RTV-A-2 Hiroc

Last updated

RTV-A-2 Hiroc
MX-774 missile.jpg
TypeSupersonic Test Vehicle
Place of originUnited States
Production history
Designer Consolidated-Vultee
Designed1946
No. built3
Specifications
Mass1,205 pounds (547 kg) empty, 4,090 pounds (1,860 kg) full,
Length31.5 feet (9.6 m)
Width6 feet 10 inches (2.08 m)
Diameter30 inches (760 mm)
EngineOne XLR35-RM-1 engine
with four chambers 2,000 pounds-force (8.9 kN) each
Propellant Liquid oxygen as oxidizer
Ethanol as fuel

The RTV-A-2 Hiroc (high-altitude rocket) was a product of the United States' first effort to develop an intercontinental ballistic missile (ICBM). The project was named MX-774. The project was canceled in 1947, but leftover funds were used to build and launch three of the planned 10 research vehicles designated RTV-A-2. [1] [2] The design included several innovations; the gimbaled thrust chambers provided guidance control, the internal gas pressure was used to support the airframe and the nose cap was separable. All of these concepts were later used on the Atlas missile and the first two on the Viking rocket. Also developed as part of MX-774 was the Azusa guidance system which was not used on the Hiroc missile but did contribute to the Atlas missile as well as many other early guided missiles launched from Cape Canveral. [3]

Contents

Design

The Hiroc missiles were 31.5 feet (9.6 m) long, had a fin span (the maximum width of the rocket, accounting for the fins) of 6 feet 10 inches (2.08 m), a diameter of 30 inches (760 mm), an empty weight including payload of 1,205 pounds (547 kg) and a gross liftoff weight (GLOW) of 4,090 pounds (1,860 kg). [4] [5]

The missile's propulsion system consisted of an XLR35-RM-1 composed of four thrust chambers, built by Reaction Motors, which produced 2,000  lbf (8.9  kN ) of thrust each and could independently swivel up to ten degrees on one axis. [6] The gimbaling motion was used to control the flight path of the missile, replacing the system of the V-2 missile that used moving fins placed within a fixed engine. [7] The gimbal system adds complexity to the engine mounting but preserves more of the energy of the rocket exhaust during maneuvering. The engine had a specific impulse of 210 s at sea level. [8]

The Hiroc missile used liquid oxygen as its oxidizer, and alcohol for its fuel. [9] The Hiroc missile did not have separate tanks for its fuel and oxidizer, which were instead contained in one tank separated by two bulkheads. [10] The airframe of the rocket was supported by nitrogen gas pressure inside the tank, which could contain propellant or nitrogen gas when stored. [11] [4] [12] Having gas pressure provide rigidity to the structure reduced the empty weight by requiring less metallic components for structural reinforcement, but made the missile fragile because it required continuous pressurization. [13] The RTV-A-2 Hiroc had an airframe to propellant ratio three times better than the V-2. [1]

The nose cone, which contained instrumentation, would separate from the rocket booster. This made the rocket lighter as only the nose cone and its instruments and recording camera had to be able to survive recovery, rather than the entire rocket. [4] The unique innovations of the Hiroc missiles, such as the gimbaled thrust chambers, and the internal pressure supported airframe, would go on to be utilized in the Atlas rockets. [14] [15] [16] Several changes were made in the Atlas, such as the aluminum used for the missiles airframe of the Hiroc, was changed to stainless steel in the Atlas. The early Atlas utilized the MX-774 project developed Azusa interferometry based guidance system which served Cape Canaveral during the early space age. [17] The engines of the Atlas missiles were also much more powerful, generating a total of 150,000 lbf (670 kN) of thrust, compared to the Hiroc's total of 8,000 lbf (36 kN) thrust. [18]

