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PostPosted: Thu Apr 04, 2013 6:24 pm 
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Wow, NOHUHU, where did you get that picture and who built the boat?

Keith

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I sail: Biscayne Bay, Everglades to Cape Romano, Ft Desoto, Cedar Key

"Any intelligent fool can make things bigger and more complex ... It takes a touch of genius and a lot of courage to move in the opposite direction." A. Einstein


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PostPosted: Thu Apr 04, 2013 6:32 pm 
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Chekika wrote:
Wow, NOHUHU, where did you get that picture and who built the boat?

Keith
Same guy who took this one. A great spy photographer I know.

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PostPosted: Thu Apr 04, 2013 10:20 pm 
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Location: Aussie living in San Diego, CA
NOHUHU wrote:
Aussie, did you see this one too?

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Hey NOHUHU - nope didn't see that beast - who belongs to it?

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PostPosted: Fri Apr 05, 2013 1:13 pm 
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Location: Punta Gorda, FL
fusioneng wrote:
The new main and jib sails will furlable soft wing type sails.
Bob


Dang, I thought I was going to have the first AI with a wing sail. The guy who builds these wings offered me a wing in exchange for some web work. Still working out details and I may not do it.

I'm not sure how I'd store and transport a hard wing. How do you make a soft one that furls?

And on the thread topic, the water has gotten warm enough that getting splashed a lot is funny to me again, as shown at the end of this video I shot on Wednesday... :mrgreen:



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PostPosted: Fri Apr 05, 2013 1:41 pm 
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Hmmm, if only you'd had some way of hiking out, Tom.

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PostPosted: Fri Apr 05, 2013 4:31 pm 
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I'm done with that spray, Tom. At least most of it. Here are my latest spray skirts.

Keith

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I sail: Biscayne Bay, Everglades to Cape Romano, Ft Desoto, Cedar Key

"Any intelligent fool can make things bigger and more complex ... It takes a touch of genius and a lot of courage to move in the opposite direction." A. Einstein


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PostPosted: Fri Apr 05, 2013 6:10 pm 
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Those look nice, Keith. What do you have to do to fold the amas?


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PostPosted: Fri Apr 05, 2013 6:47 pm 
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It is literally a stretch to fold the amas in, but I don't do that until I land. Remember, I'm also using a pair of hakas, so the spray skirts are a minor problem for folding compared to the hakas.

Each spray skirt is attached by 2 bungees + a spectra cord loop. They can attached/detached in a few seconds each.

Keith

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I sail: Biscayne Bay, Everglades to Cape Romano, Ft Desoto, Cedar Key

"Any intelligent fool can make things bigger and more complex ... It takes a touch of genius and a lot of courage to move in the opposite direction." A. Einstein


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PostPosted: Sat Apr 06, 2013 10:16 am 
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Location: Sarasota,Key West FL
Tom Ray:
My wing sail designs are nothing as elaborate as the hard wing setup on that Bravo. You will still likely be the first in the water with a working design, as I'm still out a ways before completion (my Engineering Design company is kind of busy right now, so I have to keep this fun hobby stuff on the back burner).

I have three designs that I am trying to work out the details on (been working on them about a yr now). I still have to build my small 1/4 scale prototypes on some of the designs and go through wind tunnel test ( ie... a house fan in a box, nothing fancy) to try and determine which design I will end up using.

Design 1:
Would be two inflatable skeletons that look like the fingers on your hand (one on each side of the standard Hobie mainsail), that would be under a thin mylar or rip stop nylon skin. Basically the sail will function as a standard sail when everything is deflated. When I want to use as a wing I inflate one side to puff it up into a wing shape, basically this will increase lift and lessen the amount of heel on the boat. One problem with the TI when you add lots of extra sails is, the flotation of the AMA's is not enough and you can easily bury the AMA's. The cord thickness of the wing will be 12-15% of the length. I have already built prototypes of this design and it works well. I have a small solar powered air pump that will inflate the wings with a valve that switches from one side to the other depending on which tack you are on.

If you turn the pump off the sails deflate and everything works as just standard furlable sail. another nice feature is if the sail is furled in a couple turns, the unit still creates a wing shape (in higher winds), though not perfect, but I'm figuring if I have 15-20 mph or more winds, I get more than enough power from just the sails, so I would just leave the wing inflator system off. The only thing going up to the sail would be two 1/4 vinyl tubes following the sail control line.

I expect the system to be around 25% more efficient than the standard sail, and will slip over the standard sail system (like a glove) held down by probably Velcro. Great for the low wind conditions we have in south Florida.

Both the jib and the main sail will have the same system. Because there is much less heel from wing sails I can increase the jib back up to 40 sq ft. I had to cut back on my original 40 sq ft jib because it was too much for the boat (too much heel). Basically the system will work just like those inflatable santa balloons you see at Xmas time. Shouldn't weigh more than a couple lbs, and can either be used or not used depending on the conditions.

