Forty-nine years ago this month, a USAF F-106A Delta Dart (S/N 58-0787) out of Malmstrom AFB, Montana made a wheels-up landing in a farmer’s field despite the fact that there was no pilot onboard. The pilot, Lieutenant Gary Foust, had ejected earlier when he was unable to recover the aircraft from a flat spin. This incident became known in popular culture as “The Cornfield Bomber”.
On Monday, 02 February 1970, a trio of pilots from the 71st Fighter Interceptor Squadron (FIS) took-off from Malmstrom AFB, Montana for the purpose of practicing air combat maneuvers. A fourth pilot had intended to be part of this group but was forced to abort the mission when his aircraft’s drag parachute strangely deployed on the ramp.
The pilots who took to the air that day were Major Thomas Curtis, Major James Lowe, and Faust. Each man was at the controls of a Convair F-106A Delta Dart; aka “The Ultimate Interceptor”. The three-ship formation departed Malmstrom for an area roughly 90 miles north of the base designated for the flying of air combat maneuvers and engagements.
The practice session began with a two-on-one head-on engagement. Approaching the other two aircraft at Mach 1.90 in full afterburner, Captain Curtis pulled his aircraft into the vertical. His intent was to induce the other pilots to follow him upstairs. They did so. In passing through 38,000 feet, he executed a vertical rolling scissors maneuver. However, Curtis had superior energy at the pull-up point. Thus, neither Lowe nor Foust could gain a tactical advantage in the fight. When Curtis executed a high-g rudder reversal, Foust attempted to stay with him. That’s when things deteriorated rapidly for Foust.
Foust flew his F-106A into an accelerated stall around 35,000 feet as he attempted to maintain position with Curtis. That is, his aircraft exceeded the stall angle-of-attack while simultaneously losing speed due to the motion-retarding effects of gravity and drag due to lift. The F-106A fell off into a series of post-stall gyrations followed by entry into a flat spin. The flat spin is a high angle-of-attack, deep stall condition from whence recovery was typically not possible in a Delta Dart.
Notwithstanding the futility of the task, Foust diligently applied anti-spin procedures in textbook fashion. However, the aircraft continued to fall in a flat spin. In desperation, Foust deployed his drag chute hoping that it would act as an anti-spin device. Unfortunately, the chute became totally useless for that purpose when it wrapped itself around the vertical tail of his falling steed. Running out of altitude and time, Foust had no other recourse but to abandon his airplane. He did so somewhere around 12,000 feet.
Foust was rocketed out of his Delta Dart and got a good chute. He landed in the Bear Paw Mountains, and fortunately was brought to safety by local citizens on snowmobiles. However, to the utter amazement of Foust, Curtis, and Lowe, the abandoned delta-winged aircraft snapped out of its flat spin and began to glide. Apparently, the equal and opposite reaction of the aircraft to the force produced by the rocket-powered ejection seat forced the nose of the airplane below the stall angle-of-attack. Thus, the wing began to produce lift again. Further, as part of his anti-spin procedures, Foust had configured the controls of the Delta Dart in take-off trim and brought the throttle to idle.
The net state of affairs now was that the F-106A became a pretty good glider. Gliding at about 175 knots, it ultimately made a wheels-up landing in a farmer’s snow-covered field near Big Sandy, Montana. The landing was aided by ground effect which enhanced the lift on the airplane as the vehicle neared the ground. Incredibly, the wings remained level throughout the landing slide-out. Further, late in the landing, the F-106A magically turned 20 degrees from its touchdown azimuth and avoided running into a pile of rockets directly in its path. In doing so, the airplane slipped through an opening in a fence around the farmer’s property and came to a stop.
When authorities approached the Delta Dart, they found that its canopy was gone, its ejection seat was gone, and so was its pilot. A look into the cockpit revealed that the radar scope was still sweeping for targets. And, although in idle, the still running turbojet produced a bit of thrust. Thus, periodically, the vehicle would lurch forward when the restraining snow around the it melted. Almost two hours later, the turbojet finally stopped running when the aircraft fuel supply ran out.
Remarkably, the pilotless Delta Dart sustained little damage despite the wheels-up landing. The aircraft was later trucked out of the area and sent to McClellan AFB in California for repairs. It ultimately was returned to service with the 71st FIS. Later, it entered the inventory of the 49th Fighter Interceptor Squadron at Grifffiss AFB, New York. Fittingly, a measure of closure was accorded (then) Major Gary Foust when he flew this same aircraft again in 1979. Today, USAF F-106A Delta Dart, S/N 58-0787 sits on display for posterity at the USAF National Museum at Wright-Patterson AFB in Dayton, Ohio.
