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Knight’s Edge

Sixty-two years ago this week, USAF Major William F. “Pete” Knight made an emergency landing in X-15 No. 1 at Mud Lake, Nevada. Knight somehow managed to save the hypersonic aircraft following a complete loss of electrical power as the vehicle passed through 107,000 feet during the climb.

The famed X-15 Program conducted 199 flights between June 1959 and October 1968. North American Aviation (NAA) built three (3) X-15 aircraft. Twelve (12) men from NAA, USAF and NASA flew the X-15. Eight (8) pilots received astronaut wings for flying the X-15 beyond 250,000 feet. One (1) aircraft and one (1) pilot were lost during flight test.

The X-15 flew as fast as 4,520 mph (Mach 6.7) and as high as 354,200 feet. The basic airframe measured 50 feet in length, featured a wing span of 22 feet and had a gross weight of 33,000 pounds. The type’s Reaction Motors XLR-99 rocket engine burned anhydrous ammonia and liquid oxygen to produce a sea level thrust of 57,000 pounds. The X-15 used both 3-axis aerodynamic and ballistic flight controls.

An X-15 mission was fast-paced. Flight time from B-52 drop to unpowered landing was typically 10 to 12 minutes in duration. The pilot wore a full pressure suit and experienced 6 to 7 G’s during pull-out from max altitude. There really was no such thing as a routine X-15 mission. However, all X-15 missions had one factor in common; high danger.

On Thursday, 29 June 1967, X-15 No. 1 (S/N 56-6670) made its 73rd and the X-15 Program’s 184th free flight. Launch took place at 1828 UTC as the NASA B-52B launch aircraft (S/N 52-0008) flew at Mach 0.82 and 40,000 feet near Smith Ranch, Nevada. Knight, making his 10th X-15 flight, quickly ignited the XLR-99 and started the climb upstairs.

The X-15 was performing well and Knight was enjoying the flight until 67.6 seconds into a planned 87 second XLR-99 burn. That’s when the engine suddenly quit. A couple of heartbeats later, the Stability Augmentation System (SAS) failed, the Auxiliary Power Units (APU’s) ceased operating, the X-15’s generators stopped functioning and the cockpit lights went out. This was the total hit; a complete power failure.

Pete Knight was now just along for the ride. No thrust to power the aircraft. No electrical power to run onboard systems. No hydraulics to move flight controls. Even the reaction controls appeared inoperative. The X-15 continued upward, but it wallowed aimlessly in the low dynamic pressure of high altitude flight. At this point, Knight considered taking his chances and punching-out.

The X-15 went over the top at 173,000 feet. On the way downhill, Knight was able to get some electrical power from the emergency battery. This meant that he now had some hydraulic power and could utilize the X-15’s flight control surfaces. Knight next tried to fire-up the APU’s. The right APU would not respond. The left APU fired, but the its generator would not engage.

As the X-15 descended and the dynamic pressure built-up, Knight was able to maneuver his stricken X-15. He headed for Mud Lake in a sustained 6-G turn. As he leveled off at 45,000 feet, Knight instinctively knew he could now make the east shore of the Nevada dry lake. But it was tough work to fly the X-15. Knight ended-up using both hands to fly the airplane; one hand on the side stick and one hand on the center stick.

While Knight was trying to get his airplane down on the ground in one piece, only he and his Maker knew his whereabouts. The X-15 flight test team certainly didn’t, since Knight’s radio, telemetry and radar transponder were now inop. Further, the X-15 was not being skinned tracked at the time of the electrical anomaly. Just before he touched-down at Mud Lake, Knight’s X-15 was spotted by NASA’s Bill Dana who was flying a F-104N chase aircraft.

Pete Knight made a good landing at Mud Lake. The X-15 slid to a stop. After a struggle with the release mechanism, he managed to get the canopy open. Hot and soaked with perspiration, Knight somehow removed his own helmet. A ground crewman usually did that for him. But there were no flight support people at his X-15 landing site on this day.

