[I cannot think of a name]

There’s no need for airplanes to touch to cause this kind of event - just some kind of “energizing” event that shakes the plane at the wrong time, in the wrong way, at the highest speeds. Modern aircraft are tested to be flutter free by installing a device called a shaker in the tail, and shaking the heck out of the aircraft at the highest speeds. Unfortunately World War II vintage aircraft were tested by “control stick raps” which will not reveal every situation under which flutter can occur. And of course, this was a heavily modified aircraft flying in close proximity to other heavily modified aircraft. What makes air racing exciting is also what makes it dangerous.

[mad_as_he$$]

In the video from the angle looking to the right of the operator it is clear the aircraft is shaking. Several witnesses reported the engine was hunting. I think that was just propeller harmonics has the roll commenced. It is clear it went into the asphalt with the engine running either full out or close to it.