Fifty-seven years ago today, Project Mercury Astronaut John Herschel Glenn, Jr. became the first American to orbit the Earth. Glenn’s spacecraft name and mission call sign was Friendship 7.
Mercury-Atlas 6 (MA-6) lifted-off from Cape Canaveral’s Launch Complex 14 at 14:47:39 UTC on Tuesday, 20 February 1962. It was the first time that the Atlas LV-3B booster was used for a manned spaceflight.
Three-hundred and twenty seconds after lift-off, Friendship 7 achieved an elliptical orbit measuring 143 nm (apogee) by 86 nm (perigee). Orbital inclination and period were 32.5 degrees and 88.5 minutes, respectively.
The most compelling moments in the United States’ first manned orbital mission centered around a sensor indication that Glenn’s heat shield and landing bag had become loose at the beginning of his second orbit. If true, Glenn would be incinerated during entry.
Concern for Glenn’s welfare persisted for the remainder of the flight and a decision was made to retain his retro package following completion of the retro-fire sequence. It was hoped that the 3 flimsy straps holding the retro package would also hold the heat shield in place.
During Glenn’s return to the atmosphere, both the spent retro package and its restraining straps melted in the searing heat of re-entry. Glenn saw chunks of flaming debris passing by his spacecraft window. At one point he radioed, “That’s a real fireball outside”.
Happily, the spacecraft’s heat shield held during entry and the landing bag deployed nominally. There had never really been a problem. The sensor indication was found to be false.
Friendship 7 splashed-down in the Atlantic Ocean at a point 432 nm east of Cape Canaveral at 19:43:02 UTC. John Glenn had orbited the Earth 3 times during a mission which lasted 4 hours, 55 minutes and 23 seconds. In short order, spacecraft and astronaut were successfully recovered aboard the USS Noa.
John Glenn became a national hero in the aftermath of his 3-orbit mission aboard Friendship 7. It seemed that just about every newspaper page in the days following his flight carried some sort of story about his historic feat. Indeed, it is difficult for those not around back in 1962 to fully comprehend the immensity of Glenn’s flight in terms of what it meant to the United States.
John Herschel Glenn, Jr. passed away on 08 December 2016 at the age of 95. His trusty Friendship 7 spacecraft is currently on display at the Smithsonian National Air and Space Museum in Washington, DC.
Sixty-four years ago this month, North American test pilot George F. Smith became the first man to survive a low altitude, high dynamic pressure ejection from an aircraft in supersonic flight. Smith ejected from his F-100A Super Sabre at 777 MPH (Mach 1.05) as the crippled aircraft passed through 6,500 feet in a near-vertical dive.
On the morning of Saturday, 26 February 1955, North American Aviation (NAA) test pilot George F. Smith stopped by the company’s plant at Los Angeles International Airport to submit some test reports. Returning to his car, he was abruptly hailed by the company dispatcher. A brand-new F-100A Super Sabre needed to be test flown prior to its delivery to the Air Force. Would Mr. Smith mind doing the honors?
Replying in the affirmative, Smith quickly donned a company flight suit over his street clothes, got the rest of his flight gear and pre-flighted the F-100A Super Sabre (S/N 53-1659). After strapping into the big jet, Smith went through the normal sequence of aircraft pre-launch flight control and system checks. While the control column did seem a bit stiff in pitch, Smith nonetheless decided that his aerial steed was ready for flight.
Smith executed a full afterburner take-off to the west. The fleet Super Sabre eagerly took to the air. Accelerating and climbing, the aircraft was almost supersonic as it passed through 35,000 feet. Peaking out around 37,000 feet, Smith sensed a heaviness in the flight control column. Something wasn’t quite right. The jet was decidedly nose heavy. Smith countered by pulling aft stick.
The Super Sabre did not respond at all to Smith’s control inputs. Instead, it continued an un-commanded dive. Shallow at first, the dive steepened even as the 215-lb pilot pulled back on the stick with all of his might. But all to no avail. The jet’s hydraulic system had failed. As the stricken aircraft now accelerated toward the ground, Smith rightly concluded that this was going to be a short ride.
George Smith knew that he had only one alternative now; Eject. However, he also knew that the chances were quite small that he would survive what was quickly shaping-up to be a quasi-supersonic ejection. Suddenly, over the radio, Smith heard another Super Sabre pilot flying in his vicinity frantically yell: “Bail out, George!” So exhorted, the test pilot complied.
Smith jettisoned his canopy. The roar from the airstream around him was unlike anything he had ever heard. Almost paralyzed with fear, Smith reflexively hunkered-down in the cockpit. The exact wrong thing to do. His head needed to be positioned up against the seat’s headrest and his feet placed within retraining stirrups prior to ejection. But there was no time for any of that now. Smith pulled the ejection seat trigger.
