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Fifty-two years ago this month, a XSM-64 Navaho G-26 flight test vehicle flew 1,075 miles in 40 minutes at a sustained speed of Mach 2.8.  It was the 8th flight test of the ill-fated Navaho Program.

The post-World War II era saw the development of a myriad of missile weapons systems.  Perhaps the most influential and enigmatic of these systems was the Navaho missile.

Navaho was intended as a supersonic, nuclear-capable, strategic weapon system.  It consisted of two (2) stages.  The first stage was rocket-powered while the second stage utilized ramjet propulsion.  The aircraft-like second stage was configured with a high lift-to-drag airframe in order to achieve strategic reach.

While there were a number of antecedants dating back to 1946, the Navaho Program really began in 1950 as Weapon System 104A.  The requirements included a range of 5,500 miles, a minimum cruise speed of Mach 3 and a minimum cruise altitude of 60,000 feet.  The payload included an ordnance load of 7,000 pounds delivered within a CEP of 1,500 feet.

North American Aviation (NAA) proposed a 3-phase development plan for WS-104A.  Phase 1 involved testing of the missile alone (the X-10) up to Mach 2.  Phase 2 covered the testing of the two-stage launch vehicle (the G-26) up to Mach 2.75 and a range of 1,500 miles.  Phase 3 would be the ultimate near-production vehicle (the G-38).  Only Phase 1 and Phase 2 testing took place.

The Navaho missile-booster vehicle measured 84 feet in length and weighed about 135,000 pounds at lift-off.  The launch weight for the booster was 75,000 pounds; most of which was due to the alcohol and LOX propellants.  The missile empty weight was 24,000 pounds.

On Friday, 10 January 1958, Navaho G-26 No. 9 (54-3098)  lifted-off from LC-9 at Cape Canaveral, Florida.  Climbing out under 240,000 pounds of thrust from its dual Rocketdyne XLR71-NA-1 rocket motors, missile-booster separation occurred at Mach 3.15 and 73,000 feet.  Following air-start and take-over of twin Wright XRJ47-W-5 ramjets, generating a combined thrust of 16,000 pounds, the Navaho missile initiated a near triple-sonic cruise toward the Puerto Rico target area.

As the Navaho missile approached the environs of Puerto Rico, the vehicle was commanded to initiate a sweeping right-hand turn back towards the Cape.  Unfortunately, the right intake experienced an unstart and a concommitant, asymmetric loss of thrust.  Underpowered and without a restart capability, the vehicle was subsequently commanded to execute a dive into the Atlantic.

Flight No. 8, although only partially successful, flew longer and farther than any Navaho flight test vehicle.  Only G-26 Flight No. 6 flew faster (Mach 3.5).

Although three (3) flights would follow G-26 Flight No. 8, all would suffer failure of one kind or another.  In point of fact, the Navaho Program had been canceled on Saturday, 13 July 1957.  The final six (6) Navaho flights were simply an attempt to extract the most from the remaining missile-booster rounds.  Over 15,000 NAA employees lost their jobs the day Navaho died.

Navaho was cancelled primarily due to the ascendancy of the Intercontinental Ballistic Missile (ICBM).  Very simply, an ICBM could deliver nuclear ordnance farther, faster and more accurately than a winged, unstealthy strategic missile.  Navaho’s relatively numerous technical issues and programmatic delays simply served to drive the final nail into a long-prepared coffin.

While few today remember or even know of the Navaho Program, its technology has had a profound influence on all manner of aerospace vehicles up to the present day.  Interestingly, the Space Shuttle launch vehicle concept bears a strong resemblance to the Navaho missile-booster combination.  That is, a winged flight vehicle mounted asymmetrically on a longer boost vehicle.

Posted in Aerospace, History


Dean Eklund February 28, 2010

Thank you for the information on the Navaho program. I am interested in ramjet/scramjet history. Perhaps you could provide suggestions for the reader who is interested in additional information on the topic.

Hello Dean,

Thanks for checking out our aerospace history blog and for your comments! The Navaho Program was certainly unique. Glad you enjoyed the information. I’ll put something together with respect to ramjets/scramjets so you can learn more about these interesting devices. Please e-mail me at: History@WhiteEagleAerospace.com so I’ll know which e-mail address to send the information to.

Maurice (Maury) Wilson April 16, 2011

I went to work for NAA right out of the Air Force in late Nov. 1955 at Cape Canaveral . I first worked on the X-10 and was on the first crew on the first G-26 (XSM-64) After the cancellation I worked on the X-10’s that were target drones for the Bomark program. I was on the Mechanical Launch team. I was 24 years old then and now just turned 79. In all I spent 29 years in Aerospace.

Earl Ratliff April 18, 2011

I went to work on the Navaho program in early November1956 and left in November of 1958 as a flight test engineer. I participated in every G-26 launch and attempted launch except for the last RISE launch. I spent a year and a half down range and the last six months working at the Flight Control Building. I to participated the the two BOMARC drone flights of X-10 from Flight Control. Spent almost 50 years in the aerospace industry

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