18' Osprey Multifoiler from Dr. Sam Bradfield

[Doug Lord]

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:

[Doug Lord]

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)

===============
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

[Doug Lord]

Originally Posted by Doug Lord

Dr. Sam and team have started construction of the boat! Some photos here:
http://sites.google.com/site/hydrosa...il-Home/osprey
This is going to be a Rave on Steroids-all carbon and more power.

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

[Doug Lord]

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

Sam asked me to design a wing for this project.
Matt got too busy to get it built in time for this year.
There was also a bit of a gag response to the cost.
They decided to test it first with the soft rig.
As I understand it, the intent is for a high end One Design racer.
SHC

[CutOnce]

Originally Posted by Doug Lord

Here are the Holy Grail of foiler pictures. Light air while I was there-left about two. Dr Sam(see pix below) just sent me these-I left too early!

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

[troy2000]

Originally Posted by Hussong

I have a question for you then, FMS and Gypsy. If one does not constructively criticize a new craft, then how does one ever discover what could be better? By your comment, are we to suppose that the boat is in its final form and that there's nothing to learn from the initial sailing session?

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.

[Doug Lord]

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.....

[Doug Lord]

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

[Doug Lord]

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.....

[Doug Lord]

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.