SM-64 Navaho
The North American SM-64 Navaho was a
The original 1946 project called for a relatively short-range system, a
Through this period the
Although Navaho did not enter service, its development provided useful research in a number of fields. A version of the Navaho airframe powered by a single turbojet became the AGM-28 Hound Dog, which was carried towards its targets on the Boeing B-52 Stratofortress and then flew the rest of the way at about Mach 2. The guidance system was used to guide the first Polaris submarines. The booster engine design, spun off to NAA's new Rocketdyne subsidiary, was used in various versions of the Atlas, PGM-11 Redstone, PGM-17 Thor, PGM-19 Jupiter, Mercury-Redstone, and the Juno series; it is therefore the direct ancestor of the engines used to launch the Saturn I and Saturn V Moon rockets.
Development
Postwar Army missile studies
The Germans had introduced a number of new
Vannevar Bush of the USAAF's Scientific Advisory Board was convinced that manned or automated aircraft like the V-1 were the only possible solution for long range roles. A ballistic missile capable of carrying even the smallest warhead was "at least ten years away", and when asked directly about the topic, noted:
In my opinion, such a thing is impossible. I don't think anybody in the world knows how to do such a thing and I feel confident it will not be done for a very long time to come.[2]
Army planners began planning for a wide variety of post-war missile systems that varied from short-range ballistic missiles to long range flying bombs. After considerable internal debate among Army branches, in August 1945 these were codified in a classified document outlining many such systems, among them a variety of cruise missiles, essentially V-1s with extended range and the greater payload needed to carry a nuclear warhead.[3] There were three broad outlines depending on range, one for a missile flying 175 to 500 miles (282–805 km), another 500 to 1,500 miles (800–2,410 km), and finally one for 1,500 to 5,000 miles (2,400–8,000 km). Both subsonic and supersonic designs would be considered.[4]
Competing designs
The various proposals were sent to seventeen aviation firms on 31 October 1945. Of the many proposals received, six companies were granted development contracts. Submissions for the longer-range requirements were all based on cruise missile designs, while the shorter-range examples were a mixture of designs. These were assigned designations in keeping with the USAAF's Experimental Engineering Section's "MX" series.
NAA chief designer,
A number of other designs were also accepted, but these were all cruise missile designs to fill the longer range requirements. These were
When President Harry S. Truman ordered a massive cut in military spending for FY1947, as part of the Truman Doctrine, the USAAF was forced to make major cuts to their missile development program. Missile funding was cut from $29 million to $13 million (from $396 million to $177 million in today's dollars).[2] In what became known as "the black Christmas of 1946", many of the original projects were cancelled, with the remaining companies working on a single design instead of two.[6] Only Martin continued development of a subsonic design, their MX-771-A, delivering the first SSM-A-1 Matador in 1949. The rest of the companies were told to work only on supersonic designs.[7]
Engine work
NAA began experimenting with rocket engines in 1946, firing the rockets in the company parking lot and protecting the cars by parking a bulldozer in front of the engines. They first used a 1,100-pound-force (4,900 N) design from Aerojet, and then designed their own model of 300 pounds-force (1,300 N). By the spring of 1946, captured German data was being disseminated around the industry. In June 1946 the team decided to abandon their own designs and build a new engine based on the V-2's Model 39.[5]
In late 1946, two Model 39 engines were sent to NAA for study, where they were referred to as the XLR-41 Mark I. "XLR" referred to "eXperimental Liquid Rocket", a new designation system being used by the Army Air Force. They used these as the basis for conversion from metric to SAE measurements and US construction techniques, which they called the Mark II.[5]
During this period, the company received a number of late-war reports on developments of a Model 39a engine for the V-2, which replaced the original model's eighteen separate combustion chambers with a single "shower head" plate inside a single larger chamber. This not only simplified the design, it also made it lighter and improved performance. The Germans were never able to get this working due to combustion instability and continued using the earlier design in spite of lower performance.[5]
The team that had designed the engine was now in the United States after being captured as part of Operation Paperclip. Many of them were setting up a new Army-funded research effort under the direction of Wernher von Braun. The company hired Dieter Huzel to act as a coordinator between NAA and the Army missile team. In September 1947, the company began the design of an engine incorporating the showerhead design, which they called the Mark III. Initially, the goal was to match the 56,000 pounds-force (250,000 N) thrust of the Model 39, but be 15% lighter.[5]
Work on the Mark II continued and the detailed design was completed in June 1947. In March, the company rented a large tract of land in the western San Fernando Valley north of Los Angeles, in the Santa Susana Mountains, for use in testing large engines. A rocket test center was built, using $1 million (equivalent to $13,645,306 in 2023) of corporate funds and $1.5 million (equivalent to $20,467,958.3 in 2023) from the USAAF. The first parts began to arrive in September. Development of the Mark III proceeded in parallel using a scaled-down version developing 3,300 pounds-force (15,000 N) that could be fired in the parking lot. The team made a string of changes to this and eventually cured the combustion problems.[5]
Evolving design
Another set of German research papers received by NAA concerned work on supersonic ramjets, which appeared to make a highly supersonic cruise missile design possible. Bollay began a series of parallel design projects; Phase 1 was the original
Meanwhile, aerodynamicists in the company discovered that the A-4b's
So, by June 1947, the original A-4b design had been changed at every point; the engine, airframe and navigation systems were now all new.
