THE 456th FIGHTER INTERCEPTOR SQUADRON

THE PROTECTORS OF  S. A. C.

 

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The Second Generation X-1

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Later variants of the X-1 were built to test different aspects of supersonic flight; one of these, the X-1A, with Yeager at the controls, inadvertently demonstrated a very dangerous characteristic of fast (Mach 2-plus) supersonic flight: inertia coupling. Only Yeager's skills as an aviator prevented him from dying that day; later Mel Apt would die testing the Bell X-2 under similar circumstances.

The second generation X-1s where designed to double the speed of sound and set altitude records in excess of 90,000 ft. The only productive models where the X-1A and X-1B. The X-1C, which was designed to test high speed flight armaments, was cancelled before completion. The X-1D was destroyed during what was to be its first powered flight.

Possibly the most famous flight of the second generation X-1 series occurred on December 12, 1954 with Chuck Yeager piloting the X-1A. While flying at mach 2.4 and 75,000 ft., the craft developed a slight left roll. When attempting to correct the roll the plane snapped to the right and control was lost. The plane now began a violent tumble toward the earth. Fortunately, Yeager was able to cut the engines, but he was also rendered unconscious from being tossed about in the cockpit. The plane continued out of control until Yeager mercifully recovered from his unconscious and managed to regain control at approximately 25,000 ft.

The X-1A was later jettisoned and destroyed following an in-flight explosion. The only existing example of the second generation X-1s, the X-1B is on permanent display at the USAF museum.

 

 

The X-1A

Even while the original X-1s were still flying, modified versions were being developed to study high-speed aerodynamics. Three second-generation aircraft were built: the X-1A, X-1B and X-1D. The X-1A, X-1B, and the X-1D were growth versions of the X-1. They were almost five feet longer, had an improved rocket propellant system and conventional canopies. The X-1A and X-1B were modified to have ejection seats. Their mission was to continue the X-1 studies at higher speeds and altitudes. All three of the Bell Aircraft Company manufactured planes had a 6,000-lb thrust, XLR-11 four-chambered rocket engine. The XLR-11 was built by Reaction Motors Inc. The aircraft were all air-launched from a carrier aircraft.

The X-1A was larger than its predecessor in order to carry more fuel, carried reliable turbo pumps, and had better cockpit visibility. This aircraft attained a speed of Mach 2.44 and an altitude of 90,440 feet. The X-1A was the first to begin this research after the X-1D was destroyed in an explosion on a captive flight before making any research flights. On December 12, 1953, Maj. Chuck Yeager piloted the X-1A rocket plane to a speed of Mach 2.44 (1,650 mph) in level flight at an altitude of approximately 76,000 feet. As he attained top speed, however, the X-1A tumbled violently out of control. He was encountering something new--something aerodynamicists called "inertia coupling." The airplane tumbled violently--about all three axes--for more than 40,000 feet before Yeager was able to begin to recover to wings-level, stable flight. When landed safely on Rogers Dry Lake he was, once again, the "fastest human alive" but it was quite apparent that there were still many mysteries to be solved concerning supersonic flight. Nine months later, on August 26, 1954, Maj. Arthur "Kit" Murray flew the same aircraft to a new altitude record of 90,440 feet. Those two performances were the records for the X-1 program. On July 20, 1955, the X-1A was lost just before its first NACA test flight when it had to be jettisoned from the launch aircraft following an onboard explosion.

 

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Bell X-1A in the belly of the B-29 mothership

Ordered by the Air Force on 2 April 1948, the X-1A (serial 48-1384) was intended to investigate aerodynamic phenomena at speeds above Mach 2 (681 m/s, 2,451 km/h) and altitudes greater than 90,000 feet (27 km), specifically focusing on dynamic stability and air loads. Longer and heavier than the original X-1 with a bubble GODBOBgcanopy for better vision, the X-1A was powered by the same Reaction Motors XLR-11 rocket engine. The aircraft first flew, unpowered, on 14 February 1953 at Edwards AFB, with the first powered flight on 21 February. Both flights were piloted by Bell test pilot Jean Ziegler. The aircraft was transferred to NACA in September 1954. Following modifications, including the installation of an ejection seat, the aircraft was lost on 8 August 1955 while being prepared for launch from the RB-50 mothership

 

Chuck Yeager's Wild Ride In The X-1A

 

The Bell X-1A was the first aircraft of the second generation of the X-1 variants. Longer and heavier than the original X-1 with a bubble canopy for better vision, the X-1A was powered by the same Reaction Motors XLR-11 rocket engine.

