VSTOL History and Development

8/2/2019 VSTOL History and Development

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Table of ContentsWhat goes up must come down

i. Introduction 2A brief account of my term paper.

ii. VTOL and STOL 4Pros and Cons discussed.

iii. Major Challenge 6Practical problems faced.

iv. History and Development 7The story of V/STOL aircrafts.

v. Under Development 56Aircrafts in development.

vi. Future Concepts 72Upcoming V/STOL technologies.

vii. Webography 82Websites referred.


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Developed by Dassault

Aviation, in each aircraft eight

Rolls Royce vertical lift

engines were installed

straddling the main engine.

Introductionto V/STOL(Vertical or Short Take-Off and Landing)

Conventional aircrafts require long runways for take-off and landing (known as CTOL

conventional take-off and landing). The runways required for CTOL can extend up to 3,000

metres. In many situations, long runways are not possible generating need for aircrafts that

require small or no runways.

Vertical and/or short take-off and landing (V/STOL) is a

term used to describe aircraft that are able to take-off or

land vertically or on short runways. Vertical takeoff and

landing (VTOL) describes an aircraft which do notrequire runways at all. Generally, a V/STOL aircraft

needs to be able to hover; helicopters are not typically

considered under the V/STOL classification.

Helicopters require no runways at all, but they do not

provide the efficiency of an aircraft in terms of speed and range. To overcome this problem,

aircrafts with the ability to take-off and land like a helicopter were designed and the term

V/STOL was introduced.

These types of aircraft are generally classified either as Vertical Takeoff and Landing (VTOL) or

Short Takeoff and Landing (STOL), and the two categories are often grouped together as

V/STOL.

Designing a V/STOL aircraft has many challenges involved, stability and other factors. From the

1950s till today, more than 40 aircrafts have been made and

experimented, out of which only three were successful enough to

be produced in large quantities with a fourth aircraft to be soon

joining the production.

The biggest problem with achieving V/STOL flight is that

conventional wings provide a good amount of lift for a relatively

low amount of forward thrust. Getting an aircraft off the ground

with little or no forward motion requires that engine thrustand

not wing liftsupport a significant portion of the aircraft's

weightor all of it. This usually requires big engines, lots of fuel,

and complicated flight controls, all of which weigh more.

A Bell-Boeing V-22 Osprey aircraft

lifting cargo vertically.


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Another problem is that these aircraft are often hard for the pilot to control during transition from

horizontal flight to vertical flight and back again. Computerized flight control systems and better

cockpit displays have helped with this. Some experimental V/STOL aircraft also simply have

had a hard time accelerating in forward flight after lifting off the ground.

Lockheed XFV-1 tailsitter

This "tailsitter" aircraft had two large contra-rotating

propellers on its nose. In horizontal flight, the aircraft

looked like many piston-engine fighters, although with a

large tail. When on the ground, it actually sat on its tail.

The plane would rise straight up during takeoff and

transition to forward flight.

These aircrafts were extremely difficult to control in

vertical flight (the pilots had to look over their shoulders

to see the ground when landing), and were grounded in

1956.


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VTOL and STOLits advantage and requirement

Even before the dawn of jet aircraft, aeronautical engineers have wanted to reduce the amount

of runway required by fast aircraft, preferably eliminating runways completely. They wanted an

aircraft that takes off and lands like a helicopter

but flies with the efficiency of an airplane.

V/STOL was developed to allow fast jets to be

operated from clearings in forests, from very

short runways, and from small aircraft carriers

that would previously only have been able tocarry helicopters.

The main advantage of V/STOL aircraft is closer

basing to the enemy, which reduces response

time and tanker support requirements.

In the case of the Falklands War, it also permitted high performance fighter air cover and

ground attack without a large aircraft carrier equipped with a catapult.

Fifty years ago, the first ground tests were conducted for what would become a long heritage of

Vertical and Short Take-Off and Landing (V/STOL) aircraft. Since then, 43 different types have

been built and tested. All these aircrafts built have been tried to combine the vertical flight ability

of the helicopter with a high forward speed of fixed wing aircraft. Of all these attempts, so far

only three aircrafts, the Harrier, the Forger, and the Osprey have been developed for

operational service.

A helicopter can be operated in small areas,

like top of buildings or urban areas.

Harrier Jum Jet Yakovlev Yak-38 Bell Boeing V-22 Os rey


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Some aircrafts which were created for the sole purpose of STOL also made their way to

production. These are used for transport or as strategic/tactical airlifter.

The Joint Strike Fighter (JSF) Program developed two V/STOL aircrafts which demonstrated

their propulsion concepts in 2000; one of these concepts was selected for development as an

operational aircraft to replace the Harrier in the next century.

The concept which was selected against (Boeings X-32) the other was the Lockheed Martin X-35. This prototype has been developed into F-35 Lightning II which is expected to be

operational by 2016.

A Lockheed Martin F-35 Lightning II hovering over the ground.STOVL is made possible by a lift fan placed ahead of center of gravity connectedto the engine through a driveshaft. The rear lift force is controlled by a swivelling

exhaust nozzle from the engine.

Boeing C-17 Globemaster IIIThis cargo plane is not considered aSTOL aircraft but can operate from a

shorter-than-usual runway.

Antonov An-72

It was designed as a STOL transport. It has

extremely good short field capabilities.


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Major Challengewhy the VTOL aircrafts are not as practical as they sound

The Thrust and Drag forces are usually quite a bit smaller than the Lift and Weight forces. An

efficient airplanes thrust might only need to be 1/20 to 1/60 of its weight in order for the airplane

to be pulled forward fast enough to stay in the air. (Typically its more like 1/5). This means an

airplane that weighs, say, 100 tons might only need 10-20 tons of thrust to stay in the air. But a

VTOL airplane that weighs 100 tons obviously needs 100 tons of thrust to get off the ground.

Since modern airplanes lift-to-drag ratio is about 5, 20, or up to 60, this means a VTOL airplane

needs 5, 20, or 60 times the thrust of an equivalent non-VTOL airplane.

Getting an aircraft off the ground with little or no forward motion requires that engine thrust

and not wing liftsupport a significant portion of the aircraft's weightor all of it. This usually

requires big engines, lots of fuel, and complicated flight controls, all of which weigh more. Other

complexity comes in designing and stability of the aircraft. While hovering, the aircraft needs to

be stable enough to face the winds.

Consider an Airbus A300-600R, if we wanted VTOL in that aircraft, the engines would have to

produce a minimum vertical force of 171.7kN, since the aircraft has been developed for CTOL,

it only requires a maximum force of 54.4kN which is provided by two Pratt & Whitney PW4158

turbofan aircraft en ines. Each en ine roduces a maximum thrust of 27.2kN.


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History and Developmentof the V/STOL aircrafts

From the 1940s until today, slightly more than 40 vertical/short takeoff and landing aircraft have

been tested. However, only three V/STOL aircrafts have actually gone into production. Most of

the other aircrafts were highly experimental or proof-of-concept types.

The study of the history of this topic will be grouped according to their respective concept of the

propulsion system. In V/STOL aircrafts, it is of utmost importance as the entire aircraft stays in

the air because of it. If the aircraft is hovering and the system fails then the aircraft is bound to

crash as it cannot be operated as a glider because of the low speed. Conventional aircrafts

operate at high speed and the pilots have the option to eject themself or land the aircraft.

Dividing the history in terms of different concepts of propulsion system will help us recognize theproblems faced by each system while getting to know about the different propulsion systems in

an orderly manner.

This list consists of a broad classification of the four different propulsion concepts:

1. Same propulsion system for hover and forward flight:

This class of aircraft uses a single propulsion system that alters

the direction of thrust for hover or cruise, or alters the attitude of

the aircraft itself.

E.g.:- Bell X-22A

2. Separate power plant for hover:

This class of aircraft used two separate groups of power plants:

one for hover, and one for cruise.

E.g.:- Short Brothers Short SC. 1

3. Combined power plant for hover:

This class of aircraft used its main propulsion system for both

hover and cruise, but also had a separate propulsion system for

additional hover thrust.

E.g.:- VFW VAK 191B

4. Augmented power plant for hover:

This class of aircraft used the power plant(s) to drive an auxiliary

device (either ejector augmenters or lift fans) to provide

additional vertical thrust in hover.

E.g.:- Lockheed Martin X-35


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| Same propulsion system for hover and forward flight |The Tail Sitters

A tail sitter is a type of VTOL aircraft that launches and lands on its tail.

An aircraft that points straight up permits the entire thrust of its propulsion system to be

converted directly into vertical lift. Unfortunately, while it may be somewhat easy to take off

facing up, it was considerably more difficult to land facing the opposite direction the aircraft was

traveling.

One of the most famous examples of this type of aircraft is the Ryan X-13 Vertijet. Among the

propeller-driven versions were the Lockheed XFV, and the Convair XFY Pogo. Studies and

wind tunnel models were made of a tail-sitting version of the F-16 that would be ship based. It

had a hinged nose section.The downfall of the tailsitter configuration was the lack of ability to transition the pilot to a

comfortable position from which to control his descent.[citation needed] This inability led to the

concept being abandoned as soon as the experiments that led to the development of the

Hawker Siddeley Harrier in the 1960s began to bear fruit.

