By Tom Demerly for ALERT 5.
When a manned aircraft approaches the speed of the sound it is thought to reach an invisible barrier. A barrier defined by physics. An impenetrable “sound barrier”.
No one knows what will really happen. That is the problem.
Scientists disagree; pilots think they know. Engineers have their theories.
The theory is an aircraft can accelerate through this invisible barrier and fly faster than the sound it is creating. It will become silent, literally flying ahead of its own sound.
There is also hard evidence that a manned aircraft cannot break the sound barrier.
On 27 September 1946 test pilot Geoffrey DeHavilland Jr. is killed when his experimental DH-108 aircraft disintegrates at near-supersonic speed. Some witnesses report hearing a “loud explosion” attributed to a sonic boom. Theories suggest it is the acceleration of the DH-108 past the speed of sound that causes it to break apart, killing DeHavilland.
Several reports of supersonic flight surface during and after WWII. A classified German document suggests a Messerschmitt Me 163-V4 Komet rocket plane, flown by research pilot Heini Dittmar, reaches 623.8 mph on 2 October 1941. Republic Aircraft claims their P-47 Thunderbolt propeller aircraft broke the sound barrier twice during dives in testing during 1942. But these commercial claims are not verified and are likely propaganda designed to bolster the war effort.
There are several theories why a manned aircraft cannot pierce the sound barrier. Certainly a projectile can be accelerated beyond the sound barrier, a rifle bullet does it. But a rifle bullet is solid metal. A manned aircraft is structurally different. At the moment it matches the speed of its own sound something catastrophic will happen. Shock waves will accumulate and crush the hollow fuselage. The barrier of sound will require so much energy to pierce that a manned aircraft, and its pilot, are too fragile to survive the passage. Its hollow fuselage will implode, wings rip off. It’s pilot eviscerated.
A bullet can pass through the sound barrier, but a bullet isn’t under the control of a human pilot.
10:00 Local, 14 October 1947. Air Force Flight Test Center, Muroc Army Air Field (Now Edwards AFB), Muroc (now Rogers) Dry Lake Bed, Kern County, California.
An orange rifle bullet of an airplane is slung beneath the black painted belly of a B-29 bomber. The aircraft has no protruding canopy. Its sturdy, straight wings are at odds with its sleek, bullet shape. Painted in a bright orange and wearing the words “Glamorous Glennis” on the right nose and “Bell Aircraft” on the left it looks entirely utilitarian, like a giant orange cannon shell with a flush, heavily reinforced window. But this flying projectile relies entirely on a pilot for control.
The B-29 is under the control of Major Bob Cardenas and flight engineer Jack Ridley. The big bomber, now launch aircraft, chugs to life and lumbers onto the runway for a long take-off roll, heavy and pregnant with the orange X-1 stuffed partially into its belly.
It is believed that the shape of the Bell X-1, similar in width, taper and length to a .50 caliber bullet, is capable of accelerating beyond the sound barrier and flying faster than sound itself.
The big question, at least for anyone not directly in the program, is the man inside the bullet, Captain Charles E. “Chuck” Yeager.
Chuck Yeager’s journey to this moment began years ago. No other man shares his history, character and above all, courage. WWII dominated the previous decade. It was an age of heroes, epic figures like Audie Murphy, George Patton, and Franklin Roosevelt. The country is used to heroes and patriots, but Yeager’s story starts sooner and grows bigger.
Raised in a rural setting by a determined, working class family Yeager is a tough, resourceful boy. He learns to hunt and becomes an expert marksman. He is comfortable in the outdoors. Even as a boy he is naturally smart and unusually tough. He joins the Army Air Corps after graduating from high school in 1941. He is initially a crew chief in charge of aircraft maintenance on a Beech AT-11 trainer. On his first flight he becomes airsick, but in 1942, determined to fly, he is enrolled in flight school. Following flight school he is assigned to a P-39 Airacobra unit. He experiences his first accident when his Airacobra’s supercharger explodes and Yeager bails out of the aircraft, hitting the tail during his egress. His parachute is deployed and he lives. Barely.
Yeager recovers and is assigned to fly the P-51 Mustang in an active combat unit, the 357th Fighter Group, in Leiston, England. On 4 March 1944 he scores his first aerial victory, shooting down a German Me-109.
The next day, on 5 March, his fortune changes.
At 18,000 feet above Bordeaux, France three Nazi Focke-Wulf Fw-190 fighters attack Yeager’s P-51. Yeager maneuvers expertly in his P-51, trying to convert the tactical situation after being ambushed in flight, but the Germans have the advantage of opening the engagement along with numerical superiority. Chuck Yeager is shot down. He parachutes to the ground with wounds in his feet, hands and lower leg. He is near the town of Angouleme, the target of the day’s airstrike.
