Japanese plane - shrouded pusher w/winggrids

[Montblack]

http://www.winggrid.ch/do%20and%20do%20not.htm
(Do's and Dont's designing winggrids)

Bottom of page - yellow Japanese design. Shrouded pusher ...with winggrids.

What is it? Has anyone seen this plane in magazines? I'm guessing it flies.

http://www.winggrid.ch/index.htm
It comes from this site - Winggrids.

"WINGGRID -THE SUBSTITUTE FOR SPAN
The ultimate solution for aerodynamic drag reduction and wingtip stall
resistance"


Montblack

[Bob Kuykendall]

Hoo-yeah! I love the smell of snake oil in the morning!

Bob K.

[J.Kahn]

Bob Kuykendall wrote:
> Hoo-yeah! I love the smell of snake oil in the morning!
>
> Bob K.
>
Nothing new here. A Sport Aviation article, in the late 80s if I
recall, breathlessly told the story of a C-150 with identical wing tips,
back during days when Jack Cox's articles were uniformly uncritical puff
pieces (not sure if this particular article was written by Cox, it was
just that SA never reported real criticism of homebuilts back then). I
remember it had a fancy stars and stripes paint job. This C-150 had
those venetian blind thingys on the tips plus VGs and fences and was
supposedly capable of impossibly low stall speeds, which to the extent
that stall was reduced would have been a function of the VGs mainly.
The tip 'blinds" just looked ridiculous and speed limiting.

The problem with fancy wingtips is this: If they do anything to extract
benefit from tip vortices, they only do so when the wing is working
hard, at max L/D. So such a device MAY improve rate of climb or sink
rate. It won't have all that much effect on stall speed. At higher
speeds with low AOA they are just drag makers. Who is willing to give
up 15kts of cruise just to get an extra hundred FPM of climb? Thus such
things never appear in the real world in any great quantity.

Note that the only wingtip devices that actually do anything useful are
winglets, which generate some thrust from tip circulation that is more
than their drag, and this only when the wing is at max LD. As a result,
they are only used on two types of a/c in general; gliders and high
altitude cruisers like airliners and bizjets. Both do their thing at
close to max LD, the glider for obvious reasons and the airliner because
at 36000 ft it is operating at cruise effectively in the same indicated
speed regime and AOA as the glider at max LD. In both cases the
winglets are only there because their benefit is available at the
aircraft's intended cruising speed range.

Same applies to any other wing tip device that proposes to use tip
vortice energy.

JohnK

[[email protected]]

Take a look at some of the papers on the site -

http://www.winggrid.ch/AIAA-2004-2120.pdf
http://www.winggrid.ch/AIAA-2004-2120.pdf

Since they aren't selling anything, and they are doing both real world
experiments and academic papers with plenty of data collection, I
wouldn't call them snake oil.

The effect is real. It may be too mechanically complex to be economic,
but it's more than vaporware.

[Richard Isakson]

> wrote ...
> Take a look at some of the papers on the site -
>
> http://www.winggrid.ch/AIAA-2004-2120.pdf
> http://www.winggrid.ch/AIAA-2004-2120.pdf
>
> Since they aren't selling anything, and they are doing both real world
> experiments and academic papers with plenty of data collection, I
> wouldn't call them snake oil.

Snake oil is far too nice a term for what they're peddling. Did you read
the paper? In the first sentence they throw out a hundred years of
aerodynamics and replace it with their own. Why? Because the old stuff
doesn't give the answers they want. They don't justified it further than
that. They then go on to claim span efficiency factors of 1.5 with their
system. If you understand anything at all about wing aerodynamics you would
know that's an absurdity.

Sometimes people want to believe things so badly that they can't see that
they're leading themselves astray.

Rich

[Bob Kuykendall]

Earlier, wrote:

> Take a look at some of the papers on the site...

I did. I also chatted about them with one of the aero engineers whose
work is cited in them. We agree that it's a bunch of hokum. It looks
almost like it was designed to spawn a bunch of conspiracy theories
like the ones about GM suppressing the 200 mpg carburator.