Ryan X-13 Vertijet

In 1951, Ryan was awarded an Air Force contract in 1953 todevelop an actual flying jet-powered VTOL aircraft, which was

given the designation X-13. It was only 24 ft long - just large

enough to accommodate a cockpit (with a tilted seat) and the

10,000 lb thrust Rolls-Royce Avon turbojet. Its high mounted

delta wing had a wingspan of only 21 ft, capped with flat

endplates. At the tip of the nose was a short pole ending in a

hook. The hook was used to capture a wire on a vertical trailer

bed. Once captured, the trailer was lowered to horizontal and

could be transported on the ground. Engine thrust was vectored to provide pitch and yaw

control in hover, while roll was provided by puffer jets outboard of the endplates. The first

prototype was fitted with a temporary landing gear and made its first horizontal flight on 10

December 1955. It later made full conversions to vertical attitude and back at altitude. The

second prototype followed a similar progression; on 11 April 1957, it made a vertical take-off

from the raised trailer, transitioned to horizontal flight and back, ending with hooking on the wire

"trapeze." On 28-29 July of that year, the X-13 was demonstrated in Washington, hovering

across the river to the Pentagon. The Air Force chose not to continue development of the

Vertijet because of the lack of an operational requirement.


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Convair XFY-1 Pogo

As with the Lockheed XFV-1, the Pogo used the Allison

YT40-A-14 engine and Curtiss-Wright counter-rotating

propellers, but was somewhat more compact and less

conventional in appearance. The Pogo was 31 ft long

with a 26 ft wide delta wing. A large vertical stabilizer

above the wing was matched by an equally sized ventral

fin below which could be jettisoned for an emergency

horizontal landing. The seat was inclined 45 toward the

instrument panel for vertical flight. Control in hover for the

XFY-1 were also the same as for conventional flight, but again this provided only limited control

power. Almost 300 tethered tests hanging from the ceiling of Moffett Field's airship hangar weremade in April 1954. First free hover was on 1 August 1954. The first double transition to

horizontal flight and back to a vertical landing was made on 2 November 1954. The Pogo was

flown until November 1956. As with the Lockheed XFV-1, the engine and control systems were

considered inadequate.

Lockheed XFV-1

After World War II, the US Navy was looking for ways to

improve ship defense by equipping merchant ships with

vertical take-off aircraft. A 1950 design competition

selected Convair (#24) and Lockheed to each build a

single-seat tail sitting fighter aircraft. Each used the

Allison YT40-A-14 engine (two coupled T38 power

sections mounted side-by-side) driving two 16 ft counter-

rotating three-bladed Curtiss-Wright propellers with

electric pitch control. The engines produced 5,500 eshp

with a 7,100 eshp take-off rating, resulting in over 10,000

lb of thrust. The 37 ft fuselage had mid-mounted 30 ft span wings. Control in hover was by the

same large aerodynamic surfaces as in level flight, as each was bathed in propeller slipstream;

the "X"-shaped tail arrangement minimized downwash masking. An erector trolley was used to

stand the XFV-1 in the vertical position; the tips of each tail had a small castoring wheel. A total

of 27 conventional flights were made, with the first full transitions made above 1,000 ft that Fall.

Control in hover was very weak, and the pilot had difficulty in determining sink, climb, and

rotation from normal visual cues. No vertical take-offs or landings were ever attempted. As with

the Convair XFY-1 Pogo, the engine and control systems were judged to be insufficient.


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| Same propulsion system for hover and forward flight |Deflected Slipstream Aircraftsexploiting flaps for successful STOL

Deflected slipstream is an approach to creating an aircraft that can take off and land vertically

(VTOL), or at least with a very short runway (STOL). The basic principle is to deflect the

slipstream from one or more propellers approximately 90 degrees, to create an upward thrust

for vertical takeoff and a downward air cushion for landing. Once airborne, the flaps are

retracted so the airplane can fly horizontally.

Three different craft were built in the late 1950s and early 1960s that utilized deflected

slipstream as the means of achieving vertical or short take-offs.

While no aircraft utilizing deflected slipstream technology ever entered production as a VTOL

vehicle, this technology has been used to allow short takeoff and landing (STOL) airplanes. One

noted example was the Breguet 941, which did see limited service in production mode.

The Breguet 941 was a French four-engine STOL transport aircraft developed by Breguet in

the 1960s. Although widely evaluated, it was not built in large numbers, with only one

prototype and four production aircraft being built.


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Robertson VTOL

Robertson Aircraft Corporation was formed in October 1956 to

build a four seated vertical take-off and landing (VTOL) aircraft

powered by two supercharged 340 hp Lycoming GSO-480

engines. The wing had a sliding flap system with a double-slotted

full span trailing edge flap providing all control. The flaps were retracted into the low aspect ratio

wing for horizontal flight. All fuel and oil were carried in wing tip tanks which also acted as

endplates. This capped the wing "buckets" and should have improved cruise efficiency. The

aircraft made a tethered flight on 8 January 1957 but was not pursued.

Fairchild 224 VZ-5 Fledgling

The Fairchild M-224-1 Fledgling was powered by a 1,024 shp

General Electric YT58-GE-2 turboshaft engine turning four three-

bladed Harzell metal propellers. The open cockpit had room for

the pilot as well as a jump seat. The aircraft could either sit on its

forward tricycle landing gear or rest on its two main wheels and a tail skid, providing the

Fledgling with 30 of inherent rotation to enhance the "bucket's" effectiveness. Small rotors at

the top of the T-tail controlled pitch during hover. Tethered tests were made in late 1959, but it

never flew.

Ryan 92 VZ-3 Vertiplane

The Ryan 92, designated VZ-3 by the Army in June 1956, was

intended to be a reconnaissance and liaison aircraft able to

operate from unprepared surfaces. It had a 28 ft metal fuselage

and was powered by a 1,000 shp Lycoming T53-L-1 turboshaft

engine driving a metal three-blade Harzell propeller on each side.

The propellers were situated ahead of and below the wing, so the majority of the propeller

slipstream flowed directly into the bucket formed by the extended double flaps and were turned

downward for vertical lift. Differential propeller pitch was used for roll control. Engine exhaust

was used at the tail for pitch and yaw before aerodynamic controls were effective. After

extensive wind tunnel tests and aircraft modifications the first flight was made on 21 January

1959. The engines were unable to provide sufficient power to hover without a head wind. Itcontinued flying in 1961, testing low-speed V/STOL handling characteristics.


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| Same propulsion system for hover and forward flight |

Convertiplanestilting propulsion design

The most commonly tested type of V/STOL aircraft has been the various tilting propulsion

designs, often collectively called "convertiplanes." These aircraft tilt propellers, rotors, ducted

propellers, or even their entire wings from vertical to horizontal.

Below are different types of tilting designs:

a. Tilt Shaft/Rotor

These aircraft are convertiplanes using rotating blades that function like rotors

in vertical flight and like propellers in forward flight. The rotors are long

articulated blades which have cyclic pitch control for hover. The power plantsremain stationary with the power shaft pivoting from vertical to horizontal.

b. Tilt Prop

This is basically the same as the tilt shaft/rotor concept, but with propellers

instead of rotors. A propeller, with collective but not cyclic pitch control, has

short, rigid blades with a high degree of twist.

c. Tilt Duct

Putting a propeller inside a duct can produce as great as a 50% thrust increase

due to the Bernoullis Effect, and also provide additional lift in forward flight.

Propeller pitch as well as deflector vanes in the downwash can control the

aircraft in hover and transition.

d. Tilt Wing

Tilting the entire wing, instead of just the rotor or propeller, provides the benefit

of increasing aerodynamic flow over the lifting and control surfaces during

transition, and minimizes the lift loss due to downwash in hover.Disadvantages, however, are that an additional method of control such as a tail

jet or rotor is required for control in hover, and ailerons change from roll control

in horizontal flight to yaw control in hover. Control is especially difficult in hover

during gusts due to the "barn door effect" of the wings in a vertical position.

e. Tilt Rotor

The aircraft tilted the rotors for transition from vertical to horizontal flight. Like

the larger Tilt Wings (nos. 9-11), the engines tilted together with the rotors.


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Transcendental Model 1G

The Transcendental Aircraft Company was formed by

former Piasecki workers in 1945 to investigate tilting rotor

technology. It built the single-seat open cockpit Model 1G in 1951. The 1G then made its first

flight (as a helicopter) on 6 July 1954 and made its first conversion to horizontal flight that

December. A single 160 hp Lycoming O-290-A engine powered three-bladed 17 ft rotors at

each wingtip. The piston engine had a manual two-speed reduction box that powered shafts

down each wing. At the pivot, three concentric shafts supplied input to the rotors for tilt angle,

cyclic pitch, and collective pitch. At the maximum engine speed of 3,000 rpm, rotor speed for

hover was 240 rpm, while for horizontal flight they rotated at 633 rpm. The rotors required three

minutes to transition through 82 of tilt during conversion, including the gear change. The 1,750

lb (fully loaded) 1G had a 26 ft long fuselage and a wingspan of 21 ft. The height was only 7 ft;

in fact, the 1G was so small, the pilot's head rose above the windscreen (see photo). The 1G

flew over 100 flights and 20 hours before being lost in an accident on 20 July 1955 due to a

rotor control mechanical failure. Top speed was about 160 mph. A 4,000 lb Model 2 with a 250

hp engine was tested in 1956-57, but the Air Force decided to not fund it further in order to

pursue the competing Bell XV-3.