Yeager is found by the by the French Resistance. He actually assists the partisans fighting the Nazis by making improvised explosive devices they use against the Germans. The French underground unite him with other downed pilots and an epic escape and evasion plan is started over the brutally steep Pyrenees Mountains south to Spain.
On March 30, 1944 Yeager’s ordeal as a downed pilot ends when he is recovered in Spain by a member of the U.S. Consul. He crossed the Pyrenees on foot carrying a wounded fellow airman and performed an emergency surgery on him in the alpine wilderness, saving his life.
Had Yeager’s story ended here it would have been legendary. But the story of Chuck Yeager and a new frontier of flight is just beginning.
When Yeager got back to his squadron in mid-May 1944 he only wants one thing: to fly in combat again. It takes permission from General Dwight D. Eisenhower to return Yeager to active combat flight status. It turns out to be a good decision.
On 12 October 1944 Yeager writes one of the most remarkable pages in the history of aerial combat. He shoots down five German airplanes in one day, including two without firing a shot. His experience with being attacked by the German Fw-190’s serves him well. Only this time, Yeager, whose name means “hunter” in German, is the hunter.
Yeager finds a flight of Messerschmitts and attacks. He forces two of the aircraft into violent evasive maneuvers that cause them to collide right in front of him. He presses the attack on the remaining three German fighters, shooting down all three. He destroys five enemy aircraft in minutes.
A month later Yeager becomes one of the first men to shoot down an enemy jet in combat, downing a German Me-262 and then damaging two more Me-262 jet fighters before they can use their superior speed to escape.
Incredibly, Yeager is not done. He downs four more German fighters on 27 November. His total number of aerial victories, including five in one day and one of the first enemy jets ever, is 11. He is more than a double ace.
This is the legacy of the man sitting in the orange bullet plane. He brings this airmanship and courage to the threshold of the impenetrable sound barrier. He has prevailed against mortal men in combat numerous times. Today he flies in a daring death duel with a bigger adversary, the laws of physics.
10:44 Local, 14 October 1947. Bell X-1 cockpit attached to B-29 Launch Aircraft. 20,000 feet above Air Force Flight Test Center, Muroc Army Air Force Base, Muroc Dry Lake Bed, Kern County, California.
It is freezing and dark. Chuck Yeager is wearing only light coveralls and a leather flight jacket inside the cockpit of the Bell X-1 housed in the dark belly of the lumbering B-29. Behind him is a massive 300-gallon tank of freezing liquid oxygen.
His torso throbs from a horseback riding accident two days ago that broke two ribs. The injury is so bad he has to use a sawed-off broom handle for leverage to lock the cockpit door closed before takeoff. Yeager says nothing about the injury except to close friend Jack Ridley, who helped Yeager into the cockpit today. Fearing his injury may remove him from flight status, Yeager went to a veterinarian instead of a regular doctor to have the broken ribs taped.
The checklists are done. It is Yeager’s 9th rocket powered flight and the 50th flight for the Bell X-1.
Today they will try to break through the sound barrier for the first time in human history.
Lieutenant Bob Hoover takes up the chase/observation position in a Lockheed F-80 Shooting Star in formation with the B-29/X-1 pair.
Air traffic control at Muroc Tower orders all aircraft on the ground awaiting take-off to remain in place and directs any aircraft in flight approaching the area to leave immediately.
Yeager is using special stabilizer presets today in hopes of having better control during the transonic phase of the flight. This adjustment will mean the difference between life and death to Chuck Yeager.
15 seconds to drop.
Chuck Yeager radios, “Let’s get it over with”. Major Bob Cardenas pushes the control yoke of the B-29 Superfortress down and the bomber begins to accelerate in a shallow dive. Cardenas counts down.
“10, 9, 8, 7, 6, 5,… 3, 2, 1!” He skips the number 4 in his countdown for some reason.
The mechanical yoke holding the X-1 inside the B-29 releases and Yeager’s X-1 falls clear of the B-29.
The flight immediately goes bad.
Drop speed is supposed to be precisely 260 MPH. Yeager is dropped at only 240 MPH. Heavily laden with fuel and without enough air flow over its thin wings the X-1 begins to buffet and stall. It will fall from the sky, out of control.
Yeager has developed such a degree of intuitive airmanship over the years that his reaction is instinctive. Any normal pilot may pull back to raise the nose of the aircraft to a more stable flight attitude. This would be fatal. Yeager has better reflexes. He smoothly moves the X-1’s control yoke forward, enlisting gravity as an ally of thrust and aerodynamics to accelerate the X-1.