As he attempted to get out of the X-15 cockpit, Knight pulled an emergency release. To his surprise, the headrest blew off, bounced off the canopy and smacked him square in the head. Undeterred, Knight got out of the cockpit and onto terra firma. In the meantime, a Lockheed C-130 Hercules had landed at Mud Lake. Wearily, Pete Knight got onboard and returned to Edwards Air Force Base.

Post-flight investigation revealed that the most probable source of the X-15’s electrical failure was arcing in a flight experiment system. This system had been connected to the X-15’s primary electrical bus. The solution was to connect flight experiments to the secondary electrical bus.

Reflecting on Knight’s amazing recovery from almost certain disaster, long-time NASA flight test manager Paul Bickle claimed the fete was among the most impressive of the X-15 Program. Indeed, it was Pete Knight’s clearly uncommon piloting skill and poise under pressure that gave him the edge.

Posted in Aerospace, History

Nike Hercules Deployment

Sixty-one years ago this month, the United States Army Nike Hercules air defense missile system was first deployed in the continental United States. The second-generation surface-to-air missile was designed to intercept and destroy hostile ballistic missiles.

The Nike Program was a United States Army project to develop a missile capable of defending high priority military assets and population centers from attack by Soviet strategic bombers. Named for the Greek goddess of victory, the Nike Program began in 1945. The industrial consortium of Bell Laboratories, Western Electric, Hercules and Douglas Aircraft developed, tested and fielded Nike for the Army.

Nike Ajax (MIM-3) was the first defensive missile system to attain operational status under the Nike Program. The two-stage, surface-launched interceptor initially entered service at Fort Meade, Maryland in December of 1953. A total of 240 Nike Ajax launch sites were eventually established throughout CONUS. The primary assets protected were metropolitan areas, long-range bomber bases, nuclear plants and ICBM sites.

Nike Ajax consisted of a solid-fueled first stage (59,000 lbs thrust) and a liquid-fueled second stage (2,600 lbs thrust). The launch vehicle measured nearly 34 feet in length and had a ignition weight of 2,460 lbs. The second stage was 21 feet long, had a maximum diameter of 12 inches and weighed 1,150 lbs fully loaded. The type’s maximum speed, altitude and range were 1,679 mph, 70,000 feet and 21.6 nautical miles, respectively.

The Nike Hercules (MIM-14) was the successor to the Nike Ajax. It featured all-solid propulsion and much higher thrust levels. The first stage was rated at 220,000 lbs of thrust while that of the second stage was 10,000 lbs. The Nike Hercules airframe was significantly larger than its predecessor. The launch vehicle measured 41 feet in length and weighed 10,700 lbs at ignition. Second stage length and ignition weight were 26.8 feet and 5,520 lbs, respectively.

Nike Hercules kinematic performance was quite impressive. The respective top speed, altitude and range were 3,000 mph, 150,000 feet and 76 nautical miles. This level of performance allowed the vehicle to be used for the ballistic missile intercept mission. Most Nike Hercules missiles carried a nuclear warhead with a yield of 20 kilotons.

The first operational Nike Hercules systems were deployed to the Chicago, Philadelphia and New York localities on Monday, 30 June 1958. By 1963, fully 134 Nike Hercules batteries were deployed throughout CONUS. These systems remained in the United States missile arsenal until 1974. The exceptions were batteries located in Alaska and Florida which remained in active service until the 1978-79 time period.

Like Nike Ajax before it, Nike Hercules had a successor. It was originally known as Nike Zeus and then Nike-X. This Nike variant was designed for intercepting enemy ICBM’s that were targeted for American soil. The vehicle went through a number of iterations before a final solution was achieved. Known as Spartan, this missile was what we would refer to today as a mid-course interceptor.

In companionship with a SPRINT terminal phase interceptor, Spartan formed the Safeguard Anti-Ballistic Missile System. The American missile defense system was impressive enough to the Soviet Union that the communist country signed the Anti-Ballistic Missile (ABM) Treaty 3 years before Safeguard’s deployment. Though operational for a mere 3 months, Safeguard was de-postured in 1975. This action brought to a close a 30-year period in which the Nike Program was a major player in American missile defense.