New concept
In September 1947 the
Examining the work to date, NAA abandoned the boost-glide concept and moved to the ramjet powered cruise missile as the primary design. Even with the more efficient propulsion offered by the ramjets, the missile would have to be 33% larger to achieve the required range. This required a more powerful booster engine to power the launcher, so the requirement for the XLR-41 Mark III was raised to 75,000 pounds-force (330,000 N). The N-1 INS system drifted at a rate of 1 mile per hour, so at its maximum range it would not be able to meet the Air Force's 2,500-foot (760 m) CEP. The company began development of the N-2 to fill this need and provide considerable headroom if greater range was requested. It was essentially the mechanism of the N-1 paired to a star tracker which would provide midcourse updates to correct for any accumulated drift.[5]
The Air Force assigned the missile the XSSM-A-2 designation, and then outlined a three-stage development plan. For Phase 1, the existing design would be used for technology development and as a testbed for various launch concepts, including the original booster concept, as well as rocket-track launches and air dropped versions. Phase 2 would extend the range of the missile to 2,000 to 3,000 miles (3,200–4,800 km), and Phase 3 would further increase that to an intercontinental 5,000 miles (8,000 km) while carrying a heavier 10,000 pounds (4,500 kg) warhead. The design evolution ended in July 1950 with the Air Force of Weapon System 104A specifications. Under this new requirement the purpose of the program was the development of a 5,500-mile (8,900 km) range nuclear missile.[8]
WS-104A
Under WS-104A, the Navaho program was broken up into three guided missile efforts. The first of these missiles was the North American X-10, a flying subrange vehicle to prove the general aerodynamics, guidance, and control technologies for vehicles two and three. The X-10 was essentially an unmanned high performance jet, powered by two afterburning Westinghouse J40 turbojets and equipped with retractable landing gear for take off and landing. It was capable of speeds up to Mach 2 and could fly almost 500 miles (800 km). Its success at Edwards AFB and then at Cape Canaveral set the stage for the development of the second vehicle: XSSM-A-4, Navaho II, or G-26.[9]
Step two, the G-26, was a nearly full-size Navaho nuclear vehicle. Launched vertically by a liquid-fuel rocket booster, the G-26 would rocket upward until it had reached a speed of approximately Mach 3 and an altitude of 50,000 ft (15,000 m). At this point the booster would be expended and the vehicle's ramjets ignited to power the vehicle to its target. The G-26 made a total of 10 launches from Launch Complex 9 (LC-9) at Cape Canaveral Air Force Station (CCAFS) between 1956 and 1957. Launch Complex 10 (LC-10) was also assigned to the Navaho program, but no G-26s were ever launched from it (it was only used for ground tests of the planned portable launcher).