History

In April 1946, Convair received a 1.9 million dollar contract from the US Government under Air Material Command designation Material, Experimental-774B (MX-774B) to investigate the development of ballistic missiles. [13] [19] This was one of a large number of missile projects being studied by the US Army at that time, which included both ballistic missiles and a variety of long-range cruise missiles as well. [20] The original of MX-774B called for a missile that could deliver a 5,000 pounds (2,300 kg) payload 5,000 miles (8,000 km), and which had an accuracy that allowed it to deliver it to within 5,000 feet (1,500 m) of the target. The MX-774B project was headed by Karel Bossart, who would go on to head the creation of the Atlas rockets. [21] Although development of the specification MX-774B was inspired by the German V-2 the MX-774B introduced several significant innovations, such as an integrated propellant tank, swiveling engines, pressurized body, and detachable nose cone. [22]

As a result of drastic defense cuts in 1946 and for 1947 the USAAF's missile budget was cut in half from $29 to $13 million in what became known as "the black Christmas of 1946". [23] Many of the projects were canceled outright, [24] but MX-774 instead continued with reduced funding. The project was eventually canceled in June 1947 as the Army concentrated their efforts on cruise missiles, which were more promising at that time. [25]

Convair arranged to use the remaining contract funding to launch three of the rockets, which were named RTV-A-2 Hiroc. [13] [19] The tests took place at White Sands Proving Grounds. [13] The three tests took place on 13 July 1947, 27 September, and 2 December. [4] These tests validated the concept of using gimbaled engines for propulsion and guidance. [8]

Hiroc was flown from a pad 600 feet north the White Sands blockhouse. Tracking was provided Askania Cine theodolite, cameras, Sky-screen observers and four tracking telescopes and tracking radar. White Sands Proving Ground provided housing and support for the launch program. [26]

On the RTV-A-2 (MX-774), a camera recorded the flight data displayed upon an instrument panel. Both the number of parameters recorded and the survivability of the film record were limited. Therefore, dependence upon the intact recovery of this camera was problematic. [27]

During the test on 13 July, the Hiroc reached a maximum height of 6,200 feet (1,900 m), but lost thrust after 12.6 seconds and hit the ground at 48.5 seconds, 415 feet (126 m) from the launch pad. Due to a mistake in packing, the payload recovery parachute failed to open; a camera and a few other instruments survived, so the test was deemed a partial success. [5]

During the test on 27 September, the Hiroc reached an altitude of 24 miles (39 km) at 48 seconds and a maximum velocity of 2,350 feet per second (720 m/s). The parachute failed again, this time due to a battery problem; the Hiroc began to freefall before its oxygen tank exploded at 20,000 feet (6,100 m). This caused it to break up, but a camera and some instruments survived. [5]

During the test on 2 December, the Hiroc reached a maximum height of 30 miles (48 km) and reached a maximum velocity of 2,653 feet per second (809 m/s). The parachute failed to open yet again, this time due to the nose cone damaging it after being ejected, while the Hiroc was at an altitude of 121,000 feet (37,000 m) and moving at a speed of 1,500 feet per second (460 m/s). The camera was recovered, although it was partly damaged. [5] The third Hiroc had its nose compartment extended 34 inches to allow more instrumentation. [28]

All three Hiroc missiles had partially failed due to premature closure of the liquid oxygen valve. The cause of failure was determined from a light on the instrumentation coming on when the valve closed. The cause of the valve closing was traced to vibration of solenoids which caused pressure change in the hydrogen peroxide line which allowed nitrogen to vent from engine control lines with the resultant pressure drop closing the LOX valve. [29]

In late 1948 the Air Force proposed the continuation of the MX-774 program with an additional 15 missiles for high altitude research but the proposal was refused by the Research and Development Board's Committee on Guided Missiles which decided that the more capable Navy Viking Missile RTV-N-12 was a superior high altitude research vehicle. [30] [31] Convair retained the core design team after program cancellation. That core led to Convair proposing a missile to meet the Air Force Request For Proposal MX-1593 which ultimately resulted in the Weapon System 107A, better known as the B-65/SM-65 Atlas, America's first ICBM. [32]

Related Research Articles

The SM-65 Atlas was the first operational intercontinental ballistic missile (ICBM) developed by the United States and the first member of the Atlas rocket family. It was built for the U.S. Air Force by the Convair Division of General Dynamics at an assembly plant located in Kearny Mesa, San Diego. Atlas became operational in September 1959, but was soon made obsolete as an ICBM by new development, and was retired from this role by 1965.