Posted in Aerospace, History

Crusader III First Flight

Sixty-one years ago this month, the USN/Vought XF8U-3 Crusader III interceptor prototype took off on its maiden test flight at Edwards Air Force Base, California. Vought chief test pilot John W. Konrad was at the controls of the advanced high performance aircraft.

The Vought XF8U-3 was designed to intercept and defeat adversary aircraft. Although it bore a close external resemblance to its F8U-1 and F8U-2 forbears, the XF8U-3 was much more than just a block improvement in the Crusader line. It was considerably bigger, faster, and more capable than previous Crusaders and was in reality a new airplane.

The XF8U-3 measured 58.67 feet in length and had a wing span of an inch less than 40 feet. Gross Take-Off and empty weights tipped the scales at 38,770 lbs and 21,860 lbs, respectively. Power was provided by a single Pratt and Whitney J75-P-5A generating 29,500 lbs of sea level thrust in afterburner.

A distinctive feature of the XF8U-3 was a pair of ventrally-mounted vertical tails. These surfaces were installed to improve aircraft directional stability at high Mach number. Retracted for take-off and landing, the surfaces were deployed once the aircraft was in flight.

The No. 1 XF8U-3 (S/N 146340) first flew on Monday, 02 June 1958 at Edwards Air Force, California. Vought chief test pilot John W. Konrad did the first flight piloting honors. The aircraft flew well with no major discrepancies reported. Approach and landing back at Edwards were uneventful.

Subsequent flight testing verified that the XF8U-3 was indeed a hot airplane. The type reached a top speed of Mach 2.39 and could have flown faster had its canopy had been designed for higher temperatures. The flight test-determined absolute altitude of 65 KFT was exceeded by 25 KFT in a zoom climb.

Those who flew the XF8U-3 said that the aircraft was a real thrill to fly. The Crusader III displayed outstanding acceleration, maneuverability and high-speed flight stability. Control harmony in pitch, yaw, and roll was extremely good as well.

Despite its great promise, the XF8U-3 never proceeded to production. This was primarily the result of coming up short in a head-to-head competition with the McDonnell F4H-1 Phantom II during the second half of 1958. While the Crusader was faster and more maneuverable than the Phantom, the latter’s mission capability and payload capacity were better.

Most historical records indicate that a total of five (5) Crusader III airframes were built. The serial numbers assigned by the Navy were 146340, 146341, 147085, 147086, and 147087. None of these aircraft exist today.

Posted in Aerospace, History

Final Flight: XB-70A Valkyrie, Ship 2

Fifty-three years ago today, XB-70A Valkyrie Air Vehicle No. 2 (62-0207) and a NASA F-104N Starfighter (N813NA) were destroyed following a midair collision near Bartsow, CA. USAF Major Carl S. Cross and NASA Chief Test Pilot Joseph A. Walker perished in the tragedy.

On Wednesday, 08 June 1966, XB-70A Valkyrie Air Vehicle No. 2 took-off from Edwards Air Force Base, California for the final time. The crew for this flight included aircraft commander and North American test pilot Alvin S. White and right-seater USAF Major Carl S. Cross. White would be making flight No. 67 in the XB-70A while Cross was making his first. For both men, this would be their final flight in the majestic Valkyrie.

In the past several months, Air Vehicle No. 2 had set speed (Mach 3.08) and altitude (74,000 feet) records for the type. But on this fateful day, the mission was a simple one; some minor flight research test points and a photo shoot.

The General Electric Company, manufacturer of the massive XB-70A’s YJ93-GE-3 turbojets, had received permission from Edwards USAF officials to photograph the XB-70A in close formation with a quartet of other aircraft powered by GE engines. The resulting photos were intended to be used for publicity.