George Smith’s last recollection of his nightmare ride was that the Mach Meter read 1.05; 777 mph at the ejection altitude of 6,500 feet above the Pacific Ocean. These flight conditions corresponded to a dynamic pressure of 1,240 pounds per square foot. As he was fired out of the cockpit and into the harsh air stream, Smith’s body was subjected to an astounding drag force of around 8,000 lbs producing on the order of 40-g’s of deceleration.
Mercifully, Smith did not recall what came next. The ferocious wind blast stripped him of his helmet, oxygen mask, footwear, flight gloves, wrist watch and even his ring. Blood was forced into his head which became grotesquely swollen and his facial features unrecognizable. His eyelids fluttered and his eyes were tortuously mauled by the aerodynamic and inertial load of his ejection. Smith’s internal organs, most especially his liver, were severely damaged. His body was horribly bruised and beaten as it flailed end-over-over end uncontrollably.
Smith and his seat parted company as programmed followed by automatic deployment of his parachute. The opening forces were so high that a third of the parachute material was ripped away. Thankfully, the remaining portion held together and the unconscious Smith landed about 75 yards away from a fishing vessel positioned about a half-mile form shore. Providentially, the boat’s skipper was a former Navy rescue expert. Within a minute of hitting the water, Smith was rescued and brought onboard.
George Smith was hovering near death when he arrived at the hospital. In severe shock and with only a faint pulse, doctors quickly went to work. Smith awoke on his sixth day of hospitalization. He could hear, but he couldn’t see. His eyes had sustained multiple subconjunctival hemorrhages and the prevailing thought at the time was that he would never see again.
Happily, George Smith did recover almost fully from his supersonic ejection experience. He spent seven (7) months in the hospital and endured several operations. During that time, Smith’s weight dropped to 150 lbs. He was left with a permanently damaged liver to the extent that he could no longer drink alcohol. As for Smith’s vision, it returned to normal. However, his eyes were ever after somewhat glare-sensitive and slow to adapt to darkness.
Not only did George Smith return to good health, he also got back in the cockpit. First, he was cleared to fly low and slow prop-driven aircraft. Ultimately, he got back into jets, including the F-100A Super Sabre. Much was learned about how to markedly improve high speed ejection survivability in the aftermath of Smith’s supersonic nightmare. He in essence paid the price so that others would fare better in such circumstances as he endured.
It is possible that George Smith was not the first pilot to eject supersonically. USN LCdr Authur Ray Hawkins survived ejection from his stricken Grumman F9F-6 Cougar in 1953. Aircraft speed at ejection was never definitively determined, but was estimated to be between 688 (Mach 0.99) and 782 mph (Mach 1.16). In any event, the dynamic pressure and therefore the airloads associated with Hawkins ejection were less than half that of Smith’s punch-out.
George Smith was thirty-one (31) at the time of his F-100A mishap. He lived a happy and productive thirty-nine (39) more years after its occurrence. Smith passed from this earthly scene in 1994.
Forty-five years ago this month, the USAF/General Dynamics YF-16 Lightweight Fighter (LWF) took to the air on its official first flight with General Dynamics test pilot Phil Oestricher at the controls. The YF-16 would go on to win the high stakes Air Combat Fighter competition following a head-to-head fly-off against Northrop’s very capable YF-17 Cobra.
The YF-16 was General Dynamics entry into the USAF Lightweight Fighter Program of the 1970’s. Its basic design was based on USAF Colonel John Boyd’s Energy Maneuverability (EM) Theory which posited that an aircraft with superior energy capability would defeat an aircraft of lesser energy capability in air combat. To achieve such, EM Theory dictated a small, lightweight aircraft having a high thrust-to-weight ratio, which permitted maneuvering at minimum energy loss. The YF-16 was an embodiment of this requirement.
The official first flight of the YF-16 (S/N 72-1567) took place on Saturday, 02 February 1974 at Edwards Air Force Base, California. General Dynamics test pilot Phil Oestricher (pronounced Ol-Striker) did the piloting honors. The nimble aircraft performed very well and was a delight to fly. Oestricher landed uneventfully following a brief test hop that saw the YF-16 reach 400 mph and 30,000 feet.
Interestingly, the real first flight of the YF-16 inadvertently occurred on Sunday, 20 January 1974 during what was supposed to be a high-speed taxi test. As the aircraft accelerated rapidly down the runway, Oestricher raised the nose slightly and applied aileron control to check lateral response. To the pilot’s surprise, the aircraft entered a roll oscillation with amplitudes so high that the left wing and right stabilator alternately struck the surface of the runway.
