rave v presentation for foiling week (final) (1)
TRANSCRIPT
Systems Integration: V Foils and A-Frame Sails for the RAVE V
Presented by Larry Knauer, Lead Designer, WindRider International July 2, 2015 Lake Garda, Italy
© 2015 WindRider International
© 2015 WindRider International
Base Design by Clayton Bader & Larry KnauerFoil design by Thomas Cusumano II
Stability and Structures by Jacob SimonProduction engineering Zachary Frederick
Production Technician Justin Ryan
Contributors
Then & Now
Original Rave 199842 knot Demonstrated
Rave V coming soonDesign speed 35 plus knots
http://www.windrider.com
© 2015 WindRider International
© 2015 WindRider International
1/6 Scale Model
Drawings By Clayton Bader
V Foils• Generate lift proportional to
submergence in the water• Lifting load shared by ama
and waka thus eliminating high bending loads on aka
• Easy dock clearance
© 2015 WindRider International
© 2015 WindRider International
Retractable Foils
Foils are retractable to facilitate easy launching from a beach and simplify trailering
© 2015 WindRider International
V FoilsTapered Section• Large cords at top to enable
early takeoff at around 7 knots– 70% of the lift at low speed is
from the V foil, 30% from Lifting tube
• Cord tapers down and pitch diminishes on lower foils to reduce lift and resistance at high speeds– Less than 20% of the lift is from
the V foil, 80% from lifting tube
Lower Foil
© 2015 WindRider International
Whole V Foil Models
© 2015 WindRider International
V FoilsFoils tipped with sonic lifting tubes:• For efficient lift
production, 25% lower drag than equivalent T foil
• To reduce tip vortices on V foils
• To reduce cavitation at V apex
© 2015 WindRider International
Rudder foil• Rudder foil pitch
and lift controlled by pitch of boat around the forward foils
• Lower loads on rear foil
• V foil shape not needed
© 2015 WindRider International
Full Length Rudder Foil Models
• Sonic lifting tube is 25% lower drag then the equivalent T foil
• Sonic lifting tube provides higher lateral rudder forces– Improved rudder
efficiency in shallow water
© 2015 WindRider International
Drawing by Jacob Simon and Clayton Bader
• Helps to generate a righting moment
• Reduces the wing tip vortices from the sails
• Utilizes strength of triangles eliminating side stays
A Frame Rig
Why An A Frame
© 2015 WindRider International
© 2015 WindRider International
© 2015 WindRider International
High Speed Loads Diagram
© 2015 WindRider International
Low Speed Loads Diagram
Handicap Accessibility
Similar to WindRider model WR17-AS (at right), RAVE V will also be handicap accessible with the options for custom foot and/or hand controls. Hiking will not be required. The total force needed to control the boat is just 20 lbs or less for the handicap set up, and redundant controls go to each seat.
© 2015 WindRider International
© 2015 WindRider International
Other Nice Features• Retractable pontoons will make trailering and launching the
boat from a ramp easier• It carries 2 people weighing a total of 400 lbs, with a max
boat weight of 700 lbs (300 lb boats empty weight)• May utilize ballast tanks to compensate for changes in crew
weight• The rudder is controlled by foot pedals leaving your hands
free to handle both sheets• Sheets can move together or can be adjusted individually for
trimming the forces• Price will be less than any comparable foiling boats
© 2015 WindRider International
Conclusions
• Integrated systems solution of V foil with sonic lifting tube along with A frame sail rig:– Low structural weight– Higher sail forces– Self trimming for speed– User and handicap friendly– Simplified beaching and trailering– Low initial foiling speed– Reduced drag at high speed