Design #2
This design inflates the wing similar to those paragliding wings with slits in the leading edge to force air to inflate the wings. There is no pump required with this design, and if you furl the sail in one turn, the entire sail works as just a standard sail. There are several problems with this design because you would need a minimum wind of around 10 mph+ to inflate the wing, so this might not be ideal in Florida where the winds are not that strong 10 months of the year. I'm still designing this one (really hard design). It will likely not get past the prototype stage. Same as design #1 where it will be completely furlable, and is just an add-on to the standard sail.

With both designs, no changes are needed to the basic sail except a couple velcro attachment points (same attachment points as design #1 so I can test both)

On both designs the wing will extend about 2/3 the length of the sail with the remaining 1/3 working like a flap to control angle of attack and trailing edge shape so the current sail control lines will still be used. From testing my prototype in the wind tunnel (fan in a box) I think I will be able to use the standard tell tales to read the sails correct (something that I have heard is difficult on most wing sails designs).

One other change that I am implementing is to extend my AMA's an extra foot on each side so the overall width of the boat will be 12 ft wide (same width as Windrider 17).

Design #3 is a collapsible (vertically) not furlable rigid wing design that I will run as a ketch sail going up the rear stay line (specifically for low wind conditions sailing mostly in a reach). I could also use the same design as an alternate jib design up front ( I will weigh out the options). This design has wing shaped spars that are attached every foot or so to either mylar or rip stop nylon fabric. It will look like a collapsed accordion when down about 5 inches thick (all wadded up). I will have a halyard at the back of my mast topper where I can raise the sail and pull it tight creating a rigid wing. This wing would be self centering so there would be no sail control line (just turns and pivots automatically to follow the wind creating a vacuum on the front surface). The plan is to have the top half shaped for a left tack and the lower half shaped for a right tack. Basically depending on which tack you are on you raise and lower the sail to get the correct tack, the unused shape wads up either at the top or the bottom of the mast. This sail will weigh about 3-5 lbs. It will only work in certain low wind conditions (<12mph) and will be based on an eppler 420 wing shape. This sail will be small 3 ft wide x around 16 ft tall.

Design #4
This will be my favorite since everyone knows how much I love my spinnakers. This design is a furlable screacher sail about 130-150 sq ft. My plan is to use soft latex foam (like they use in pillows) to make a double wall sail filled with this soft foam pillow fill. The first third of the sail would be filled so when unfurled it creates an improved wing shape (to help create better airflow over the screacher with much less heel). My current 135 sq ft G2 spinnaker only works downwind from 100-260 degrees. I'm hoping this new screacher will work more like a huge genoa (mostly in low winds). Currently my spinnaker can only get to 1=1 with the wind with no amplification of the wind, I'm hoping my new screacher design will be able to amplify the wind a little (except in a direct downwind). In low wind the leading edge of my current spin collapses and flutters very easily, I'm hoping the double wall sail will prevent the collapse.

One design challenge with adding any sails to TI's is you pretty much have to have a bow sprit so the sails can be tilted so they can also create lift for the bow (to prevent nose diving, and to get the bow out of the water so you can plane), and also so you can get enough air in between the sails because the mainsail on the TI is mounted so far forward. Also you don't want to over stress the mast, my reasoning for converting to the wing sails, less heel and stress on the system while being able to fly more sail area at a given wind plus wing sails are supposedly 25% more efficient.

I expect the whole works will cost 2-3 hundred bucks to make. My intent is with the exception of the ketch sail for all the sails to continue to fit into the standard Hobie sail bag, and take no more than the 30-40 minutes it now takes to get the boat off the roof and all rigged and ready to go out in the water. We just got back from 3 weeks of sailing and fun down in the keys (only broke 1 rudder pin this trip, hitting the bottom in a nasty surf at Higgs beach).
Here is my boat rigged on the car and ready for the trip down to KW, it was very windy on the way down so I had much extra strapping.
Image
Image

One problem I have is I've been running my current setup for almost 3 yrs now and am perfectly happy with what I have, I just like to go out every weekend weather permitting and just use the current setup, not much incentive to add more, but I like to learn and design/build the stuff as part of my hobby.
Good luck on your wing sail, I think they are in all of our futures.
Bob


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PostPosted: Sun Apr 07, 2013 4:05 pm 
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Wow Bob, that definitely was NOT your shortest post ever, but it WAS your best!

Thanks and good luck with the plans.


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PostPosted: Mon Apr 08, 2013 7:25 pm 
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Yes, thanks for the detailed answer. I figured you must be planning something inflatable for furling. I'll have to bring that up with the guy who made that Bravo wing. The accordion idea is also interesting.

I like the idea of an inflatable wing because it solves the storage and furling problems and because it seems like it should lend itself to creating an assymetric wing like most airplanes have.


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