18' Osprey Multifoiler from Dr. Sam Bradfield

Osprey-Dual Independent Wands

Just noticed that the picture below is a perfect illustration of dual independent wands. "Wands" are surface sensors tied directly to the flap on each foil. The more angled back the wand the more angle down for the flap(resulting in lift up for the foil). In the picture, you can see that the wand on the port side is angled back further than the wand on the starboard side which means that the port foil is developing more lift than the one on the starboard side which is typical of the foil system on starboard tack.

click on image to see both wands:

 

Some interesting comparative stats:
---W/SA=pounds per sq.ft. sa / smaller number =better
---SA/ws= sail area in sq.ft. divided by wetted surface in sq.ft./ foilers flying
---Osprey to get wing rig......

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C Class cat

LOA 25'
Beam 14'
SA 300sq.ft
Boat weight 300lb
crew(estimate) 2@ 175lb=350lb.
Sailing weight(estimate) 650lb
W/SA= 2.16
SA/ws(estimate)=8.42/1

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A Class Cat

LOA 18'
Beam 7.9'
Boat weight 150lb.
crew(estimate) 175lb.
Sailing weight(estimate) 325lb
W/SA= 2.17
SA/ws(estimate)= 6.96/1

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Mirabaud

LOA 32.8'
Beam 17.7'
SA (upwind) 344 sq.ft.
---downwind 527.2 sq.ft.
Boat weight 374lb
crew(estimate) 3@ 175=525lb.
Sailing weight (estimate) 899lb.
W/SA= 2.61
SA/ws= 18/1 (on foils)

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Moth

LOA 11'(12.75 incl gantry)
Beam 7.2'
SA 86 sq.ft.
Boat weight 66lb.
crew(estimate) 175lb
Sailing weight (estimate) 241lb
W/SA= 2.8
SA/ws=13.65/1 (on foils)

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Osprey

LOA 18'
Beam 20'(+foil tips)
SA 350 sq.ft.
Boat weight 400lb.
crew(estimate) 175lb(or less!-foils develop virtually unlimited RM)
Sailing weight (estimate) 575lb
W/SA= 1.64
SA/ws= 18/1

 

Osprey

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Turns out the boat ,at 400lb. ,is made with glass hulls, carbon beams, mast and main foils!

 

Bradfield Osprey foiler

From Steve Clark on the Osprey thread under multihulls on SA:

 

Wow. Conditions look very light and the boat is fully foiling. It will be great to see the progress of the boat in stronger conditions - and closer to it's performance potential.

Getting the boat in the water is a major milestone. Getting it foiling and stable is another. Tuning it to optimal performance potential is as much challenge as the build process (but a lot more fun than fairing).

Keep the updates coming.

--
CutOnce

 

That's strictly a rhetorical question, because I saw nothing 'constructive' about your criticism. I don't know anything about foilers, but I can identify BS when I get downwind of it.

How can you complain about the nose being high as though it's a serious concern when it was the very first launch, you aren't sure what the wind conditions were, you don't know at what point the pictures were taken (before, during or after trimming the boat for optimal performance), and you don't even know how high the nose is designed to be when the boat's properly trimmed?

Seems to me you were just being a wet blanket, because for some reason enthusiasm, optimism and good cheer seem to offend you. Maybe you should go find a goth chick to lay your doom and gloom on; it might turn her on. But it doesn't do much for anyone here.... we're all glad to see another boat on the water, and it looks like a successful first outing to me.

 

Bradfield Osprey

The boat is still in the shop getting the new carbon rudder ,screecher, and a few other tid bits. Will follow up for the next flight.....

 

Osprey

Short video: http://www.youtube.com/watch?v=satoHeLfZJM

 

Osprey

Very good longer video of Osprey ,two up: http://vimeo.com/35372827
Matt McDonald owner of Falcon Marine, the builder of the boat, is sailing in this video.
Correction: Mike McGarry(sp?) sailing.....

 

An article published on the front page of SA claims the Osprey weighs 475lb
and the sail area in the pictures and video is 240 sq.ft.. Funny, because I was contemplating that my SRT would have 350 sq.ft and it looked like a much bigger rig than what is on Osprey. I measured it off a picture and came up with 240 sq.ft.. I was given the specs by both Tom Haman and the Man himself. Funny.

Changes the specs a bit-still excellent:
1) SA/ws is now 12.34/1 slightly worse than a Moth,
2) W/SA(175lb. crew)= 2.7/1 slightly better than a Moth with a 175lb crew. Worse than a C Class and A Class cat. See post 17.