I've seen multiple on-board and other angles of the shunt and, especially, Wheldon's car.
It went airborne after his front mounted the rear tyres of the car directly ahead, piroutted 360 degrees mid-air, landed top end (cockpit exposed) onto the wall and caught fire as it scraped arcoss the highfence.
It didn't look like his car came back down in one piece.
Others were very lucky indeed as there were bits of car and wreckage strewn everywhere, some still on fire.
Again, RIP and sincerest condolences to his family and friends. I distinctly remember his post Indy 500 interview in Victory Lane earlier in May. Seemed like a good, humble bloke.
Shame.