Ever since the Wright brothers used a falling weight from a tower to accelerate some of their early aircraft on takeoff when winds alone were not enough, the need to apply external energy to achieve flying speed has been recognized and pursued in different ways. The Wright’s device was an early form of a catapult, a system much-modified and used by aircraft carriers still.
But another takeoff booster found favor because it could be attached to many types of aircraft and did not require a modified runway or takeoff surface. Commonly known as JATO, for jet-assisted takeoff, it is also called RATO for rocket-assisted takeoff. You get the idea from either acronym — a special thruster helps accelerate the aircraft to give it flying speed more quickly.
The applications for JATO appealed to aeronautical planners. In Germany, the huge Me 321 transport, fully loaded, lumbered along too slowly for too long to achieve takeoff in the usable length of the airfield unless add-on rocket boosters could accelerate the beast. Seaplanes could get unstuck from the surface of the water more quickly.
And C-130 Hercules transports could operate from short or high-altitude airstrips with the boost provided by attachable JATO bottles.
The dawn of JATO coincided with World War II. While many aircraft were tested for JATO compatibility, it was not commonly used on most of them.
The British made limited use of a rocket bottle attached to a Hawker Hurricane, mounted on some convoy freighters and launched at the sight of German anti-convoy bombers. The spent booster rocket fell to the sea, and the Hurricane could hopefully fly to land or ditch nearby so its pilot could be rescued by the convoy.
The notoriously slow acceleration of early jet engines gave the designers of Boeing’s revolutionary swept-wing B-47 Stratojet cause to employ JATO to help heavy B-47s quickly reach flying speed. Early B-47s were built with an internal JATO system with 18 nozzles pointing aft; others used 30 or more attachable external rockets that could be dropped when spent.
Boeing also made provision for JATO use with the 727 trijet airliner, a feature that could be important in high altitude airfields with high density altitude.
During the Cold War, the United States tried creative ways to keep a nuclear reaction force viable in Europe in the face of a possible Soviet strike that could render runways unserviceable. The American answer was ZELMAL — Zero-length launch, mat landing.
It started with tests at Edwards Air Force Base with a trailer-mounted F-84 Thunderjet propelled to flight speed by a large booster rocket. Presuming runways would be unusable, the modified F-84 was intended to land, wheels up, on a portable rubber mat. The ZEL part worked; MAL, not so much, with a test F-84 bouncing off the mat and onto the ground beyond in a filmed test.
The concept matured with the potential to launch a nuclear-armed F-100 Super Sabre with a rocket booster from a standing start — just the ZEL portion. This time, the plan called for the F-100 pilot to deliver a nuclear weapon on target and then fly back to friendly territory and bail out.
West Germany explored ZEL with an F-104G tested at Edwards AFB and the Soviets tried it with the MiG-19. But ZEL remained an exhilarating test, not an operational reality.
The availability of missiles and V/STOL aircraft helped make ZEL obsolete. Improvements in engine performance generally reduced the need for JATO in other operations.
For many years, the U.S. Navy Blue Angels’ support aircraft, a C-130, made a spectacular JATO-assisted takeoff during team performances at air shows. But as the last stockpile of JATO bottles was depleted, the JATO demonstrations concluded in 2009.