The mishap formation, consisting of the XB-70A, a T-38A Talon (59-1601), an F-4B Phantom II (BuNo 150993), an F-104N Starfighter (N813NA), and an F-5A Freedom Fighter (59-4898), was in position at 25,000 feet by 0845. The photographers for this event, flying in a GE-powered Gates Learjet Citation (N175FS) stationed about 600 feet to the left and slightly aft of the formation, began taking photos.

The photo session was planned to last 30 minutes, but went 10 minutes longer to 0925. Then at 0926, just as the formation aircraft were starting to leave the scene, the frantic cry of Midair! Midair Midair! came over the communications network.

Somehow, the NASA F-104N, piloted by NASA Chief Test Pilot Joe Walker, had collided with the right wing-tip of the XB-70A. Walker’s out-of-control Starfighter then rolled inverted to the left and sheared-off the XB-70A’s twin vertical tails. The F-104N fuselage was severed just behind the cockpit and Walker died instantly in the terrifying process.

Curiously, the XB-70A continued on in steady, level flight for about 16 seconds despite the loss of its primary directional stability lifting surfaces. Then, as White attempted to control a roll transient, the XB-70A rapidly departed controlled flight.

As the doomed Valkyrie torturously pitched, yawed and rolled, its left wing structurally failed and fuel spewed furiously from its fuel tanks. White was somehow able to eject and survive. Cross never left the stricken aircraft and rode it down to impact just north of Barstow, California.

A mishap investigation followed and (as always) responsibility (blame) for the mishap was assigned and new procedures implemented. However, none of that changed the facts that on this, the Blackest Day at Edwards Air Force Base, American aviation lost two of its best men and aircraft in a flight mishap that was, in the final analysis, preventable.

Posted in Aerospace, Final Flight, History

First United States Spacewalk

Fifty-four years ago this month, Gemini Astronaut Edward H. White II became the first American to perform what in NASA parlance is referred to as an Extra Vehicular Activity (EVA). In everyday terms, it is referred to as a “spacewalk”.

White, Mission Commander James A. McDivitt and their Gemini spacecraft were launched into low Earth orbit by a two-stage Titan II launch vehicle from LC-19 at Cape Canaveral Air Force Station, Florida. The Gemini-Titan IV (GT-4) mission clock started at 15:15:59 UTC on Thursday, 03 June 1965.

On the third orbit, less than five hours after launch, White opened the Gemini IV starboard hatch. He stood in his seat and mounted a camera to capture his historic space stroll. He then cast-off from Gemini IV and became a human satellite.

White was tethered to Gemini IV via a 15-foot umbilical that provided oxygen and communications to his EVA suit. A gold-plated visor on his helmet protected his eyes from the searing glare of the sun. The spacewalking astronaut was also outfitted with a hand-held maneuvering unit that used compressed oxygen to power its small thrusters. And, like any good tourist, White also took along a camera to photograph the event.

Ed White had the time of his all-too-brief life in the 22 minutes that he walked in space. The sight of the earth, the spacecraft, the sun, the vastness of space, the freedom of movement all combined to make him excitedly exclaim at one point, “I feel like a million dollars!”.

Presently, it was time to get back into the spacecraft. But, couldn’t he just stay outside a little longer? NASA Mission Control and Commander McDivitt were firm. It was time to get back in; now! He grudgingly complied with the request/order, plaintively lamenting: “It’s the saddest moment of my life!”

As Ed White got back into his seat, he and McDivitt struggled to lock the starboard hatch. Both men were exhausted, but ebullient as they mused about the successful completion of America’s first space walk.

Gemini IV would eventually orbit the Earth 62 times before splashing-down in the Atlantic Ocean at 17:12:11 GMT on Sunday, 07 June 1965. The 4-day mission was another milestone in America’s quest for the moon.

The mission was over and yet Ed White was still a little tired. But then, that was really quite easy to understand. In the time that he was spacewalking outside the spacecraft, Gemini IV had traveled almost a third of the way around the Earth.

Posted in Aerospace, History