The final operational version, the G-38 or XSM-64A, was the same basic design as the G-26 only larger. It incorporated numerous new technologies,
and the inertial guidance system was later used as the guidance system on the first U.S. nuclear-powered submarines.Development of the first-stage rocket engine for the Navaho began with two refurbished V-2 engines in 1947. That same year, the phase II engine was designed, the XLR-41-NA-1, a simplified version of the V-2 engine made from American parts. The phase III engine, XLR-43-NA-1 (also called 75K), adopted a cylindrical combustion chamber with the experimental German impinging-stream injector plate. Engineers at North American solved the combustion stability problem, which had prevented it being used in the V-2, and the engine was successfully tested at full power in 1951. The Phase IV engine, XLR-43-NA-3 (120K), replaced the poorly-cooled heavy German engine wall with a brazed tubular ("spaghetti") construction, which was becoming the new standard method for
Operational history
The first launch attempt, on 6 November 1956, failed after 26 seconds of flight. Ten failed launches followed, before another got off successfully, on 22 March 1957, for 4 minutes, 39 seconds of flight. A 25 April attempt exploded seconds after liftoff, while a 26 June flight lasted only 4 minutes, 29 seconds.[10]
Officially, the program was canceled on 13 July 1957, after the first four launches ended in failure. In reality the program was obsolete by mid-1957 as the first Atlas ICBM began flight tests in June and the Jupiter and Thor IRBMs were showing great promise. These ballistic missiles however would not have been possible without the liquid fuel rocket engine developments accomplished in the Navaho program. The launch of the Soviet Satellite Sputnik in October 1957 only finished Navaho as the Air Force shifted its research money into ICBMs. But the technologies developed for the Navaho were reused in 1957 for the development of the AGM-28 Hound Dog, a nuclear cruise missile which entered in production in 1959.
The Soviet Union had been working on parallel projects, The Myasishchev RSS-40 "Buran" and Lavochkin "Burya" and a little later, the Tupolev Tu-123. The first two types were also large rocket-boosted ramjets, while the third was a turbojet-powered machine. With the cancellation of the Navaho and the promise of ICBMs in the strategic missile role, the first two were canceled as well, though the Lavochkin project, which had some successful test flights, was carried on for research and development purposes, and the Tupolev was reworked as a big, fast reconnaissance drone.
Operators
- United States: The United States Air Force canceled the program before accepting the Navaho into service.
Survivors
One remaining X-10 is on display at the United States Air Force Museum Research and Development Gallery.
A Navaho booster rocket, though not marked as such, is currently displayed in front of a VFW post in Fort McCoy, Florida.
The other remaining Navaho missile was previously displayed outside the south entrance gate of
Notable appearances in media
The 1960s series
Specifications
Data from [citation needed]
General characteristics
- Length: 67 ft 11 in (20.7 m)
- Wingspan: 28 ft 7 in (8.71 m)
- Gross weight: 64,850 lb (29,420 kg)
- Powerplant: 2 × Wright Aeronautical XRJ47-W-5 ramjets, 15,000 lbf (67 kN) thrust each
- Powerplant: 2 × XLR83-NA-1 rocket boosters, 200,000 lbf (890 kN) thrust each
Performance
- Maximum speed: 1,700 kn (2,000 mph, 3,200 km/h) (design. Reality 2 500 km/h)
- Maximum speed: Mach 3
- Range: 3,500 nmi (4,000 mi, 6,500 km) (design)
- Service ceiling: 77,000 ft (23,000 m)
- Thrust/weight: 0.46
Armament
- 1 × W41 nuclear warhead
See also
Aircraft of comparable role, configuration, and era
Related lists
- List of military aircraft of the United States
- List of missiles
References
Notes
- ^ Rosenberg 2012, p. 39.
- ^ a b c Mindling & Bolton 2008, p. 57.
- ^ Rosenberg 2012, p. 41.
- ^ a b Rosenberg 2012, p. 42.
- ^ a b c d e f g h Wade.
- ^ Rosenberg 2012, p. 44.
- ^ Rosenberg 2012, pp. 42, 95.
- ^ Gibson 1996, p. 15.
- ^ Gibson 1996, pp. 18, 24.
- ^ Werrell 1998, p. 98.
- ^ Mason.
- ^ afspacemuseum.
Bibliography
- Gibson, James (1996). The Navaho Missile Project: The Story of the Know-How Missile of American Rocketry. Schiffer. ISBN 9780764300486.
- Mindling, George; Bolton, Robert (2008). U.S. Air Force Tactical Missiles. Lulu. ISBN 9780557000296.
- Rosenberg, Max (2012). The Air Force and the National Guided Missile Program. Defense Lion. ISBN 9780985973001.
- Werrell, Kenneth P. The Evolution of the Cruise Missile. Montgomery, Alabama: Air University, Maxwell Air Force Base. 1998, First edition 1995. .
- Mason, Curt. "projecthabu.com/post/151537963920/cape-canaveral-air-force-station-in-florida". Retrieved 30 June 2017.
- @afspacemuseum (23 March 2021). "Rupert has located the Navaho Missile which arrived for assembly this morning. We are over the moon excited to see it again at the south gate!" (Tweet) – via Twitter.