Matt Hall nearly crashes at Red Bull Air Race Championships - Windsor, Ontario

[Stoney]

From the picture, that Eppler airfoil is probably closer.

[Ex-jazz]

From the picture, that Eppler airfoil is probably closer.

Yes, it's actually looking like Eppler modification from the wing tip section

[eagl]

Looked like maybe a tiny bit of a tip-stall or maybe a twitch on the rudder pedals that over-rotated him.

I saw another one just as bad, on a course in the desert with towering rock formations.  A little (200 ft tall) rock pedestal had the gates on it, and the approach to that gate was a turn where most competitors were pulling around 10 Gs.  The guy gloc'd around the turn and did a bounce-and-go off of the rock pedestal while still recovering from the gloc, and came just a few ft from plastering himself straight into the side of the rock.

[eagl]

Actually, I think its the design of the aircraft.  Obviously they both suffered from tip stall, and if wasn't for those full span ailerons, neither of them would have been able to get the aircraft to hit flat. 

Earlier in the video clip there were at least 2 spots where it looked at first like he was just over-using the rudders to help the plane turn, but on second view maybe he is using the tip-stalls on purpose to help roll (sort of like short 90-deg snap rolls) but the plane was twitchy enough that it snapped on him when he didn't want it to, halfway through what should have been a stable high-G turn.

But look at the rest of the vid...  His plane does a lot of wiggling around and my read was that he was either really standing on the rudders to help roll, or he was tip-stalling an awful lot, maybe on purpose.