As Oestricher desperately fought to maintain control of his wild steed, the situation became increasingly dire as the YF-16 began to veer to the left. Realizing that going into the weeds at high speed was a prescription for disaster, the test pilot quickly elected to jam the throttle forward and attempt to get the YF-16 into the air. The outcome of this decision was not immediately obvious as Oestricher continued to struggle for control while waiting for his airspeed to increase to the point that there was lift sufficient for flight.
When the YF-16 finally became airborne, it departed the runway on a heading roughly 45 degrees to the left of the centerline. Oestricher somehow maintained control of the aircraft during the rugged lift-off and early climbout phases of flight. The pilot then successfully executed a go-around, entry into final approach, and landing back on the departure runway. A tough way to earn a day’s pay by any standard!
History records that the YF-16 went on to win the Air Combat Fighter (ACF) competition with Northrop’s YF-17 Cobra. The production aircraft became known as the F-16 Fighting Falcon, of which more than 4,500 aircraft, in numerous variants, were built between 1976 and 2010. The now-famous aircraft has clearly fulfilled the measure of its creation as evidenced by its presence in the military inventory of more than 25 countries worldwide. Significantly, America’s Ambassadors in Blue, The United States Air Force Thunderbirds, have flown the F-16 in air demonstrations since 1983.
While its initial foray into the air did not necessarily lend confidence that such would be the case, the YF-16 did survive its flight test career. Aviation aficionados may view the actual aircraft at the Virginia Air and Space Center located in Hampton, Virginia.
Sixty-one years ago today, the United States successfully orbited the country’s first space satellite. Known as Explorer I, the artificial moon went on to discover the Van Allen Radiation Belts, the extensive system of charged particles trapped in the magnetosphere that surrounds the Earth.
The Explorer I satellite was designed and fabricated by the Jet Propulsion Laboratory (JPL) under the direction of Dr. William J. Pickering. The satellite’s instrumentation unit measured 37.25 inches in length, 6.5 inches in diameter, and had a mass of only 18.3 lbs. With its burned-out fourth stage solid rocket motor attached, the total on-orbit mass of the pencil-like satellite was 30.8 lbs.
Explorer I was launched aboard a Jupiter-C (aka Juno I) launch vehicle from LC-26 at Cape Canaveral, Florida on Friday, 31 January 1958. Lift-off at occurred at 22:48 EST (0348 UTC). With all four stages performing as planned, Explorer I was inserted into a highly elliptical orbit having an apogee of 1,385 nm and a perigee of 196 nm.
Arguably the most historic achievement of the Explorer I mission was the discovery of a system of charged particles or plasma within the magnetosphere of the Earth. These belts extend from an altitude of roughly 540 to 32,400 nm above mean sea level. Most of the plasma that forms these belts originates from the solar wind and cosmic rays. The radiation levels within the Van Allen Radiation Belts (named in honor of the University of Iowa’s Dr. James A. Van Allen) are such that spacecraft electronics and astronaut crews must be shielded from the adverse effects thereof.
Explorer I operational life was limited by on-board battery life and lasted a mere 111 days. However, it soldiered-on in orbit until reentering the Earth’s atmosphere over the Pacific Ocean on Tuesday, 31 March 1970. During the 147 months it spent in space, Explorer I orbited the Earth more than 58,000 times. Data obtained and transmitted by the satellite contributed markedly to mankind’s understanding of the Earth’s space environment.
Perhaps the greatest legacy of Explorer I was that it was the first satellite orbited by the United States. Unknown to most today, this accomplishment was absolutely vital to America’s security, and indeed that of the free world, at the time. The Soviet Union had been first in space with the orbiting of the much larger Sputnik I and II satellites in late 1957. However, Explorer I showed that America also had the capability to orbit a satellite. History records that this capability would quickly grow and ultimately lead to the country’s preeminence in space.
Fifty-eight years ago this month, NASA successfully conducted a critical flight test of the space agency’s Mercury-Redstone launch vehicle which helped clear the way for the United States’ first manned suborbital spaceflight. Riding the Mercury spacecraft into space and back was a diminutive 44-month old male chimpanzee by the name of HAM.
Project Mercury was America’s first manned spaceflight program. Simply stated, Mercury helped us learn how to fly astronauts in space and return them safely to earth. A total of six (6) manned missions were flown between May of 1961 and May of 1963. The first two (2) flights were suborbital shots while the final four (4) flights were full orbital missions. All were successful.
The Mercury spacecraft weighed about 3,000 lbs, measured 9.5-ft in length and had a base diameter of 6.5-ft. Though diminutive, the vehicle contained all the systems required for manned spaceflight. Primary systems included guidance, navigation and control, environmental control, communications, launch abort, retro package, heatshield, and recovery.