The main difference though, was in the fuel system. It had larger fuel tanks and a turbo-driven fuel pump to enable the X-1A to operate under power for much longer than the original X-1, which enabled it to fly higher farther and faster than the original X-1.

When Bell's company test pilot Jean "Skip" Ziegler flew it, Chuck flew as a chase pilot on these flights. But Ziegler got "spooked" by the aircrafts handling. When he looked out of the canopy at the wings, he saw shockwaves forming and told Yeager that his "aileron's were buzzing like mad", Yeager told him to "Press On and it will smooth on out for you" and continue with the flight, as this was an identical trait of the original X-1. Ziegler didn't "Press On" and the same thing happened on his next two flights.

Thinking that the airplane was unstable, he began to worry Bell's engineers with his concern. Bell's engineers decided to have the airplane returned to the plant at Buffalo for static ground testing.

Ziegler also went back to Buffalo and while he was there, he took part in a fueling test of the X-2, another Bell experimental rocket-powered research airplane. While flying with the X-2 mated to the B-50 motherplane, Skip was in the cockpit when the LOX (liquid oxygen) tank suddenly blew up at 20,000 feet. Ziegler and the X-2 were torn from the B-50 and fell the 20,000 feet to the bottom of Lake Ontario. Poor Ziegler had no chance. As Yeager says in his autobiography "same old story, another civilian test-pilot in over his head".

Bell asked the Air Force if they would take over the testing of the X-1A and requested that Yeager take over as test-pilot. General Boyd agreed and and brought back together Jack Ridley, Dick Frost & Jack Russell, Yeager's crew chief (the old X-1 team) to help.

Any pilot flying the original X-1 new that if they ever had to bail out they would end up both sides of the wing and had no chance of survival. The parachute they had served no other purpose than that something to sit on. The X-1A was another kettle of fish entirely. When the pilot was strapped in, the canopy was bolted down and the only way of survival was to land the airplane successfully!

Yeager flies the X-1A

Chuck Yeager first flew the X-1A on November 21st 1953, the flight was perfect and Yeager flew on out to Mach 1.3 at 45,000 feet. The airplane flew beatifully and exactly like the X-1 and Yeager felt right at home.

Two more flights on December 2nd and December 8th produced speeds of Mach 1.5 & Mach 1.9. Yeager had told his crew chief, Jack Russell, "Hey, you sumbitch, if I get a fire warning light, I'm gonna strap you in my lap on the next ride and let you deal with it." Russell and the rest of his ground crew knew Chuck's neck was on the line and kept the rocket chambers so clean that they were germ-free!

Fourth Powered Flight - December 12th 1953

Over the years Chuck Yeager was to set many speed and altitude records in the Bell X-1 and the Bell X-1A. In fact he still holds the world airspeed record for a straight winged aircraft of Mach 2.44 or 1648 mph.

This record was set on the 12th December 1953 in the X-1A. On this flight he was strapped into the cockpit of the X-1A which was shackled to the belly of the B-50 motherplane and dropped from high altitude over Edwards Air Force Base in southern California, he lit the Four Rocket Chambers and proceeded to climb to 76000 feet, nosing the airplane over he commenced with his speed run. When he reached his maximum speed of Mach 2.44 the aircraft suffered from roll coupling and he began a wild and violent tumble towards the desert floor.

Careening all over the sky, the airplane was snapping, rolling and spinning all at once, pilots call this "going divergent on three axis", Chuck called it hell.

The X-1A had no ejection seat, so to save himself he also had to save the aircaft. After spinning and tumbling for 51000 feet in 51 seconds, the ship flipped into a normal spin at 30,000 and Chuck thought "I know how to get out of this" and began standard spin recovery.

He broke the cockpit canopy with his head and it was only due to the superb skills of the pilot that he and the aircaft survived.

