The war against gravity has been fought on various battlefields.
On one, designers try to get heavier-than-air machines off the ground vertically,
or at least in a very short space. On the other, designers strive to achieve,
regardless of the length of takeoff, the greatest altitude possible.
VTOL (Vertical Takeoff and Landing) demands both vertical and horizontal thrust
components. With a few exceptions these components have been provided by the same
power plants, either by tilting wings (and usually their attached engines), diverting
or ducting engine thrust, or tilting the entire aircraft to a vertical takeoff
and landing position.
As for high altitude, the heavier-than-air achievers in that field have been military
designs - 'black', or highly secret, at that - very different from the VTOL types,
and uniquely advanced for their time.
VTOL - TAIL-SITTERS:
RYAN X-13 VERTIJET - Ryan's 1947 investigations
of tail-sitting VTOL jet designs led to the delta-winged X-13 which flew in 1955
and made its first transitional flight in 1957.
LOCKHEED XFV-1 - The XFV-1 Salmon was a competitor
with Convair's XFY-1 Pogo in a 1950 competition to design a VTOL fighter
with performance superior to existing fighters. The program ended before the Salmon
achieved vertical takeoff.
CONVAIR XFY-1 POGO - Convair's tail-sitter was
their 1954 offering to achievement of vertical takeoff for fighter aircraft. It
was discarded when it was recognised it would never compete with the performance
of contemporary fighter aircraft.
SNECMA C.450-01 - The French acquired rights
to a tail-sitting annular wing design in 1952, and the unusually configured aircraft
flew successfully in 1959.
VTOL - TILTING WINGS/ENGINES:
BELL MODEL 200 / XV-3 - Bell's early interest in the
VTOL concept is embodied in the 1950 XV-3 project. The powerplant resided in the
fuselage, driving tiltable wing-tip rotor units.
BELL MODEL 65 ATV - The Bell Model 65 was a test aircraft
built mainly of components of various existing civil types in 1952, testing the
concept of rotating turbojet power plants for VTOL.
CURTISS-WRIGHT X-19 - An unusual entry into VTOL by
Curtiss-Wright was the 1963 X-19, with tilting rotors on the tips of both the
wings and the extended tailplane. It explored the use of 'radial lift' from the
rotors to provide lift even when tilted forward, thus allowing for smaller wings.
L.T.V. XC-142 - Developed in 1964 by Vought-Hiller-Ryan
(later Ling-Temco-Vought) the XC-142 was a tilt-wing tactical transport.
BELL X-22 - In 1965 Bell produced the X-22, another design with tilting rotors.
It was an unusual configuration, two engines mounted close in to the forward fuselage,
and two on a mainplane mounted near the rear of the aircraft.
BELL MODEL 301 / XV-15 - Bell's 1973 experimental
tilt-rotor aircraft is a developmental link between the company's Model 200 of
1950 and the Bell Boeing V-22 Osprey of today, and draws on Bell's extensive
experience with rotor aircraft.
BELL BOEING MODEL 901 / V-22 OSPREY - The Osprey
was built to serve a US multi-service requirement, and first flew in 1989. It
is one tilting-rotor design which is actually entering production and service
VTOL - DEDICATED THRUST/LIFT ENGINES:
SHORTS SC.1 - A British entry into the VTOL arena
was the 1957 Shorts SC.1, which used a composite system of five separate engines
for vertical and horizontal thrust.
DORNIER DO.31 - A German design of 1964, the DO.31 prototype's
approach to VTOL was to have separate detachable engine pods on the wing tips
to provide hover and low speed lift. The second prototype used thrust deflection
from the two main engines, with the lift pods as optional attachments.
VTOL - THRUST DIVERSION:
BELL MODEL 68 / X-14 - The X-14 was another Bell test
aircraft patched together from bits of civilian aircraft, this time for 1957 tests
of thrust diversion in VTOL aircraft.
Bell X-22A - The X-22A joint-service research design
was sponsored by the US Navy to investigate the feasibility of an arrangement
of four tilting duct power plants for VTOL aircraft.
RYAN MODEL 92 VERTIPLANE - Ryan's 1958 VTOL
test bed, also known as the VZ-3RY, employed a different source of takeoff lift.
Rather than tilting wings, engines or nozzles, it used oversized wing flaps to
deflect and contain the airflow from its twin propellors.
HAWKER SIDDELEY P.1127 - The design which broke through
and produced the Kestrel and the Harrier, the first successful VTOL
jet fighters to enter full scale production in both Britain and the USA. Its descendants
have seen action on many occasions.
YAKOVLEV YAK-36 FREEHAND - The Russian entry
into early VTOL research was the Yak-36 of the mid-1960s, powered by two turbojets
in the fuselage whose thrust could be deflected by external nozzles.
HIGH ALTITUDE AIRCRAFT:
BRISTOL TYPE 138 - In the 1930s, the piston-powered
Bristol 138 carried a pilot in a special pressure suit to the ten-mile mark above
LOCKHEED U-2 and TR-1 - The Lockheed U-2 was so secret
that early sightings of an aircraft at impossible altitudes in the 1950s were
allowed to remain as 'UFO reports'. It flew high enough to be thought of as untouchable,
until Russia downed one. Originally used by the CIA, it has soldiered into the
1990s as the TR-1A reconnaissance aircraft.
LOCKHEED A-11, A-12, YF-12 and SR-71 BLACKBIRD
- Considered to be one of the most impressive military jets ever built, the SR-71
of the 1960s remained officially the world's fastest air-breathing aircraft into
the 1990s. The A-12 and SR-71 were superb intelligence gathering aircraft, though
the YF-12 interceptor variant was not developed.
AURORA - possibly the widest rumoured of all
present-day black aircraft projects, Aurora remains the one about which
the least is known. It has therefore been the subject of the wildest speculations.