Contact   Imprint   Advertising   Guidelines

Back to the drawing board- how will we beat Sail Rocket?

forum for kitesurfers


User avatar
Bille
Very Frequent Poster
Posts: 2654
Joined: Sun Sep 04, 2011 5:37 pm
Kiting since: 2003
Local Beach: Lake Mohave
Gear: Ozone Edge
Brand Affiliation: Barz Optics
Jaybar Dynabar V7

Re: Back to the drawing board- how will we beat Sail Rocket?

Postby Bille » Fri Nov 30, 2012 3:22 am

I think that the equipment we got Now is still good for another 10 to 20Kt
IF
the human piloting had some fairings, and changed his stance to reduce drag ?

The down-hill snow skiers go well over 100mph using just gravity for power.

If we did that And went to a more rigid airfoil then who knows how fast a kite could go.

BILLe

User avatar
polarstorm
Medium Poster
Posts: 99
Joined: Tue Jul 14, 2009 2:40 am
Kiting since: 0
Local Beach: Sauble, Santa Rita, Valmitao
Favorite Beaches: Santa Rita, Valmitao
Style: Freestyle
Gear: Cabrinha (little goat)
Brand Affiliation: None

Re: Back to the drawing board- how will we beat Sail Rocket?

Postby polarstorm » Fri Nov 30, 2012 5:08 am

BWD wrote:The kiter himself is the greatest limit at this point!
The human body turned sideways is not as aerodynamic as a fuselage.
The control system requires dealing with heeling forces etc. using the body to control board and kite.
The lines are more of a problem the faster you go, and so on...
Once they get to v3 sailrocket, they may see 80+ knots.
It's very hard to get there!
But kiters can go faster than the current 55.65kts, and will...
How to improve design for this?
Everybody has ideas...
;)


Agreed, scale the kite up, and harness the kite directly to the board with larger fins.. remove the human limitation of having to hold the kite down... Nobody is holding down the sail on the sailrocket.. there's some guy maneuvering a joystick or something. I was under the impression that this competition was with regular commonly used vehicles..

plummet
Very Frequent Poster
Posts: 4497
Joined: Sat Aug 29, 2009 11:25 pm
Kiting since: 33
Local Beach: God created the naki so the hardcore people would have a place to live.
Favorite Beaches: Shhhhhhhhhhhhh...........
Style: Always searching for flow!
Gear: If you take 3.1415 from opinion. You get onion!
Brand Affiliation: What do yo call an Alligator in a vest? ............... An Investigator.

Re: Back to the drawing board- how will we beat Sail Rocket?

Postby plummet » Fri Nov 30, 2012 5:22 am

First up get a dude legless dude and create some foils for his legs so they create aparent wind and go super fast.... sorta like the cheeta legs of kite surfing.

User avatar
Bille
Very Frequent Poster
Posts: 2654
Joined: Sun Sep 04, 2011 5:37 pm
Kiting since: 2003
Local Beach: Lake Mohave
Gear: Ozone Edge
Brand Affiliation: Barz Optics
Jaybar Dynabar V7

Re: Back to the drawing board- how will we beat Sail Rocket?

Postby Bille » Fri Nov 30, 2012 5:51 am

plummet wrote:First up get a dude legless dude and create some foils for his legs so they create aparent wind and go super fast.... sorta like the cheeta legs of kite surfing.


I'm gonna DO that !!
Dump the feet off my prosthetics ; plug the straight into the foil with carbon airfoil.
Won't be needing the surfboard for flotation on that one ; At Mohave, i gotta use a
life jacket anyway, it's a law.

BILLe

User avatar
ChristoffM
Medium Poster
Posts: 196
Joined: Tue Jul 19, 2011 5:26 pm
Kiting since: 2005
Local Beach: Langebaan and Cape Town.
Favorite Beaches: Anywhere in the Cape, South Africa.
Style: Hydrofoils! (And surf and old school)
Gear: Cape Town Foilboard and Spotz hydrofoils.
Any kite that can keep up with the hydrofoils.
Brand Affiliation: Cape Town Foilboards
Location: Langebaan (Cape Town)
Contact:

Re: Back to the drawing board- how will we beat Sail Rocket?

Postby ChristoffM » Fri Nov 30, 2012 6:00 am

I don't think kites are the limiting factor yet. Once boards improve, then kites will definitely need to improve. But that should not be too difficult. We could make them like paraskiflex or C-quads, but with racing profile. The kite will hindenburg uncontrollably if it is truly low drag, but we can add a small fifth line to distort the profile and add drag to allow flying at low speeds until we are cruising. Then pull or release the fifth line and the kite becomes super efficient.

What good is there to try and chase a silly speed record? Well we don't get a awesome new system for everyday use, but certain parts of the system provide innovations for everyday use. Sail rocket just proved that a fin could work up to 65 knots (whereas most literature shows that above 50 knots a water foil efficiency becomes useless).