Mercury spacecraft launch vehicles included the Redstone and Atlas missiles. Both were originally developed as weapon systems and therefore had to be man-rated for the Mercury application. Redstone, an Intermediate Range Ballistic Missile (IRBM), was the booster for Mercury suborbital flights. Atlas, an Intercontinental Ballistic Missile (ICBM), was used for orbital missions.
Early Mercury-Redstone (MR) flight tests did not go particularly well. The subject missions, MR-1 and MR-1A, were engineering test and development flight tests flown with the intent of man-rating both the converted launch vehicle and new manned spacecraft.
MR-1 hardly flew at all in that its rocket motor shut down just after lift-off. After soaring to the lofty altitude of 4-inches, the vehicle miraculously settled back on the launch pad without toppling over and detonating its full load of propellants. MR-1A flew, but owing to higher-than-predicted acceleration, went much higher and farther than planned. Nonetheless, MR flight testing continued in earnest.
The objectives of MR-2 were to verify (1) that the fixes made to correct MR-1 and MR-1A deficiencies indeed worked and (2) proper operation of a bevy of untested systems as well. These systems included environmental control, attitude stabilization, retro-propulsion, voice communications, closed-loop abort sensing and landing shock attenuation. Moreover, MR-2 would carry a live biological payload (LBP).
A 44-month old male chimpanzee was selected as the LBP. He was named HAM in honor of the Holloman Aerospace Medical Center where the primate trained. HAM was taught to pull several levers in response to external stimuli. He received a banana pellet as a reward for responding properly and a mild electric shock as punishment for incorrect responses. HAM wore a light-weight flight suit and was enclosed within a special biopack during spaceflight.
On Tuesday, 31 January 1961, MR-2 lifted-off from Cape Canaveral’s LC-5 at 16:55 UTC. Within one minute of flight, it became obvious to Mission Control that the Redstone was again over-accelerating. Thus, HAM was going to see higher-than-planned loads at burnout and during reentry. Additionally, his trajectory would take him higher and farther downrange than planned. Nevertheless, HAM kept working at his lever-pulling tasks.
The Redstone burnout velocity was 5,867 mph rather than the expected 4,400 mph. This resulted in an apogee of 137 nm (100 nm planned) and a range of 367 nm (252 nm predicted). HAM endured 14.7 g’s during entry; well above the 12 g’s planned. Total flight duration was 16.5 minutes; several minutes longer than planned.
Chillingly, HAM’s Mercury spacecraft experienced a precipitous drop in cabin pressure from 5.5 psig to 1 psig just after burnout. High flight vibrations had caused the air inlet snorkel valve to open and dump cabin pressure. HAM was both unaware of and unaffected by this anomaly since he was busy pulling levers within the safety of his biopack.
HAM’s Mercury spacecraft splashed-down at 17:12 UTC about 52 nm from the nearest recovery ship. Within 30 minutes, a P2V search aircraft had spotted HAM’s spacecraft (now spaceboat) floating in an upright position. However, by the time rescue helicopters arrived, the Mercury spacecraft was found floating on its side and taking on sea water.
Apparently, a combination of impact damage to the spacecraft’s pressure bulkhead and the open air inlet snorkel valve resulted in HAM’s spacecraft taking on roughly 800 lbs of sea water. Further, heavy ocean wave action had really hammered HAM and the Mercury spacecraft. The latter having had its beryllium heatshield torn away and lost in the process.
Fortunately, one of the Navy rescue helicopters was able to retrieve the waterlogged spacecraft and deposit it safely on the deck of the USS Donner. In short order, HAM was extracted from the Mercury spacecraft. Despite the high stress of the day’s spaceflight and recovery, HAM looked pretty good. For his efforts, HAM received an apple and an orange-half.
While the MR-2 was judged to be a success, one more flight would eventually be flown to verify that the Redstone’s over-acceleration problem was fixed. That flight, MR-BD (Mercury-Redstone Booster Development) took place on Friday, 24 March 1961. Forty-two (42) days later USN Commander Alan Bartlett Shepard, Jr. became America’s first astronaut.
MR-2 was HAM’s first and only spaceflight experience. He quietly lived the next 17 years as a resident of the National Zoo in Washington, DC. His last 2 years were spent living at a North Carolina zoo. On Monday, 19 January 1983, HAM passed away at the age of 26. HAM is interred at the New Mexico Museum of Space History in Alamogordo, NM.
Sixty-six years ago this month, the USN/Douglas XF4D-1 Skyray fighter flew for the first time at Edwards Air Force Base in California. Douglas test pilot Robert O. Rahn was at the controls of the single-engine, carrier-based, supersonic-capable aircraft.
