Hiller X-18

infobox Aircraft
name = X-18
type = Experimental prototype
manufacturer = Hiller Aircraft Corporation



caption = Ground testing the X-18 tiltwing
designer= Stanley Hiller Jr
first flight=24 November avyear|1959
primary user=
more users=
introduction=
retired=
number built= One
status=Aircraft scrapped avyear|1964
unit cost=
variants with their own articles=

The X-18 was an experimental cargo transport aircraft designed to be the first testbed for tiltwing and STOVL (short take off and vertical landing) technology.

Development

Design work started in 1955 by Stanley Hiller Jr and Hiller Aircraft Corporation received a manufacturing contract and funding from the U.S. Air Force to build the only X-18 ever produced.

To speed up construction and conserve money the plane was constructed from scavenged parts including a Chase C-122 Avitruc fuselage and the turboprops came from the Lockheed XFV-1 and Convair XFY-1 Pogo experimental airplanes program. The tri-bladed contra-rotating propellers were a giant 16 ft (4.8 m) across. The Westinghouse turbojet engine had its exhaust diverted upwards and downwards at the tail to give the plane pitch control at low speeds.

ervice history

The first test flight was on November 24, 1959, ultimately recording 20 flights out of Edwards AFB. A number of problems plagued the X-18 including being susceptible to wind gusts when the wing rotated, acting like a sail. In addition the turboprop engines were not cross-linked, so the failure of one engine meant the airplane would crash.

On the 20th and final flight in July 1961, the X-18 had a propeller pitch control problem when attempting to hover at 10,000 ft and went into a spin. The crew regained control and landed, but the X-18 never flew again. However ground testing of the tiltwing concepts continued. Eventually a test stand that the plane was mounted on failed and the plane was severely damaged in the fall. The program was finally cancelled on January 18, 1964 and the X-18 was cut up for scrap.

pecifications (X-18)

aircraft specifications
plane or copter?=plane
jet or prop?=both
ref=
crew=2-3
capacity=
payload main=
payload alt=
length main= 63 ft 0 in
length alt= 19.2 m
span main= 48 ft 0 in
span alt= 14.6 m
height main= 24 ft 7 in
height alt= 7.5 m
area main=
area alt=
airfoil=
empty weight main= 26,786 lb
empty weight alt= 12,150 kg
loaded weight main=
loaded weight alt=
useful load main=
useful load alt=
max takeoff weight main= 33,000 lb
max takeoff weight alt= 14,850 kg
more general=
engine (jet)=Westinghouse J34
type of jet=turbojet engine for pitch control
number of jets=1
thrust main= 3,400 lbf
thrust alt= 15.2 kN
thrust original=
afterburning thrust main=
afterburning thrust alt=
engine (prop)= Allison T40-A-14
type of prop=turboprop engines
number of props=2
power main= 5,500 hp
power alt= 4,100 kW
power original=
max speed main=253 mph
max speed alt= 407 km/h
cruise speed main=
cruise speed alt=
stall speed main=
stall speed alt=
never exceed speed main=
never exceed speed alt=
range main=
range alt=
ceiling main= 35,300 ft
ceiling alt= 10,800 m
climb rate main=
climb rate alt=
loading main=
loading alt=
thrust/weight=
power/mass main=
power/mass alt=
more performance=
armament=
avionics=

ee also

aircontent

related=

similar aircraft=
* LTV XC-142
* Canadair CL-84

sequence=
* X-15 - X-16 - X-17 - X-18 - X-19 - X-20 - X-21

lists=
* List of military aircraft of the United States
* List of VTOL aircraft

see also=
* Tiltwing
* Tiltrotor

External links

* [http://www.tiltrotormech.com/aircraftpages/hiller_x_18.htm Hiller X-18]
* [http://avia.russian.ee/vertigo/hiller_x-18-r.html X-18 History]
* [http://www.studenten.net/customasp/axl/plane.asp?cat_id=12&ple_id=502&page=0 X-18 Images]
* [http://www.airbornegrafix.com/HistoricAircraft/VTOL/Hiller.htm X-18 Images and History]