JATO, is a type of assisted take-off for helping overloaded aircraft into the air
by providing additional thrust in the form of small rockets. The term JATO is
used interchangeably with the term RATO, for Rocket-Assisted Take Off.
Early experiments and World War II Early experiments using rockets to boost
gliders into the air were conducted in Germany in the 1920s, and later both the
Royal Air Force and the Luftwaffe introduced such systems in World War II.
The British system used fairly large solid fuel rockets to shoot planes off a
small ramp fitted to the fronts of merchant ships, known in service as
Catapult armed merchantmen, in order to provide some cover against German
maritime patrol planes. After firing, the rocket was released from the back of
the plane to fall into the water and sink. The task done, the pilot would fly
to friendly territory if possible or parachute from the plane, hopefully to
be picked up by one of the escort vessels. Over two years the system was
only employed nine times to attack German aircraft with eight kills
recorded for the loss of a single pilot. The Luftwaffe also used the technique
with both liquid-fueled and solid fuel, often jettisonable rocket motors in
order to help their small bombers, and the enormous Gigant, Messerschmitt Me
321 glider, conceived in 1940 for the invasion of Britain, and used to supply
the Russian front which also had air tow assistance from up to three
Messerschmitt Bf 110 heavy fighters in a so-called Troika-Schlepp arrangement,
into the air with loads that would have made the takeoff run too long otherwise,
but with much attendant risk of aerial collision from the trio of vee-formation
Bf 110s involved in a simultaneous towplane function. This became
especially important late in the war when the lengths of usable runways were
severely curtailed due to the results of Allied bombing. Their system typically
used Walter HWK 109-500 or -501 Starthilfe liquid-fuel monopropellant
rocket engines driven by chemical decomposition of "T-Stoff", essentially
almost pure hydrogen peroxide. A parachute pack at the blunt-contour
front of the motor's exterior housing was used to slow its fall after being
released from the plane, so the system could be re-used. First experiments were
held in 1937 on an Heinkel He 111, piloted by test-pilot Erich Warsitz at
Neuhardenberg, a large field about 70 kilometres east of Berlin, listed as a
reserve airfield in the event of war. Other German experiments with JATO were
aimed at assisting the launch of interceptor aircraft such as the
Messerschmitt Me 262C, as the Heimatschützer special versions, usually
fitted with either a version of the Walter HWK 109-509 liquid fuelled rocket
engine from the Me 163 Komet program either in the extreme rear of the
fuselage or semi-"podded" beneath it just behind the wing's trailing edge, to
assist its Junkers Jumo 004 turbojets, or a pair of specially rocket-boosted
BMW 003R combination jet-rocket powerplants in place of the Jumo 004s,
so that the Me 262C Heimatschützer interceptors could reach enemy bomber
formations sooner. Two prototypes of the Heimatschützer versions of the Me 262
were built and test flown, of the three designs proposed.
In early 1939, the United States National Academy of Sciences provided
$1,000 to Theodore von Kármán and the Rocket Research Group at the Guggenheim
Aeronautical Laboratory to research rocket-assisted take-off of aircraft.
This JATO research was the first rocket research to receive financial assistance
from the U.S. government since World War I when Robert Goddard had an Army
contract to develop solid fuel rocket weapons. In late 1941 von Kármán and his
team attached several 50-pound thrust, solid fuel Aerojet JATOs to a light
Ercoupe plane, and Army Captain Homer Boushey took off on test runs. On the
last run they removed the propeller, attached six JATO units under the wings,
and Boushey was thrust into the air for a short flight, the first American to
fly by rocket power only. Both armed services used solid fuel JATO during the
war. Post WWII
After World War II JATO became particularly common owing to the low
slow-speed thrust of then-current jet engines or for assisting heavy aircraft;
the prop-engined Avro Shackelton used Armstrong Siddeley Viper turbojets for
takeoff. As the take-off thrust of jet engines has grown, JATO has fallen from
favor. It is still used, however, when heavily-laden aircraft need to take off
from short runways or when operating in "Hot and high" conditions.
Two similar zero-length launch experimental programs were carried out
by the US Air Force and by the Soviet VVS at around the same time in the late
1950s, both using high-thrust, short thrust duration booster designs of very
similar appearance and function. The US Air Force used a modified Republic F-84,
designated EF-84G, which used the MGM-1 Matador cruise missile's solid fuel
booster. The Soviet VVS used a modified MiG-19 fighter, designated SM-30,
launched from a special launcher, and using a nearly identical solid-fueled
rocket booster design to that of the EF-84G. The F-100 and F-104 were also
used for zero-length launch experiments. Operation Credible Sport was a United
States military operation plan in late 1980 to rescue hostages held by Iran
using C-130 cargo planes modified with rocket engines to enable a very short
take off and landing. The plan was canceled after an accident during the
test landing when the forward-facing JATO units designed to slow the aircraft
the landing fired before the downward-facing units designed to
cushion the landing, causing the aircraft to crash-land.
The JATO JUNIOR Was an attempt by Aerojet Engineering to introduce smaller
JATO unit to small commercial aircraft, but was blocked by the U.S. Navy Bureau
of Aeronautics. Aerojet claimed than the smaller JATO bottle, delivering 250
pounds of thrust for 12 seconds can help a light private plane, that normally
requires almost 900 feet of runway to clear a 50 foot high obstacle, could do
the same with 300 feet of runway with a JATO Jr unit.
The Boeing 727 had provision for Aerojet JATO assist for use in "hot and high"
situations. Urban legend
The JATO Rocket Car is an urban legend that relates the story of a car equipped
with JATO units that is later found smashed into a mountainside. This story
is often given as an example of a Darwin Award; however it appears to be
apocryphal, with no basis in fact. The legend has been examined several
times on the Discovery Channel show MythBusters. For the first attempt, in a
2003 pilot episode, the crew replicated the scene and the thrust of the JATO
with some commercially-available amateur rocket motors. The car did go very fast,
outrunning the chase helicopter, but nowhere near the 300 mph reported in the
original story, and failed to become airborne. The myth was revisited in
2007, using a different configuration of rockets in an attempt to make the car
fly; however, it exploded before reaching the end of its launch ramp. The
myth was again revisited in 2013 in the 1st Episode of Mythbusters Series 12 -
as a celebration for the 10th year on air.
A JATO-equipped 1958 Dodge Coronet car on the El Mirage dry lake was used for a
TV advertisement to demonstrate the power of their 'total contact' brakes.
This was broadcast during The Lawrence Welk Show in the late 1950s.
Gallery See also
Assisted take-off References
Notes External links
Video of the Heinkel He 111 fitted with Walter's rocket boosters
"Birth of JATO." Popular Science, July 1946, pp. 74–75.
Boeing 727 using JATO on YouTube C-130 Lockheed Hercules JATO on YouTube