<span class="mw-page-title-main">Model rocket</span> Small recreational rocket

A model rocket is a small rocket designed to reach low altitudes and be recovered by a variety of means.

<span class="mw-page-title-main">Convair</span> 1943–1996 American aerospace manufacturer

Convair, previously Consolidated Vultee, was an American aircraft-manufacturing company that later expanded into rockets and spacecraft. The company was formed in 1943 by the merger of Consolidated Aircraft and Vultee Aircraft. In 1953, it was purchased by General Dynamics, and operated as their Convair Division for most of its corporate history.

<span class="mw-page-title-main">Aerobee</span> American sounding rocket

The Aerobee rocket was one of the United States' most produced and productive sounding rockets. Developed by the Aerojet Corporation, the Aerobee was designed to combine the altitude and launching capability of the V-2 with the cost effectiveness and mass production of the WAC Corporal. More than 1000 Aerobees were launched between 1947 and 1985, returning vast amounts of astronomical, physical, aeronomical, and biomedical data.

<span class="mw-page-title-main">PGM-17 Thor</span> Intermediate Range Ballistic Missile (IRBM)

The PGM-17A Thor was the first operational ballistic missile of the United States Air Force (USAF). It was named after the Norse god of thunder. Able to reach Moscow from Europe, it was deployed in the United Kingdom between 1959 and September 1963 as an intermediate-range ballistic missile (IRBM) with thermonuclear warheads. Thor was 65 feet (20 m) in height and 8 feet (2.4 m) in diameter. It was later augmented in the U.S. IRBM arsenal by the Jupiter.

<span class="mw-page-title-main">SM-62 Snark</span> Surface-to-surface cruise missile

The Northrop SM-62 Snark is an early-model intercontinental range ground-launched cruise missile that could carry a W39 thermonuclear warhead. The Snark was deployed by the United States Air Force's Strategic Air Command from 1958 through 1961. It represented an important step in weapons technology during the Cold War. The Snark was named by Jack Northrop and took its name from the author Lewis Carroll's character the "snark". The Snark was the only surface-to-surface cruise missile with such a long range that was ever deployed by the U.S. Air Force. Following the deployment of ICBMs, the Snark was rendered obsolete, and it was removed from deployment in 1961.

<span class="mw-page-title-main">Thrust vectoring</span> Facet of ballistics and aeronautics

Thrust vectoring, also known as thrust vector control (TVC), is the ability of an aircraft, rocket, or other vehicle to manipulate the direction of the thrust from its engine(s) or motor(s) to control the attitude or angular velocity of the vehicle.

<span class="mw-page-title-main">Atlas II</span> American rocket

Atlas II was a member of the Atlas family of launch vehicles, which evolved from the successful Atlas missile program of the 1950s. The Atlas II was a direct evolution of the Atlas I, featuring longer first stage tanks, higher-performing engines, and the option for strap-on solid rocket boosters. It was designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. Sixty-three launches of the Atlas II, IIA and IIAS models were carried out between 1991 and 2004; all sixty-three launches were successes, making the Atlas II a highly reliable space launch system. The Atlas line was continued by the Atlas III, used between 2000 and 2005, and the Atlas V which is still in use.

<span class="mw-page-title-main">Aerojet General X-8</span> Experimental spin-stabilized rocket for very high altitude research

The Aerojet General X-8 was an unguided, spin-stabilized sounding rocket designed to launch a 150 lb (68 kg) payload to 200,000 feet (61.0 km). The X-8 was a version of the prolific Aerobee rocket family.

<span class="mw-page-title-main">North American X-10</span> Experimental missile to test design features of the SM-64 Navaho missile

The North American X-10 was an unmanned technology demonstrator developed by North American Aviation. It was a subscale reusable design that included many of the design features of the SM-64 Navaho missile. The X-10 was similar to the development of the Bell X-9 Shrike project, which was based on features of the GAM-63 RASCAL.

<span class="mw-page-title-main">Viking (rocket)</span>

Viking was a series of twelve sounding rockets designed and built by the Glenn L. Martin Company under the direction of the U.S. Naval Research Laboratory (NRL). Designed to supersede the German V-2, the Viking was the most advanced large, liquid-fueled rocket developed in the United States in the late 1940s, returning valuable scientific data from the edge of space between 1949 and 1955. Viking 4, launched in 1950, was the first sounding rocket to be launched from the deck of a ship.