The Douglas XF4D-1 was the prototype version of the United States Navy’s F4D-1 Skyray. Designed to intercept adversary aircraft at 50,000 feet within 300 seconds of take-off, development of the Skyray began in the late 1940’s. As an aside, the Skyray nickname derived from the type’s large delta wing which gave it the appearance of a Manta ray.
The Skyray was originally designed to be powered by a Westinghouse XJ40-WE-6 turbojet capable of 7,000 lbs of sea level thrust. However, when significant developmental problems were encountered with that power plant, Douglas substituted an Allison J35-A-17 turbojet to support early flight testing of the XF4D-1. With a maximum sea level thrust of 5,000 lbs, the J35 rendered these early airframes significantly under-powered.
A pair of XF4D-1 Skyray airframes were built by Douglas. Ship No. 1 was assigned tail number BuAer 124586 while Ship No. 2 received the designation BuAer 124587.
On Tuesday, 23 January 1953, XF4D-1 Ship No. 1 (BuAer No 124586) departed Edwards Air Force Base on its first ride into the wild blue. Doing the piloting honors on this occasion was highly regarded Douglas test pilot Bob Rahn. The delta-winged beauty performed well on this maiden flight which concluded with Rahn making an uneventful landing back at Edwards.
Extensive flight testing of the Skyray, including carrier trials, continued through 1955. The Westinghouse XJ40-WE-8 appeared on the scene during this time. Rated at 11,600 lbs of sea level thrust in afterburner, this power plant allowed the Skyray to establish several speed records in California during October of 1953. Specifically, a speed of 752.944 mph was registered within a 3-kilometer course over the Salton Sea followed by 100-kilometer closed course mark of 728.11 mph at Edwards AFB.
Unfortunately, the XJ40 would prove to be very temperamental and unreliable. Inflight engine fires, explosions, and component failures constantly plagued the Skyray program. Westinghouse never did solve these problems to the satisfaction of the Navy. As a result, the service eventually opted to power production aircraft with the Pratt and Whitney J57-P-8 turbojet (10,200 lbs of sea level thrust).
The Douglas F4D-1 Skyray went on to serve with the United States Navy and Marines from 1956 through 1964. A total of 420 aircraft were produced. While never used in anger, the Skyray was a solid performer and served well in its intended role as a point design interceptor.
The Skyray holds the distinction of being the last fighter produced by the Douglas Aircraft Company before this legendary aerospace giant merged with McDonnell Aircraft to form McDonnell Douglas.
Fifty-five years ago today, a USAF/Boeing B-52H Stratofortress landed safely following structural failure of its vertical tail during an encounter with unusually severe clear air turbulence. The harrowing incident occurred as the aircraft was undergoing structural flight testing in the skies over East Spanish Peak, Colorado.
Turbulence is the unsteady, erratic motion of an atmospheric air mass. It is attributable to factors such as weather fronts, jet streams, thunder storms and mountain waves. Turbulence influences the motion of aircraft that are subjected to it. These effects range from slight, annoying disturbances to violent, uncontrollable motions which can structurally damage an aircraft.
Clear Air Turbulence (CAT) occurs in the absence of clouds. Its presence cannot be visually observed and is detectable only through the use of special sensing equipment. Hence, an aircraft can encounter CAT without warning. Interestingly, the majority of in-flight injuries to aircraft crew and passengers are due to CAT.
On Friday, 10 January 1964, USAF B-52H (S/N 61-023) took-off from Wichita, Kansas on a structural flight test mission. The all-Boeing air crew consisted of instructor pilot Charles Fisher, pilot Richard Curry, co-pilot Leo Coors, and navigator James Pittman. The aircraft was equipped with accelerometers and other sensors to record in-flight loads and stresses.
An 8-hour flight was scheduled on a route that from Wichita southwest to the Rocky Mountains and back. The mission called for 10-minutes runs of 280, 350 and 400 KCAS at 500-feet AGL using the low-level mode of the autopilot. The initial portion of the mission was nominal with only light turbulence encountered.
However, as the aircraft turned north near Wagon Mound, New Mexico and headed along a course parallel to the mountains, increasing turbulence and tail loads were encountered. The B-52H crew then elected to discontinue the low level portion of the flight. The aircraft was subsequently climbed to 14,300 feet AMSL preparatory to a run at 350 KCAS.
At approximately 345 KCAS, the Stratofortress and its crew experienced an extreme turbulence event that lasted roughly 9 seconds. In rapid sequence the aircraft pitched-up, yawed to the left, yawed back to the right and then rolled right. The flight crew desperately fought for control of their mighty behemoth. But the situation looked grim. The order was given to prepare to bailout.
Finally, the big bomber’s motion was arrested using 80% left wheel authority. However, rudder pedal displacement gave no response. Control inputs to the elevator produced very poor response as well. Directional stability was also greatly reduced. Nevertheless, the crew somehow kept the Stratofortress flying nose-first.