Managing to be humorous in his radio message to Jack Ridley, he said "I think I can get back to base okay, Jack. Boy, I'm not gonna do that again. Those (Bell) guys were so right (warning against going faster than Mach 2.3). If I hadda (ejection) seat you wouldn't still see me sitting in here".

 

Summing up

There were no more high speed attempts in the X-1A, the Air Force concentrating on high altitude flight, Major Arthur "Kit" Murray getting up to 90,400 feet. After Chuck's last flight in the X-1A, he and the Air Force decided that he should get out of the testing business before he became another statistic (and road) at Edwards Air Force Base.

On this subject, Chuck Yeager is the only living test-pilot to have a road named after him at Edwards AFB (Yeager Boulevard), all the other roads at the base are named after pilots who augured in.

 

 

The X-1B


 

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X-1B on display at the USAF Museum


The X-1B was one of a series of rocket-powered experimental research airplanes designed for investigation of various problems associated with supersonic flight. Specifically, the mission of the X-1B was flight research pertaining to aerodynamic heating and pilot reaction control systems. It made its first powered flight on Oct. 8, 1954.

On all test missions, the X-1B was carried to launching altitude, normally 25,000-35,000 feet, nestled under a “mother” airplane. It was then released in mid-air and rocket power was applied and, under full throttle, lasted less than five minutes. After all fuel (an alcohol-water mixture) and liquid oxygen had been consumed, the pilot glided the airplane to earth for a landing.

SPECIFICATIONS:
Span: 28 ft.
Length: 35 ft. 7 in.
Height: 10 ft. 8 in.
Weight: 16,590 lbs. loaded
Armament: None
Engine: Reaction Motors XLR-11-RM-6 four-chamber rocket engine of 6,000 lbs. thrust
Serial number: 48-1385

PERFORMANCE:
Maximum speed: 1,650 mph
Landing speed: 170 mph
Maximum altitude: 90,000 ft.

 

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The X-1B was virtually identical to the X-1A. It is shown here at the Langley Research Center in Virginia during instrumentation tests prior to shipment out to Edwards. There was also a very similar X-1D, but it only flew once, a glide flight with Skip Ziegler in late July, 1951. When Pete Everest tried to make the first powered flight about a month later, it blew up on him. Pete managed to climb out into the B-50 mothership before the crew jettisoned the X-1D over the Mojave. (There was no X-1C. This would have been similar to the X-1A, B, and D, only armed. The program was cancelled.)

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X-1B pilots included Jack McKay (NACA), Jack Ridley (USAF), Kit Murray (USAF), Bob Stephens (USAF), Stuart Childs (USAF), Horace Hanes (USAF), Richard Harer (USAF), J. Stanley Haltoner (USAF), Pete Everest (USAF), and future astronaut and first man on the Moon Neil Armstrong (NACA), who made the plane's last flight on Jan. 23, 1958. Armstrong's flights centered on testing reaction-control thrusters, which would later be crucial to X-15 and spacecraft control systems

 

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The panel of the X-1B. on the upper left of the panel are the switches to pressurize and vent the propellant tanks, and prime the fuel pumps and shut off the fuel and LOX. Just below these are the 4 CHAMBER switches to activate the XLR-11 chambers. On the right side of the upper panel are the INSTRUMENTATION switches for the flight-test equipment. The top row of guages, L-R: accellerometer (G-meter), Machmeter, altimeter, fuel outlet pressure, 2 chamber pressure guages, a small Hobbs-style meter showing cylinder seconds fuel remaining, and a small oxygen cylinder pressure guage. Middle row, L-R: airspeed (knots), artificial horizon, turn-and-bank, a plackard showing the radio call number of the X-1B (Air Force or NACA/NASA 81385) and the 250-kt airspeed limit on lowering the flaps, fuel tank and dome pressure, LOX tank and dome pressure, and a blinker for the oxygen flow. The smaller guages on the bottom row, L-R, are first stage dome pressure, first stage line pressure, turbine governor balance pressure, a clock, Angle-of-Attack, cabin pressure, a temperature guage (probably source temp), H2O2 tank pressure, and source pressure. The pedestal contains the rudder trim wheel, electrical switches, circuit breakers, and fire handle.