Bell XV-3

One of the founders of Transcendental left to take

the lead on the design of the Bell XV-3, which

began under a joint Army-Air Force program in

1951. The XV-3 used the reliable 450 hp Pratt &

Whitney R-985 radial engine mated to a two-speed

manual gearbox, similar in principal to that of the

Transcendental 1G. The fuselage was 30 ft long

and had a 31 ft wing span. It made its first flight as a helicopter in August 1955, but crashed two

months later before completing a full conversion. Extensive wind tunnel and rig tests wereconducted after this, with pilots practicing the conversion process and gear changes (which

required significant manipulation of the pitch and throttle controls and took about 20 seconds) in

the tunnel. Rotor instability concerns led to a change from 23 ft three-bladed full-articulated

rotors to 24 ft two-bladed semi-rigid rotors. The second XV-3 made its first flight on 12

December 1958, with a full conversion only 6 days later. Conversions over the full 90 could be

conducted in 10 seconds. Inadequate power and high weight growth precluded the XV-3 from

hovering out of ground effect. The XV-3 made 110 full conversions and over 250 flights before it

was damaged in a wind tunnel test in 1965 when a rotor housing separated from the aircraft.

The ejection seats were thankfully never needed: they ejected downward.


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| Same propulsion system for hover and forward flight | Tilt Prop |

Curtiss-Wright X-19

Using the radial force lift concept proven by the X-

100, Curtiss-Wright designed a six-passenger civil

executive transport, originally designated the X-

200. As a part of the Army/Navy/Air Force Tri-

Service Assault Transport Program, the Air Force

contracted for conversion of two prototypes, designated X-19 and extensively modified for

military requirements with ejection seats, rescue hoist, mock refueling probe and a fuselage

stretch for improved passenger access. The 44 ft long aircraft was powered by two Lycoming

T55-L-7 turbo shaft engines producing 2,650 shp each. At the end of each tandem wing was a13 ft three-bladed wide chord, high twist propeller. In order to eliminate gyroscopic and torque

effects, propellers located diagonally rotated in the same direction. Roll, pitch and yaw were all

controlled by differential propeller pitch. Empty weight as flown reached 10,000 lb, and gross

weight over 12,000 lb. The first aircraft hovered on 20 November 1963, but suffered a hard

landing. It was repaired, but problems with the control system and a series of mechanical

problems plagued the program. On 25 August 1965 a transmission part failure caused an

asymmetric lift situation, which allowed the crew to validate the operation of their ejection seats.

When the program was canceled four months later, the first aircraft had made 50 flights, but for

a total of only four hours. The second aircraft was never flown.

The American armed forces had expressed an interest in this formula for reconnaissance,

transport and tactical support, but the X-19's performance in the airplane mode was not brilliant.

Despite a maximum cruise speed of 650km/h, its payload capacity was less than 550kg. The

first pro-totype was quite badly damaged on its second flight in November 1963 and the second

was never flown.

General characteristics

Crew: Two

Payload: 544 kg

Length: 12.83 m

Wingspan: 5.94m (forward) / 6.55m

(aft)

Height: 5.2 m

Max takeoff weight: 6,196 kg

Powerplant: 2 Avco Lycoming

T55-L-5 turboshaft, 2,200 shp

(1,640 kW) each

Performance

Maximum speed: 454 mph (730

km/h)

Range: 325 miles (523 km)


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| Same propulsion system for hover and forward flight | Tilt Duct |Bell X-22

The X-22A was the Navy contracted and

managed portion of the Tri-Service Assault

Transport Program. The Bell X-22A was 39 ft

long, featured side-by-side pilot seats, and had a

gross weight of 17,000, including six passengers

or a 1,200 lb payload. It was powered by four 1,250 shp GE YT58-GE-8D turboshaft engines

that were cross-linked and had 35% excess power in case one of the engines failed in hover.

Span over the canard (including the 7 ft diameter three-bladed ducted propellers) was 23 ft;

across the rear wingtip ducts it was 39 ft. Theducts rotated non-differentially from 0 to 95 and

had spanwise elevons across the center of the

duct. Differential propeller pitch and the elevons

were used to control the X-22A in hover. In

forward flight, the ducts provided a significant

amount of the aerodynamic lift. The first aircraft

was rolled out on 25 May 1965. It made its first

hovering flight in March 1966, and was tested to

transition angles of up to 30 at speeds of up to 100 kt. That August, the first prototype was lost

in a hard landing after only three hours of flying time due to a hydraulic failure. The second

prototype made its first flight in January 1967 and performed hundreds of complete transitions.

It reached a maximum speed in forward flight of 315 mph, and had a range of 450 miles. In

early 1968, the X-22A's variable stability and control system was demonstrated, which allowed

for research into hover and transition flight characteristics of other possible V/STOL aircraft. On

30 July 1968, it set a record by hovering at an altitude of over 8,000 ft. Flying until 1980, it

accrued about 200 hours in the air.


Crew: Two

Length: 12.07 m

Wingspan: 11.96(rear) / 7.01m(front)

Height: 6.31 m

Empty weight: 4,763 kg

Max takeoff weight: 8,020 kg

Powerplant: 4 General Electric-YT58-GE-

8D turboshafts, 1,267 hp (932 kW) each

* Propeller Diameter: 2.13 m

Performance

Maximum speed: 410 km/h /

255 mph

Range: 712 km

Service ceiling: 8,475 m

Hovering Altitude with Wing

In Ground: 3,658 m

Hovering Altitude

without Wing In

Ground: 1,829 m


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Interesting is the fact that with this program there was a research and development

period (1958-1963) of a considerable length before the first prototype was constructed.

The R&D would produce a design that would incorporate a number of significant

innovations. Included were the following features:

A large chord wing which was to be immersed in the propeller slipstream

Huge propellers on a pair of power plants

All engines, rotors, and the tail rotor which were connected together by intricate

shafts and gear boxes

Conventional-style cockpit controls

Stability augmentation system for reduction of pilot workload in low-speed flight

conditions


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| Same propulsion system for hover and forward flight | Tilt Wing |

Canadair CL-84

The Canadian CL-84, begun in November

1963, was a quarter the size of the XC-142.

It weighed 8,100 lb empty, could make a

vertical take-off at 12,200 lb, or a short

take-off at 14,700 lb. The wings were 33 ft long and housed two 1,450 shp Lycoming T53-

LTC1K-4A turboprops which powered the cross-linked 14 ft four-bladed propellers. Pitch control

was provided by two counter-rotating two-bladed horizontal propellers, which in horizontal flight

were stopped and aligned to minimize drag. Roll control was by differential pitch, and yaw was

controlled with ailerons. It made its first vertical flight inMay 1965, and first conventional flight that December.

A total of four aircraft were built, including one which

was not flown. US pilots evaluated it extensively,

including demonstrations on amphibious ships and the

Pentagon helipad. Neither government was sufficiently

interested to order production aircraft. Two aircraft

were destroyed in non-fatal accidents due to

mechanical failures.


Crew: 2

Capacity: 12 passengers

Length: 14.415 m

Wingspan: 10.46 m

Height: 4.34 m Airfoil: NACA 633-418


Max takeoff weight: 6,577 kg (STOL),

5,710 kg (VTOL)

Powerplant: 2 Lycoming T53 shaft-

turbines, 1,500 shp (1,100 kW) each

Main rotor diameter: 2.13 m

Propellers: 4-bladed, 4.27 m diameter

Performance

Maximum speed: 321 mph

(517 km/h; 279 kn)

Cruise speed: 301 mph (262 kn;

484 km/h)

Never exceed speed: 415 mph

(361 kn; 668 km/h)

Range: 421 mi (366 nmi; 678 km)

with max wing fuel, VTOL, & 10%

reserves

Rate of climb: 4,200 ft/min(21 m/s)

Aircraft transformation from vertical tohorizontal flight.


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| Same propulsion system for hover and forward flight | Tilt Wing |

LTV XC-142_________________________________

The XC-142 aircraft was the third aircraft

evaluated in the Tri-Service Assault

Transport Program. It used four cross-

linked 3,080 shp General Electric T64-

GE-1 engines, each driving a 15.5 ft four-

bladed propeller. The wing could tilt

through 100 allowing the XC-142 to hover in a tailwind. The tail rotor folded to the port side to

reduce the stowage length and to protect against accidental damage during loading. This cargo

aircraft was 58 ft long, had a wingspan of 67 ft and was capable of transporting 32 troops and

gear or 8,000 lb of cargo. It had a rear loading ramp and had a maximum gross weight of

41,000 lb for a vertical take-off, or 45,000 lb for a short take-off. It made its first conventional

flight on 29 September 1964, first hover on 29 December 1964, and first transition on 11

January 1965. Air Force trials included cargo flights, cargo and paratrooper drops, and desert,

mountain, rescue, and carrier operations. Five aircraft were built, but mechanical failures

(primarily the cross-shaft and gear boxes which could be damaged during wing flexing) and

operator error caused four of them to be damaged in hard landings. The XC-142 suffered from

excessive vibration and noise, resulting in a high pilot workload. During the program, the XC-

142 accrued 420 hours by 39 different pilots as an operational evaluation aircraft.