As regards the topic of winglets raised by another poster, they're
great for span-limited and bending-moment-limited situations, which is
why they're popular on sailplanes and airliners. L/D-wise it's more
effective to just make the wing longer - that is, a 2-foot span
extension usually increases the performance more than a 2-foot tall
winglet. But of course, extra span drives the wing bending moment up
more, so there are many cases where you can have a winglet but not the
equivalent span extension.

[Richard Lamb]

Bob Kuykendall wrote:
> Earlier, wrote:
>
>
>>Take a look at some of the papers on the site...
>
>
> I did. I also chatted about them with one of the aero engineers whose
> work is cited in them. We agree that it's a bunch of hokum. It looks
> almost like it was designed to spawn a bunch of conspiracy theories
> like the ones about GM suppressing the 200 mpg carburator.
>
> As regards the topic of winglets raised by another poster, they're
> great for span-limited and bending-moment-limited situations, which is
> why they're popular on sailplanes and airliners. L/D-wise it's more
> effective to just make the wing longer - that is, a 2-foot span
> extension usually increases the performance more than a 2-foot tall
> winglet. But of course, extra span drives the wing bending moment up
> more, so there are many cases where you can have a winglet but not the
> equivalent span extension.
>

That feathered tip is about the exact opposite of Steve Wittman's tiny tip
trapezoid approach.

(for the newbies)
Some early NACA reports indicated that the outer one-chord-length of wing
span was disturbed by the tip vortex. (That vained thing might show some
promise in this respect, but the drag of it - just due to increased surface
area alone - and all ALL speeds???)

Anyway,
If the tip chord were reduced, what would happen to the total wing tip vortex?

The story goes Steve decided to test this eye-dia by modifying one wing tip.
He took off and tip-toed around the pattern holding near full aileron to hold
near level. Landed, rolled it back into the hanger and fixed the OTHER tip.

Steve's tip modification did indeed reduce the sink rate for any given speed.
Ergo...


Richard

May you always have a Tailwind...

[Wallace Berry]

In article t>,
Richard Lamb > wrote:


> The story goes Steve decided to test this eye-dia by modifying one wing tip.
> He took off and tip-toed around the pattern holding near full aileron to hold
> near level. Landed, rolled it back into the hanger and fixed the OTHER tip.
>
> Steve's tip modification did indeed reduce the sink rate for any given speed.
> Ergo...
>
>
> Richard
>
> May you always have a Tailwind...



Is there someplace on the web with information on the Witman wing tip
design? I'd love to have a write up with the particulars without having
to buy a set of Tailwind plans. I've looked all over the web and haven't
found it. I have a little wood wing homebuilt that would dearly love to
have those wingtips.

Thanks

Wallace

[Skywise]

"Richard Isakson" > wrote in
:

> > wrote ...
>> Take a look at some of the papers on the site -
>>
>> http://www.winggrid.ch/AIAA-2004-2120.pdf
>> http://www.winggrid.ch/AIAA-2004-2120.pdf
>>
>> Since they aren't selling anything, and they are doing both real world
>> experiments and academic papers with plenty of data collection, I
>> wouldn't call them snake oil.
>
> Snake oil is far too nice a term for what they're peddling. Did you
> read the paper? In the first sentence they throw out a hundred years of
> aerodynamics and replace it with their own. Why? Because the old stuff
> doesn't give the answers they want.

This Doonesbury is appropriate:

http://www.uclick.com/client/wpc/db/2006/03/05/index.html

Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html
Quake "predictions": http://www.skywise711.com/quakes/EQDB/index.html
Sed quis custodiet ipsos Custodes?

[[email protected]]

OK.

How are they getting an increase in L/D while decreasing span and
adding drag?

(And before the serious flames begin, neither I nor they are selling
anything.)

[Bob Kuykendall]

Earlier, wrote:
>
> OK.
>
> How are they getting an increase in L/D while decreasing span and
> adding drag?
>
> (And before the serious flames begin, neither I nor they are selling
> anything.)

The short answer is, they're not. Their verbiage and treatises dance
around it by carefully comparing apples to oranges.

[Richard Isakson]

> wrote ...
> How are they getting an increase in L/D while decreasing span and
> adding drag?

