When it was once felt we’d never break the speed of sound, was there a mathematical and/or physics explanation(s) given to back this idea? …Much like how people attempted to use irrational epicycles (which kinda worked, but lacked any rhyme or reason) to explain retrograde planetary motion in a non-Copernican “solar” system.
…Or, did the unbreakable sound barrier belief simply grow by legend alone from the countless failed trials as empircal proof? Is anyone credited with proving or disproving (at that day and age) that it is, indeed, a barrier (or not) - in theory alone? (i.e.: Before Chuck Yeager did it in practice?) Or, did all the theory follow?
[Aside: Related to this, how much did Bernoulli know about the far-reaching implications of his principle? I WAG more times than not the empiricial evidence comes first, and then the theory to explain it follows…except for Einstein’s work explaining why the speed of light remains the next barrier to try to break, for one! …Mostly because no lab would be capable of testing out many of his then-radically new ideas!]
I think the idea of the speed of sound as a barrier was largely derived from the experiences of pilots who tried to approach or exceed it. As planes neared the sound barrier, shock waves were created that caused the behavior of the plane to abruptly change, rarely for the better. Sometimes these effects resulted in severe damage or loss of the aircraft. Controls might go dead or reverse their usual effect.
i don’t know the full answer, but I can get you started.
The original problem was that wings weren’t swept back. Thus the wings caused severe turbulence that threatened to tear the plane apart as you approached the sound barrier.
That was the thinking behind it being impossible. Once the swept back wing design was introduced, Chuck was able to break the barrier.
As has already been noted and this photo of theX-1 under the B-29shows, the X-i didn’t have swept back wings.
The breakthrough was actually in the “flying tail” in which the ordinarily fixed horizontal stabilizer was made adjustable by a motor drive. This enabled the pilot to retrim the aiplane for trans and super sonic flight.
The argument against breaking the sound barrier weren’t really theoretical, they were based on beliefs about design limitations and aircraft stability crossing over the barrier. Bullets broke the sound barrier all the time so they knew that manmade objects could do it, they just didn’t know if the could build something big and safe enough to transport a human across the barrier. It was a pretty tough problem to solve the shock wave buildup over the wings and control surfaces that starts to get really get bad as you near the barrier.
BTW, Bernoulli’s principle is not nearly as important to airplane flight as you have probably been led to believe. Angle of Attack (aka simple air deflection) of the wings and control surfaces is much more important to flight. We had a couple of very lengthy threads about this a while ago. I will see if I can find them.
The “sound barrier” was never a theoretical barrier but rather an engineering challenge. No one ever doubted that it was possible to go faster than sound in theory, so disproving the sound barrier in theory would have been meaningless.
Epicycles were as rational as any other explanation which could have been advanced for planetary motion in ancient times. In order to preserve a geocentric universe and circular planetary motion–both of which seem very natural and rational until you know better–you must resort to epicycles. Before Newton’s Theory of Universal Gravitation, elliptical orbits seemed like a strained, irrational, “ad hoc” construct.
Swept back wings, specifically the leading edge, is one way of dealing with a supersonic shockwave. As long as the leading edge is behind the cone shaped shock wave the leading edge can be very blunt. The F-14 has a very founded leading edge on the wing, making it suitable for low speed flight at 20º sweep but that doesn’t matter at 68º when flying up to mach 2.
Supersonic planes that do not have a leading edge swept back further than the mach angle usually have a thin, sharp leading edge.
You can’t break the light barrier as it’s a theoretical not a practical barrier and would be fairly shocking if Lorentz invariance was not fundamental (though I think some theroies connected with quantum grvaitydo discard Lorentz invaraince).
What is the Lorentz invariance? I thought it is Einstein’s theories that give us the reason why we cannot break the light barrier. As it was explained to me, your mass continues to increase as you approach the speed of light which, in turn, spawns a vicious cycle of more and more energy needed to keep accelerating an ever-increasing mass. - Jinx