<span class="mw-page-title-main">SM-64 Navaho</span> 1950s supersonic intercontinental cruise missile

The North American SM-64 Navaho was a supersonic intercontinental cruise missile project built by North American Aviation (NAA). The final design was capable of delivering a nuclear weapon to the USSR from bases within the US, while cruising at Mach 3 at 60,000 feet (18,000 m) altitude. The missile is named after the Navajo Nation.

<span class="mw-page-title-main">WAC Corporal</span> Sounding rocket

The WAC Corporal was the first sounding rocket developed in the United States and the first vehicle to achieve hypersonic speeds. It was an offshoot of the Corporal program, that was started by a partnership between the United States Army Ordnance Corps and the California Institute of Technology in June 1944 with the ultimate goal of developing a military ballistic missile.

<span class="mw-page-title-main">Spaceflight before 1951</span> List of spaceflights prior to the year 1951

Spaceflight as a practical endeavor began during World War II with the development of operational liquid-fueled rockets. Beginning life as a weapon, the V-2 was pressed into peaceful service after the war at the United States' White Sands Missile Range as well as the Soviet Union's Kapustin Yar. This led to a flourishing of missile designs setting the stage for the exploration of space. The small American WAC Corporal rocket was evolved into the Aerobee, a much more powerful sounding rocket. Exploration of space began in earnest in 1947 with the flight of the first Aerobee, 46 of which had flown by the end of 1950. These and other rockets, both Soviet and American, returned the first direct data on air density, temperature, charged particles and magnetic fields in the Earth's upper atmosphere.

<span class="mw-page-title-main">Hermes program</span> United States Army missile research program

Project Hermes was a missile research program run by the Ordnance Corps of the United States Army from November 15, 1944, to December 31, 1954, in response to Germany's rocket attacks in Europe during World War II. The program was to determine the missile needs of army field forces. A research and development partnership between the Ordnance Corps and General Electric started November 20, 1944 and resulted in the "development of long-range missiles that could be used against both ground targets and high-altitude aircraft."

<span class="mw-page-title-main">1952 in spaceflight</span> List of spaceflights in 1952

Groundwork was laid for the launch of the first artificial satellite with the scheduling of the International Geophysical Year for 1957-58. This scientific endeavor would involve dozens of nations in a global investigation of physical phenomenona, on the ground and in space.

<span class="mw-page-title-main">GAM-63 RASCAL</span> Air-to-surface missile

The GAM-63 RASCAL was a supersonic air-to-surface missile that was developed by the Bell Aircraft Company. The RASCAL was the United States Air Force's first nuclear armed standoff missile. The RASCAL was initially designated the ASM-A-2, then re-designated the B-63 in 1951 and finally re-designated the GAM-63 in 1955. The name RASCAL was the acronym for RAdar SCAnning Link, the missile's guidance system. The RASCAL project was cancelled in September 1958.

<span class="mw-page-title-main">RTV-A-3 NATIV</span> Missile

The RTV-A-3 NATIV was an experimental missile developed by North American Aviation for the United States Air Force in the late 1940s to test and evaluate guided missile technologies. The North American Test Instrumentation Vehicle (NATIV) was developed as part of the MX-770 program which was created towards the end of WWII with the intent of developing a long range missile.

A thruster is a spacecraft propulsion device used for orbital station-keeping, attitude control, or long-duration, low-thrust acceleration, often as part of a reaction control system. A vernier thruster or gimbaled engine are particular cases used on launch vehicles where a secondary rocket engine or other high thrust device is used to control the attitude of the rocket, while the primary thrust engine is fixed to the rocket and supplies the principal amount of thrust.

The ORDCIT program to develop a ballistic missile called Corporal was a progressive one. The original design was called XF30L20,000 which envisioned a 30 in (760 mm) diameter liquid fueled missile with a 20,000 lbf (89 kN) thrust engine and was ventured in the summer of 1944. The WAC Corporal sounding rocket was developed in 1945, providing experience with liquid fueled ballistic rocketry. The second phase gave experience with a redesigned and refined rocket and engine the following year. What was learned was applied to the Corporal program.

