How It Works-Amazing Vehicles

Vertol VZ-2

One of the fi rst fully functional VTOL

aircraft, the Boeing Vertol VZ-2 paved

the way for the gargantuan V-22 Osprey

“ The VZ-2 sported twin rotors

powered from a single 700hp

turboshaft engine”

Unlike the Vertol VZ-2, Bell’s

X-14 experimental VTOL

aircraft was crafted and

designed to be as close to

existing aeroplanes as

possible, with it even being

constructed from parts of

other existing aircraft. Not

only were its w ings fi xed but

its engine was in the standard

horizontal position and, with

a top speed of 180 miles per

hour and operational ser v ice

ceiling of 20,000 feet, the X-14’s

design appeared

conventional. However, the

X-14 was one of the fi rst VTOL

aircraft to utilise the emerging

concept of multi-directional

engine thrust, relying on a

system of movable vanes to

control the direction of its

engine’s power.

Interestingly, after a couple

of years of successful fl ights,

the aircraft was delivered to

the NASA Ames Research

Center as – in addition to

prov iding a great deal of data

on VTOL fl ight – its control

system was similar to the one

proposed for the lunar module

and it was deemed a worthy

test vehicle for space training.

Indeed, Neil Armstrong, the

fi rst man to walk on the moon,

fl ew the X-14 as a lunar-

landing trainer and it was

continually used by

NASA until 1981

(seeing a total

of 25 pilots

climb in

and out of

its cockpit)

when it

was

retired

from

service.

An experimental fi xed-w ing

aircraft, the X-14 pushed back the

boundaries of VTOL technology

Many VTOL aircraft have been

designed in the past 50 years,

however most fall into one of two

categories; those based on

vectoring engine nozzles, and

those that adopt tilt-wing

technolog y. The Vertol VZ-2 falls

into the latter categor y and was a

wildly experimental research

aircraft built in 1957 to investigate

the tiltwing approach to VTOL.

Resembling a conventional

helicopter, albeit with an

extended plane-like T-tail, the VZ-

2 had an uncovered tubular

framework fuselage and a single-

seater bubble canopy.

The VZ-2 sported t w in rotors

powered from a single 700hp

turboshaft engine, which

positioned on its rotatable w ings,

in partnership w ith a series of

small ducted fans in the T-tail,

prov ided thrust and lift. Due to its

lightweight design, the maximum

speed achieved was 210mph and

it had a low operational ser v ice

ceiling of 13,800ft as well as a

minuscule range of 210km.

Despite these shortcomings,

the Vertol proved a ver y

successful and fruitful

experiment as over its eight-year

life span it made 450 fl ights,

including 34 with full vertical to

horizontal transitions. The

heritage of the VZ-2 can be seen

today in the titanic tilt-rotor

design and technology used on

the V-22 Osprey.

Bell X-14

The Bell X-14 on a

demonstration fl ight

The X-14 being prepped on

runway before a test fl ight

The fi rst non-

transition test

fl ight of the VZ-2

© George Chirn ilevsk y

Bell X-14

Crew: 1

Length: 7. 6 2 m

Wingspan: 10.36m

Height: 2.40m

Weight: 3,100lb

Engine: 2x Armstrong Siddeley

Viper 8 Turbojet

The statistics...

Vertol VZ-2

Crew: 1

Length: 8.05m

Wingspan: 7. 5 9 m

Height: 4.57m

Weight: 3,700lb

Engine: 1x Avco Lycoming

YT53-L Turboshaft

The statistics...

AIR