Crew: 2

Capacity: 32 fully equipped troops

Payload: 8,000 lb (3,336 kg)

Length: 58 ft 1 in (17.71 m) Wingspan: 67 ft 6 in (20.60 m)

Height: 26 ft 1 in (7.95 m)

Empty weight: 22,595 lb (10,270 kg)

Max takeoff weight: 44,500 lb (20,227

kg) (STOL)

Powerplant: 4 General Electric T64-

GE-1 turboprop, 2,850 hp (2,126 kW)

Performance

Maximum speed: 694 km/h at 6,100 m

Cruise speed: 463 km/h at sea level

Combat radius: 757 km

Ferry range: 6,100 km Service ceiling: 7,620 m

Rate of climb: 34.5 m/s


23/83

22


24/83

23

| Same propulsion system for hover and forward flight | Tilt Rotor |

Bell XV-15

Over twenty years after they began work

on the XV-3, Bell received a contract to

begin work on their 13,000 lb Research

Tilt Rotor aircraft, which was designated

XV-15. The 42 ft fuselage housed side-by-

side pilot seats. At each tip of the 35 ft

span wings, a 1,550 shp Lycoming T53-LTC1K-4K turboshaft engine powered a 25 ft diameter

three-bladed rotor. The engines and rotors tilted through 90 and were cross-linked in the event

of engine failure. The rotors were semi-rigid stainless steel with a high twist and no flapping

hinges. Control at low speeds was by cyclic and collective blade angle adjustments. The first

hover of the joint Army/NASA XV-15 was performed on 3 May 1977. The first aircraft was later

tested extensively in the wind tunnel. Aircraft number two made its first hover on 23 April 1979.

It made the first conversion to horizontal flight on 24 July 1979. In the next several years, the

XV-15 conducted extensive tests, shipboard landings, and achieved a maximum speed (in a

dive) of 397 mph. By 1986, it had made 1,500 conversions in 530 flight hours. The aircraft was

flight tested aboard the USS Wasp in 1990 to evaluate shipboard compatibility issues of the tilt

rotor concept.


Crew: Two (pilot, copilot)

Length: 42 ft 1 in (12.83 m

Wingspan: 57 ft 2 in (17.42 m) with

turning rotors)

Rotor diameter: 25 ft (7.62 m)

Height: 12 ft 8 in (3.86 m)

Airfoil: NACA 64A015


Max takeoff weight: 13,000 lb (6,000 kg)

Powerplant: 2 Avco Lycoming LTC1K-

4K turboshaft engine

Engine power ratings:

1,550 shp (1,156 kW) normal takeoff

power (10 min max)

1,802 shp (1,354 kW) emergency

power (2 min max)

Performance

Maximum speed: 300 knots (345

mph, 557 km/h)

Stall speed: 100 knots when in

airplane mode ()

Range: 445 nmi (515 mi, 825 km)

Service ceiling: 29,500 ft (8,840

m)

Disc loading: 13.2 lb/ft ()

Hovering altitude: 8,800 ft (2,635

m) out of ground effect


25/83

24

Bell Boing V-22 Osprey

The U.S. Navy/Marine Corps was given the lead in 1983. The JVX combined requirements fromthe Marine Corps, Air Force, Army and Navy. A request for proposals (RFP) was issued in

December 1982 for JVX preliminary design work. Interest in the program was expressed by

Arospatiale, Bell Helicopter, Boeing Vertol, Grumman, Lockheed, and Westland. The DoD

pushed for contractors to form teams. Bell partnered with Boeing Vertol. The Bell Boeing team

submitted a proposal for a enlarged version of the Bell XV-15 prototype on 17 February 1983.

This was the only proposal received and a preliminary design contract was awarded on 26 April

1983.

The JVX aircraft was designated V-22 Osprey on 15 January 1985; by that March the first sixprototypes were being produced, and Boeing Vertol was expanded to deal with the project

workload. Work has been split evenly between Bell and Boeing. Bell Helicopter manufactures

and integrates the wing, nacelles, rotors, drive system, tail surfaces, and aft ramp, as well as

integrates the Rolls-Royce engines and performs final assembly. Boeing Helicopters

manufactures and integrates the fuselage, cockpit, avionics, and flight controls. The USMC

variant of the Osprey received the MV-22 designation and the Air Force variant received CV-22;

this was reversed from normal procedure to prevent Marine Ospreys from having a conflicting

designation with aircraft carriers (CV). Full-scale development of the V-22 tilt-rotor aircraft began

in 1986. On 3 May 1986 the Bell-Boeing partnership was awarded a $1.714 billion contract for

V-22 aircraft by the Navy. At this point all four U.S. military services had acquisition plans for V-

22 versions.

Unlike a helicopter, the V-22 doesn't have to be disassembled and transported in a transport

aircraft. With a single refueling it can fly for upto 3380km.

Power for the Osprey, which is about half the size of a C-130, comes from a pair of General

Electric T64-GE-717 turboshaft engines, each rated at 6150hp. The power is definitely needed,

since the V-22 weighs in at about 24800kg maximum take-off weight in a STOL configuration,and about 19840kg in a pure VTOL mode. Its empty weight is just over 14880kg.

The rotor diameter is a large 11.6m, with an overall fuselage length of about 17.4m. With the

rotors in the take-off position, the height of the vehicle is just over 6m. The width of the vehicle,

with the rotors turning, is almost 26m. Those rotors, by the way, are capable of rotating through

97 degrees and are constructed of graphite/glass fiber. In fact, 33 percent of the weight of the

Osprey is fabricated of that high-tech material. The rotors also possess separate cyclic control

swashplates for sideways flight and fore-and-aft control during hover. Lateral attitude is

maintained by differential rotor thrust. Once the V-22 achieves horizontal flight, the engines

have assumed a position parallel to the fuselage.


26/83

25

Bell-Bo

eingV-22Osprey

worldsfirstproductiontilt-rotorairc

raft


27/83

26

A V-22 in-flight refuelling in process.

First production Osprey to join the V-22 Navy flight test program since resumption of flight evaluations in May

2002. Aircraft is shown in compact storage configuration.


28/83

27

Inside the Osprey

Propulsion

As mentioned above,

the Osprey has two

rotors with three-

bladed, 38-ft (11.6-m)

propellers. Each

propeller is driven by

an Allison AE 1107C

turboshaft engine that

is capable of producingover 6,000 horsepower.

Each engine drives its

own rotor and transfers

some power to a mid-wing gear box. This gear box drives the tilting mechanism. In the event of

an engine failure, the Osprey is capable of running on only one engine. In this case, power from

the remaining engine is distributed to the two rotors through an interconnecting drive shaft.

Fuel

The Osprey has 16 fuel tanks, 10 integrated

into the wings and six in the fuselage. The

feed tanks directly supply the engines with

fuel from the other tanks, and fuel transfer is

automatic. As the fuel flows from the tanks,

pressurized nitrogen gas fills the tanks to

reduce the possibility of fire. Depending upon

the configuration of the Osprey, it can hold

from 1,450 to 3,640 gallons (5,489 to 13,779

liters) of fuel.

CockpitControls

The cockpit of the Osprey holds a pilot and co-pilot. In addition, there is a fold-down seat in the

center behind the pilots for a flight engineer. The instrument panels have multi-functional

displays, similar to the new glass cockpit of the space shuttle. The displays hold information


29/83

28

about the engines (such as oil pressure, temperatures and hydraulic pressures) and flight (such

as fuel data, attitude and engine performance). There are also keypads used to interact with the

flight computer and sticks used to control the flight maneuvers.

Communications

The Osprey is equipped with multi-band radios (AM, FM, UHF, VHF) for voice transmission and

radio reception. It also has navigational beacons and radios, radar altimeters and an internal

intercom/radio system for communications among the crew and troops onboard.

Payload

The Osprey can hold up to 24 troops and carry up to 20,000 lb (9,072 kg) in its cargo bay, which

is 5.7 ft wide by 5.5 ft high by 20.8 ft long (1.72 x 1.68 x 6.35 m). The cargo bay has fold-down

seats along the walls and a ramp that is used to load or deploy cargo and troops. Deployment

can also take place in the air by parachute. In addition to the 20,000-lb load in the cargo bay,

the Osprey has an external hook-and-winch system that allows it to carry up to 15,000 lbs

(6,803 kg) of cargo in tow.

Stowage

When the Osprey lands on the deck of a ship, it can be folded up for down-time. The blades and

the wings are both foldable.


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29

Recent development

On 28 September 2005, the Pentagon formally approved full-rate production for the V-22. The

plan is to boost production from 11 a year to between 24 and 48 a year by 2012. Of the 458

total planned, 360 are for the Marine Corps, 48 for the Navy, and 50 for the Air Force at an

average cost of $110 million per aircraft, including development costs. The V-22 had an

incremental flyaway cost of $67 million per aircraft in 2008, but the Navy hopes to shave about

$10 million off that cost after a five-year production contract in 2013.

On 15 April 2010, the Naval Air Systems Command awarded Bell-Boeing a $42.1 million

contract to design a new integrated avionics processor to resolve electronics obsolescence

issues and add new network capabilities

Mission improvements have been developed for the "Block C" version. A contract for the Block

C upgrade and other improvements was awarded to Bell-Boeing in late 2009. Deliveries of

Block C upgrades are ongoing in 2010.

U.S. Naval Air Systems Command is working on upgrades to increase the maximum speed

from 250 knots (460 km/h; 290 mph) to 270 knots (500 km/h; 310 mph), increase helicopter

mode altitude limit from 10,000 feet (3,000 m) to 12,000 feet (3,700 m) or 14,000 feet (4,300 m),

and increase lift performance.

