News Home Video Gallery Newsletters Photo Gallery Cruising Int
Sail-World.com : Dirtboats and iceboats - Sailing a solid wing with a slotted flap
Dirtboats and iceboats - Sailing a solid wing with a slotted flap


'Holy Gale 2013'    John Eisenlohr    Click Here to view large photo

I’ve been designing sailing and building dirtboats and iceboats powered by solid wings since the early 90’s. I believe in keeping things simple with my wings. I use an external slotted flap. It pivots near the trailing edge of the main wing or as some say first element. We have found positive control is the best and safest way to control our wings at high speeds.

Positive control means that there is zero slop in the control system. This is achieve via chain and sprocket systems about 13 to one ration that drive the main wing angle of attack. Prior to positive control some tried to control there wings with a simple main sheet system much like the AC 45’s and 72’s. With our higher speed ranges that can be disastrous due to the wing back winding in a tack and going into an uncontrollable flutter. The forces can translate through the whole boat causing the all the wheels to alternately go airborne in a violent dance of death. In fact the first wing I ever made pre positive control met a quick demise after depowering (sheeting out a little) entering a jibe. I ended up with a trailer full of fire wood.

The flap is controlled by a spring loaded trigger system that engages into an angles index system. We use zero to thirty degrees of flap deflection depending on conditions. Our wings are very simple compared to even an AC 45 because our flaps don’t twist. Twist may be beneficial to depower but so far no one has ventured in that direction.

I’ve had my dirtboat up to 83 mph in racing conditions and the same boat up to 80 mph on the ice pleasure sailing.

I attended and raced at the annual Holy Gale held at Smith Creek Nevada July 26 – 30 2013. We had wind every day and some good racing. I ended up with a third in the coarse racing and a third in the enduro with my class two wing boat. The boat weighs over 1000 lbs. with me in it. It 28’ long, 22’ wide and the wing in it’s tallest form is 27’ tall. It can start sailing in about a five mph wind and reach speeds in 40 mph range in those conditions depending on the surface. One evening after racing I decided to make a video describing how to sail a slotted flap wing. I thought the video might be timely for others watching the America’s Cup to understand the basic trimming principle of solid wings with slotted flaps.


by John Eisenlohr

  

Click on the FB Like link to post this story to your FB wall

http://www.sail-world.com/index.cfm?nid=111648

2:41 PM Sat 6 Jul 2013GMT


Click here for printer friendly version
Click here to send us feedback or comments about this story.







Cruising USA













The Galley Guys take on the Vancouver International Boat Show by Greg Nicoll with Frank Leffelaar and Friends,


Are you ready to enter that marina? by Captain John Jamieson, Florida










Remember to properly dispose of obsolete distress beacons by Australian Maritime Safety Authority,




World ARC fleet bids farewell to Bali by World Cruising Club,














World ARC crews in Bali by World Cruising Club,


Could your sailing navigation use a tune-up? by Captain John Jamieson, Florida








The Boat Cookbook by BoatBooks,








World ARC fleet now arriving in Bali by World Cruising Club,






World ARC fleet to enter Indian Ocean for the first time
What can you do to prevent electrocution and ESD?
Pack this sailing gear for 'hands-free' lighting
Salty Dawg Rally Seminar Series planned October 8 in Annapolis
Europe tightens up on skippers competency certification
World ARC fleet departs Darwin under full sail
NOAA expedition discovers ship’s timepiece silent for nearly 200 years
Blue Planet Odyssey - Northwest Passage gate opens
A Cruising Guide to the Dominican Republic 6.0 now available
Africa Europe Challenge introduces 'Spectator's Package'
Niagara-on-the-Lake, a popular cruising destination in Canada
The crowd-pleasing comforts of catamaran cruising
'Sailing Stones' of Death Valley seen in action for the first time
20 coral species listed as threatened under the Endangered Species Act
A case of crossed wires? A shocking situation!
OHPRI Teen Summer Camps make a splash
How amazingly awe-inspiring the Arctic really is
Boaters urged to attend anchoring meetings next week in Florida
New atlas provides thorough audit of marine life in the Southern Ocean
Canal Boating in the Alsace with the Galley Guys
World ARC fleet arrives in Darwin   
Timeless Tonga - Charter sailing in a Polynesian paradise *Feature   
A fine conclusion to the ARC Baltic 2014   
Where in the world are our strongest corals?   
Incredible efforts to save yacht from being lost at sea   
ARC Baltic fleet visit six countries and six capitals in six weeks   
Helen Island, Palau -a beautiful and unique place   
Barnacle Busting   
From Penguins to Polar Bears   
Cornell turns back from the North West Passage   
Polar research: Six priorities for Antarctic science   
Missing German tourists in the hands of Abu Sayyaf Group   
NCI granted dedicated VHF Channel   
Positive news for cruising boats in Greece   
Bivalves' ability to clean chemicals from waterways   
Are You Sailing with 'Weak Links' in your sailing rigging?   
Week-long cruise turns into 16-year round-the-world voyage   
World ARC fleet cruising the Coral Coast   
Yacht penalized for calling unannounced into Port Resolution   
Galley Guys on the Malty Seas   


For this week's complete news stories select    Last 7 Days
   Search All News
For last month's complete news stories select    Last 30 Days
   Archive News







Sail-World.com  


















Switch Default Region to:

Social Media

Asia

Australia

Canada

Europe

New Zealand

United Kingdom


http://www.sail-world.com/event_images/image/Twitter_logo_small.png http://www.sail-world.com/event_images/image/FaceBook-icon.png  

United States

Cruising Northern

Cruising Southern

MarineBusiness World

PowerBoat World

FishingBoating World

 

Contact

Commercial

News

Search

Contact Us

Advertisers Information

Submit news/events

Search Stories/Text

Feedback

Advertisers Directory

Newsletter Archive

Photo Gallery

 

Banner Advertising Details

Newsletter Subscribe

Video Gallery

Policies

 

 

 

Privacy Policy

 

 


Cookie Policy

 

 



This site and its contents are © Copyright TetraMedia and/or the original author, photographer etc. All Rights Reserved.  Photographs are copyright by law.  If you wish to use or buy a photograph contact the photographer directly.
XLXL NEW Cru USA
LocalAds   DE  ES  FR  IT