I have been experimenting with the different tails and shims (and mast placement) and I have a question for Cliff and team. Can you explain what you are doing with the tail designs to create the different feels? For example, if I go from Shiv to Shunt and keep everything else the same I do feel more front foot pressure. Are you doing something different than if I simply shimmed the Shiv to create front foot pressure? For max efficiency, I prefer not to shim too much. Another way to ask the question is this- is switching to the Shunt the same thing as shimming the Shiv? Or is there something else going on? Would love to see this discussion on your next UniFoil tech talk shows on YouTube. Thanks!
I’m not Clif but the main difference between those tails seems to be the the airfoil. The back foot tail has a symmetrical foil and the front foot has a higher camber airfoil. The angle of attack they are set at is probably different to account for this change too.
A symmetric airfoil on a tail wing will stall at a lower speed but cause extra drag when creating front foot pressure at high speed. This makes it a good choice when takeoff and riding in low energy is a priority. A symmetric tail also moves the center of pressure of the foil backwards, especially at low speeds. This loosens up the foil in roll and yaw.
A cambered airfoil will stall at a higher speed but is much more efficient at higher speed. It also moved the center of pressure of the foil forwards. This kind of tail will be more stable and predictable.
These are also reasons it’s hard to compare tails by angle of attack as a highly cambered tail might need 0° while a symmetrical tail could need more like 4° to create the same feeling of front to back foot pressure.
The style of tail you choose will depend on the exact foil setup and how you are using it. As a general rule, you want just enough camber in the section as not to push the tail out of its best l/d range. Ideally, the foil designer knows the loadings and can design tails for specific setups and purposes.
Hard to tell in the water if a shiv with 1* is different than the shunt with 0* though
Here’s another question for those who have tested them all: Is the shank the fastest? or is the shiv?
I can’t tell but I’ve been loving the shunt 0*
Can you put the KD R series on unifoil? That tail is unreal for turbulence munching and seems super duper efficient as well / good at high speed. The uni foil red tails look sweet too haven’t tried them
KD- you are awesome! However, now I am sure this needs to be discussed on the podcast or via YouTube. Lot’s to unpack here.
Yes you can use RSeries and all bottom mount KD tails on UniFoil and they work very well.
Anyone try the marlin on Unifoil?
Just got the 14 Marlin for my Hyper2 170 and really like it. I find it much more stable through the speed range and find myself holding pressure through turns without wobbles. Its also amazing for bump riding on the wing, glides so good. Foot pressure feels nice and balanced . Only other tails I have are the 13 pack from Uni, so maybe I just like a wider tail that doesn’t slip as easy. Regardless, Im stoked on the Marlin and am going to keep it on the rig for the foreseeable future.
heyo , sorry been away
thanks Kane !! pretty much spot on … the three stabs all have their profile set at 2 degrees.
the shank relies on the angle of attack AOA to generate lift , whereas the other two have a degree of lift already from the camber
so good question , whats the difference between just shimming a shank ( the symmetrical stab rear foot) to have the same foot pressure as a shunt (front foot cambered foil)
and the answer is … drum roll … because the pressure changes thru the speed range.
so with a symmetrical stab (shank) you can shim it for front foot pressure which it will have at low speed but as you go thru the speed range the shift of pressure will change to youre rear foot (within reason)
the shunt will continue to increase front foot pressure
however , this is dependent on the front wings forward pitching moment and the wing loading , this varies from wing to wing and thats why i encourage foilers to experiment with setup
hope this helps