On 18 February 2011, Marine Commandant General James Amos indicated Marine MV-22sdeployed to Afghanistan surpassed 100,000 flight hours and were noted as having become "the

safest airplane, or close to the safest airplane in the Marine Corps inventory. The average V-22

mishap rate based on flight hours over the past 10 years, has been approximately half the

accident rate for the USMC aircraft fleet. The V-22's accident rate is the lowest of any Marine

rotorcraft.

Picture showing the body structure of V-22.


31/83

30


Crew: Four (pilot, copilot and two flight

engineers)

Capacity:

24 troops (seated), 32 troops (floor

loaded), or

9,070 kg of internal cargo, or up to

6,800 kg of external cargo

1 Growler light internally

transportable ground vehicle

Length: 57 ft 4 in (17.5 m) Rotor diameter: 38 ft 0 in (11.6 m)

Wingspan: 45 ft 10 in (14 m)

Width with rotors: 84 ft 7 in (25.8 m)

Height: 6.73 m; overall with nacelles

vertical (5.5 m; at top of tailfins)

Wing area: 301.4 ft (28 m)


Loaded weight: 47,500 lb (21,500 kg)

Max takeoff weight: 60,500 lb (27,400

kg)

Powerplant: 2 Rolls-Royce

Allison T406/AE 1107C-

Liberty turboshafts, 6,150 hp (4,590 kW)

each

Performance

Maximum speed: 250 knots (463 km/h,

288 mph) at sea level / 305 kn(565 km/h; 351 mph) at 15,000 ft

(4,600 m)

Cruise speed: 241 knots (277 mph, 446

km/h) at sea level

Range: 879 nmi (1,011 mi, 1,627 km)

Combat radius: 390 nmi (426 mi, 722

km)

Ferry range: 1,940 nmi (2,230 mi, 3,590km) with auxiliary internal fuel tanks

Service ceiling: 25,000 ft (7,620 m)

Rate of climb: 2,320 ft/min (11.8 m/s)

Disc loading: 20.9 lb/ft at 47,500 lb GW

(102.23 kg/m)

Power/mass: 0.259 hp/lb (427 W/kg)

Armament

1 7.62 mm (.308 in) M240 machine

gun or0.50 in (12.7 mm) M2 Browning

machine gun on ramp, removable

1 7.62 mm (.308 in) GAU-17 minigun,

belly-mounted, retractable, video remote

control in the Remote Guardian System

Rolls-Royce Allison AE 1107C-Liberty turboshaft engine


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31

NassauAmphib

iousReadyGroup,showingfou

rV-22sin2010.TwoV-22sarein

com

actstorageconfiguration.


33/83

32

The

HarrierJumpJetFamily

worlds

onlytrulysuccessfulVTO

Ljetaircraft


34/83

33

The Story of Harriervectored thrust at its best

The Harrier was developed from the Hawker P.1127/Kestrel aircrafts.

The Hawker/Bristol funded P.1127 development began in 1957. The Bristol Pegasus engine

(originally with only 11,000 lb thrust) was developed for the aircraft with heavy US funding

support. It was based on the earlier

Orpheus engine, and had a bifurcated

jet pipe and vectoring front and rear

nozzles. The P.1127 made its first

hover on 21 October 1960 on tethers,

but this was not considered to be

beneficial to feel out the aircraft

response, so the first untethered hover

was made less than a month later, on

19 November 1960. First conventional

flight was made on 7 July 1961 and first

double transition on 12 September 1961. Control power was low about all axes, which,

combined with suck-down and limited height control

power, resulted in a high pilot workload in hover. Hot

gas ingestion was overcome with a low forward speedin takeoff and landing. One of the two initial test

aircraft crashed, with the pilot ejecting safely. The

British government began supporting the

development before the first flight, funding the first

two prototypes, and later four more. Pegasus 3

power was increased to 13,500 lb thrust. In 1962, the UK, US and Germany initiated a tripartite

program, funding nine

improved P.1127 Kestrels for

use by a UK-led tri-national

squadron which conducted

operational trials. These used

Pegasus 5 engines, with thrust

increased to 15,500 lb. The

Kestrel paved the way for the

Harrier GR.1 in 1966.

Hawker Siddeley P.1127 hovering mid-air.

The Bristol Pegasus Engine.

Hawker Siddeley Kestrel FGA.1


35/83

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Development

First-generation Harriers

The Hawker Siddeley Harrier GR.1/GR.3 and

the AV-8A Harrier were the first generation of

the Harrier series, the first operational close-

support and reconnaissance attack aircraft

with vertical/short takeoff and landing

(V/STOL) capabilities. These were developed

directly from the Hawker P.1127 prototype and

the Kestrel evaluation aircraft.

The British Aerospace Sea Harrier is a naval

V/STOL jet fighter, reconnaissance and attack aircraft, a development of the Hawker Siddeley

Harrier. The first version entered service with the Royal Navy's Fleet Air Arm in April 1980 as

the Sea Harrier FRS.1, and was informally known as the Shar. The upgraded Sea Harrier FA2

entered service in 1993. It was

withdrawn from Royal Navy service

in March 2006. The Sea Harrier FRS

Mk.51 is in active service with the

Indian Navy, which operates the jet

from its aircraft carrier INS Viraat.

While Harriers have taken part in

various conflicts, both the Sea

Harrier and Harrier GR.3 cut their

teeth during the Falklands War,

flying an astounding six sorties per

aircraft per day on average and

destroying an impressive 20 enemy

aircraft without suffering a single air-to-air loss. The Harriers vectored thrust gave it asignificant advantage over opposing Argentinian jets, and gave rise to reporter Brian

Hanrahans famous line: I am not allowed to say how many planes joined the raid, but I

counted them all out and I counted them all back.

A Sea Harrier lands on the flight deck of the Indian

aircraft carrier INS Viraat


36/83

35

Second-generation Harriers

The Harrier was extensively redeveloped by McDonnell Douglas and British Aerospace, leading

to the AV-8B Harrier II.[2] Both were built by companies that are now parts of Boeing and BAE

Systems.

The Boeing/ BAE

Systems AV-8B Harrier

II is a family of second-

generation V/STOL jet

multi-role aircraft of the

late 20th century. British

Aerospace license-built

the Harrier

GR5/GR7/GR9. The AV-

8B is primarily used for

light attack or multi-role

tasks, typically operated

from small aircraft

carriers. Versions are used by several NATO countries, including Spain, Italy, and the United

States. The BAE Systems/Boeing Harrier II is a modified version of the AV-8B Harrier II that

was used by the Royal Air Force (RAF) and the Royal Navy until 2010.

Between 1969 and 2003, 824 Harrier variants were delivered. While manufacture of new

Harriers concluded in 1997, the last remanufactured aircraft (Harrier II Plus configuration) was

delivered in December 2003 which ended the Harrier production line.[3

British Aerospace Harrier (II) GR9 taxis at RIAT (Royal International

Air Tattoo) 2008 in UK.

US Marine Corps AV-8B Harrier


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Kestrel FGA.1 HarrierGR3/AV-8A Sea HarrierFA2 Harrier GR9 AV-8B+Harrier

Crew One (Two for trainer versions)

Length 13.0 m 14.4 m 14.2 m 14.1 m 14.5 m

Wingspan 6.99 m 7.70 m 7.70 m 9.25 m 9.25 m

Height 3.28 m 3.45 m 3.76 m 3.56 m 3.56 m

Empty Weight 4,540 kg 5,530 kg 6,370 kg 5,670 kg 6,340 kg

Maximum take-

off weight

(short takeoff)

7,710 kg 11,800 kg 11,900 kg 14,100 kg 14,100 kg

Max speed 877 km/h 1,180 km/h 1,180 km/h 1,070 km/h 1,070 km/h

Combat radius 370 km 556 km 556 km

Engine Pegasus 6Pegasus 11 Mk

101

Pegasus 11 Mk

106

Pegasus 11 Mk

107

Pegasus 11 Mk

105

Thrust 15,000 lbf (66.7 kN)21,800 lbf

(97.0 kN)

21,800 lbf

(97.0 kN)

24,750 lbf

(110 kN)

23,500 lbf

(105 kN)

Radar None None Blue Vixen None AN/APG-65


38/83

37


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38

| Separate Power Plant for Hover |

The Flying Bedsteadusing jet engines for vertical flight

Otherwise known as the Rolls-Royce Thrust-Measuring Rig (TMR), an experimental aircraft that

was first flown on Aug. 2, 1954 and used in the early development of VTOL (vertical takeoff-

and-landing) aircraft. The TMR was fitted with two MK4 Nene jet engines, which were standard

Sea Hawk engines modified only by an air bleed system that allowed 10% of the engine

compressor air to bleed off for the control systems of the rig. The efflux from the jet pipes a

central one and a bifurcated one from the other engine was turned downward through 90.

Two 95-gallon fuel tanks were fitted under the engines and the whole rig supported by four

hydraulic oleo legs. A platform across the structure above the engines had a seat bolted to ittogether with a conventional type control column and pedals. The TMR was controlled by

bleeding air from the engine through the control valves to diametrically opposed pipes, each

equipped with a nozzle that could swivel 30 in either direction for turning the rig left or right

The thrust-to-weight ratio of the rig was critical: any vertical takeoff (VTO) aircraft must have an

engine thrust that's greater than the total weight. The latter was minimized so as to keep within

a 25% thrust advantage. Each engine provided a thrust of 3,850 lbs, which, added to the 325

lbs thrust from each of the bleed nozzles, gave a total available thrust of 8,350lbs. This

compared with a total weight for the rig, complete with pilot and full fuel tanks, of 7,196lbs.

