First Launch: 1956-11-06. Last Launch: 1958-11-18. Number: 11 . Longitude: -80.56 deg. Latitude: 28.45 deg.
Continuing problems with APU reliability delayed the launch to November. Various problems extended the countdown from the planned 7 hours 30 minutes to 14 hours 30 minutes. Successful launch, then vehicle pitched up and disintegrated 26 seconds after launch, impacting 4 km down range. It was found the pitch rate gyro had been installed backward.
G-26 number two / booster 6 lifted off after a 9 hour 48 minute countdown with nearly five hours of holds, on the first attempt after two successful static firings. However failure of a launch lanyard meant the kerosene start-pod on the booster remained attached. This sheared off at 4500 m, causing extensive booster damage. Thrust decayed. The cruise stage separated at Mach 1.3 at 28,300 feet, but this was below ramjet ignition speed. However the pilot on the ground was able to assume radio control of the vehicle, and flew it in a glide over the ocean, even demonstrating landing gear deployment before it pancaked into the water.
Vehicle 4 was still not ready for the first Broomstick flight, so vehicle 5 was substituted. It took five attempts before a 15.6 second static test cleared the booster for launch on 29 March. 8 hours and 42 minutes of hold stretched the five-hour countdown out into the evening. The booster ignited, rose 1.3 m, then shut down. The vehicle fell back onto the pad, exploding. Cause was a 15-second timer that was supposed to shut the engines down 15 seconds after the vehicle hold-downs released if a lanyard had not been pulled free of the vehicle as it rose off the ground. The 15 seconds had been reached before the lanyard pulled free, but by then the vehicle had risen off the pad. This made 15 attempts to launch a Navaho, with only two booster ignitions, both resulting in loss of the vehicle. The Northrop crews at the Cape dubbed their competitor the "Never-Go Navaho" to counter jibes directed at them about the "Snark-infested waters" off the launch area. The Air Force was not amused, and had a tiger-team review of the G-26 on a system-basis which recommended several procedures. Meanwhile G-38 launch plans were further delayed over internal USAF wrangles over launch facility construction.
The missile launched from the repaired LC-9 on the third attempt. At T+42 seconds, Mach 1.63, and 7,000 m altitude, a fire occurred in the engine compartment after a failure of a regenerative cooling valve to the gas generator. The turbopump shut down, and one engine went out. Nevertheless the vehicle continued, first on one engine, then coasting, to 12,000 m altitude, and the booster separated successfully. But the cruise stage was below ramjet ignition velocity. Again ground control could bring the cruise stage under control as a glider, flying it to an impact 87 km downrange
The booster worked well, the cruise stage separated at 23.5 km altitude. The ramjets ignited, and the cruise stage accelerated to Mach 3.5. After 15 minutes, the missile began drifting off-course, and ground control took over and banked the missile. One of the ramjets flamed out, and the missile was commanded into a terminal dive and impacted 930 km downrange.
The booster functioned well, and the cruise stage separated at 20.4 km altitude and Mach 3.24. The ramjets ignited, but before the ground knew that, the telemetry dropped out completely due to a faulty voltage regulator on the missile. Range safety ordered the missile's self destruction at T+75 seconds.
The booster functioned well, the cruise stage separated at 22 km and Mach 3.15. The ramjets ignited and the cruise stage flew at a sustained speed of Mach 2.8 for forty minutes over a distance of 2000 km. Then the vehicle began a turn for the return to the Cape for recovery. However it seemed the turn was not fast enough; ground control took over, and yet again the right ramjet flamed out in a ground-piloted bank. The missile was commanded into a terminal dive at sea.
North American had received funding to fly seven surplus G-26 missiles in a program dubbed RISE (Research Into Supersonic Environment), ostensibly to obtain real-world data on Mach 3 flight for the F-108 interceptor and B-70 bomber that they were developing for the USAF. On this first attempt, the booster performed well, but after separation the cruise stage fuel system failed, and ramjet ignition never occurred. The cruise stage impacted 150 km downrange.