Was the X-1 first?

I was doing some research about absolute firsts for Waynos' thread, and he brought up the question of whether the X-1 was the first to go supersonic or not. I've found a lot of circumstantial evidence to support that it actually was beaten by several weeks by the XP-86, but was wondering if anyone has any stronger evidence. This is the evidence so far:

The F86 Sabre was the first swept-wing jet fighter to fly with the United States Air Force. It had very good performance for the time, going supersonic in a shallow dive just a few weeks AFTER Chuck Yeager became the first man to break the sound barrier, flying the rocket propelled X1. Sabres were pitted against MiG15s during the Korean war; the MiG could outclimb the Sabre, but the Sabre was faster in a dive and had better horizontal maneuverability. Overall, some people consider the MiG slightly superior to the Sabre, but because of better pilot training the Americans achieved a better than 8-to-1 kill ratio against the communist pilots. Ironically, both aircraft were powered by the same jet engine, the British designed Nene.
www.richard-seaman.com...

However, it appears that yes it DID beat Yeager into supersonic flight.

The airspeed indicator wound up to about 405 mph, and seemed to get stuck there. Yet, there was no doubt that the XP-86 was still accelerating. Everything felt normal, until passing below 30,000 feet where a tendency to roll needed some minor correction. George pushed the nose over a bit more. Then, suddenly, the airspeed indicator jumped beyond 470 mph and continued to go up. Passing 25,000 feet, Welch eased back on the stick and pulled back the throttle. Once again, there was a bit of wing roll and the airspeed indicator jumped back from 520 to 450 mph (520 mph indicated translates to 720 mph true at this altitude, uncorrected).

Prior to heading back to North American to brief the engineers, George telephoned Millie Palmer. Excitedly, Millie related that a terribly loud ba-boom had nearly blown her out of bed. The time was noted and it corresponded to George’s dive. “Pancho”, Millie related, “is really pissed. You know how she feels about Yeager.” Apparently, Pancho claimed the boom was a result of mining operations going on 30 miles away to the north. Of course, no one had previously heard any mining explosions, nor could that account for rattling windows only on the east facing side of the Fly Inn. Welch chuckled and swore Millie to secrecy.

After briefing the engineering team at North American, Welch tracked down Ed Horkey. There were some “funny” instrument readings during the dive, and George was looking for some answers.

Horkey guessed that Welch had run into a previously unknown Mach effect. Indeed he had. What Welch had observed was a phenomenon that would later be called, “Mach jump”. Today, “Mach jump” is generally considered solid evidence of speeds in excess of Mach 1. Of course, on October 1, 1947, no had ever seen it before.
home.att.net...

It appears that the F-86 prototype DID break the sound barrier, however due to the politics involved it was covered up, until Chuck Yeager and the X-1 "officially" broke the sound barrier in October of 1947. I don't think we'll get much more proof than what I've found here. OFFICIALLY, it went supersonic AFTER the X-1 did, however based on what they found during test flights, I would have to say that it ACTUALLY went supersonic before the X-1 did. They were aware of the fact that the F-86 was potentially capable of supersonic flight, however were told not to do anything to prove that, until AFTER Chuck Yeager and the X-1 officially broke the sound barrier. They were informed by Stuart Symington, who was Secretary of the Air Force. He didn't want any thunder stolen from their pet project, the X-1. Larry Bell, of Bell Aircraft had apparently learned that the XP-86 could potentially break the sound barrier, and complained to the President that North American was trying to upstage their test flights. Politics does it again.

Shortly before the X-1's famous flight, North American test pilot George Welch had been conducting high-speed dives of the XP-86. During these flights, he had noticed odd behavior of the aircraft's speed indicator which jumped erratically as he approached Mach 1. Later on, this phenomenon would come to be known as "Mach jump" and is indicative of encountering shock waves at transonic speeds near the speed of sound. Witnesses on the ground had also reported hearing the tell-tale "BA-BOOM" sound, which is indicative of the sonic boom created by a supersonic vehicle.

Welch flew two of these possible supersonic flights before the X-1 officially broke the sound barrier, one on 1 October 1947 and the other on 14 October, mere minutes before Yeager achieved Mach 1.06. Unfortunately for Welch, his aircraft was not equipped with instrumentation to determine conclusively just how fast he had gone. It was not until 13 November that ground stations were used to measure the speed of the XP-86 in a dive, during which the aircraft was clocked at Mach 1.02 and 1.04 on two separate attempts. Since the dive angles during the measured attempts had been the same as those on his earlier flights and the aircraft had not undergone any modifications, it is quite possible that George Welch was not only the first to fly supersonically in a jet-powered plane, but the first to break the sound barrier as well.
www.aerospaceweb.org...


Here's the link to the Absolute Firsts thread:
www.abovetopsecret.com...

Dr. Richard P. Hallion, then USAF Historian, addressed this question in 1999 in a letter to Col. Jimmy Doolittle, USAF (ret.) at the Society of Experimental Test Pilots.

Hallion writes:

"There have been a few rumors through the years that the XP-86 and George Welch might have flown faster than sound prior to Chuck Yeager, but I must stress that documentation of this event has always been lacking.

The facts that are beyond question are these:
1) The XP-86 Sabre arrived at Edwards (then Muroc) and began flight testing on October 1, 1947, prior to Chuck Yeager's Oct. 14, 1947 flight to Mach 1.06.
2) In April 1948, powered by the same kind of engine (the J35; production F-86's had the more powerful J47), the XP-86 dove through Mach 1 (probably to about Mach 1.01 or so) piloted by Welch.
3) Therefore, the XP-86 was clearly a genuine transonic aircraft that could transit through the speed of sound, though admittedly only in a dive.