References

Citations

  1. 1 2 Neufeld 1990, pp. 47.
  2. ↑ Kennedy, Gregory P, “The Rockets and Missiles of White Sands Proving Ground 1945-1958,” Schiffer Military History, Atglen, PA, 2009 ISBN   978-0-7643-3251-7, p 63
  3. ↑ Rosenberg, Max, “The Air Force and the National Guided Missile Program 1944-1950,” USAF Historical Division Liaison Office, June 1964, p 48
  4. 1 2 3 4 Gruntman 2004, p. 214.
  5. 1 2 3 4 A Photo-History Of Atlas Precursors.
  6. ↑ Sutton, George P, “History of Liquid Propellent Rocket Engines,” American Institute of Aeronautics and Astronautics, Reston Virginia, 2005 ISBN   1-56347-649-5, p 314
  7. ↑ Dornberger, Walter (1952). V-2. New York: Viking. English translation 1954.
  8. 1 2 Gruntman 2004, p. 215.
  9. ↑ Rocket Engine, Liquid Fuel, XLR35-RM-1.
  10. ↑ Kennedy, Gregory P, “The Rockets and Missiles of White Sands Proving Ground 1945-1958,” Schiffer Military History, Atglen, PA, 2009 ISBN   978-0-7643-3251-7, p 63
  11. ↑ Waller, Chuck, and Powell, Jerome “Atlas the Ultimate Weapon,” Apogee Books, Burlington, Ontario, Canada, 2005 ISBN   1-894959-18-3, p 17
  12. ↑ Launius & Jenkins 2015, p. 73.
  13. 1 2 3 4 McMurran 2008, pp. 212–213.
  14. ↑ McMurran 2008, p. 212.
  15. ↑ Gruntman 2004, p. 216.
  16. ↑ Astronautix.
  17. ↑ Waller, Chuck, and Powell, Jerome “Atlas the Ultimate Weapon,” Apogee Books, Burlington,Ontario, Canada, 2005 ISBN   1-894959-18-3, p 16
  18. ↑ Gruntman 2004, p. 235.
  19. 1 2 Gruntman 2004, p. 212.
  20. ↑ Rosenberg 2012, p. 42.
  21. ↑ Gruntman 2004, p. 210.
  22. ↑ Waller, Chuck, and Powell, Jerome “Atlas the Ultimate Weapon,” Apogee Books, Burlington,Ontario, Canada, 2005 ISBN   1-894959-18-3, p 16
  23. ↑ Rosenberg 2012, p. 77-78.
  24. ↑ Rosenberg 2012, p. 44.
  25. ↑ Neufeld 1990, pp. 36–37.
  26. ↑ Kennedy, Gregory P, “The Rockets and Missiles of White Sands Proving Ground 1945-1958,” Schiffer Military History, Atglen, PA, 2009 ISBN   978-0-7643-3251-7, p 64
  27. ↑ Neufeld 1990.
  28. ↑ Kennedy, Gregory P, “The Rockets and Missiles of White Sands Proving Ground 1945-1958,” Schiffer Military History, Atglen, PA, 2009 ISBN   978-0-7643-3251-7, p 66
  29. ↑ Kennedy, Gregory P, “The Rockets and Missiles of White Sands Proving Ground 1945-1958,” Schiffer Military History, Atglen, PA, 2009 ISBN   978-0-7643-3251-7, p 66
  30. ↑ DeVorkin, David H., “Science With A Vengeance,” Smithsonian Institution, /Springer-Verlag New York, Berlin, Heidelberg, 1992/1993, ISBN   0-387-94137-1 p 178-179
  31. ↑ Rosenberg, Max, “The Air Force and the National Guided Missile Program 1944-1950,” USAF Historical Division Liaison Office, June 1964, p 50
  32. ↑ Waller, Chuck, and Powell, Jerome “Atlas the Ultimate Weapon,” Apogee Books, Burlington,Ontario, Canada, 2005 ISBN   1-894959-18-3, p 21-22

Books

Websites

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.