Originally posted by Grimm
I am taking it that Yeager's flight was fully documented and was there for the "offical" breaking of the barrier?
If the F86 did so before hand, it must not have been documented and is based on a pilot report?
I guess this doesnt make much sense to credit Yeager for being the first, if many guys did it before him. I hope Widewing can pipe in here with a bit of an explanation. 
If someone were up on murder charges facing the weight of evidence equal to that supporting Welch as being first, they would almost certainly be convicted.
You be the judge.
Motive: Welch clearly demonstrated a desire to push the Sabre through Mach 1. His discussions with the design engineers at North American and with his friends and family are proof positive of this.
Opportunity: Welch had two opportunities to dive the XP-86 prior to Yeager’s record flight.
Weapon: There can be no doubt that the XP-86 could exceed Mach 1 in a dive. This was officially established on November 13, 1947. There were no changes made to the aircraft that could improve performance between October 1 and November 13. So, there is NO DOUBT that the XP-86 was capable of supersonic flight from day one.
Witnesses: There were hundreds, if not thousands of people who felt and heard the two sonic booms of October 1 and 14. Some have since testified to hearing the booms. In addition, we have the testimony of those who spoke with Welch where he admitted to making unauthorized supersonic dives.
Additional evidence: Welch’s flight logbook contains entries for all supersonic flights, including those not authorized. "Mach Jump": Welch was the first to report this phenomenon. No one had observed "Mach Jump" prior to the flight. Yet, today it is considered as decisive evidence of supersonic flight (according to several scientists at Dryden).
Summation: Welch announced his intention to dive the XP-86 through the sound barrier. Welch had at least two opportunities to do so. Welch was flying an airplane that was easily capable of exceeding Mach 1 in a dive. Chase pilot Bob Chilton had his P-82 pounded by a sonic boom while waiting for Welch (Chilton was orbiting below). Welch told several credible people that he had flown through the sonic barrier. There were hundreds of witnesses, including one Major General and other high ranking military and civilian personnel who heard and felt the sonic booms. Welch witnesses a phenomenon that only someone who had exceeded Mach 1 would see. He reported it before any other pilot, he could not simply invent an unanticipated dynamic behavior. Welch's logbook lists the two flights as high Mach (the same terms used for the official speed runs) for October 1, and 14. Secretary of the USAF Symington discussed Welch's unauthorized supersonic excursions with NAA's Kindelburger (documented in Kindelburger's personal papers). Symington was very concerned that the XP-86 had upstaged the very expensive XS-1 program. He had been informed of Welch's flight by several sources, including Larry Bell. At Muroc, it was common knowledge that the XP-86 had already eased past Mach 1.
Official speed runs were conducted by NAA with NACA in November of '47 (about a month after Yeager's "official" run) and officially established that the XP-86 was able to exceed Mach 1 in a dive (with full control, mind you).
In my opinion, the evidence is overwhelming that Welch and the XP-86 were the first.
By the way, Geoffrey de Havilland was killed on September 27, 1946 when his DH.108 Swallow came apart at Mach 0.88 due to excessive pitch control while trying to recover from a dive passing 8,000 feet. John Derry, flying a much modified DH.108 did manage to exceed Mach 1 on September 6, 1948 during a dive from 45,000 feet. Unlike the Sabre, the DH.108 was completely out of control and Derry was fortunate to survive. Derry was the first Brit to exceed Mach 1 in a British built aircraft. However, Brit test pilot Roland Beaumont was the first Brit to fly faster than the speed of sound.... He was also flying the XP-86 at Muroc (now Edwards AFB). That event happened on May 21, 1948.
My regards,
Widewing