Unfortunately for those who would like to believe in the Welch story, and though I personally think the Sabre was certainly the jet era's most beautiful and evocative aircraft, I have to say that I am a disbeliever in the claim that it exceeded Mach 1 before the XS-1, for the following reasons:

1) I have never seen any record or indication that George Welch, prior to his tragic death in a F-100 inertial coupling accident, ever publicly claimed in any forum (or, so far as I know, to anyone at all) that he exceeded Mach 1 prior to Chuck Yeager.
2) Further, there are no Air Force or NACA records that suggest that the XP-86 flew faster than the speed of sound before the XS-1, and no North American Aviation company records have come to light that suggest this either.
3) To my knowledge, no other record or bit of 'hard' evidence has ever been offered to suggest that it could have happened, though Alex Henshaw's letter suggests otherwise (see below for details).

Even given that the XP-86 went through Mach 1 the following April, it is a long step to take the argument to the next level, and allege that Welch, on one of the first few flights, went supersonic. The two most prominent aviation historians who have studied and written about the Sabre, notably Ray Wagner of the San Diego Aero-Space Museum and Robert F. Dorr, have not turned up any proof whatever to support this allegation. Indeed, Dorr, while repeating rumors that the Sabre might have flown supersonic before the XS-1, concludes that 'Many years later, it can only be speculated that the XP-86 could have flown at supersonic speed before the XS-1.' [Dorr, F-86 Sabre (Osceola WI: Motorbooks Inc., 1993), p. 10]. For my part, in the 2nd edition of my own book Supersonic Flight: Breaking the Sound Barrier and Beyond (published in the UK, hence the 'British' spelling below) I addressed this issue in the following terms: 'There have been persistent rumours since 1947 that Welch broke the speed of sound before Chuck Yeager, but that the Air Force hushed it up. While Welch was reportedly an individual who might well have attempted to do so, an event of this sort would, in all likelihood, have generated more substantial proof than mere rumour, and, for its part, North American (now Rockwell) has always stated that the first supersonic foray of the XP-86 was on 26 April 1948, which is consistent with the Sabre's planned flight test programme. Until--if ever--substantial evidence is produced, rumours that the Sabre was first seemingly fall into the same mythic category as rumoured flights before the Wrights, or propeller-driven aeroplanes that exceeded the speed of sound. And in any case (as with the Wrights) it was the XS-1 that had the impact upon both aeronautical science and the popular imagination alike. What is worth noting is that the pace of aeronautical development in the 1940s was so explosive that a prototype jet fighter could arrive for flight testing with potential performance believed limited only to specialized research aeroplanes only two to three years before.' [Hallion, Supersonic Flight: Breaking the Sound Barrier and Beyond [London: Brassey's, 1997 ed.), p. 114].

Even allowing that Welch was an adventurous sort, the idea of taking America's first sweptwing high-speed fighter airplane through the speed of sound prior to the much more carefully thought out assault on Mach 1 (by the XS-1) that had been underway for almost the previous two years is, at least in my view, both reckless and highly unlikely given that:
--the plane had never flown prior to 1 October, and thus was at the very beginning of its flight test program. Further, it was of a then-new and very radical--and unproven--configuration.
--it was a one-of-a-kind prototype in a time period when aircraft companies were struggling to stay alive (much like the post-Cold War drawdown we are now in, but even more extreme) and thus, essentially worth more than its weight in gold. Loss of the prototype might have crippled or even resulted in cancellation of the Sabre program, with a potentially disastrous impact on North American. It would not have been risked so lightly, I think. . .

--even on its first flight it had had a mechanical problem with its nose landing gear that almost doomed it to a belly landing and thus, as a result, there would likely have been a 'proceed cautiously' attitude on the part of the test team as they began to expand its envelope.

--in Sept. 1946, flying a sweptwing (though tailless) a/c, British test pilot Geoffrey de Havilland had been killed when it departed in a violent longitudinal pitch from transonic trim changes which were not at all well understood until well after this time. It strikes me as highly unlikely that Welch would risk a sweptwing prototype on a plunge into such uncharted aerodynamic territory as the speed of sound.

Admittedly, in the early 1950's, there were supersonic jet fighters that went beyond Mach 1 on their first flight--for example the YF-100, the YF-105, and the XF8U-1--but that was after six to eight years of experience with transonic and supersonic aerodynamics, when we knew what worked and what didn't: not at all like the fall of 1947.

Finally, all of us know Edwards, and know that, while you might keep something secret for a while, you can never really keep it secret for long! (Just think about innumerable programs, both white and black, and some things that happened that we all remember where people vowed something would 'never get out' . . .) I can't imagine that anything like this could have been kept quiet, especially over the last fifty years.

For all these reasons, I personally find it at best unconvincing that George Welch and the XP-86 flew beyond Mach 1 before Chuck Yeager, and will remain a firm disbeliever until substantial irrefutable proof is offered up."

Sorry about the extended quote, but Dr. Hallion wanted this information to be shared as widely as possible among interested parties.

What strikes a chord with me from that reply is the consideration that everyone in aviation knew about, and was utterly horrified by, the death of Geoffrey De Havilland Jnr (son and heir to the De Havilland aircraft company) in what was universally believed to be a very advanced and well design aircraft, this is then coupled with the fact that the XP-86 had itself only just begun its test programme. These are two very salient points that I had not considered before.

They certainly make the event seem less likely, but the the cockpit reports from the XP-86 are still there, and supersonic flight would not be claimed by the XP-86 pilot if he (or anyone) didn't know he HAD gone supersonic because its manifestations were not known until the X-1 did it officiallly and as intended. It is therefore still possible, I feel, that the true speed of that XP-86 flight might only have been realised in retrospect by applying subsequent experience to the resultsa of that test flight.

So, possible then, but far from definite, just as before