Okay hear me out and this may sound like the ramblings of a lune but i just thought the following.
Surely a perfectly flat tight sail would more effectively convert wind energy into forward momentum rather than a full sail which would first have the wind hit it at a slight angle pushing the sail in that direction rather than perfectly straight forward.
I realise there are practicalities in operating a very high tension sheet but this lives purely in the hypothetical realm.
Does this make sense or have i been drinking drain cleaner again.
Ta Lemmers…
According to my college physics 101 professor, a curved sail is generally superior in all situations. There are sails made out of rigid materials, and they generally are curved, even though they could be flat. Everybody who sails knows that you can adjust the slack in your sail, and that sometimes a tighter sail is better, for example when tacking. You can tell this just from the feel.
Now, then, it’s been a LONG time since my physics 101 class, but the explanation was something like this: Although this is an oversimplification, you can imagine that a sail works when air particles bounce off of it. The momentum imparted to the sail depends not only on the direction that the wind is coming from, but also the direction that it ends up going when it bounces off the sail. A curved sail helps redirect the wind away from the sail in exactly the direction that the sail is pointing, which is better at pushing the vehicle in the correct direction.
Another way to look at this is if it is a pure matter of air pressure. A curved surface will be better at creating air pressure inside the curve. It’s like if you’re driving and you hold something out the window. When you hold a rigid board out of the window, it will be hard to hold in place, but the air pressure won’t build up behind it as much as a sack, for example. If you hold a sack out the window, it will probably just be ripped out of your hands.
Sails don’t really work like that. Sails are actually more like a wing. They create lift but pull sideways instead of lifting like airplane wings.
There are also crazy racing sailboats that use a ridged wing.
Isn’t it loon?
Maybe “lune” is how we are supposed to refer to moon people 🤷♂️
I’d agree with you, but we already have ‘lunatic’ for that, lol
I’m thinking if the sail was flat and taught the air would push around the sail and you would lose a lot of energy through resistance or like wind moving laterally. Whereas the traditional sail kinda cups and holds the wind force and creates more pushing force towards the center rather than the edges.
Cause airflow is like fluid dynamics right? Imagine spraying a hose at a wall vs a sheet hanging from four corners.
But I’m high and kinda drunk so who TF even knows.
think in the inverse: is a spatula better at serving liquid than a ladle? You’re trying to capture the kinetic energy of a fluid using a sail.
A lot depends on the angle you are heading relative to the wind and how strong and variable the wind is and how easily you want to be able to steer or hold your course.
The simplest case that I think you might be wrong is going down wind, especially in light air, you want the sail to catch the wind like a bag and direct it toward a central point to add all the vague forces into one direction instead of just twisting the sail one way or another. Like I didn’t think you actually want the wind hitting the outer edges of the sail straight on as this would just move the sail, not the boat.
Stiff, even hard not cloth sails are useful to go into the wind at a slight angle, where they are optimized in shape like an airplane wing, and they even talk of the force generated as lift.