The B-52H crew informed Boeing Wichita of their plight. A team of Boeing engineering experts was quickly assembled to deal with the emergency. Meanwhile, a Boeing-bailed F-100C formed-up with the Stratofortress and announced to the crew that most of the aircraft’s vertical tail was missing! The stricken aircraft’s rear landing was then deployed to add back some directional stability.
With Boeing engineers on the ground working with the B-52H flight crew, additional measures were taken in an effort to get the Stratofortress safely back on the ground. These measures included a reduction in airspeed, controlling aircraft center-of-gravity via fuel transfer, judicious use of differential thrust, and selected application of speed brakes.
Due to high surface winds at Wichita, the B-52H was vectored to Eaker AFB in Blytheville, Arkansas. A USAF/Boeing KC-135 was dispatched to escort the still-flying B-52H to Eaker and to serve as an airborne control center as both aircraft proceeded to the base. Amazingly, after flying 6 hours sans a vertical tail, the Stratofortress and her crew landed safely.
Safe recovery of crew and aircraft brought additional benefits. There were lots of structural flight test data! It was found that at least one gust in the severe CAT encounter registered at nearly 100 mph. Not only were B-52 structural requirements revised as a result of this incident, but those of other existing and succeeding aircraft as well.
B-52H (61-023) was repaired and returned to the USAF inventory. It served long and well after its close brush with catastrophe in January 1964. The aircraft spent the latter part of its flying career as a member of the 2nd Bomb Wing at Barksdale AFB, Louisiana. The venerable bird was retired from active service in July of 2008.
Seventy years ago this week, the USAF/Bell XS-1 became the first aircraft of any type to achieve supersonic flight during a climb from a ground take-off. The daring feat took place at Muroc Air Force Base with USAF Captain Charles E. “Chuck” Yeager at the controls of the rocket-powered XS-1.
Rocket-powered X-aircraft such as the XS-1, X-1A, X-2 and X-15 were air-launched from a larger carrier aircraft. With the test aircraft as its payload, this “mothership” would take-off and climb to drop altitude using its own fuel load. This capability permitted the experimental aircraft to dedicate its entire propellant load to the flight research mission proper.
The USAF/Bell XS-1 was the first X-aircraft. It was carried to altitude by a USAF/Boeing B-29 mothership. XS-1 air-launch typically occurred at 220 mph and 22,000 feet. On Tuesday, 14 October 1947, the XS-1 first achieved supersonic flight. The XS-1 would ultimately fly as fast as Mach 1.45 and as high as 71,902 feet.
All but two (2) of the early X-aircraft were Air Force developments. The exceptions were products of the United States Navy flight research effort; the USN/Douglas D-558-I Skystreak and USN/Douglas D-558-II Skyrocket. The Skystreak was a turbojet-powered, straight-winged, transonic aircraft. The Skyrocket was supersonic-capable, swept-winged, and rocket-powered. Each aircraft was originally designed to be ground-launched.
In the best tradition of interservice rivalry, the Navy claimed that the D-558-I at the time was the only true supersonic airplane since it took to the air under its own power. Interestingly, the Skystreak was able fly beyond Mach 1 only in a steep dive. Nonetheless, the Air Force was indignant at the Navy’s insinuation that the XS-1 was somehow less of an X-aircraft because it was air-launched.
Motivated by the Navy’s affront to Air Force honor, the junior military service devised a scheme to ground-launch the XS-1 from Rogers Dry Lake at Muroc (now Edwards) Air Force Base. The aircraft would go supersonic in what was essentially a high performance take-off and climb. To boot, the feat was timed to occur just before the Navy was to fly its rocket-powered D-558-II Skyrocket. Justice would indeed be served!
XS-1 Ship No. 1 (S/N 46-062) was selected for the ground take-off mission. Captain Charles E. Yeager would pilot the sleek craft with Captain Jackie L. Ridley providing vital engineering support. Due to its somewhat fragile landing gear, the XS-1 propellant load was restricted to 50% of capacity. This provided approximately 100 seconds of rocket-powered flight.
On Wednesday, 05 January 1949, Yeager fired all four (4) barrels of his XLR-11 rocket motor. Behind 6,000 pounds of thrust, the XS-1 quickly accelerated along the smooth surface of the dry lake. After a take-off roll of only 1,500 feet and with the XS-1 at 200 mph, Yeager pulled back on the control yoke. The XS-1 virtually leapt into the desert air.
