the ends square.The vertical members are not a necessary element of the warren truss.They simply make better use of material.If all members were diagonal,there would have to be more of them,since the diagonals would otherwise get too long .Incidentally,the term warren truss is simply,descriptive, referring to the maze of members looking like a rabbit warren.

>Incidentally,the term warren truss
>is simply,descriptive, referring to the maze of members
>looking like a rabbit warren.

The Warren truss was patented by James Warren and Willoughby Monzoni in 1848. I think we should all build Monzoni wings.

>>Incidentally,the term warren truss
>>is simply,descriptive, referring to the maze of members
>>looking like a rabbit warren.
>
>The Warren truss was patented by James Warren and Willoughby
>Monzoni in 1848. I think we should all build Monzoni wings.
>
>Preston

Ron B.
F4Fguy

ARRRGH! Y'got me!Those urban engineering legends will get you every time.
Didn't do my home-work,or (more likely) cut that day).

>>Incidentally,the term warren truss
>>is simply,descriptive, referring to the maze of members
>>looking like a rabbit warren.
>
>The Warren truss was patented by James Warren and Willoughby
>Monzoni in 1848. I think we should all build Monzoni wings.
>
>Preston

Ron B.
F4Fguy

Manzoni?Isn't he the guy who invented the ice rink cleaner?

That's Frank Zamboni, see http://web.mit.edu/invent/iow/zamboni.html

which reminds me of

"The device is named after a real person?" he said.

"Oh, yes. Fine old Lancashire name. From the French, I believe. You'll be telling me next you've never heard of Sir Humphrey Gadget--"

"Oh, now come on--"

"--who devised a gadget that made it possible to pump out flooded mineshafts. Or Pieter Gizmo? Or Cyrus T. Doodad, America's foremost black inventor? Thomas Edison said that the only other contemporary practical scientists he admired were Cyrus T. Doodad and Ella Reader Widget. And--"

Holy smokes!

You guys are so smart!

Allways nice to learn something that I thought I already knew.

Thanks

As the terms are used in colloquial modelling language, a Warren truss wing would have the ribes arranged to form triangels with the apex at the leading edge and the base at the trailing edge and vice versa. A geodetic wing would have the ribes arranged form a number of X's with the top and bottom of the X's at the leading and trailing edge. The X's might overlap, or not, and either structure could have ribes running from the leading to the trailing edge at about right angles. (Seems to me that Buckydomes are constructed of polygons, at least in part.)

Anyway, this is a useful, if not technically correct, answer to the original question. I do hope the new term "ribes" will catch on.

>Looks like a bridge to me, with a deck and 3 trusses
>(one on each side and one on the top).
>
>Preston

Yes, you are correct. Trusses are planes, and that is a structure with Warren trusses.

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"Who overrefines his argument brings himself to grief." -Francesco Petrarch

900 glue joints????

that is alot. But that wing looks way cool.

Did you ever get over the crud that had you grounded at Huntersville?

Can I coin the name "angled rib wing"? Naa! ... Mr. Warren should get credit. After all, it was his design that INSPIRED a lighter and stronger wing.

Should we include Mr. Geodese?

Hi Steve I got over it but was weak for a month. I took the Juno to Brodak and the man who bought Bill Little USA-1 bought the Juno be for I flew it on Sunday.He has a very large collection of classic and I-BEAM planes and the chance of another Juno coming along was small.
Ed

Steve This is not the 900 glue joint plane but it's 500+ in the wing and stab.This plane was built for the 1990 nats. I was second row center at the 1988 nats with 17-18 points and it was a clear silk Juno so I tried to build a better I-Beam and this was to be that plane.This plane was my best effort and it was a black paint job.I picked up the wrong clear for the last top coat and it looked great.The next morning the finish was all cracked.It looked like a dried up pond bottom.I didn't recover it till four year later and I was pretty much out of flying by then.It still lives somewhere in Florida
Ed

That plane, and the Red one are (were) amazing. I hope you build another Juno like that.

Glad you are finally feeling better.

Some day when the wife lets me out of the basement I'm gonna go by Bill Little's and get a training session in building I-Beams. They are pretty cool.

Absolutely gorgeous, Ed.

It makes my heart sing.

Oh the humanity! Oh the structure!

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"With sixty staring me in the face, I have developed inflammation of the sentence structure and definite hardening of the paragraphs." -James Thurber

Very nice!

>Please forgive my ignorance, But what is the difference
>between a Warren Truss wing and a Geodetic wing??
>
>Larry, NorCal Circle Jerks

Hey Larry,
Look what you went and started with your innocent question!

What you do imagine John Cocking would have to say on the subject of warren geo design and construction theory? Can't you just picture it? Cracks me up.

Will call you tonight. The Messr kicks a## big time. Much fun ahead.

Kim

>Please forgive my ignorance, But what is the difference
>between a Warren Truss wing and a Geodetic wing??

The Warren Truss is typically used on bridges. Take a look at any old steel girder bridge, you will probably find a "top spar" and a "bottom spar" joined by "Lazy Z's", "W's" or similar scheme. Another would be ribs in X format, with a chordwise rib bisecting the X. This is called "Union Jack" in Free Flight lingo. A look at the Brit flag will explain that. Another method is "eggcrate", all ribs are diagonal, and not far apart. This is closest to true Geodesic. This is typically made up with rectangular rib blanks, carved and sanded to airfoil contours after assembly, then the spars "let in" last. Attaching a pic of a stunter from So. Africa as an example, in "Bruise" color scheme.

If you are actually interested in a stiff wing, the D-Box or webbed C-tube with cap strips is very good, but can be improved by adding diagonal ribs inside the sheeted LE. The secret is dividing the squares and rectangles into triangles. The closer to equilateral, the better. By putting the diagonals inside the D-box or fully webbed C-tube, you have a closed cell, divided into triangles, and each component stiffens the other. The diagonal ribs stiffen the LE sheeting, the LE sheeting stiffens the rib. Since they're shorter, they weigh less, do more good, and cost less $. Triangles are rigid, rectangles not. Steve