The background is:
- Britain sent data on the Miles M.52 supersonic jet to the US, so at least some Americans knew about the flying tail before the X-1 (first supersonic flight in 1948), and the Germans did some work on flying tails
https://en.wikipedia.org/wiki/Miles_M.52
- most of the pre X-1 planes that crashed didn't reach Mach 1, but they did lose control. Those are called loss of control due to compressibility, not supersonic flights.
- as the article says, the DC-8 flew ok up to Mach 0.97 in previous flights, so they thought things were fine. Note that in every Mach 1.0 flight that I've read about, the airspeed indicator jumps from around Mach 0.96 to 1.0, perhaps meaning the indicator is not accurate around Mach 1.0.
The same happens in many cases. What's a successful breakthrough is usually not only technological. UK was extremely indebted after the second world war, mostly to USA. https://www.exchangerates.org.uk/articles/1325/the-200-year-...
Of course there was the wider sad story of management problems in UK industry and the long decline after the war.
Our inability to follow through in recent decades can be depressing.
Hopefully SABRE/Skylon doesn't turn out to just be vaporware.
Having said that, London had food rationing for 9 years after the war, and really didn't have the money or facilities that the Americans had. (A B-29 was used as the mothership for the X-1!)
The W article below mentions "After the rocket plane experienced compressibility problems during 1947, it was modified with a variable-incidence tailplane following technology transfer with the United Kingdom."
https://en.wikipedia.org/wiki/Bell_X-1
Additionally, around half the X-plane pilots died, so Britain avoided a lot of test pilot fatalities. The US poured unlimited funding and talent into the program, with everybody being stars/aces (Yeager, Hoover, etc.) Both were injured seriously and almost died in various X-plane tests.
One X-plane test pilot set a record, then just quit and started a gun range.
Supersonic airflow does weird things, and tends to separate from the horizontal stabilizer well ahead of the control surfaces on the trailing edge. Early transonic aircraft would go supersonic in a dive, wouldn't have the control authority to get out of it, and would careen into the ground.
They eventually figured out that the entire tail needs to be the control surface if they wanted it to remain effective beyond mach 1.
I thought this would have been well known by the time the DC-8 flew, but perhaps not, because if it had been, nobody in their right mind would have attempted a stunt like this.