The aerodynamic loads were so high during gear retraction that the actuator rod broke and the wing flaps tore away. Unfazed, Yeager’s eager steed climbed rapidly. Eighty seconds after brake release, the XS-1 hit Mach 1.03 passing through 23,000 feet. Yeager then brought the XS-1 to a wings level flight attitude and shutdown his XLR-11 powerplant.
Following a brief glide back to the dry lake, Yeager executed a smooth dead-stick landing. Total flight time from lift-off to touchdown was on the order of 150 seconds. While a little worst for wear, the plucky XS-1 had performed like a champ and successfully accomplished something that it was really not designed to do.
Yeager was so excited during the take-off roll and high performance climb that he forgot to put his oxygen mask on! Potentially, that was a problem since the XS-1 cockpit was inerted with nitrogen. Fortunately, late in the climb, Yeager got his mask in place just before he went night-night for good.
Suffice it to say that the United States Navy was not particularly fond of the display of bravado and airmanship exhibited on that long-ago January day. The Air Force had emerged victorious in a classic contest of one-upmanship. Indeed, Air Force honor had been upheld. And, as was often the case in the formative years of the United States Air Force, it was a test pilot named Chuck Yeager who brought victory home to the blue suiters.
Sixty-five years ago this month, USAF Major Charles E. Yeager set an unofficial world speed record of 1,650 mph (Mach 2.44) in the Bell X-1A flight research aircraft. In the process, the legendary test pilot very nearly lost his life when the aircraft departed controlled flight shortly after rocket motor burnout.
The USAF/Bell X-1A was a second generation X-aircraft intended to explore flight beyond Mach 2. It measured 35.5 feet in length and had a wing span of 28 feet. Gross take-off weight was 16,500 pounds.
Like its XS-1 forebear, the X-1A was powered by an XLR-11 rocket motor which produced a maximum sea level thrust of 6,000 lbs. The XLR-11 burned 9,200 pounds of propellants (alcohol and liquid oxygen) in roughly 270 seconds of operation.
Departing Edwards Air Force Base, California on Saturday, 12 December 1953, Yeager and the X-1A (S/N 48-1384) were carried to altitude by a USAF B-29 mothership (S/N 45-21800 ). X-1A drop occurred at 240 knots and 30,500 feet. Within ten seconds, Yeager lit off three of the XLR-11’s four rocket chambers and started to climb upstairs.
Yeager fired the 4th chamber of the XLR-11 passing through 43,000 feet and initiated a pushover at 62,000 feet. The maneuver was completed at 76,000 feet; higher than planned. In level flight now and traveling at Mach 1.9, the X-1A continued to accelerate in the thin air of the stratosphere.
Yeager quickly exceeded Scott Crossfield’s briefly-held Mach 2.005 record set on Friday, 20 November 1953. However, he now had to be very careful. Wind tunnel testing had revealed that the X-1A would be neutrally stable in the directional channel as it approached Mach 2.3.
As Yeager cut the throttle around Mach 2.44, the X-1A started an uncommanded roll to the left. Yeager quickly countered with aileron and rudder. The X-1A then rapidly rolled right. Full aileron and opposite rudder failed to control the roll. After 8 to 10 complete revolutions, the aircraft ceased rolling, but was now inverted.
In an instant, the X-1A started rolling left and then went divergent in all three axes. The aircraft tumbled and gyrated through the sky. Control inputs had no effect. Yeager was in serious trouble. He could not control his aircraft and punching-out was not an option. The X-1A had no ejection seat.
Chuck Yeager took a tremendous physical and emotional beating for more than 70 seconds as the X-1A wildly tumbled. Normal acceleration varied between plus-8 and negative 1.3 G’s. His helmet hit the canopy and cracked it. He struck the control column so hard that it was physically bent. His frantic air-to-ground communications were distinctly those of a man who was convinced that he was about to die.
As the X-1A tumbled, it decelerated and lost altitude. At 33,000 feet, a battered and groggy Yeager found himself in an inverted spin. The aircraft suddenly fell into a normal spin from which Yeager recovered at 25,000 feet over the Tehachapi Mountains situated northwest of Edwards. Somehow, Yeager managed to get himself and the X-1A back home intact.
The culprit in Yeager’s wide ride was the then little-known phenomenon identified as roll inertial coupling. That is, inertial moments produced by gyroscopic and centripetal accelerations overwhelmed aerodynamic control moments and thus caused the aircraft to depart controlled flight. Roll rate was the critical mechanism since it coupled pitch and yaw motion.
The X-1A held the distinction of being the fastest-flying of the early X-aircraft until the Bell X-2 reached 1,900 mph (Mach 2.87) in July of 1956. Yeager’s harrowing experience in December 1953 would be his last flight at the controls of a rocket-powered X-aircraft. For his record-setting X-1A mission, Chuck Yeager was awarded the 1953 Harmon Trophy.
