Definition of Sailing?

Or if you wish to include gliding:

The utilization of the interaction of two natural forces for the determinate propulsion of a vehicle.

Don't like the word "natural" but I couldn't think of another. One of the two forces, of course, would be gravity.

Now it's really getting crazy

 

Getting way too deep into this, one could describe how said vehicle uses a couple between two media to effect propulsion?

OK OK I'll stop!

 

you mean propulsing the adhesion between the gasses we sail in

 

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Says who? Give me a break! Wind is the essence of sailing.... You may be able to contrive other forms of movement similar to sailing but sailing requires wind .

 

Yipster
English is my second language---I don't have a first!
So once an idea has filtered through the disorganized mess of my brain and then translated by dutchman, we have something really scary...but you know I think I get your drift.

 

So Doug...what about solar sailing? Space ships do it.

 

sailing

You answered your own question, DG: you didn't say what about sailing you said what about solar sailing....Similar to(perhaps) but not including...

 

How about this:
"Extracting propulsive energy from the airmass moving past another medium, such as water, ice, or ground."

This eliminates passively drifting objects like leaves, balloons, or free buoys moving down a river.

You could make the concept more general by allowing the "other medium" to be another airmass with a different velocity. In this case you can "sail" in the shear layer between them using a dirigible equipped with two sails -- one sail is in the airmass above, and another sail (a keel in effect) is in the airmass below. As long as the shear layer is present, such a dirigible could move in almost any direction, outside of the minimum pointing angle limits.

"Sailing" on a horizontal air shear layer can be more easily done with heavier-than-air vehicles if done dynamically. The albatross does this in the shear layer (boundary layer) just above the ocean surface. A much more spectacular example is "Dynamic Soaring" by RC gliders, in the lee side shear layer behind a mountain crest. The current speed record is 301 mph in roughly a 45 mph wind shear layer velocity. Here's some info and a bunch of videos:
http://en.wikipedia.org/wiki/Dynamic_soaring

 

Its when a sailboat moves because theres wind.when ur sailboat dosent have any wind and u sit there it isnt sailing,its hell.you get the idea.

 

No, please don't stop. You are making great progress. Yes, there must be a couple between two media. Yes there must be propulsion. Yes, it is a vehicular concept. Keep it coming!

Dave

 

And as I said before I think it must be determinate propulsion. Not random drifting in a fluid stream.
So...
The determinate or controlled propulsion of a vehicle effected by a couple developed between at least one natural energy source and an interfacing counter influence.

Damn...I am not a trained physiscist and I've run out of words. I'd say without causing me to get a headache that isabout as close as I can get.

I'm geting the impression you already have a source for this deifinition or come up with one yourself.

 

Thanks for coming into the thread, Mark. I feel honored.

I think we're all seeing that, just as with the "definition of 'boat'" thread, it is sometimes a semantics issue, but moreover, it's a matter of stating what sailing *isn't*, then developing a (hopefully simple) definition from what's left.

So, sailing is clearly propulsion. Devices whose primary job is to produce power aren't sailcraft, then (unless they move!)

It's also clear that another friend of mine, Pater Sharp, accurately defines at least of 6 sailing "contexts:" air/water, air/air, water/solid, water/water, solid/air, and solid/solid. Ordinary water "sailing" uses one of these, land/ice sailing another. Mark points out a third (air/air), and I proposed a fourth and fifth in an earlier email (water/water and water/solid), and hinted at the sixth, solid/solid. Only this last fails to appear naturally--unless you consider things like plate techtonics or iceberg/landmass motion (which I suppose *should* be considered, so I retract the "fails to appear naturally" comment). Yeah, I can imagine a "sailcraft" designed to exploit the movement of continental plates in order to move things--like, maybe million-ton "sailboats."

Actually, Peter counts 12 contexts; introducing reference point of view to each of the above; thus he defines a difference between sailing on motionless water with wind and sailing in a current on a windless day. I count these as identical, as they only differ in relative point of view, but there you are.

Question; are there other contexts for sailing? Are Mark's suggestions re: slope soaring or time-shifted sheer boundary flight (the albatross), both of which use potential energy (gravity) to "couple" the differing media sailing? Including--or excluding--things like potential energy would go a long ways towards a common definition; Is gliding sailing? The sport gets its energy entirely from transient vertical movements of air masses, then cleverly translates this energy to horizontal movement (horizontal movement = propulsion, no? Thus horizontal motion--or more generally, motion parallel to the interface between media--is probably a requirement of sailing. Do you agree or disagree?)

Also, should the utilization of vertical movements of the media (more generally, movement perpendicular to the interface) be "allowed" in sailing? Slope soaring certainly requires uplift of wind currents--and also gravity as a "working fluid" even though no net potential energy is gained (or does it? Mark?). Careful, if we allow vertical movement of the media, things like soaring become sailing, as do things like "slope soaring" of wind deflected off waves, which seabirds use extensively. Is this sailing?

I like the concept of momentum exchange between the coupled media as part and parcel of "sailing." Without momentum exchange, there is only drifting, not sailing (does this mean that a leaf, or a clipper ship, moving directly downwind is only "drifting," not "sailing"?) I also like the restriction to movement (generally) in a plane parallel to the interface between media (thus a sailboat must stay on the surface of the sea, in order to remain a sailboat. Amick Flying boats, therefore, aren't sailcraft (search "freepatentsonline" for Amick Flying boat if not familiar with it.)

Then again, though massless, photons do have momentum. Thus "solar sailing" is possible--or is it? Where's the second medium for coupling photon momentum exchange to? Gravity? Hmmm. Gravity is a force, not a moment...

Cheers,

Dave

 

No, I really don't, and I haven't. I've wrestled with this for a long time, though. Definitions are important.

 

The crazy thing is that solar sailing does actually rely on gravity as well. Much of how it is used is counter intuitive. The crazy thing is that a vehicle can sail and increase speed going directly toward the sun without using power conversion as we normally think of that. Any way in order to have a derterminate effect on the coarse of said vehicle we do need the second effecting force of gravity.
Somebody can correct me if I'm wrong, but ouside the effect of gravity, and if we could still have the effects of photons we would be rudderless and require artificial propulsion of some sort to direct our course.

 

NASA, via NIAC (NASA Institute for Advance Concepts) recently funded an investigation into both horizontal air shear exploitation and also buoyancy-altering LTA/HTA soaring for extra-planetary exploration 2 years ago. Some interesting stuff in their final report here: http://www.niac.usra.edu/studies/st...-01 00:00:00.0&end_date=2005-03-31 00:00:00.0

Or try this, using SnipURL: http://snipurl.com/13d1p