Handling improved as fuel was consumed; total running time was about 15 minutes.

Rolls-Royce Thrust Measuring Rig in flight.


40/83

39

The Lunar Landing Research Vehicle(LLRV), of the early 1960s, was alsoreferred to as the "Flying Bedstead."

The first rig, called XA314, made an initial ground run on Jul. 3, 1953 before first attempting to

lift off the ground on Jul. 6, piloted by wing-commander Harvey Hayworth, Rolls Royce chief test

pilot. During these early days of testing, it was felt that for safety's sake the rig should be

tethered; consequently, a large gantry was built and cables attached to either side and above

the rig from cable drums built into the gantry.

After several months in the workshops the rig was

rolled out again, put under the gantry, and a tethered

flight carried out to test the new modifications. These

were so successful that preparations were made for

the first free flight. This took place on Aug. 3, 1954,

and was piloted by Capt. Ron Shepherd before a

distinguished audience. The rig rose slowly into the

air and was held steady in a hover attitude. Duringthe next four months a number of free flights were

made, all at a height of 13-15 ft. but one flight was

made up to 50ft. to ensure that there was no ground

effect influencing the rig. The purpose of the rig was,

as the name suggests, to test turbojet engines for

lifting purposes and to develop techniques for

controlling such an aircraft.

Following successful trials of the TMR, Rolls-Royce began development of the Rolls-Royce

RB.108 direct-lift turbojet.

Of squat, compact design for mounting vertically, the

RB.108 differed from conventional turbojet engines in

having its bearings and oil system designed for prolonged

operation in the vertical attitude. First bench-tested in 1955

by Alan A. Griffith, who had conceived the idea of a

specialised lift jet in 1941, thrust was 2,130 lbf (966.15 kg)

from a weight of 269 lb (122 kg), giving a thrust/weight

ratio of 8:1.

The RB.108 was used in the Short SC.1, which used four

for lift with an additional one mounted at an angle at the

rear for propulsion, and the Mirage Balzac, which used

eight vertically-mounted RB.108s for lift. The Vereinigte

Flugtechnische Werke (VFW) SG 1262 used five RB.108s, three mounted in tandem on the

centreline, with one RB.108 on either side.

Preserved RB.108 at theRoyal Air Force Museum


41/83

40


42/83

41

| Separate Power Plant for Hover |Short SC.1________________________________

Work began in 1954 to design a test

aircraft that could demonstrate the utility

of the recently developed Rolls-Royce

RB.108 lift engine, producing 2,130 lb

thrust each (a thrust to weight of 8:1).

The Short Brothers SC.1 was powered

by four RB.108 lift engines vertically mounted on gimbals in the center fuselage and one

RB.108 cruise engine in the rear for forward flight. Gross weight was 7,700 lb, with a total

vertical thrust 8,600 lb. Overall length was 30 ft; the wingspan was 23.5 ft. Bleeds from the four

lift engines powered nose, tail and wing tip reaction jets for control at low speeds. First CTOL

flight was made on 2 April 1957, first tethered vertical flight was on 26 May 1958, first free

vertical flight was on 25 October 1958; first transition was on 6 April 1960. The SC.1

experienced the typical suck-down and hot-gas ingestion problems discovered during V/STOL

development programs. It appeared at the Farnborough air show in 1960 and Paris air show in

1961 (for the latter it flew the English Channel both ways). Maximum speed was only about 250

mph due to the low thrust of the single cruise engine. Pilot workload was very high during

landing, just when pilot attention was most important. The lift engines had to be started as late

as possible, due to the high combined fuel consumption of the five engines. The ignitionprocedure was very labor intensive, as was transition from wing-borne to jet-borne flight. The

second test aircraft crashed on 2 October 1963 due to a controls malfunction, killing the pilot. It

was rebuilt and the two aircraft continued to fly until 1967.


Crew: 1

Length: 25 feet 6 inches (7.77 m)

Wingspan: 23 feet 6 inches (7.16 m)

Height: 10 ft 8 in[6]

(3.25 m)

Airfoil: NACA 0010[6]

Empty weight: 6,260 pounds (2,839 kg

Loaded weight (VTOL): 7,700 lb (3,490 kg))

* Powerplant:

Lift: 4 Rolls-Royce RB108 turbojets,

2,130 lbf (9.47 kN) each

Forward flight: 1 Rolls-Royce RB108

turbojet, 2,130 lbf

Performance


(214 knots, 396 km/h)

Range: 150 miles (130 NM, 240km)

Service ceiling: 8,000 ft[6]

(2,440

m)

Rate of climb: 700 ft/min[6]

(3.6

m/s)

Wing loading: 38.1 lb/ft2

(186.0

kg/m2)

Thrust/weight:

(CTOL): 0.265

(VTOL): 1.11


43/83

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Dassault Mirage III V

The III V (V for "vertical") was a Mirage III airframe, modified with eight RB.162-31 lift engines

(generating 5,400 lb thrust each, or 16:1 thrust to weight!), long-stroke landing gears, and

various doors to minimize the undesirable effects of the lift engine exhausts. It was 59 ft long,

with a 29 ft wingspan, and weighed about 30,000 lb. It was powered by a SNECMA TF-104

(12,000 lb thrust dry, 20,000 lb in afterburner). Control power was improved over the Balzac,

with similarly located control jets at the nose, tail and wingtips. First hover was achieved on 12

February 1965. The TF-104 was upgraded to a TF-106 for the first supersonic flight. First

transition was conducted in March 1966. The second aircraft was fitted with a 10,750 lb thrust

Pratt & Whitney TF30. It is the fastest V/STOL aircraft on record, achieving Mach 2.04 on 12

September 1966. The eight engines didn't leave much room for fuel and a visiting US Air Force

pilot had to eject, destroying one of the two aircraft when he ran out of fuel during low-speed

and hover operations. The other III-V was also lost. With the entire fuselage filled with lift

engines, the Balzac and the III V seemed to prove that with enough lift engines, any aircraft

could be converted to V/STOL. The problem, however, was that there was no room for anything

else. The Mirage III V weighed about 3,000 lb over the basic Mirage III, which cost about half

the payload and fuel.


Crew: 1

Length: 18 m (59 ft 5 in)

Wingspan: 8.72 m (28 ft 7 in)

Height: 5.55 m (18 ft 2 in)

Loaded weight: 12,000 kg

Powerplant:

1 Snecma TF104B turbofan,4,725 kg (19,842 lb)

8 Rolls-Royce

RB162 lift turbojet, 2,000 kg each

Performance

Maximum speed: Mach 2.04


44/83

43

Dassault Balzac V

Although there was no British requirement for the RB.108 lift engine, Dassault in France was

interested in developing a supersonic vertical take-off and landing fighter. The first step was to

take eight of the existing RB.108 lift engines and install them in the Mirage III prototype airframe

001. The rebuilt aircraft, nicknamed Balzac, weighed about 13,500 lbs. It had a fattened and

stretched fuselage (43 ft), but the same 24 ft span wings. The inlet duct for the cruise engine,

the 4,850 lb thrust Bristol Orpheus, ran down the center of the lift engine collection. The front

four engines were also separated from their rear counterparts by the main landing gear to

balance the center of gravity. Each lift engine pair shared an inlet door and an exhaust door.

First tethered hover was performed on 12 October 1962, with the first free hover made 6 days

later. First conventional flight was made on 1 March 1963. During transition, all the lift engine

doors created quite a bit of drag. On 27 January 1964, during one of the first transition attempts,

it crashed in a "falling leaf" accident, killing the pilot. It was rebuilt and killed another pilot on 8

September 1965; this time it was beyond repair.


Crew: 1 Length: 13.1 m (42 ft 11.75 in)

Wingspan: 7.3 m (23 ft 11.25 in)

Height: 4.6 (m 15 ft)

Empty weight: 6,124 kg (13,500 lb)

Loaded weight: 7,000 kg (15,432 lb)

Powerplant:

1 Bristol Siddeley Orpheus BOr 3

Cruise turbojet, 21.57 kN

8 Rolls-Royce RB108-

1A lift turbojet, 9.6 kN each

Performance

Maximum speed: 1,104 km/h

(686 mph) at sea level

Wing loading: 257.3 kg/m

(52.7 lb/ft)

Thrust/weight (jet): 1.12:1 in

vertical flight

Endurance: 15 minutes


45/83

44

The Sud-Ouest S.O.1221 Djinn is a French

two-seat light helicopter. The helicopter

rotors were driven by compressed-air jets

at the end of each blade. It was the only

tip jet helicopter to enter production

A Catherine Wheelfirework.

Fireworks are placedat the ends of the

wheel and rotate thesame.

| Combined power plant for hover |

The Tip Jetscatherine wheel in play

Tip jet refers to the jet nozzles located at the tip of some helicopter

rotor blades. The objective is to spin the rotor, much like a Catherine

wheel firework.

Some tipjets rely solely on compressed air, provided by a separate

engine, to create jet thrust. Others use an afterburner type system to

burn fuel in the compressed air at the tip (tip-burners) to enhance the

thrust. Some are ramjets or even a complete turbojet engine. Some

are rocket tip jets that run off stored propellant such as hydrogen

peroxide.

Tipjets replace the normal shaft drive and have the advantage of

placing no torque on the airframe, so no tail rotor is required.

