Kite Foiler!?

Kite Foilers

Here is a link to an illustration of a kite powered tri:
designers dream or reality? - Boat Design Forums
Address:http://www.boatdesign.net/forums/showthread.php?p=128522
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And here's a link to a couple of inventions by John Bellacera that may make controlling a kite foiler much easier:
Kite Control Bars for Kiteboarding, Kitesurfing and Kiteboating
Address:http://www.kitecontrolsystems.com/ Changed:2:11 PM on Thursday, March 8, 2007
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I'm convinced that the application of modern kite technology to a small bifoiler may be the best of both worlds and perhaps be the fastest and easiest as well. There are still those pesky long lines though......
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Another cool idea from Peter Lynn:
NABX Articles
Address:http://www.nabx.net/articles_read.php?author=product&id=10 Changed:3:29 PM on Saturday, March 10, 2007
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And this:
Jellyfish-Foiler - Radical French Sailing Concept
Address:http://foxxaero.homestead.com/indsail_004.html Changed:11:13 AM on Monday, August 30, 2004

 

Yeah Doug there is no doubt about it; a bi-foiler under kite power will be ssooohh faaaassssttt!!! (Faster than a kiteboarder or windsurfer).

The energy needs to be transferred directly to the hull not through the human. (the human element suffers muscular fatigue at some point and has to compensate accordingly) The control device is mounted to the hull/deck and has a universal with the ability to set the kite and fly it in a static position.

The kite control devices I have can be flown at variable altitudes (line lengths) and are still able to sheet the kite.

It is really cool to see that you get it, maybe investors might see as well.

John

 

Kite Foiler

John, the kite foiler I visualize would be a little over 10' LOA with a seat and a monohull. The kite would be attached in such a way that the crew had direct control and could dump power(or the kite instantly). The foils would be a bi-foil system with the main foil supporting 80% of the weight and the system would use a centerline wand.The rudder foil would be attached to the transom-not to a rudder gantry-and the mainfoil would be in a trunk; both would be retractable. All up weight of a proto about 59lb. Max crew weight 220lb(or so). The hull would be designed as a planing hull not skinny like a Moth-primarily to make it easier on the crew to get started and because very light air sailing is not a design requirement.
Some problems I've identified:
1) There is cultural "war" in this area between windsurfers and kiteboarders mainly due to the antics of a few untrained, inconsiderate kite guys a few years ago.They would come to Kelly Park and lay out their kite lines taking up most of the available beach. They would also sail very close to windsurfers and apparently there was an accident where a windsurfer was hurt. In order to getaway from all that this kite foiler would be designed to carry the kite and paddle out-away from shore and other boats - and then launch the kite. Is this us vs them thing true all over the country? I understand that most modern kites can be water launched; do you see any flaw in this "paddle out" idea?
2) The kitefoiler would be steered using foot pedals.
3) Do you think that with proper set up and practice that a kitefoiler could be sailed with 10-15° of windward heel upwind like the Moths?
4) Is an instant release and/or depowering system ,as I suggested above, practical? I'm a little familiar with some of the newer kites-at least that they CAN be depowered...
5) It is known that 85-86 sq.ft. of sail per sq.ft. of foil area is ideal (for early takeoff) with a foil loading of around 158lb. per sq.ft. on the main foil for a Moth. At the weight quoted above(59+220=279lb./126.8kg) the sail area using a sail similar to a Moth sail would have to be around 121 sq.ft. How would you imagine this would be translated to kite size?
John, your comments would be most appreciated!

 

OK Doug –
So you’re saying that 80.5sq.ft. of SA (sail area) = 1sq.ft. of F(foil) area (ratio), or in kite measurement (7.8 sq meters) =1sq.ft. of foil. If this is true, than I believe that foil area could be reduced due to the amount of lift a kite would generate.

From using the ‘air-chair’ foil (shown in the picture) Corey and I where able to use a 12m kite (129sq.ft of SA) in a 10knot breeze plenty powered with the ability to do aerial rotations.

(Corey 185lbs)

Granted a ‘boat hull’ would weigh more that a board, I’m not experienced enough with foils to size them up with a boat hull or in this case an ‘outrigger’. However I would say that the ‘outrigger’ would be considerably on the light side.

1. There is cultural "war" in this area between windsurfers and kiteboarders mainly due to the antics of a few untrained, inconsiderate kite guys a few years ago.They would come to Kelly Park and lay out their kite lines taking up most of the available beach. They would also sail very close to windsurfers and apparently there was an accident where a windsurfer was hurt. In order to getaway from all that this kite foiler would be designed to carry the kite and paddle out-away from shore and other boats - and then launch the kite. Is this us vs them thing true all over the country? I understand that most modern kites can be water launched; do you see any flaw in this "paddle out" idea?

My response: I think the kiters get a bad reputation because of the fact that they take up so much beach area to rig and launch, and land their kites. Most accesses are public and from the public’s perspective, yeah kiters take up a lot of space and make them uncomfortable with all the lines and kites in the air so close to the shore line. With a variable line kite controller you could say launch the kite to 10-15m’s in height; sail out a ways and continue to launch the kite to 20-25m’s.

2) The kitefoiler would be steered using foot pedals.

My response: That’s what I see, the technology is already in place and works well.

3) Do you think that with proper set up and practice that a kitefoiler could be sailed with 10-15° of windward heel upwind like the Moths?

My response: Yes, I believe it is possible. I don’t have any time on a moth, however I can keep the same windward tact as formula ‘Windsurfers’ and have beaten a few to weather now and then. I have worked with Bill Hansen (Windwing founder) now designing formula sails under his name Hansen Sails. http://www.hansensails.com/Home
Bill and I had made some significant breakthroughs in kite development and design, hopefully we will be able to work together again someday soon. He is really a great designer very innovative.

4) Is an instant release and/or depowering system ,as I suggested above, practical? I'm a little familiar with some of the newer kites-at least that they CAN be depowered...

My response: Yes, you need to be able to depower the kite greatly, and have a backup instant release. A higher projected kite will naturally give you more AOA (angle of attack) which = depower. This is the current direction kite development is going. On our own dime Bill and I are working on a couple of kites, one is a 12m kite with a projected area of 85%. This is pretty exciting to me because it’s all power and de-power with very little drag, totally efficient and safe.

5) It is known that 85-86 sq.ft. of sail per sq.ft. of foil area is ideal (for early takeoff) with a foil loading of around 158lb. per sq.ft. on the main foil for a Moth. At the weight quoted above(59+220=279lb./126.8kg) the sail area using a sail similar to a Moth sail would have to be around 121 sq.ft. How would you imagine this would be translated to kite size?

My best guess: A 12m kite might match planning speed, however with the lift generated by the kite the kitefoiler might be on the foils earlier. The kite would be able to generate apparent wind and fly static in the best AOA position, where as the sails on the moth would not be able to do so. All in all there are more advantages with a kitefoiler creating lift, reducing drag, more available sail angles to maintaining planning speed.

regards, John

 

Kite Foiler

John, thanks very much! Very encouraging info....