Directly against the wind?

[ancient kayaker]

I WAS building another type of SDU, not relying on rotating elements like windmills but using an oscillating sailng and daggerboard suspended over the bow, which would tow the boat as it moved side-to-side. The hope was that, in addition to the SDU thing it would also sail on normal points like any other sailboat, hopefully with the same kind of efficiency. I got about 80% through the build and stopped, discouraged by the complexity. Still not sure whether to go ahead and finish it.

There is no reason to suppose it wouldn't work, but I have reservations about practicality.

The same kind of problem arises with the windmill/propeller idea: when it comes time to run downwind or sail on a reach the need for universal joints and reversable gearboxes spoil the simplicity.

[Windmaster]

Bataan

Yep he did do it.

What you described is almost exactly the same as the craft in the video that started this thread off isn't it?

Shame Herreshoff never built a fullsize version.

They didn't have the Internet in those days, that's why it's almost forgotten.

But the video doesn't make any claims to be the first, just a demonstration of the ease with which it can be done.

Why don't you build one yourself? Instructions are here: http://www.sailwings.net/windspinner.html...

[Windmaster]

Originally Posted by ancient kayaker

I WAS building another type of SDU, not relying on rotating elements like windmills but using an oscillating sailng and daggerboard suspended over the bow, which would tow the boat as it moved side-to-side. The hope was that, in addition to the SDU thing it would also sail on normal points like any other sailboat, hopefully with the same kind of efficiency. I got about 80% through the build and stopped, discouraged by the complexity. Still not sure whether to go ahead and finish it.

There is no reason to suppose it wouldn't work, but I have reservations about practicality.

The same kind of problem arises with the windmill/propeller idea: when it comes time to run downwind or sail on a reach the need for universal joints and reversable gearboxes spoil the simplicity.

Peter Worsley seems to have considered that last part and writes an interesting article here: http://www.sailwings.net/art.html I believe his design was patented in 1995.

[ancient kayaker]

Originally Posted by Windmaster

Peter Worsley seems to have considered that last part and writes an interesting article here: http://www.sailwings.net/art.html I believe his design was patented in 1995.

Peter and I have exchanged emails on this and other topics: he has done some interesting work.

[messabout]

The down side of this spiffy idea is that it is not at all efficient. Sailing into the wind implies that there will be aero drag from the hull, its appendages, and its occupants, the big prop will absorb some of the wind force to produce more drag. Then there is the friction losses in the mechanism itself. Add all that up and you have an arrangement that makes VMG no better than a conventional sail rig.

Some time ago, Wooden Boat mag did a feature article about the Maine experimenter that Alan mentioned. He says that his boats are fun but not particularly efficient.

[Windmaster]

Originally Posted by messabout

The down side of this spiffy idea is that it is not at all efficient. Sailing into the wind implies that there will be aero drag from the hull, its appendages, and its occupants, the big prop will absorb some of the wind force to produce more drag. Then there is the friction losses in the mechanism itself. Add all that up and you have an arrangement that makes VMG no better than a conventional sail rig.

It's like comparing a plane with a helicopter, you can't say which is best. They are just different. If the windmill boat does not go to windward faster than a conventional sailboat, then it can go directly at least, and that can be advantageous in confined waters.
Also it can "hover" - that is, remain stationary in the water and not be pushed downwind no matter how strong the wind is, thus relieving partly, or even completely the strain on an anchor cable. Since it doesn't use any fuel whilst doing this, it can do this indefinately.

Whilst going directly to windward, the air drag or windage of any boat is obviously a factor, conventional sailboats also. Great improvements can be made by streamlining.

There is friction in the system of course, but the windmill boat has the advantage of leverage. For example if the "sail" (rotor blade) moves certain distance, and the boat moves a lesser distance, then the force is amplified, this cancels out any friction in the system.

[ThinAirDesigns]

Originally Posted by gggGuest

First done in the 1930s...

Originally Posted by Windmaster

By Whom?

