Predictions for Ram Airs in 2021

[TheJoe]

Oh shit PMU is still kicking. Bout time to give up on this horse. You have been kicking it for years.

[Trent hink]

Probably the main reason we don't use rigid wings is that they are fragile.

It's interesting that one of the very first commercial designs for kitesurfing was a rigid frame kite; Cory Roseler's Kiteski.

[Matteo V]

Probably the main reason we don't use rigid wings is that they are fragile.

It's interesting that one of the very first commercial designs for kitesurfing was a rigid frame kite; Cory Roseler's Kiteski.

Rigid frames actually sacrifice versatility, for efficiency within a narrow range.

Aircraft designers would love to get rid of flaps, both leading edge and trailing edge. Much more effecient in increasing lift at lower speed and decreasing drag at higher speeds is to change the foil section itself. Soft sails can do this.

That said, the inflatable leading edge of a tube kite or wing is extremely oversized for the top end speeds that they operate at. Thus there is efficiency to be gained in many higher speed applications of rigid wings and kites. The origional "KiteWing" was much more effecient than the new inflatable versions, for example.

[geron]

https://www.kiteworld.co.uk/acatalog/Re ... tml#SID=78

this kite; floats (carbon fiber frame is sealed) (or can be sealed), has about 3sq meter area (good for 25 knot large wing hidrofoiling), light weight and seems to have grate control for drifting and eficient upwind. 4 lines and no bridles that tangle. Has anybody tried this kites with a hidrofoil and a regular 4 line 24m bar?
no pump jaja

[10minmayl]

Rigid frames actually sacrifice versatility, for efficiency within a narrow range.

Aircraft designers would love to get rid of flaps, both leading edge and trailing edge. Much more effecient in increasing lift at lower speed and decreasing drag at higher speeds is to change the foil section itself. Soft sails can do this.

Do you mean that when one sheeting in, you are modifying the shape by increasing the depth to an extent that wouldn't be possible with a rigid kite? Is powering up the equivalent of deploying lift flaps on a wing? I suppose that is the "power mode" in the offshore video earlier. I always thought that sheeting in just changed the angle of attack.

That said, the inflatable leading edge of a tube kite or wing is extremely oversized for the top end speeds that they operate at. Thus there is efficiency to be gained in many higher speed applications of rigid wings and kites. The origional "KiteWing" was much more effecient than the new inflatable versions, for example.

Do you know of any niche developments in wings/kites? I presume for the low-end a large leading edge is fine, but must cause pretty severe top end issues. Windsurf sails seem to have a much finer leading edge from the glances I've given them, and are in effect rigid.


Thought that just occured: with a kite one can power up by sheeting in, which in effect changes the shape of the sail to give more depth and therefore more power. A windsurf sail cannot be modified as easily in real time, so only the angle of attack is changed, not the depth, which is less efficient. Is this true? Do kites change the AOA when sheeting in or the depth?

[Matteo V]

Windsurfing sails can drastically change thier shape with adjustable down hauls and out hauls. Effectively, you are inducing more camber to the cross section, and more "twist off" at the head of the sail.

Foil kites, with thier more rigidly supported structure (fron the bridle connection front to back), actually have more ability to adjust camber from sheeting.

Inflatables, with only thier leading edge supported, rely on canopy tension and can "cone" which can effectively change camber in a percentage of the sail.


There's way more to it than I could explain or even understand. But once again, an airplane with variable foil cross section would be the pinnacle of aeronautical engineering. And it's something we take for granted in sailing and kiting.

[br44]

https://www.kiteworld.co.uk/acatalog/Re ... tml#SID=78

this kite; floats (carbon fiber frame is sealed) (or can be sealed), has about 3sq meter area (good for 25 knot large wing hidrofoiling), light weight and seems to have grate control for drifting and eficient upwind. 4 lines and no bridles that tangle. Has anybody tried this kites with a hidrofoil and a regular 4 line 24m bar?
no pump jaja

I fly a Revolution kite, Power Blast. On the beach only. Great kites but very, very different. Try one and you’ll see that your proposal is no more than a mere fantasy.

[Pump me up]

Probably the main reason we don't use rigid wings is that they are fragile.

Fragility, cost, and the tiny potential market are definitely factors. But rigid wings attached to the end of kite lines, like the racing hang glider attached, are inevitable. They will have unbeatable lift and efficiency. The will to win will find a way.

[10minmayl]

Windsurfing sails can drastically change thier shape with adjustable down hauls and out hauls. Effectively, you are inducing more camber to the cross section, and more "twist off" at the head of the sail.

Sorry point was that they cannot adjust "on the fly", I'm very familiar with how much fine tuning they can do, and the caveat there is the longboard racing sails that have out/down-haul lines for on the fly adjustments, but kitesurfing has that fine control at the fingertips.

Foil kites, with thier more rigidly supported structure (fron the bridle connection front to back), actually have more ability to adjust camber from sheeting.

Inflatables, with only thier leading edge supported, rely on canopy tension and can "cone" which can effectively change camber in a percentage of the sail.

There's way more to it than I could explain or even understand. But once again, an airplane with variable foil cross section would be the pinnacle of aeronautical engineering. And it's something we take for granted in sailing and kiting.

Interesting I'm guessing older kites (the last kite I owned was a Naish Torch bless her) didn't change camber when sheeting in, but more modern kites and especially foils would have engineered a way to increase the effective variability of camber.



What about slats? When these kites become rigid suddenly all kinds of opportunities for increasing range.
Crude example leading edge slats to increase lift at lower speeds, activating surface controls from the bar.

wing.gif (19.15 KiB) Viewed 1048 times

Fragility, cost, and the tiny potential market are definitely factors. But rigid wings attached to the end of kite lines, like the racing hang glider attached, are inevitable. They will have unbeatable lift and efficiency. The will to win will find a way.

Totally. Why they don't exist yet at the top end I find interesting, "unbeatable lift and efficiency" would compel someone.

[AndersP]

It would be a recipy for disaster to have rigid kites in situations where other people are around!
Just imagine a kitefoil race with 30 hardwings in the air, doing 50 knots

For speed record attempts it may work very good.