The X-1B's new reaction control thruster system required some special training to operate. There were none of today's sophisticated simulators. Instead, they built the Iron Cross-a set of metal beams on a gimball with thrusters at the ends of the beams. The beams were arranged in such a way that they accurately simulated the center of mass of the X-1B. An entire mission profile could be simulated on the Iron Cross, which was later used to train pilots for the X-15's RCS. This 1956 photo shows NACA pilot Stan Butchart at the controls of the device.

 

 

 

 

 

 

 

 

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X-1B on display at the USAF Museum

The Bell X-1B was a second-generation X-1 used by the U.S. Air Force for pilot familiarization before being turned over to NACA in December 1954. The X-1B was similar to the Bell X-1A except for the installation of wingtips extensions for its last three flight. The X-1B had a modified fuselage with greater capacity for fuel tanks, an improved cockpit, and a turbopump fuel system as compared with the X-1. The NACA used the X-1B primarily for aerodynamic heating and reaction-control research from 1956 to 1958. The aircraft was fitted with special instrumentation for exploratory aerodynamic heating tests. It had over 300 thermocouples installed on it. The X-1B was the first aircraft to fly with a reaction-control system; a prototype of the reaction-control system used on the X-15 and other piloted test aircraft. . Midway through its flight test program, the X-1B was equipped with an Reaction Motors, Inc. XLR-11-RM-9 engine which differed, from the other XLR-11s, only in having an electric spark, low-tension interrupter type ignition in place of the older high-tension type. The X-1B was given to the Air Force Museum at Wright-Patterson Air Force Base Dayton, Ohio, on January 27, 1959, for preservation and display. This aircraft completed a total of 27 glide and powered flights by eight U.S. Air Force and two NACA test pilots.

 

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The X-1B was equipped with aerodynamic heating instrumentation for thermal research (over 300 thermal probes were installed on its surface). It was similar to the X-1A except for having a slightly different wing. The X-1B was used for high speed research by the US Air Force starting from October 1954 prior to being turned over to the NACA in January 1955. NACA continued to fly the aircraft until January 1958 when cracks in the fuel tanks forced its grounding. The X-1B completed a total of 27 flights and achieved a maximum speed of Mach 2.44 (830 m/s, 2,989 km/h). A notable achievement was the installation of a system of small reaction rockets used for directional control, making the X-1B the first aircraft to fly with this sophisticated control system, later used in the     X-15. The X-1B is now on display at the National Museum of the United States Air Force, Wright-Patterson Air Force Base at Dayton, Ohio.

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X-1B

Mission: Designed to double the flight abilities of the original X-1, these planes were meant to fly at speeds exceeding Mach 2, with maximum altitudes above 90,000 ft. The X-C (not completed) was to be a test platform for USAF weapons. The X-D was to be used for high speed heat testing.
Major Accomplishments: Accomplishments were limited, due to the early destruction of the X-1D and the cancellation of the X-1C. The X-1A made a total of 15 glide and powered flights (14 for USAF and 1 for NACA). The X-1B, the most productive of the planes, made a total of 27 flights (glide and powered). The X-1A was instrumental in research into 'inertia coupling', the inability of aircraft to maintain stability at high speeds.
Power Source: One (1) Reaction Motors XLR-11-RM-5 (E6000-D4 rocket). 6,000 lbs thrust (2,722 kg) Fueled by ethyl alcohol/water mix and liquid oxygen.
Wing Span: 28' 0"

Length: 35' 8"

Weight (Loaded): 16,487 lb
Maximum Achieved Speed: Mach 2.44 (1,650 mph)
 Maximum Achieved Altitude: 90,000'

 

 

The X-1C

 

The X-1C was cancelled while still in the mock-up stage.

The X-1C was intended to test armaments and munitions in the high transonic and supersonic flight regimes. It was canceled while still in the mock-up stage, as the birth of transonic and supersonic-capable aircraft like the North American F-86 Sabre and the North American F-100 Super Sabre eliminated the need for a dedicated experimental test platform.

 

 

The X-1D

 

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The X-1D had short career, just one flight. On 24 July 1951, its nose gear failed during landing. The X-1D was destroyed in August 1951 after being jettisoned from its B-50 carrier plane, following an explosion.