In engine-out scenarios the presence of tipjets on

the rotor increases the moment of inertia, hence

permitting it to store energy, which makes doing a

successful autorotation landing somewhat easier,

however the tipjet also very typically generates

significant extra air drag, which demands a higher

sink rate and means that a very sudden transition

to the landing flare must occur for survival, with

little room for error.

In the field of VTOL aircrafts, only two aircrafts

were built comprising of the tip jets, namely, Fairy

Rotodyne and McDonnell XV-1.

Rotor Mast and BladeThe picture shows one of the two tip jet blades of the French Sud-Ouest helicopter.

Note the nozzle at the mast of the blade.


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McDonnell XV-1

McDonnell's tip jet autogyro, the XV-1, was

powered by a single 550 hp Continental R-

975-19 nine-cylinder radial piston engine. It

drove two air compressors to power the 31

ft three-bladed rotor for vertical lift, and powered a 6 ft diameter two-bladed propeller mounted

at the rear of the fuselage for forward flight. A small rotor at the end of each tail boom provided

yaw control. Overall length was 50 ft, with a 26 ft wingspan. Empty weight was 4,300 lb which

increased to a maximum gross weight of 5,500 lb. First tether test was in 1954, with the first free

flight on 11 February of that year. First transition to horizontal flight was on 29 April 1954. The

second of the two aircraft was damaged in autorotation testing in December 1954. On 10

October 1955, the XV-1 exceeded contemporary rotor-wing speed records by hitting 200 mph.With conventional helicopters improving their cruise speeds, however, the program was

canceled in 1957.

Fairey RotodyneThe British company Fairey had built several

compound helicopters in the 1940s. One of

these was modified with tip jets as the Jet

Gyrodyne in 1953. Based on this data, Fairey

designed the 33,000 lb Rotodyne, a 40

passenger transport powered by two 2,800 shp

Napier Eland 3 turbine engines. The fuselage was 59 ft long with nearly 3,300 cubic feet of

internal volume, ending in rear clamshell loading doors. The 60 ft diameter four-bladed rotor

was rotated by tip-jets in vertical flight and autorotated in cruise, providing about half of the

aerodynamic lift. During transition, the engine power was transferred by hydraulic clutches to

two four-bladed tractor propellers mid-mounted on the 46 ft wide wings. In hover and forward

flight, yaw was controlled by differential propeller pitch, while pitch and roll were produced by

the cyclic rotor pitch. Aerodynamic surfaces augmented control in forward flight. First flight in

helicopter mode was on 6 November 1957. The first transitions were begun in April 1958, with

problems making satisfactory tip jet relights at altitude being solved by that October. Tip jet

noise was extremely unpleasant, driving a significantly modified production version with lower

pressure tip jets. Despite apparent commercial interest, Fairey was taken over by Westland,

causing the program to fizzle out in about 1962.


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EWR VJ 101C

The supersonic VJ 101C, built by the

German EWR ("Consortium") of

Messerschmitt, Heinkel and Blkow,

employed a lift plus lift/cruise propulsion concept, powered by six Rolls-Royce/MTU RB.145

turbojet engines. Two of these engines were mounted in tandem aft of the cockpit; the other

four engines were in pairs in wingtip swivelling nacelles. On the second of the two experimental

aircraft, the VJ 101C X2, the wingtip mounted engines were equipped with afterburners which

increased their available thrust from 2,750 to 3,650 pounds each. The first VJ 101C hovering

flight occurred on 10 April 1963, and the first horizontal takeoff was accomplished on 31 August

1963. A double transition (vertical takeoff through conventional flight followed by a vertical

landing) was achieved on the sixth flight on 20 September 1963. The non-afterburning X1

became the world's first supersonic V/STOL aircraft in July 1964 when it broke the sound barrier

in a shallow dive. This aircraft was lost in an accident on 14 September 1964. This occurred

when the aircraft became uncontrollable immediately after a horizontal takeoff. The pilot ejected

at an altitude of ten feet during an uncommanded roll. He survived but suffered crushed

vertebrae. The accident was found to have been caused by a roll-rate gyro which had been

installed with reversed polarity. Prior to its loss, the VJ 101C X1 had completed 40 aerodynamic

flights, 14 full transition flights and the Hannover Air Show presentation on 3 May 1964. The VJ101C X2 flew its first hovering free flights on 12 June but did not attempt to use its afterburning

capabilities for vertical takeoffs until 10 October 1964; within two weeks, the VJ 101C X2

demonstrated complete transitions from vertical to horizontal flight and back to a vertical landing

using afterburning. It suffered from high temperature and erosion issues, and crashed when it

ingested hot exhaust gases and suffered a significant thrust loss while attempting to land on an

elevated platform. The rotating nacelle design was abandoned, and the proposed follow-on, the

VJ 101D, dispensed with the wingtip-mounted engines but retained the lift plus lift/cruise

propulsion concept. Its use of RB.162 five lift engines and two aft fuselage RB.153 lift/cruise

engines (with internal thrust deflectors) was very complex and the VJ 101D was canceled after

engine testing had begun.


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The Yakovlev Yak-38 (Russian: -38, NATO reporting name: Forger) was Soviet Naval

Aviation's first and only operational VTOL strike fighter aircraft, in addition to being its first

operational carrier-based fixed-wing aircraft. It was developed specifically for and served

exclusively on the Kiev class aircraft carriers.

The Yak-38 Forger used two in-line Rybinsk RD-36-35FVR lift engines (6,722 lb thrust each)

immediately behind the cockpit inclined with the engine exhaust at 13 rearward. One Soyuz

Tumanskiy/Khatchaturov R-27V-300 turbojet (13,444 lb thrust) was mounted in the center

fuselage and exhausted through two hydraulically actuated vectoring nozzles (connected by a

transverse shaft), one on each side of the fuselage just aft of the trailing edge of the wing. The

first prototype flew in 1971 and the Yak-38 (originally designated the Yak-36M) first appeared to

the West in July 1976 when the Kiev deployed with a developmental squadron of Forger-As and

traveled through the Mediterranean. The normal complement for the Kiev-class through deckaircraft carrier was a dozen single-seat Forger-As and one or two twin-seat trainer Yak-38U

Forger-Bs. The primary roles were fleet defense (particularly against shadowing maritime

surveillance aircraft), reconnaissance, and anti-ship strike, but was never used in combat. The

Forger was removed from front line service in 1992-93, although a few remained in the

inventory for another year as limited proficiency training aircraft. A total of 231 aircraft had been

built by the time production ended in 1988.

Yakovlev Yak-38


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Design

The first drawings showed a supersonic aircraft strongly resembling the Hawker P.1154 in study

in the United Kingdom but with two R27-300 engines. Supersonic performances would have

implied many difficulties of development, and it was decided to initially develop a relatively

simple aircraft limited to Mach 0.95. Although the Yak-38 and Yak-38M were developed from

the land-based Yakovlev Yak-36, the aircraft had almost nothing in common.

The prototype VM-01 was finished on 14 April 1970. Though outwardly similar to the British

Hawker Siddeley Harrier, it followed a completely different configuration. Together with a

vectorable thrust engine in the rear used during flight, two smaller, and less powerful, engines

were housed in the front portion of the fuselage and used purely for take-off and landing.[note 1]

The aircraft used a similar layout to the German experimental VTOL strike fighter, the VFW VAK

191B, which began development in 1961, and the contemporary Dassault Mirage IIIV.

The Yak 36 was sent for tests in May and June 1970. Mikhail Deksbakh carried out the first

flight of the VM-02 in conventional flight mode on 15 January 1971. The VM-03 made its first

flight in short take-off mode on 25 May 1971. Sea trials aboard the aircraft carrier ("aviationcruiser") Kiev were observed in 1975. A total of 231 Yak-38 aircraft were produced, including 38

two-seat trainers (Yak-38U). These were based on the four Kievs.

The Yak-38 used a hands-free landing system. The aircraft could negotiate a

telemetry/telecommand link with a computer system in the aircraft carrier which would allow it to

be guided onto the deck with no interaction from the pilot.

Another advanced feature that Yak-38 possessed was an automatic ejection seat. When one of

the take-off engines failed, once the aircraft rolled past 60 degrees the pilot was automatically

ejected from the aircraft. The take-off engines did suffer some reliability problems while in

service and this system saved the lives of a few Russian naval aviators.

A diagram showing the lift forces on a Yak-38 in VTOL mode


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Powerplant

Supersonic performance was considered for the VM during the design phase (an early concept

proposed an aircraft with two 64.7-kN Tumanskii R-27VM-300 engines and theoretically capable

of a speed of 2000 km/h at altitude), but this was rejected in favour of a more easily attainable

Mach 0.95 capability.

For lift and cruise modes, a single R-27V-300 engine equipped with a plenum chamber directed

thrust through two rotating exhaust nozzles, these being arranged as one each on either side ofthe rear fuselage, each with a rotational arc of 95. The production R-27V-300 was certified at a

thrust rating of 66.7 kN in late 1976; the initial rating of this unit had been 57.9 kN. The engine

was essentially a vectored-thrust, non-afterburning version of the turbojet used in the MiG-23

and had previously been employed (in a twin installation) by the experimental Yak-36.

The main engine alone did not develop enough power or provide the required stability for

vertical flight modes, and was therefore supplemented by two 28.4-kN thrust Kolesov RD-36-

35FV lightweight lift engines. The basic version of this turbojet, the RD-36-35, had previously

been used to reduce the take-off run of experimental versions of the MiG-21, MiG-23, Su-15and Tu-22R; two pairs of RD-36-35s were also installed in the prototype Su-24 tactical bomber.