The aircraft falls, gains its correct flying speed, and becomes smooth and controlled.
Yeager fires the four rockets that power the Bell X-1. It feels like a traffic accident, the aircraft blasted forward with violent acceleration. He climbs to 36,000 feet.
Yeager retards the throttle to conserve rocket fuel. He is flying on two of the four rockets as he continues to climb to 40,000 feet where the speed run will be made.
40,000 AGL (Above Ground Level), Yeager reignites the two rockets advancing to full power. The flight is relatively smooth with little buffeting. The elevator trim settings are working and the aircraft has good control authority.
42,000 feet, Mach .96.
There is a movement in the aircraft’s Mach meter that appears to be a malfunction at first, a brief jump of the needle above Mach 1.
The Bell X-1 continues to fly smoothly. Chuck Yeager has piloted the aircraft through the sound barrier smoothly and without incident. Unlike later Hollywood depictions of violent vibration and buffeting in the cockpit, man’s first trip through the sound barrier is smooth and controlled under the experienced hands of perhaps the greatest pilot who ever lived.
On the ground there are two sonic booms. But the X-1 remains intact under the control of Chuck Yeager.
The sound barrier is broken. Man can fly faster than the speed of sound. Our concept of physics, flight and human boundaries is changed forever.
There is one brief, significant buffet during his deceleration from Mach 1, as though physics is providing one last protest like a dejected child who just lost a game.
Yeager brings the aircraft back to lower altitude, performing a series of victory rolls in the X-1. The rest of his flight profile is controlled and normal. He glides to a landing after all his rocket fuel is burned out.
Chuck Yeager and the Bell X-1 have done it, they broke the sound barrier.
Several news stories are leaked before the program is transitioned to “classified” status. Aviation is entering a new era of competitiveness with adversaries that are advancing at a similar rate. National secrets must be protected.
In the years that follow the door kicked open by Chuck Yeager gives way to a new threshold for man. Manned flight goes well beyond the sound barrier and begins to enter space, then the moon. Yeager’s victory over our perception of limitations sets the new paradigm for challenging the known and exploring the unknown. He is an explorer and adventurer on the order of Ferdinand Magellan, Christopher Columbus, Sir Edmund Hillary, Roald Amundsen and later Jacques Piccard and Don Walsh in their deep submersible Trieste along with the Gemini and Apollo astronauts.
It can be argued that a fear of failure and deceleration of human ambition have not produced men like Chuck Yeager in the past few decades. That humanity has turned its ambitions to earthly and commercial goals, and that heroes are somehow less grand, less bold, less sweeping in their achievements and scope. If this is the case the celebration of Chuck Yeager and the few men like him is an essential part of our future, and a re-ignition of our greatest dreams.
Chuck Yeager’s career as a pilot was far from over. Having been awarded the prestigious MacKay and Collier trophies for his Mach-busting flight the year before Yeager continued as a test pilot. He flew captured Russian MiGs and was a chase pilot for the first woman to break the sound barrier. In 1953 his luck nearly came to end when, in another record setting Mach 2.4 flight, Yeager’s aircraft tumbled out of control from a newly discovered phenomenon called “inertia coupling”. The Bell X-1A he was flying dropped nine miles completely out of control, over 50,000 feet. But once the aircraft had fallen into thicker air Yeager once again called upon his superior airmanship to recover from the spin, right the aircraft and land normally.
Yeager’s career continued as he transitioned back to a fighter pilot and unit commander flying the F-86 Sabre and later the F-100 Super Sabre. His flight testing/record setting career ended following an accident in an F-104 Starfighter, a particularly unforgiving aircraft. His combat career, however, was far from over. Yeager flew a remarkable 127 combat missions over Vietnam in the sleek, British designed B-57 Canberra twin engine light bomber. In 1968 Yeager transferred back to fighters, flying the F-4 Phantom II for the 4th Tactical Fighter Wing at Seymour-Johnson AFB in North Carolina.
Yeager left the Air Force as a Brigadier General, a remarkable achievement for a man who never graduated from college. Although retired in 1975 Yeager flew USAF aircraft as recently as 2012, when he commemorated his first Mach-busting flight by piloting a modern F-15 Eagle multi-role combat aircraft to greater than Mach 1, likely becoming the oldest pilot to break the sound barrier in a modern combat aircraft.
Chuck Yeager is still alive and, all of us at ALERT 5, hope he somehow finds his way to read this, one of many thousands of tributes to his incredible airmanship and phenomenal life.