Loose luff main

[ebb]

To have a better setting main, why not have an unattached luff?
The mast squirrels the wind right where the driving power is generated. Right?

[Mike Goodwin]

Wont stay flat and the halyard tension would have to be many times greater.
Then think of all that sail laying on the deck , spilling everywhere while you are trying to get the main doused.
It would be like the old time roller furling that was free standing , never worked very good at all .

[ebb]

Hey Mike, howrthings?
Bird's wings aint flat.
And by gum last time I flew, and it was the last time, the 747's leading edge wasn't flat either.

Certainly would have to have one hell of a lazyjack system to collect the sail coming down.
Yet the gaff sail I had was laced, and it could have been loosened (if not for the gaff) and flown away from the mast.

So, to bring this bit of flog forward: why not lace the main to the mast? Or if not laced, then looped? If not looped, then still extended away from the mast on rope stubbs?

If we've freed the foot from the boom,
why not free the luff from the stick. :confused:


"Question same old sameolds."

[CapnK]

Check this one out - a mast-aft rig (pics below). Very interesting, puts the burble-producing mast section behind the sail. I called up the naval architect who owns this site ( Running Tide Yachts (http://www.runningtideyachts.com/sail/) ) and spoke with him at length about the feasibility of such a rig being retrofitted to a monohull. Basically, the main problem (no pun intended) is keeping the luff straight - to do so requires a massively strong spar which can take the loads imparted by the enormous tensions involved in keeping the forestay straight, so as to keep the luff straight. Fitting that spar into the after end of a monohull probably ain't gonna happen. :)

A 747 flies at several hundreds of miles per hour, while our Ariels, though nearly that fast, aren't quite... ;) If you want to compare it to a wing section of an aeroplane, probably an ultralight would be a better comparison, and they have, by and large, straight leading edge surfaces (viewed from above).

Have the luff stand off by loops or lines might be better, but it would have to be a good distance away to get out of the turbulence created by the mast.

Interesting idea, though, ebb - it'll give me some things to ponder this afternoon instead of thinking about work. :)

http://www.runningtideyachts.com/assets/250perspectivefullsail.gif

http://www.runningtideyachts.com/assets/250profilefullsail.gif

[ebb]

jus keeping the brain from geting too corny or flakey.

Only pointing out that the jet wings were arched. Looked loose to me!

And the first thing I'd ask the arch i teck is why the leading edge HAS to be straight? What proof. Who or what sez so?

Like that all staysail rig - are the stays all that straight? I think it just so happens the luff is straight because that is the easiest way to make a mast. Also easier to hoist sail on straight track.
But your guy asked the question, didn't he? the mast is a way to keep sails up and the mast doesn't HAVE to influence the shape of the sail.

My guess is that the luff can be curved, everything in nature is. Tho I understand the crossover from inspiration to mechanical contraption isn't always efficient. In a perfect world maybe the mast would have been curved.

Wind tunnel experiments on perfect mast shapes must have been done in the past. Perhaps showing smoke eddies streaming mast and sail. Can we assume that no one has tested a detachted sail model because it never occured to anybody to do it?

I would imagine the disturbed air is much less or maybe nullified if there was space between the sail and mast.

Certainly could control reefing, lowering and raising the sail with strap around the mast or retroed to the track.

Guess it's not worth experimenting with. right? Depending on the optimum space we'd end up with one hell of a crane up top, or a vestigial gaff!

I've noticed the loose foot of a modern Ariel main can be made uncommonly straight