There were many cases of pilots breaking the sound barrier in a dive prior to the X-1, even during World War II, and even some of them living to tell the tale. That was never in dispute.

The point of the X-1 has always been that it was the first human piloted plane that broke the sound barrier in level, controlled, and repeatable flight.

>There were many cases of pilots breaking the sound barrier in a dive prior to the X-1, even during World War II,

Aerospace engineer and amateur WWII historian here: I'm not aware of any credible claims from that era. The only WWII-era claims to have broken the sound barrier (by piloted craft) I've seen can be attributed to poor pitot tube design which gives erroneously high indicated airspeed readings when the ram pressure gets high enough.

A reconnaissance Spitfire I believe is what got closest, at something like .9 of Mach measured by a fancy pitot system at the RAF test establishment.

Aerospace engineer and amateur historian... nice! Would you enlighten us about the main problems with Hans Guido Mutke claims?

It basically boils down to the fact that machmeters hadn't been invented yet, because the physics of supersonic flight wasn't sufficiently understood back then.

Shock waves develop inside the pitot tube under certain conditions, and that causes a spike (or sometimes a drop) in pressure which is interpreted by the instrument as a corresponding rise or drop in airspeed.

Edit: as for the 262 claim itself it was pretty handily debunked in a post-war NACA technical note. If you dig around on the NTRS you can find it.

From Wikipedia: " Compressibility in pitot tubes of the time often resulted in exaggerated speed readings near the speed of sound, particularly in German equipment, which was adversely affected by supply shortages as the war progressed"

https://en.wikipedia.org/wiki/Hans_Guido_Mutke

In other words, it's the same problem that the piston-engined aircraft of the time had: Anomalous readings at high speed.

As usual, the Germans were first, with the V-2 reaching Mach 5 in the 1940's, which was to an extent controllable (they landed in England.)

For an airplane to reach Mach 1, this mainly requires thin wings and enough power/dive. To control it, you need a flying tail, and swept wings and "waisting" the fuselage reduces the amount of power needed.

So almost all of the planes in WW2 were "too thick" and incapable of supersonic flight, though could have exceeded Mach 1 with modified wings, tail and in a dive.

The US P-80 (1945) and F-86 (1949) jets had underpowered engines, in the sense that all early jet engines had limited power.

However the F-86 had swept wings, and later versions of the F-86 had a flying tail, so if you pointed it at the ground, you could get a sonic boom without losing control.

Source: I study aerodynamics.

tuyiy

Or running speed records. I heard many stories from veterans that during ranher training they did numbers better than the official Olympic records.

rangers aren’t above being delusional

The X-1 could break the sound barrier in level flight. That is to say, it could move across geography, in a measurable way, faster than the speed of sound.

Creating a sonic boom in a deep and dangerous dive is an interesting quirk in a fighter, but it doesn’t set new speed records that would interest the general population.

> Or was it?

Yes, it was. Betteridge's Law strikes again.