To parallel the Surfing Industrial Complex, I have decided to name this tail design the AKA-Stoneburner.
The design is real and the story true -- no satire, no mock.
I had an idea over 2 years ago. The original design concept was de novo and inspired by the dolphin tail (a marine cetacean).
It started as an all curves design and evolved into an angular (modified) dolphin tail. As such, it had/has nothing to do with the Johnson Stealth or Tomo surfboard tail designs. I never saw either before I created this modified dolphin tail design.
I was too lazy to hand draw a dolphin tail or get out my large aluminum french curve. So I used Photoshop to rotate, flip, re-size and print 2 copies of a Griffin fin template that was posted at Sways awhile back. I taped the printed copies together to create a conceptual dolphin-tail diagram (the black line curves). I put the diagram in a drawer.
After several days of rumination, I took the conceptual dolphin-tail diagram out of the drawer. I decided I did not like the curved shape created by the Griffin fin templates. I decided to use a fin that I own (the red pencil-line curve) to create a modified dolphin-tail curve.
Weeks and months passed. The design evolved into an angular dolphin tail (yellow, pink and blue highlighted lines), the AKA-Stoneburner.
It is all about physics.
Let the games begin ...
Weeks and months passed. The design evolved into an angular dolphin tail (yellow, pink and blue highlighted lines), the AKA-Stoneburner.
It is all about physics.
Let the games begin ...
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August 20, 2013
Find the popes in the pizza.
If you look closely, the diagram contains at least 4 different design variants.
BTW the AKA-Stoneburner name is tongue-in-cheek mock.
BTW the AKA-Stoneburner name is tongue-in-cheek mock.
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August 22, 2013
I posted the original inspiration and concept evolution so some could see how I arrived at the design.
It is interesting to see how others interpret the design. It is a bit like art. Everybody sees something different, and has their own take about using the concept.
A template is 2-dimensional. There is a 3rd dimension. That dimension is the component that motivated the development of my modified dolphin-tail concept. The tail template is the foundation for the 3-D element (the secret sauce) ...
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August 25, 2013
Since I have given one Swaylock's member the recipe for my secret sauce, it seems only fair that I post the essence for everybody.
I am a scientist at the core. One of the basic tenets of true science is to make information/discoveries available to all.
A template is 2-dimensional (horizontal layout). The 3rd dimension would be the shape or profile of the tail in vertical section. The main ingredient for my secret sauce is the asymmetric foil. I developed the angular dolphin-tail concept because I felt it would be the best foundation for incorporating an asymmetric foil. Basically, the modified dolphin tail is a WingTail -- not to be confused with bumps on a rail.
More later ...
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I have made a career of helping others make money with my ideas, depressing at times. Furthermore, patents are a scam. They are for those with unlimited funds (corporations and the wealthy).
Patents are like poker with a $10K - $20K minimum bet. If you cannot call the raise, you lose.
Patents are like poker with a $10K - $20K minimum bet. If you cannot call the raise, you lose.
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August 26, 2013
Below are my perceptions about incorporating asymmetric foil into a Wing-Tail surfboard:
Below are my perceptions about incorporating asymmetric foil into a Wing-Tail surfboard:
I found this Greenlight diagram at the beginning of August. I decided it would be a useful tool for communicating my perceptions about the performance mechanism of a wing-tail with asymmetric foil. The Greenlight diagram is conceptual.
The axis of the foil chord (wing rib) would be oriented at a 45-degree angle relative to the center/stringer line, towards the nose. Envision the "apparent" water flow relative to the bottom of the surfboard tail at a 45-degree lean angle. The axis of orientation could potentially range from 40-60 degrees relative to the nose of the board. A 45 degree axis of orientation would be the all-around general purpose angle.
The word "drive" can be vague when used to describe surfboard performance. I will use it here to describe the force that opposes side-slipping during the centrifugal acceleration of turning.
My take on the principal forces opposing gravitational and centrifugal acceleration is that they are shifting and transitioning in and out of ram lift and centripetal force. Both would be related to velocity, mass and total bottom surface in contact with water.
As the board and surfer lean into a hard turn, much of the bottom surface is out of contact with the water. Most of the water contact is being made in the tail section. Apparent water flow shifts from parallel to the stringer to 45 degrees across the stringer (relative to the nose). As the board leans into a turn there is less surface area in contact with the water to generate centripetal force and prevent side-slipping and spin-out. As the fins move from perpendicular to horizontal relative to the water surface, there effectiveness diminishes.
For hard turns generated by "driving" off the rail and/or tail, surface area is needed to resist drifting and spin-out. The deeper the lean angle or tighter the cutback, the less bottom and fin surface available to push against the water and resist side-slipping/drift (photos below).
As you approach the 45-degree lean, the angled wingtail foil (wing section either side) begins to generate lift as a foil, reaching a peak when apparent water flow is at a 45-degree angle to the stringer line. My perception is, that would generate significant resistance via lift with minimal surface area (in addition to centripetal force) -- snappier responsiveness in hard turns.
That is, a wing-tail foil surface area of 23 sq. in. (right or left side only) should generate approximately 325 lb of lift ("drive") at 12 mph -- independent of centripetal force.
My choice of bottom for the wingtail concept is flat in the tail section.
August 27, 2013
amAnother, simple application for asymmetric foil is a Square WingTail.
The foils are triangles rather than trapezoids:
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August 27, 2013
pm
The last ingredient for the sauce:
I chose the NACA 4415 profile as my general purpose shape for the WingTail foils.
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August 30, 2013
I believe the lift is progressive, hitting maximum after the turn has been initiated and when a 45-degree lean angle has been reached, to augment the turn. I could be wrong.
The tail wings represent a very small area of the surfboard, at the tail's tips -- about 25 sq. in. per wing (e.g. 5" x 5"). As lean angle nears 45 degrees, the wings should be fully immersed. More air than around a fin? I cannot say.
The design calls for the foil chord (e.g. long axis of a wing rib) to be angled toward the nose at a 45-degree angle relative to the stringer/center line. This differs from the foil chord axis (wing rib) of an airplane which is parallel to the fuselage (center line).
Whether this will generate signficant lift and a performance change, I cannot say with any degree of certainty. The asymmetric foil shape is a concept for testing. The tail wings are horizontal fins as well.
There are many possible wingtail foil profiles.
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March 15, 2015
This post has become too long. To see the latest evolution and progression of this tail shape click the following link:
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