So will the next set of speed records be on foils? Or are there rules that prevent it?
The rules that prevent it are more likely to be laws of physics than human-made rules. Reynolds numbers become massively more critical for laminar flow over a foil at higher speeds. This is the limit that windsurfers have been chipping away at with fin design for the past 25 years. While foils, and windsurfing fins, are way more efficient than a twintip in terms of lift/drag ratios at lower speeds, the potential for cavitation, aeration, turbulence etc is much higher at high speeds. The assymetrical (but basically twintip) kite speed boards already have an aerated low-pressure-side to the lift-creating body (the top of the board, angled), so there are no issues with flow deterioration as speed increases - the "flow" is already messy, you just need more lift to overcome the drag, hence Luderitz in 50 knot winds.
This is not to say that foil design can't get there (Hydroptere makes it work even with the ridiculously inefficient foil angles necessary for it to be self-stabilising), just that the difference between 35 knots and 55 is vast.
The other factor is the depth of available courses with enough wind. The ditch at Luderitz is just deep enough short windsurfing fins.
Speed events still pretty new for kite foiling and not much mass R&d yet into pushing the top end yet, but the likes of Nico Parlier already doing 44knots in training & during events such Defi Kite
^^ by jingos an intelligent, well articulated explanation from someone who clearly knows what they're talking about. A rarity around here. 
Select to expand quoteMaxVMGRacing said..
Speed events still pretty new for kite foiling and not much mass R&d yet into pushing the top end yet, but the likes of Nico Parlier already doing 44knots in training & during events such Defi Kite
Any more info/links to the 44 knot session? I knew they were already cracking 30, but 44 is huge. Are they using smaller foils for this stuff?
Most of the local aus foilers are hitting 30-32 on their course racing foils weekly,
30 seems to be failry easy for most riders in most conditions by most of the foils. Even in light conditions, sub 15knots on a foil and foil kite you can crack 30.
35knots is is alot more rare, and gusty conditions has a big impact on foil control & top speed
30.7knots in 13knots wind: 19m Ozone R1, Spotz 2 freeride Foil www.movescount.com/moves/move67779221
Some details from Defi Kite from Nico top speed at the race 39.6 ozonekites.com/news/article/nico-parlier-wins-2015-defi-kite
Will see if i can track down the details for his 40+ runs from awhile back.
The Speed wings seems to be about the half the size, not much bigger than the rear wings
Trying to track down the gps track that aslo had pic of the wing he used for that run. Ive miss quoted, it was just under 43 knots not 44 but still damn impressive! and would be hell scary travelking that fast on a foil!!www.sailingscuttlebutt.com/2015/05/19/kite-racing-increasing-the-altitude/
First time out on the speed wing in super gusty conditions.... bit like learning to foil all over again.
Could have gone faster by there is definetly a mental hurdle around 30knots that has you second guessing yourself.
Conditions Gusty frontal 17-28knots
Spotz 2 Speedwing + 8m Ozone R1
Max 32.2knots
Highest 30sec Avg: 30.4knots
www.movescount.com/moves/move76257609
Marc Blanc strapless. With strapless (at least with a pushing foil), in theory, you should be able to go as fast as someone strapped, and you can leave the foil behind when getting yarded.
