What defines low end/low speed foiling in a wing?

[Peter_Frank]

More area plus more span gives you more roll stability at lower speeds, but will of course ride really slow and no acceleration nor any fun left

PF

I have a MHL 150 (their biggest wing) and can do 20mph on it easily, but I can also ride it at +/- 5mph. There is a lot of fun in jibing and surfing the waves.

Okay, sorry, I should have noted that it is very individual WHERE the limit goes... But there is one.

Some would never ride a wing bigger than 600 cm2 (corresponds to a 93 square inch in MHL terms) not in waves nor for freeride or freestyle.
Others could happily have fun with even a 1000 cm2 wing (155 sq.inch)

But at some point when it gets even bigger, for you maybe around 1500 cm2 (233), or when you get more experienced, you will dislike the slow wings with no acceleration nor speed at all.

We just have different personal preferences, and stages in our kitefoil life, regarding WHAT size - but I am sure it is the same issue, that at some point size destroys the fun, when everything gets too slow and draggy

I dont like speed, but for me @77 kg it is above 600-700 cm2 (93-109) it starts to get "boring", for typical wings that is.
Others love bigger wings, others love smaller wings - I like these medium sizes the most.

PF

[Peter_Frank]

Regarding AR and lift.

Of course lower AR wings has a lot more drag and dont go upwind well, that is obvious.

But when really "fat", the loss of lift is very noticeable.

Here is an example based on how lift reduces at lower AR, where I have taken the lift coefficient 1.2 (which is the stalling Cl for an Eppler 817) and the loss is not very distinct when over 4 in AR, but below, it really has an impact.
At really low AR less than 1 it might be even lower than I show here, but you get the idea.

Our wings are in the neighbourghood 3 to 6 or 7 in Aspect Ratio usually.



So yes, the lower AR wings will start later than the high AR ones.
At some point the drag of the high AR ones might increase, as the reynolds number gets too low - this is very profile specific, ie the exact design, and often only at lower aoa.
Typically they are all turbulent at max lift at our reynolds numbers, so not much or any difference IMO.

One could also make the same curve regarding upwind ability, which is affected way way more than total lift - but that was not the topic of this thread

Even more distinct than the higher drag and some loss of lift, is the increased aoa that low AR wings need, to obtain their lift - which is another reason why they are "easier" to ride, not as sensitive.

PF

[palmbeacher]

Okay, sorry, I should have noted that it is very individual WHERE the limit goes... But there is one.

Some would never ride a wing bigger than 600 cm2 (corresponds to a 93 square inch in MHL terms) not in waves nor for freeride or freestyle.
Others could happily have fun with even a 1000 cm2 wing (155 sq.inch)

But at some point when it gets even bigger, for you maybe around 1500 cm2 (233), or when you get more experienced, you will dislike the slow wings with no acceleration nor speed at all.

I agree it is all very personal. I went from a Liquid Force foil (large wing) to a 2015 MHL (medium wing) to a Slingshot Ghost Whisper (small wing). To complement my GW I got the Lift 150, and I actually enjoy riding it quite a bit more than my GW. Yes, the GW is about 40% faster but the MHL is much easier to handle in the waves and I can ride at similar angles as my other foil. Before getting out during low tide and onshore wind was a pain, now with my shorter mast and bigger foil it is so much easier. With my 2 years of foil experience I don't miss the acceleration at all, this foil is fast enough for me.