The only way for this system to do what they claim is they would have to add
energy to the airflow. Perhaps they just forgot to tell us about a small
embedded jet engine.

Rich

[Richard Riley]

These guys selling snake oil too?

http://www.star-tech-inc.com/papers/aiaa/aiaa.pdf

http://tinyurl.com/g66ln

http://jeb.biologists.org/cgi/reprint/180/1/285?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&author1=tucker&andorexacttitle=and&andorexacttitleabs=and&andorexactfulltext=and&searchid=1142007709486_1153&FIRSTINDEX=0&sortspec=relevance&journalcode=jexbio

Alsio
SPEDDING, G. R. (1992). The aerodynamics of flight. In Mechanics of
Animal Locomotion (ed. R. McN.
Alexander). Berlin: Springer-Verlag.

SPILLMAN, J. J. (1987). Wing tip sails; progress to date and future
developments. Aeronaut. J. 91,
445-453.

Or did we reach the totality of knowledge on wing tip design with
Whittman's experiment?

[Bob Kuykendall]

Earlier,

Richard Riley wrote:

> These guys selling snake oil too?
>
> http://www.star-tech-inc.com/papers/aiaa/aiaa.pdf
>
> http://tinyurl.com/g66ln
>
> http://jeb.biologists.org/cgi/reprint/180/1/285?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&author1=tucker&andorexacttitle=and&andorexacttitleabs=and&andorexactfulltext=and&searchid=1142007709486_1153&FIRSTINDEX=0&sortspec=relevance&journalcode=jexbio
>...

Not at all. They make a convincing case that carefully-implemented
multiple element winglets can reduce induced drag so as to improve best
L/D over some range of Cls, especially for wings with low aspect ratio.
What they don't try to do is sell such configurations as a panacea, a
"substitute for span."

As all good sailplane pilots know, the only substitute for span is
talent. The difference between the two is that you can _buy_ span.

Thanks, Bob K.

[Richard Lamb]

Bob Kuykendall wrote:
> Earlier,
>
> Richard Riley wrote:
>
>
>>These guys selling snake oil too?
>>
>>http://www.star-tech-inc.com/papers/aiaa/aiaa.pdf
>>
>>http://tinyurl.com/g66ln
>>
>>http://jeb.biologists.org/cgi/reprint/180/1/285?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&author1=tucker&andorexacttitle=and&andorexacttitleabs=and&andorexactfulltext=and&searchid=1142007709486_1153&FIRSTINDEX=0&sortspec=relevance&journalcode=jexbio
>>...
>
>
> Not at all. They make a convincing case that carefully-implemented
> multiple element winglets can reduce induced drag so as to improve best
> L/D over some range of Cls, especially for wings with low aspect ratio.
> What they don't try to do is sell such configurations as a panacea, a
> "substitute for span."
>
> As all good sailplane pilots know, the only substitute for span is
> talent. The difference between the two is that you can _buy_ span.
>
> Thanks, Bob K.
>
While there was some discussion about heavy jet wings, the data in the
paper indicated that the tests were performed at very low Reynolds
Numbers - 161K to 300K.

Our light experimental usually run at least 3,ooo,ooo.

They are studying Eagle wings - not 747's...

Richard

[Richard Lamb]

Richard Riley wrote:
> These guys selling snake oil too?
>
> http://www.star-tech-inc.com/papers/aiaa/aiaa.pdf
>
> http://tinyurl.com/g66ln
>
> http://jeb.biologists.org/cgi/reprint/180/1/285?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&author1=tucker&andorexacttitle=and&andorexacttitleabs=and&andorexactfulltext=and&searchid=1142007709486_1153&FIRSTINDEX=0&sortspec=relevance&journalcode=jexbio
>
> Alsio
> SPEDDING, G. R. (1992). The aerodynamics of flight. In Mechanics of
> Animal Locomotion (ed. R. McN.
> Alexander). Berlin: Springer-Verlag.
>
> SPILLMAN, J. J. (1987). Wing tip sails; progress to date and future
> developments. Aeronaut. J. 91,
> 445-453.
>
> Or did we reach the totality of knowledge on wing tip design with
> Whittman's experiment?
>

Wittman's Wonderful Wing Widget

Yep, I think so!