Aircraft number #48-1386 was the first of the second generation of supersonic rocket planes. Flown from EB-50 Superfortress A, number #46-006, it was to be used for heat transfer research. the X-1D was equipped with a new low-pressure fuel system and a slightly increased fuel capacity. There was also some minor changes to the avionics set.

On 24 July, with Bell company test pilot Jean Ziegler at the controls, the X-1D was launched over Rogers Dry Lake on what was to become the only successful flight of its career. The unpowered glide was completed after a nine-minute descent, but upon landing, the nose gear failed and the aircraft slid ungracefully to a stop. Repairs took several weeks to complete and a second flight was scheduled for mid-August. The X-1D was lost in a fuel explosion during preparations for the first powered flight.

Aircraft number #48-1386 was the first of the second generation of supersonic rocket planes. Flown from EB-50 Superfortress A, number #46-006, it was to be used for heat transfer research. the X-1D was equipped with a new low-pressure fuel system and a slightly increased fuel capacity. There was also some minor changes to the avionics set.

On 24 July, with Bell company test pilot Jean Ziegler at the controls, the X-1D was launched over Rogers Dry Lake on what was to become the only successful flight of its career. The unpowered glide was completed after a nine-minute descent, but upon landing, the nose gear failed and the aircraft slid ungracefully to a stop. Repairs took several weeks to complete and a second flight was scheduled for mid-August. The X-1D was lost in a fuel explosion during preparations for the first powered flight.

 

The X-1D (48-1386), the first of the second generation of supersonic rocket planes produced by Bell Aircraft Corporation arrived at Edwards Air Force Base in July 1951,suspended from the bomb bay of a Boeing EB-50A (46-006). It was to be used for heat transfer research. The X-1D was equipped with a new low-pressure fuel system, a slightly increased fuel capacity, and minor changes in cockpit instrumentation.

On 24 July, with Bell company test pilot Jean Ziegler at the controls, the X-1D was launched over Rogers Dry Lake on what was to become the only successful flight of its career. The unpowered glide was completed after a nine-minute descent, but upon landing, the nose gear failed and the aircraft slid ungracefully to a stop. Repairs took several weeks to complete and a second flight was scheduled for mid-August.

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This mission, on 22 August 1951, at first seemed routine. The X-1D was carried aloft by the EB-50A. As the mated aircraft ascended through 7,000 feet, Lt. Col. Frank Everest entered the cockpit of the X-1D with the assistance of flight test engineer Jack Ridley. Everest noted that the nitrogen source pressure indicator was giving a very low reading. After discussing the problem with Bell engineers aboard the EB-50, the decision was made to abort the mission and jettison the X-1D's propellants.

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Shortly after Everest initiated the jettison process, an explosion rocked the aircraft's aft end. The chase pilot underneath the EB-50A saw flames and smoke. Everest hurriedly climbed from the X-1D's cockpit and moments later Ridley pulled the drop handle, releasing the shackles holding the X-1D in place. Less than a minute later, the research aircraft was a twisted pile of wreckage on the desert floor southwest of Rogers Dry Lake.

Initially a mystery, the cause of the accident was eventually attributed to Ulmer leather gaskets uniting chemically with liquid oxygen from the propellant system. When subjected to shock or vibration, the combination detonated causing the initial explosion.


 

The X-1E

 

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The X-1E, christened ‘Little Joe’ with Joe Walker.

The X-1E resulted from a significant reconstruction of the X-1-2 (s/n 46-063) in order to pursue the goals originally set out for the X-1D and X-1-3, both lost in explosions in 1951.

The changes included:

The X-1E first flew on 15 December 1955, a glide flight under the controls of USAF test-pilot Joe Walker. Walker left the X-1E program in 1958, after 21 flights, attaining a maximum speed of Mach 2.21 (752 m/s, 2,704 km/h).. NACA research pilot John B. McKay took his place in September 1958, completing five flights in pursuit of Mach 3 (1,021 m/s, 3,675 km/h). before the X-1E was permanently grounded following its 26th overall flight, in November 1958, due to the discovery of structural cracks in the fuel tank wall.

The Bell X-1E

 

Specification (Bell X-1)

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General characteristics

Performance

 

Specification (Bell X-1E)

General characteristics

Performance

 

 

 

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Last Updated

06/12/2009

 

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