Originally Posted by Boston

Whom, would be the guy who's idea has been stolen by some few, who have at this point driven several valued members away from of the forum with there deceitful and disingenuous spamming of this site.

As to DDWFTTW, there has never been any evidence presented that it was done in the '30s. Until now I've never even hear rumor as to such.

By all accounts so far it was first done in the the '60s by a team of engineers from Douglas Aircraft, but they weren't the ones who came up with the idea and as they did it to settle a bet between friends, they didn't document their exploits in a way that satisfied very many critics.

AMO Smith (google him), the Supervisor of Aerodynamics Research and Chief Aerodynamics Engineer at Douglas and one of his wind tunnel engineers, Dr. Andrew Bauer discovered the idea in a paper presented by a midwestern student who was was angling for a summer internship.

Unfortunately, no one remembers who the student was (they didn't get the intern position) so credit for the actual invention will apparently remain nebulous for all time.

Bauer believed the student was correct and AMO believed DDWFTTW to be impossible. They made a bet and Bauer assembled a small team, built and sucessfully tested the device. AMO paid off on his bet and by all acounts it was near 40 years before anyone tried it again.



Contrary to Bostons baseless assertions, we have always given full credit to Bauer and crew -- note the *very first* entry in our project blog where we do just that.

http://www.fasterthanthewind.org/200...l-started.html

JB

[Windmaster]

Hi "Thinair"

I think this thread is about going directly upwind. Not going directly downwind.

[ThinAirDesigns]

Originally Posted by Windmaster

Hi "Thinair"

I think this thread is about going directly upwind. Not going directly downwind.

I completely agree, however Downwind was mentioned which caused "Boston" to again make false comments regarding our project.

Whenever Boston does this "they stole the idea" routine, I like to make sure the record is straight.

For what it's worth, we will this winter built a new rotor for our vehicle and set a new record in the upwind catagory of going faster than the wind upwind. The current record is in the .64 WS range. We will be able to exceed 1.0 rather easily.

Carry on.

JB

[ancient kayaker]

There's some more information on sailing directly into the wind at Sailing Directly Upwind and for those who are interested in DDWFTTW it is discussed at Tacking Downwind (faster than the wind) ... there are probably other threads on these topics too.

[messabout]

Here is another rumor for Thinair. Davinci did some drawings of a device of this nature waaaay before 1930.

I am intrigued by this machine. Three cheers for the new physics. We are going to output as much, or more, energy than has been input. The big oil companies ain't gonna like this

Have you heard about the perpetual motion machine that consists of a motor which drives a generator which powers the motor?

[ThinAirDesigns]

Originally Posted by messabout

Here is another rumor for Thinair. Davinci did some drawings of a device of this nature waaaay before 1930.

Wouldn't surprise me -- Davinci was a bada** who had drawings of a lot of cool stuff.

I am intrigued by this machine. Three cheers for the new physics. We are going to output as much, or more, energy than has been input. The big oil companies ain't gonna like this

Have you heard about the perpetual motion machine that consists of a motor which drives a generator which powers the motor?

Not sure how serious you are above, but for sure our device is a consumer of energy and not a producer.

JB

[Windmaster]

Please Please!

You have hijacked the thread.

This thread is about going directly upwind against the wind.

Not going directly downwind faster than the wind, which, although interesting has, as far as we know, has no practical purpose.

Going directly upwind against the wind does have practical purpose.

DDWFTTW has plenty of threads of its own.

[ThinAirDesigns]

Windmaster ... get a grip. I've hijacked nothing and didn't even bring it up first -- I have responded only to someone who made a false accusation which deserved a response (Boston) and to someone who address me directly on the topic. (messabout).

JB

[Windmaster]

Originally Posted by ThinAirDesigns

Windmaster ... get a grip. I've hijacked nothing and didn't even bring it up first -- I have responded only to someone who made a false accusation which deserved a response (Boston) and to someone who address me directly on the topic. (messabout).

JB

It's hard to make sense of Boston's post, but I thought it was about sailing upwind and considered replying, but then thought it was not worth replying.