The SMART (Supersonic Military Air Research Track) firing which I witnessed was the third in a series of ten tests designed to determine the structural limitations of the North American F-86 seat-ejection system in the transonic region. The sled was placed on the track at a predetermined point, and following range clearance and count down, it was fired. Surging down the track, it jettisoned the seat and then entered a deceleration sequence, starting with the firing of reverse-firing rockets and coming to a dead stop at the end of a mechanical arrestor system. In this run the sled completed the test, from start to stop, in about seven seconds, covering more than 3,000 feet of track and reaching a maximum speed of 612 miles per hour.
Experimental rocket sled tracks are no doubt the most valuable tools at present for evaluating escape systems of high-performance aircraft. The 12,000-foot SMART track, located in southwest Utah on top of Hurricane Mesa, was built and is operated by, the Coleman Engineering Co., Los Angeles, Calif., under contract with ARDC. It is a unique track because one end, called the “muzzle,” ends at the brink of a 1,000-foot precipice. Ejection seats are hurled into space at the end of the track where the complete cycle of escape can be studied. The sled itself is constructed in two sections, fastened together. One is the test section and the other is the pusher vehicle. Both sections ride the track, on “slippers,” which grip the rails. The test vehicle is large enough to accommodate a full-sized operational ejection seat, life-size dummy, and parachutes complete with instrumentation. The pusher section, powered by a battery of rockets, also has reverse-firing rockets mounted on the sides facing forward to slow the sled’s forward speed at the end of the test run.
The track is constructed of crane rails, welded into two continuous 12,000-foot lengths, spaced fifty-six inches apart and laid on concrete with its foundation in bedrock. Controls and instrumentation consist of the usual telemetering equipment, camera stations, oscillographs, and tape recorders to provide vast amounts of data on each test run. The first test run at Project SMART was made on July 8, 1955. Tests have been conducted at supersonic speeds and the track is designed to reach speeds of Mach 2. Downward ejection seats, such as those used in the F-104 and B-47, can be tested on this track because of its unique feature of hurling test equipment through space to complete the cycle of emergency escape.
During the same week, at Patrick AFB, Fla., I was in the crowd of 20,000 who were invited to witness the first public launching of a Martin TM-61 Matador guided missile as part of the Armed Forces Day program. Launched by ARDC’s AF Missile Test Center, the tactical missile served the dual purpose of making its first public debut while carrying out a routine test. Following the usual coordination flares, range clearance, and count down, the RATO bottle under the missile was fired, and the Matador blasted off its zero-length launcher in a cloud of smoke and dust. Two and one-half seconds later it was over the ocean, closely followed by a North American F-86 chase plane. Both missile and plane, streaming marker smoke, disappeared in climbing flight on their down-range mission. It was a routine launching as far as the missile crew was concerned, but to the crowd lining the fence it was a spectacular sight.