To my knowledge, this is the only light plane wing tip design that makes
a measurable difference in flight.
If you can measure it, it's there!

Best I can do for now is a pic of a (modern) all wood outer panel -
before installing the top skin. It's a work in progress, but gives
an idea of the shape.
http://home.earthlink.net/~tp-1/w10-tip.jpg
The originals were brazed up steel and fabric. (yeah right!)


The Unofficial Tailwind Page is located at:
A lot of info there - including flight reports and old reprints.
http://www.chlassociates.com/Aviation/Tailwind.htm


I had a link to the '05 race winner, (210 mph on 160 hp?) but I can't
find it right now. Pretty thing!


Richard

(X the X to reply)

[Montblack]

("Richard Lamb" wrote)
> http://home.earthlink.net/~tp-1/w10-tip.jpg
> The originals were brazed up steel and fabric. (yeah right!)
>
>
> The Unofficial Tailwind Page is located at:
> A lot of info there - including flight reports and old reprints.
> http://www.chlassociates.com/Aviation/Tailwind.htm


home.earthlink.net/~tp......... link doesn't work for me.

Lose the capital "T" in Tailwind for your link to work:
http://www.chlassociates.com/Aviation/tailwind.htm
This link works.

http://www.chlassociates.com/Aviation/
Or play around in here


Montblack

[Richard Lamb]

Montblack wrote:
> ("Richard Lamb" wrote)
>
>> http://home.earthlink.net/~tp-1/w10-tip.jpg
>> The originals were brazed up steel and fabric. (yeah right!)
>>
>>
>> The Unofficial Tailwind Page is located at:
>> A lot of info there - including flight reports and old reprints.
>> http://www.chlassociates.com/Aviation/Tailwind.htm
>
>
>
> home.earthlink.net/~tp......... link doesn't work for me.
>
> Lose the capital "T" in Tailwind for your link to work:
> http://www.chlassociates.com/Aviation/tailwind.htm
> This link works.
>
> http://www.chlassociates.com/Aviation/
> Or play around in here
>
>
> Montblack


Try it now?
http://home.earthlink.net/~tp-1/w10-tip.jpg

[Richard Lamb]

Montblack wrote:

Lose the capital "T" in Tailwind for your link to work:

http://www.chlassociates.com/Aviation/tailwind.htm
This link works.

http://www.chlassociates.com/Aviation/
Or play around in here


Montblack


Again. Thanks.
I might finally have it worked out.

http://www.home.earthlink.net/~tp-1/w10-tip.jpg
Wittman W-10 all wood wing tip.


http://www.home.earthlink.net/~tp-1/
This should give the folder index
or start a web page "index.htm" - if one existed?



Richard

[Richard Lamb]

"Buttercup"

Steve's "parts hauler"
http://www.chlassociates.com/Aviation/buttercup.htm

The second (of 3) pictures shows Steve examining the unique
Leading Edge flap on Buttercup.

Leading edge flaps are effective when used in conjunction
with a corresponding trailing edge flap.

Buttercup had longer wings - and longer trailing edge flaps.

On a Tailwind style wing, half the TE flaps - the other half ailerons.

So, to spread the effect further out on the wings, droop the ailerons
as the flaps go down?



Richard

[Montblack]

("Richard Lamb" wrote)
> Steve's "parts hauler"
> http://www.chlassociates.com/Aviation/buttercup.htm
>
> The second (of 3) pictures shows Steve examining the unique
> Leading Edge flap on Buttercup.


What are the Cougars?


Montblack

[Richard Lamb]

Montblack wrote:

> ("Richard Lamb" wrote)
>
>> Steve's "parts hauler"
>> http://www.chlassociates.com/Aviation/buttercup.htm
>>
>> The second (of 3) pictures shows Steve examining the unique
>> Leading Edge flap on Buttercup.
>
>
>
> What are the Cougars?
>
>
> Montblack

I believe that would be Leonard Reaves's (s?) Folding Wing version with
the messed up landing gear...

Richard