luff vs boom length

jingebritsen · Joined: 21 Aug 2002 Posts: 3371

now that's some techy fiddling going on there. for those that like it. lots to play with. those that don't, "OMG, get me away from the insanity!"

was the wind particularly light that day? the sailor's stance looks like planing is a come and go kinda thing. or a defensive, "i have to muscle the crap out of this right now." i'd certainly like to try some of these sails, first hand. looks like fun for my techy side of life.

DelmarEdward · Joined: 05 Aug 2012 Posts: 72

The high aspect foil may be more efficient, but i don't think it's more powerful at lower wind speeds. Doesn't being more efficient in a foil mean a longer surface area with undisturbed air flow? Doesn't power come from the depth of the camber?

I would think then that a low aspect sail with a deep draft is more powerful AND less efficient, which would be what you want to plane early.

Isn't this the same thing that happens with an airplane wing during take off and landing with the flaps?

DelmarEdward · Joined: 05 Aug 2012 Posts: 72

as an aside for those with not much to do on rainy windless sunday morning there is an interesting thread on wing efficiency on airliners.com.

Note the gliders wing- very high aspect, but it also never has to have the power to take off and climb, only glides down.

U2U2U2 · Posted: Sun Sep 30, 2012 10:16 am Post subject:

I think David Ezzys answer on your long/short question, says that their is no definitive answer, too too many variables, except both long is best

comparison to aircraft seems to come up more so in relation to fins, I can see some relation , but to me our forces are different, particularly when turning.

on aircraft their are plenty of designs that look like they would never be able to fly at all.. the Short Brothers sky van being but one, the first time I saw one , I said looks like the box it came in , where is the plane ?

theses were actually quite stable to fly in, for about a hour transit

jingebritsen · Joined: 21 Aug 2002 Posts: 3371

that plane reminds me of the bumble bee, or the 747. neither of those look ready to fly either.

isobars · Joined: 12 Dec 1999 Posts: 20935

swchandler · Joined: 08 Nov 1993 Posts: 10588

Remember the "Guppy"?

dllee · Joined: 03 Jul 2009 Posts: 5329 Location: East Bay

Theory, long booms are better for light air.
Preference...U2 prefers shorter boom, taller luff.
Me, preference, whatever works the better.
We know the newest NP's and Hansen's have super long booms for their biggest

U2U2U2 · Posted: Sun Sep 30, 2012 2:47 pm Post subject:

U2U2U2 · Posted: Sun Sep 30, 2012 2:50 pm Post subject: