In the southwestern part of the US state of California, in the Mojave Desert, there is the largest US Air Force Flight Test Center - Edwards Air Force Base. The base is named after the American military pilot Captain Glen Edwards. This pilot distinguished himself during the fighting in North Africa. Flying in a twin-engine Douglas A-20 Havoc bomber (known as Boston in the USSR), Glen Edwards, operating mainly at low altitudes, flew more than 50 sorties against German tank and transport convoys, bombed positions of German artillery, warehouses, bridges, and airfields. In 1943, this outstanding pilot was recalled to the United States, where he took part in tests of new aircraft models.
During World War II, the California Flight Test Center was known as Muroc Army Air Field. Here, the American military tested the latest aircraft, intended for adoption, as well as prototypes and experimental models. Having survived in a military meat grinder, Captain Glen Edwards died after the war; on June 5, 1948, he crashed in the crash of the prototype Northrop YB-49 jet bomber. In December 1949, in recognition of the merits of Captain Edwards, Murok AFB received his name.
The site where the Edwards airbase is now located was very well suited for the construction of a large airfield and target fields. The dried-up Rogers Lake, remote from large settlements, created an almost perfectly flat solid surface on which any type of aircraft could be landed without restrictions. The weather conditions in California, with a lot of sunny days a year, were the best match for aviation requirements in terms of flight safety. All this led to the fact that in the 30s of the last century, the federal authorities began to buy out land in this area. Initially, here, far from prying eyes, it was planned to test new types of aviation weapons - mainly large-caliber bombs. The first bombing of annular targets built on the surface of the lake took place in 1935. At the same time, not far from the Happy Lower Riding Club ranch, the construction of the first runway began. In 1937, a major aviation exercise took place here, during which the American high-ranking military officials appreciated all the advantages of this place. As the founder of the base, the commander of the 1st wing, Colonel Henry Arnold put it: "The surface of the dried lake is smooth as a billiard table, and if necessary, all available American aircraft can be placed here." In the 1930s and 1940s, huge sums of money at that time - $ 120 million were spent on the purchase of additional areas, the construction of capital structures, a concrete runway, target fields and the creation of laboratory testing infrastructure. Runway length 3600 m.
Shortly after the Japanese attack on Pearl Harbor in California, B-18 Bolo, A-29 Hudson and B-25 Mitchell bombers of the 41st Bomber Air Group moved from Davis Montana to Arizona. At the Murok airbase, several training detachments were created, where they trained pilots, navigators, bombers and technicians for the 4th bomber command. In mid-1943, the B-24 Liberator appeared at the airbase and the only courses in the country that graduate specialists in aerial photography were opened. At the same time, the first long-range P-38 Lightning fighters began to arrive in Murok for development by combat pilots. Usually the duration of training for navigators and pilots was 8-12 weeks. Prior to arriving in California, future pilots underwent flight training in light biplane at initial training schools.
After the start of work on the reactive theme, the Air Force command required a secluded test site to test new technology. The prototype of the first American jet fighter, Bell Aircraft P-59 Airacomet, arrived at the test station located on the outskirts of a dry salt lake on September 21, 1942, and the first flight took place within 8 days.
Jet P-59 Airacomet accompanied by P-63 Kingcobra
However, the P-59 did not live up to expectations. According to its flight data, the first American jet fighter had no particular advantages over aircraft with a propeller-driven group. As a result, the P-59 Airacomet built in a small series was used exclusively for training purposes.
The vicinity of Murok airbase became the site of tests of the first American cruise missile Northrop JB-1. The development of the projectile began after the British shared information about the German "flying bombs" V-1 ("Fieseler-103").
JB-1
For its characteristic appearance, the cruise missile received the nickname Bat. Unlike the German "V", the JB-1 had a large wing area and looked like a full-fledged manned aircraft. The first launch, which took place in December 1944, ended in failure. The unmanned aerial vehicle crashed, barely breaking away from the launch pad. It soon became clear that the design of the "bat" was not optimal, and the military lost interest in this model.
In 1944, in the vicinity of the base, construction began on two tracks with a length of 600 and 3000 meters for ground high-speed tests of jet technology and rescue equipment.
In 1959, a third track with a length of 6100 meters appeared, on which the UGM-27 Polaris SLBM engines were tested. At the moment, the rails of the tracks 300 and 6100 meters long have been dismantled, and the three-kilometer structure in the south-west of the base is abandoned.
After the end of the war, the airbase was transferred to the disposal of the Material and Technical Command. In 1945, a Lockheed P-80 Shooting Star jet fighter, as well as an experienced Consolidated Vultee XP-81 with a combined power plant, were tested at the airbase.
XP-81
The XP-81, designed as a long-range escort fighter, flew at cruise using a V-1650-7 Merlin piston engine, and launched a GE J33 turbojet engine during air combat. Although the experienced fighter developed a speed of 811 km / h during testing, more advanced jet engines were on the way, and it did not go into series.
In February 1946, the first prototype of the Republic F-84 Thunderjet fighter arrived at the airbase. Compared to the XP-81, this aircraft fully met the requirements of the military, and in 1947 it was put into service. Operation in combat units revealed problems with the engine and insufficient strength of the wing, which in turn required additional tests and the creation of new modifications. The main problems were solved in 1949 with the F-84D variant.
F-84B
After the advent of swept-wing fighters, which possessed higher speed and superior vertical maneuver, the Thunderjet was reclassified as a fighter-bomber. In this role, the F-84 went through the entire Korean War and was actively transferred to the NATO allies.
In parallel with testing prototypes of combat aircraft, aircraft intended for research purposes were tested at the air base. At the end of 1946, the Bell X-1 rocket plane was delivered to California.
Rocket plane X-1
The design of this apparatus with a liquid-propellant rocket engine operating on alcohol and liquid oxygen began in 1944 to study the problems of jet propulsion. To launch the X-1, an "air launch" was used, the apparatus rose into the air under the belly of a B-29 bomber specially adapted for this, and the jet engine was launched in the air.
Suspension X-1 for carrier aircraft
On October 14, 1947, Captain Chuck Yeager exceeded the speed of sound on the X-1 for the first time. Until the beginning of 1949, more than 70 sorties were carried out on the X-1. During the flights of the first modification, it was possible to achieve a speed of 1,500 km / h and an altitude of 21,000 meters. Later, on the basis of the X-1, more advanced versions were created, differing in the presence of means of rescuing the pilot, improved engines and improved aerodynamics, and the presence of thermal protection.
We must pay tribute to the courage of American test pilots who made extremely risky flights in aircraft that initially did not have ejection seats.
X-1A
Despite the fact that the design of the X-1 began in the mid-40s, the life cycle of these rocket planes turned out to be quite long. Flights of the X-1E modification continued until November 1958. Shortly before the cessation of operation due to the detection of cracks in the walls of the fuel tanks, a speed of 3675 km / h was reached. The data obtained during the experiments were used in the design of all American supersonic aircraft created in the 50-70 years. On the X-1 series vehicles, options for external suspension of weapons and thermal protection were also tested.
In 1948, the status of a flight test center was officially assigned to the Murok airbase. In many ways, this "untied the hands" of the Air Force command; by the beginning of the 50s, test and test squadrons engaged in programs for creating combat aircraft for tactical and strategic commands were concentrated here. In California, research aircraft, jet engines and ejection seats were also tested. Since the tests of rocket-planes with liquid-propellant rocket engines took on a wide scale, to test engines on the mountain plateau east of the dried lake in the early 50s, a control and test station was built, where special stands for real firing tests of jet engines still function.
The first prototype bomber intended for the Strategic Air Command undergoing trials at Murok was the Northrop YB-49. This aircraft, according to its "flying wing" scheme, repeated the piston YB-35, but had 8 Allison J35 turbojet engines. An aircraft with a maximum takeoff weight of 87969 kg and a wingspan of 52, 43 m could reach a maximum speed of 793 km / h. The combat radius with 4500 kg of bomb load was 2600 km.
YB-49 takes off
On June 5, 1948, one of three built YB-49s crashed in a plane crash, killing 5 crew members, including Captain Glen Edwards. Subsequently, due to control problems and unreliable operation of the engines, the serial construction of the bomber was abandoned.
Shortly after the renaming of Murok Air Force Base to Edwards, large-scale work began here to expand it and transform it into a central test air base for the United States Air Force. In April 1951, this was formalized when Edwards AFB was transferred to the Air Force Research and Development Command, after which the Air Force Flight Test Center and the Test Pilot School were formed.
United States Air Force Test Center Headquarters, Edwards AFB
In the first half of the 50s, the main focus of the flight test center was research in the field of jet propulsion, aimed at achieving the maximum values of speed and flight altitude, for which specially designed aircraft were used. On the Douglas D-558-2 Skyrocket 20 rocket plane, dropped from a B-29 bomber, on November 20, 1953, it was possible to double the speed of sound.
The moment of separation of D-558-2 from the carrier aircraft
Like the experimental X-1, the D-558-2 Skyrocket used a jet engine powered by alcohol and liquid oxygen. An additional Vestingauz J-34-40 turbojet engine was available to provide independent takeoff and cruise flight. On this aircraft, data were obtained on controllability at supersonic speeds and the influence of various suspensions (bombs and tanks) on the behavior of the aircraft was investigated.
Three years later, Captain Ivan Kinchelo on the Bell X-2 Starbuster, unhooking from the B-50 bomber, managed to reach a record height of 38,466 meters. In the future, this device was able to accelerate to a speed of 3370 km / h at an altitude of 19000 meters.
The moment of separation of the X-2 rocket plane from the V-50
The Kh-2 rocket plane became the first American manned aircraft, on which a special thermal protective coating of the new part was used to overcome the "thermal barrier", and the airframe was also made of heat-resistant steel. Particular attention was paid to the thermal insulation of the cab. So, the front glazing consisted of two panes. The glasses retained their strength up to a temperature of 540 ° C and absorbed infrared rays.
In the 50s, more than 40 types of jet aircraft passed through the test center at Edwards AFB. Including fighters adopted for service and being built in large series: F-86 Saber, F-100 Super Saber, F-101 Voodoo, F-102 Delta Dagger, F-104 Starfighter, F-105 Thunderchief and F-106 Delta Dart … The Strategic Air Command received B-52 Stratofortress and B-58 Hustler bombers, as well as KS-135 tankers. It was at the Edwards airbase that the U-2 high-altitude reconnaissance aircraft, the military transport C-130 Hercules and the C-133 Cargomaster were given a start in life. Some of the vehicles created in the 50s turned out to be surprisingly durable; strategic bombers B-52H, reconnaissance U-2S, "air tankers" KS-135 and the latest modifications of the extremely successful C-130 truck are still in service.
Satellite image of Google Earth: B-58, which made an emergency landing in the desert
Various aircraft have repeatedly made forced landings in the vicinity of the airbase. So, in the desert south-west of the main structures of the base, there are still B-47 Stratojet and B-58 Hustler bombers. Currently, these rather large and well-visible vehicles are used as navigational reference points.
In the late 50s, a program was launched in the United States, the goal of which was to overcome the Mach 4 speed and altitude of 100 km in manned flight. Especially for this, the next "rocket plane" X-15, launched according to the "air launch" scheme, was designed.
X-15
A more rocket-like manned experimental aircraft made its first flight on June 8, 1959. And later he set a number of records of altitude and flight speed, which have not been broken so far. On July 19, 1963, Joseph Walker reached an altitude of 105.9 km, and on October 3, 1967, William Knight accelerated the X-15 to a speed of 7273 km / h. Formally, the FAI determined that an altitude of 100 km is considered the boundary of the atmosphere. But since 1960, in the United States, near space was considered an altitude of more than 80 km and pilots who exceeded this boundary had the right to be considered astronauts. In total, the Kh-15 took off 199 times, while 13 flights were carried out at an altitude of more than 80 km, and the 100 km line was crossed twice. In fact, the X-15 was a spaceplane, astronauts Neil Armstrong and Joe Angle flew on it.
X-15 after dropping from the B-52
A specially modified B-52 bomber was used as a launch platform for the X-15. After separation from the carrier aircraft, the X-15 was accelerated using an XLR99 LPRE with a maximum thrust of 254 kN. A feature of this engine, where ammonia was used as fuel, and liquid oxygen was the oxidizer, was the ability to adjust the thrust and multiple starts. The resource of one engine was 20 starts.
Part of the airframe, made of heat-resistant nickel alloy, was covered with an ablation layer. The tail unit of the characteristic shape provided controllability at hypersonic speeds. Landing was carried out on special runners in the tail section, a landing gear with a wheel was produced in front. Before landing, the lower keel was dropped. Unlike the rocket gliders of the early models, the X-15 was equipped with an ejection seat, which theoretically ensured the rescue of the pilot at an altitude of 37 km. Naturally, during the flight, the pilot was in a sealed spacesuit. After ejection at high altitude, special steering surfaces came into play, providing stabilization and braking before opening the parachute system.
The rescue system installed on the Kh-15 has never been tested in practice. But this does not mean that rocket flights were safe. One of the three built X-15s during the 191st voyage collapsed in the air during the descent. The wreckage of the apparatus was scattered over an area of 130 km ², test pilot Michael Adams was killed. During the test flights of the X-series vehicles, many people died and suffered in numerous incidents. Loss of control, explosions and fires took place. So, on May 12, 1953, during the refueling of the X-2 in the air, when the rocket plane was still in the bomb bay of the carrier aircraft, an explosion occurred. The X-2 separated from the bomber instantly burned up in the air. Killed pilot Skip Ziegler and two crew members of the B-50, preparing the rocket plane for flight. Prior to that, two X-1s were lost in similar incidents. The second copy of the X-2 also crashed during the descent due to loss of control, the pilot Milburn Apt ejected, but due to high speed he could not use the main parachute. But the risk was justified, during the flights of rocket gliders, it was possible to collect valuable information about the behavior of aircraft at supersonic speeds and in airless space, to test life support systems that can function in space and to test the concept of controlled planning with inoperative engines. In 1958, after the creation of the National Aeronautics and Space Administration (NASA), the specialists of this agency took an active part in experiments with the X-15.
X-24B
NASA also tested with the Air Force: M2-F2, M2-F3, HL-10, X-24A and X-24B. All these devices were created for testing controlled gliding descent from a great height. The information gathered during the experiments was later used in the design of the Space Shuttle's reusable "space shuttle". Some of these experimental rocket gliders are currently installed at the Edwards Air Force Base Memorial.
HL-10 at Edwards Air Force Base Memorial
To test X-series rocket gliders and prototypes of the "space shuttle" on the surface of a dried salt lake, northeast of the main structures of the air base, a giant compass with a diameter of more than 1 km was depicted, and the markings of several runways were drawn. One of them with a length of 11, 92 km is the longest in the world.
Satellite image of Google Earth: Edwards airbase, view from a height of 13 km
It was on the surface of the salt lake in the late 70s that the prototype of the reusable spacecraft Enterprise (OV-101) landed. He never flew into space, but was only used to practice landing and transportation techniques.
After the first launch of the reusable spacecraft Columbia on April 12, 1981, the Shuttle landed on the surface of a dry salt lake in Arizona. This runway has long been viewed as a reserve runway in case the space shuttle fails to land in Florida due to weather conditions. The space shuttles landed on the runway northeast of the airbase 54 times, the last being Discovery, which landed on August 28, 2009.
To transport reusable space shuttles, specially modified Boeing-747 aircraft with attachments in the upper fuselage and a modified tail unit were used. A special stand was built at the base to load the Shuttle onto a transport aircraft.
Simultaneously with research programs in the interests of the space agency, bombers: B-52H Stratofortress and F-111 Aardvark, fighters: F-4 Phantom II, military transport: C-141 Starlifter and C-5 passed through the Air Force test center in the 60s Galaxy. The flights of the Lockheed YF-12A attracted general attention; it was on the basis of this machine that the SR-71 high-speed high-altitude reconnaissance aircraft was subsequently created. At Edwards AFB, almost all of the US Air Force combat aircraft, with the exception of the most secret ones, were tested. So, for testing the "stealthy" F-117, the technical personnel and pilots of the Air Force Test Center were sent away from prying eyes, to the remote Tonopah airbase in Nevada.
F-15A during the first flight
In the 70s, based on the experience of local conflicts in the Middle East and Southeast Asia, the United States began to create a new generation of combat aircraft. After a collision with Soviet MiGs, the US Air Force command revised its views on the tactics of air combat. Along with the possibility of supersonic interception, the new fighters were supposed to have high maneuverability and have cannon armament on board. The American response was the F-15 Eagle, a heavy twin-engine fighter with powerful radar and medium-range missiles. The niche of a light, more massive fighter was taken by the relatively inexpensive single-engine F-16 Fighting Falcon.
YF-16 and YF-17 in flight during comparative tests in 1974
Simultaneously with the prototype YF-16, its twin-engine competitor YF-17 was tested at Edwards AFB. In the future, this aircraft, losing to the F-16 in the Air Force, turned into a very successful carrier-based fighter F / A-18 Hornet.
The high vulnerability of American fighter-bombers from anti-aircraft fire and MANPADS during their direct air support to ground units in Vietnam revealed the need to create specialized attack aircraft. It became clear that along with the high-speed "air defense breakthroughs", acting against point-of-interest targets, low-speed, well-protected vehicles were needed. As a result, after a comprehensive cycle of tests, including those at Edwards AFB, the A-10 Thunderbolt II attack aircraft entered service in 1977.
A-10A
In the 70s, the main bombers of the B-52 Strategic Aviation Command became too vulnerable to the heavily fortified Soviet air defense system. Therefore, a bomber with an intercontinental range was required, capable of carrying the entire spectrum of nuclear and conventional aviation weapons and making supersonic throws. As part of this concept, Rockwell International has created the B-1 Lancer multi-mode strategic variable-wing bomber.
Prototype B-1A at Edwards AFB
The first copy of the B-1A arrived at Edwards AFB in December 1974. Due to the fact that numerous innovations that had not yet been tested before were implemented on the plane, the tests were very difficult. At the first stage, in each flight, there were failures or malfunctions in the operation of onboard systems, many complaints were caused by the complexity of ground maintenance. Compared to the well-mastered B-52 bomber, the new B-1A seemed overly complex and capricious. Nevertheless, on tests, the aircraft showed good flight data: a maximum speed of 2237 km / h and a ceiling of 18300 meters. The bomb bay held a 34-ton payload. But at the same time "Ulan" was very expensive in production and operation, and the government canceled the order. After the election of President Ronald Reagan, the B-1 program was revived. When designing the B-1B variant, the main emphasis was placed on overcoming air defense at low altitudes and equipping the aircraft with the most advanced electronic warfare defensive systems.
Satellite image of Google Earth: B-52H and B-1B bombers at Edwards airbase
Like the first version, the improved B-1B was also tested in California. Tests of the aircraft and its weapons lasted from 1980 to 1985, after which the bomber was put into service. However, not everything went smoothly. Initially, the aircraft was imposed numerous restrictions on the minimum altitude and flight speed. Over the years of operation, out of 100 built bombers, 10 crashed in accidents.
On October 4, 1984, the B-1B made an emergency landing on an unpaved runway designed for the Shuttles. Due to a hydraulic failure, the front landing gear did not come out. Due to the relatively soft surface of the dried-up lake, the aircraft did not receive critical damage and was subsequently rebuilt.
In the 80s, the personnel of the test center were mainly engaged in developing more advanced weapons, navigation and communication systems for the types of combat aircraft already adopted for service and testing new modifications. In December 1986, the F-15E Strike Eagle fighter-bomber entered trials. In the US Air Force, this aircraft was supposed to replace the multipurpose F-4 Phantom II. If it is possible to effectively work on ground targets, the F-15E has a fairly high potential for an air fighter. The aircraft entered service in April 1988, and since then has been actively used in various strike operations conducted by the Air Force of the United States, Israel and Saudi Arabia.
F-15E serial fighter-bomber
Also in Arizona, aircraft of the F-15 STOL / MTD modification (Short Takeoff and Landing / Maneuver Technology Demonstrator - Shortened takeoff and landing and demonstration of increased maneuverability) were tested. Due to the introduction of rotary flat nozzles and VGO, the roll angular velocity increased by 24%, and pitch - by 27%. The length of the takeoff run and the run has been significantly reduced. During the tests, the ability to land on a wet strip with a length of 985 meters was demonstrated (for the F-15C fighter, 2300 meters are required).
F-15 STOL / MTD
A further development of the F-15 STOL / MTD model was the F-15ACTIVE (Advanced Control Technologies for Integrated Vehicles, which literally translates as Advanced Control Technologies for Integrated Vehicles), with a new fly-by-wire control system that combined control of the PGO, engine and rotary nozzles … This modification of the Eagle demonstrated very good maneuverability, as the Pugacheva Cobra was repeatedly performed on the F-15ACTIVE. This modification of the fighter was not serially built, but a number of technical solutions worked out on it were used to create the 5th generation F-22A fighter.
A distinctive external feature of the F-15ACTIVE, converted from the F-15 STOL / MTD, is a very spectacular bright white-blue-red paint. In the second half of the 90s, F-15ACTIVE was acquired by NASA, and flew until 2009.
As part of the project to radically improve the flight performance of the F-16 Fighting Falcon, an experimental F-16XL aircraft with a deltoid wing with an area increased by 1, 2 times was created. That, together with the fuselage extended by 1, 42 meters, made it possible to increase the fuel supply in the internal tanks by 80% and carry the combat load on the wing assemblies twice as much. Composite materials were widely used in the new wing to save weight.
F-16XL
As conceived by the developers, this wing shape was designed to provide low drag at high subsonic or supersonic speeds without loss of maneuverability in the range of 600-900 km / h. Increasing the wing area and optimizing the airfoil curvature provided an increase in lift by 25% at supersonic speeds and 11% at subsonic speeds. When creating the F-16XL, it was also planned to achieve supersonic cruising speed at high altitude without afterburner, but this was never implemented.
For conversion into the F-16XL used single F-16A, which were in storage. Since the front part of one of the fighters was badly damaged in a flight accident, during the conversion, it was decided to replace it and make the plane a two-seater.
In March 1981, the United States Air Force announced a competition for a new, improved tactical fighter, and both F-16XLs took part. Due to the increased capacity of the fuel tanks, the F-16XL had a 40% longer flight range, and the delta wing made it possible to hang twice as many weapons as on the F-16A. The test program turned out to be very busy, in total, single and two-seater experimental fighters made 798 flights. According to General Dynamics engineers, their car had a good chance of winning, but the military ultimately preferred the F-15E. In the second half of 1988, both F-16XLs were transferred to NASA, where they were involved in experiments aimed at studying airflow around the wing at supersonic speeds.
Until 2012, the F-15ACTIVE and F-16XL aircraft were at the Ames Dryden Flight Research Center at Edwards AFB. Now these vehicles are placed in the airbase memorial sites.
Satellite image of Google Earth: aircraft T-38A, F-15ACTIVE and F-16XL at the experimental test site of Edwards airbase, image 2012