Two Yak-38M aircraft parked at the stern of the Minsk. The Yak-38M had better engines, a

slightly altered and better aerodynamic shape and was therefore slightly faster and had a better

range than the original Yak-38. The initial colour scheme worn by the AV-MF Yak-38 consisted

of dark green anti-corrosion paint on the undersides of the aircraft, with dark blue upper

surfaces. This was later replaced by a light grey over dark grey scheme, frequently associated

with the Yak-38M. An unusual green-over-silver tiger camouflage scheme, reportedly seen on

an aircraft onboard Leningrad in 1986, was probably applied for one cruise only. Special

camouflage schemes may also have been applied to aircraft involved in the Romb-1 trials in

Afghanistan in 1980.


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The RD-36-35FVs were simple, single-shaft units arranged in vertical tandem configuration

within the forward fuselage immediately aft of the cockpit, and angled aft at 10 from the

vertical. In order to ensure a smooth transition from vertical to horizontal flight or vice versa

the lift engines were ultimately fitted with deflector vanes that directed the thrust over a range of

30 fore and aft. A rear-hinged door incorporating 24 spring-loaded louvres covered the intakesfor the lift engines during horizontal flight.

Additional control for the low-speed and VTOL flight regimes was provided by main-engine

bleed air, dispensed from reaction-control valves located above and below the wingtips, and

below the nose and tailcone.


Crew: One

Length: 16.37 m (50 ft 1 in)


Height: 4.25 m (14 ft 5 in)

Wing area: 18.5 m (199 ft)


(16,281 lb)

Loaded weight: kg (lb)

Max takeoff weight: 11,300

kg (28,700 lb)

Powerplant: 1 x Tumansky

R-28 V-300 turbojet, 66.7 kN

(15,000 lbf)

Powerplant: 2 Rybinsk RD-

38 turbojets, 31.9 kN (7,870lbf) each

Performance

Maximum speed: 1 280 km/h (795 mph)

Range: 1,300 km (807 miles)

Service ceiling: 11,000 m (36,089 ft)

Rate of climb: 4,500 m/min (14,760 ft/min)

Wing loading: kg/m (lb/ft)

Thrust/weight: 1+

Armament

Guns: GSh-23L 23mm gun pod (GP-9).

Hardpoints: 4 with a capacity of 4,400 lb and

provisions to carry combinations of:

Rockets: various types of rockets (up to 240

mm).

Missiles: 2 anti-ship or air-to-surface Kh-

23 (AS-7 Kerry). The Kh-23 required a

guidance pod on one of the pylons. R-60 or R-

60M (AA-8 Aphid) air-to-air missiles could be

carried under the external pylons.

Bombs: two FAB-500 or four FAB-250

general purpose bombs under pylons, two

incendiary ZB-500, or two nuclear RN-28

bombs.

Other: external tanks.


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Yakovlev Yak-141________________________________

The Yak-41 program was initiated in

1975, about the same time that the Yak-

38 was first being deployed. The

supersonic Freestyle was optimized for

air defense with an attack capability as a

secondary role. The first conventional flight was made on 9 March 1987 and the first hover on

29 December 1989. The first official details were not released by the Soviet Union until the 1991

Paris Air Show (re-designated as the Yak-141) by which time the two flying prototypes had

accumulated about 210 hours in the air. A dozen FAI-recognized Class H. III records forV/STOL were set in April 1991, consisting of altitudes and times to altitudes with loads. In flight

testing, the Freestyle achieved a maximum speed of 1.7 Mach, and maneuverability was

repeatedly claimed to be almost as good as that of the MiG-29 Fulcrum (although the small

wings of the Freestyle make this extremely doubtful). Flight testing was originally intended to

continue until 1995, but development was stopped in August 1991 due to the shrinking Soviet

military budget. Yakovlev funded the development from its own resources for a while, in the

hopes of attracting a foreign investor. The second flight prototype was destroyed after a hard

landing on the Admiral Gorshkov aircraft carrier on 5 October 1991. The following year, the

surviving prototype was demonstrated at the Farnborough Air Show, but the design bureau was

still unable to find a market for the design.


Crew: 1

Length: 18.36 m (60 ft 2 in)


Height: 5.00 m (16 ft 5 in) Empty weight: 11,650 kg (25,683 lb)

Max takeoff weight: 19,500 kg (42,989

lb)

Powerplant: 1 MNPK Soyuz R-79V-

300 lift/cruise turbofan

Dry thrust: 108 kN (24,300 lbf)

Wet Thrust: 152 kN (34,170 lbf)

Lift engines: 2x RKBM RD-41 turbojets41.7 kN (9,300 lbf) thrust each)

Performance

Maximum speed: 1,800 km/h (Mach

1.4+)

Range: 2,100 km (1,305 mi)

Ferry range: 3,000 km (1,865 mi)

Rate of climb: 15,000 m/min (49,213

ft/min)

Armament

Guns: 1 30 mm GSh-

301 cannon with 120 rounds

Hardpoints: 4 underwing and 1

fuselage and provisions to carry

different combinations


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| Augmented power plant for hover | Rotor |

Kamov Ka-22

The Ka-22 Vintokryl ('Screw Wing') was a

large twin-turboshaft powered

convertiplane that debuted at the Soviet

National Aviation Day display on 9 July

1961 in Tushino. At each end of the high,

straight wing, was a 6,500 shp Soloviev D-25VK engine which powered a four-bladed rotor for

vertical flight and a four-bladed propeller for cruise. Each engine was progressively clutched

between the two systems to transition between the two modes of flight. The engine was a nine-

stage single spool turboshaft modified from the 5,500 shp D-25V engine used on the Mil Mi-6,Mi-10, and V-12 helicopters. The final turbine stage was a free-wheel that drove the gearbox.

The fuselage housed a loading ramp that could be used for freight or vehicles, and could carry

36,400 lb of cargo or 80 seats (although this was never done). The tricycle landing gear was

fixed and the entire nose area was glazed for good visibility, especially in landing. The high

flight deck accommodated two pilots, a radio operator and engineer. Flight testing began on 20

April 1960. On 7 October 1961, the Vintokryl set a Class E. II speed record of 221.4 mph over a

15/25 km course. On 24 November 1961, it lifted a record payload of 36,343 lb to a height of

6,562 ft (2 km), as well as several other payload to altitude records. The Ka-22 was abandoned

after a crash in 1964.


Crew: 5

Capacity: 16,500 kg

Length: 27 m (102 ft 10 in)

Diameter: 22.5 m (85 ft 9 in)

Height: (inside cargo hold)

2.8 m (10 ft 8 in)

Gross weight: 42,500 kg

(93,700 lb)

Powerplant: 2 D-

25VK turboshafts, 4,045 kW

(5,500 hp) each each

Performance

Maximum speed: 350 km/h

(220 mph)

Range: 450 km (280 miles)

Service ceiling: 5,500 m

(21,000 ft)


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| Augmented power plant for hover | Rotor |

Piasecki 16H-1

The 37 ft long privately developed Piasecki

16H-1 weighed 11,000 lb and had a wingspan

of 20 ft. The five-seat Pathfinder was originally

powered by a 550 hp Pratt & Whitney PT6B-2 turboshaft engine. The engine powered a 41 ft

fully articulated three-bladed rotor and a 5.5 ft three-bladed ducted propeller in the tail (called a

"ring-tail") to provide forward thrust and directional and anti-torque control with four vertical

vanes in the duct. Gross weight was 2,611 lb and fuselage length was 25 ft. The 16H-1 made its

first flight on 21 February 1962. Overall, the Pathfinder had the handling qualities of a

conventional helicopter, but used its wings and pusher propeller to off-load the rotor and

increase its maximum forward velocity to 148 kt. 185 flight hours were accumulated before May

1964, when Piasecki was contracted to test a high speed modification, the 16H-1A Pathfinder II.

It was equipped with a 1,250 shp T58 turboshaft engine, a new drive system and propeller to

handle the increased power. The rotor size was increased to 44 ft diameter, and the fuselage

was stretched to accommodate eight seats. Flight testing resumed on 15 November 1965 and it

accrued over 40 hours in the air by May 1966, reaching speeds of 195 kt. Later, it was

redesignated the 16H-1C when the engine was upgraded to a 1,500 shp T58-GE-5.


Crew: two pilots

Capacity: up to six

passengers

Length: 11.4 m

Wingspan: 10.0 m

Main rotor diameter: 44 ft 0

in (13.4 m)

Height: 11 ft 4 in (3,45 m)

Empty weight: 4,800 lb

(2,165 kg)

Gross weight: (4,870 kg

Powerplant: 1 General

Electric T58-GE-8 turboshaft,

1,250 hp (930 kW) each

Performance


(370 km/h)

Cruise speed: 175 mph (280

km/h)

Range: 950 miles (1,530 km)

Service ceiling: 18,700 ft

(5,700 m)


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The Future of VTOLunder development

F-35B Lightning II

The Lockheed Martin F-35 Lightning II is a family of single-seat, single-engine, fifth generation

multirole fighters under development to perform ground attack, reconnaissance, and air defense

missions with stealth capability. The F-35 has three main models; one is a conventional takeoff

and landing variant, the second is a short take off and vertical-landing variant, and the third is a

carrier-based variant.

A conventional take-off and landing aircraft (CTOL) for the (US) Air Force; A carrier based variant (CV) for the

Documents

VSTOL History and Development