And chasing a record is simply a nice challenge that keeps one thinking and innovating. With Sail Rocket's speed now it has become more of a theoretical challenge than a physical one, until we find some major break through.

longwhitecloud
Very Frequent Poster
Posts: 1907
Joined: Fri Sep 11, 2009 3:15 am
Kiting since: 0
Style: Fast, anti lawnmower.
Gear: Wipika Freeair 8.5 2 liner and Picklefork.
Brand Affiliation: iansmusic.com - free music for your kite videos

Re: Back to the drawing board- how will we beat Sail Rocket?

Postby longwhitecloud » Fri Nov 30, 2012 9:05 am

Gotta do some tricky stuff to prevent cavitation at super high speeds so things don't go horribly pear shaped speed wobble style.

snobdr
Frequent Poster
Posts: 245
Joined: Tue Jan 13, 2009 6:29 pm
Kiting since: 0
Local Beach: Dewey, Atlantic City
Brand Affiliation: None
Location: south east pa PKF SUX!!!

Re: Back to the drawing board- how will we beat Sail Rocket?

Postby snobdr » Fri Nov 30, 2012 2:40 pm

I see alot of talk about better kites but remember the buggy guys have already gone faster even faster then the sailrocket. I think the record on land is around 72 knots on a 2.7m foil.

User avatar
davesails7
Very Frequent Poster
Posts: 1804
Joined: Sun Apr 01, 2007 7:36 pm
Kiting since: 2006
Local Beach: Virginia Beach
Gear: Flysurfer Sonics 9,11,15
Spotz2 w/Delta Board
Mako 130
Brand Affiliation: None

Re: Back to the drawing board- how will we beat Sail Rocket?

Postby davesails7 » Fri Nov 30, 2012 3:04 pm

ChristoffM wrote:Sail rocket just proved that a fin could work up to 65 knots (whereas most literature shows that above 50 knots a water foil efficiency becomes useless).


Who says you can't use a fin/foil at over 50 knots?

Cavitation doesn't just happen at a certian speed. Cavitation happens when pressure gets too low on the low pressure side of the foil.

Propellers are foils and they operate at much higher speeds than 50 knots.

If you are getting cavitation on a foil, it is because there is too much load on too little area. To solve it you increase the area while keeping the total load the same.

User avatar
ChristoffM
Medium Poster
Posts: 196
Joined: Tue Jul 19, 2011 5:26 pm
Kiting since: 2005
Local Beach: Langebaan and Cape Town.
Favorite Beaches: Anywhere in the Cape, South Africa.
Style: Hydrofoils! (And surf and old school)
Gear: Cape Town Foilboard and Spotz hydrofoils.
Any kite that can keep up with the hydrofoils.
Brand Affiliation: Cape Town Foilboards
Location: Langebaan (Cape Town)
Contact:

Re: Back to the drawing board- how will we beat Sail Rocket?

Postby ChristoffM » Fri Nov 30, 2012 4:05 pm

Dave you are right. I do not know why I have 50 knots in my head? Maybe where most of the problems lie most of the time and I made wrong assumption?

But faster foils like propellers and higher speed motorized hydrofoils make use of supercavitating foils don't they? I do not think sail rocket had such a design, otherwise the fence they added would not make sense, but I must admit I do not know much about their system.

I found this on http://www.hydrofoil.com/whyhydrofoil.htm

This design is still currently the world’s fastest hydrofoil having exceeded 130 MPH in 1976. His developmental progress has been published in industry journals and periodicals worldwide and Ken is considered the world’s foremost authority on supercavitating hydrofoil design.


So supercavitating foils can go very fast (130mp=112knots). But I do not know how efficient they are and whether that could work.

Do you know what is the limiting factor holding back a course race boards from going over 50 knots? Maybe it is the kites and not the large fins? I am sure it is the fins starting to cavitate?

User avatar
edt
Very Frequent Poster
Posts: 3977
Joined: Fri Jul 16, 2010 6:27 am
Kiting since: 2010
Local Beach: ford lake Michigan
Style: unhooked and hooked boots only
Gear: slingshot, north, liquid force, cmb, pansh
Brand Affiliation: None

Re: Back to the drawing board- how will we beat Sail Rocket?

Postby edt » Fri Nov 30, 2012 4:28 pm

miss geico goes 200mph without cavitating with this prop

Image

We need better kites. Right now we have an enormous tube, which limits our upwind performance. So the kiter has to have massive strength like Rob Douglas in order to resist the downwind pull.

With a more efficient kite, you don't need as much strength resisting the kite's drag and kiters could do another 30 knots. Cabrinha designed these kites for going 20-30 knots, not 60-70.

Like the initial post said, we have to go back to the drawing board, and it's going to require a big R&D effort by Cabrinha or maybe Ozone, they might be interested too, lots of money and time thrown into a one of a kind kite.

I think our boards are ok, because that is the one part where kiters are able to tinker easily with the board, tweak it, build it up, build it down, change shape, for very low cost, so I think our boards already have a lot of R&D put into them from kiters doing trial and error until they got it right.


Return to “Kitesurfing”

Who is online

Users browsing this forum: Bing [Bot], cor, jaros, scottnorby, sindarlotodo and 21 guests