Bell XV-3

Last updated
XV-3
XV-3-US-Army-4148.jpg
The second Bell XV-3 during flight testing (c.1959)
RoleExperimental VTOL aircraft
National originUnited States
Manufacturer Bell Helicopter
First flight11 August 1955
StatusDisplay
Primary userUS Air Force and Army Joint Research Project
Number built2

The Bell XV-3 (Bell 200) is an American tiltrotor aircraft developed by Bell Helicopter for a joint research program between the United States Air Force and the United States Army in order to explore convertiplane technologies. The XV-3 featured an engine mounted in the fuselage with driveshafts transferring power to two-bladed rotor assemblies mounted on the wingtips. The wingtip rotor assemblies were mounted to tilt 90 degrees from vertical to horizontal, designed to allow the XV-3 to take off and land like a helicopter but fly at faster airspeeds, similar to a conventional fixed-wing aircraft.

Contents

The XV-3 was first flown on 11 August 1955. The first prototype use three blade rotors, and had issue with flutter crashing two months after its first flight. Tests were conducted on the second prototype with 2-blade rotors and flew successfully.

Although it was limited in performance compared to later types, the aircraft successfully demonstrated the tiltrotor concept, accomplishing 110 transitions from helicopter to airplane mode between December 1958 and July 1962. The XV-3 program ended when the remaining aircraft was severely damaged in a wind tunnel accident on 20 May 1966. [1] The data and experience from the XV-3 program were key elements used to successfully develop the Bell XV-15, which later paved the way for the V-22 Osprey. [2]

The remaining prototype survived to the 21st century when it was restored by Bell, with a two-year restoration that included engineers that worked on the XV-3 originally. It was then transferred to the U.S. National Museum of the Air Force in Dayton, Ohio, where it was put on display.

Design and development

XV-3 in forward flight Bell XV-3.jpg
XV-3 in forward flight
Bell XV-3 in a hover, 1955. This was first version with 3-blade rotors and crashed. Bell Aircraft Corp. introduces the XV-3, File No. 907-3854 (cropped).jpg
Bell XV-3 in a hover, 1955. This was first version with 3-blade rotors and crashed.
XV-3 test, in vertical flight with 2 blade rotors Xv-3 Test@NASA.jpg
XV-3 test, in vertical flight with 2 blade rotors

In 1951, the Army and Air Force announced the Convertible Aircraft Program and released the Request for Proposals (RFP) to solicit designs from the aircraft industry. In October 1953, Bell Helicopter was awarded a development contract to produce two aircraft for testing purposes. [3] The original military designation was XH-33, classifying it as a helicopter, but its designation was changed to XV-3 in the convertiplane series. The designation was changed once again in 1962 to XV-3A when the V-prefix was changed to mean VTOL.[ citation needed ] The leading designers were Bob Lichten and Kenneth Wernicke. [2]

The first XV-3 (serial number 54-147) flew on 11 August 1955 with Bell Chief Test Pilot Floyd Carlson at the controls. On 18 August 1955, the aircraft experienced a hard landing when the rotor developed dynamic instability. Bell attempted to remedy the situation, and flight testing resumed on 29 March 1956 after additional ground runs. Bell continued to expand the flight envelope of the XV-3, but on 25 July 1956, the same rotor instability occurred again. Flight testing of the XV-3 resumed in late September 1956. Then, on 25 October 1956, the aircraft crashed when the test pilot blacked out due to extremely high cockpit vibrations. The vibrations resulted when the rotor shafts were moved 17 degrees forward from vertical. The test pilot, Dick Stansbury, was seriously injured, and the aircraft was damaged beyond repair. [2]

Bell modified the second XV-3 (serial number 54-148) by replacing the three-bladed rotors with two-bladed rotors, and after taking extensive precautions, the second XV-3 began testing at the National Advisory Committee for Aeronautics' (NACA) Ames Aeronautical Laboratory wind tunnel facility on 18 July 1957. Flight testing for aircraft #2 began on 21 January 1958 at Bell's facility. By April, the aircraft had expanded the flight envelope to 127 miles per hour (204 km/h) as well as demonstrating full autorotation landings and 30-degrees forward transitions with the rotor pylons. On 6 May 1958, another instance of rotor instability occurred when the pylons were advanced to 40-degrees forward pylon angle, and the XV-3 was grounded once more. The XV-3 returned to the Ames wind tunnel in October 1958 to collect more data before it could be flown again. As a result of the wind tunnel testing, the rotor diameter was reduced, wing structure was increased and strengthened, and the rotor controls were stiffened.

The XV-3 resumed flight testing at Bell's facility on 12 December 1958. On 18 December 1958, Bell test pilot Bill Quinlan accomplished the first dynamically stable full conversion to airplane mode, and on 6 January 1959, Air Force Captain Robert Ferry became the first military pilot to complete a tiltrotor conversion to airplane mode. [4] Flight testing at the Bell facilities was completed on 24 April 1959, and the aircraft was shipped to Edwards Air Force Base. The military flight testing of the XV-3 began on 14 May 1959. Promoted to the rank of Major, Robert Ferry would coauthor the report on the military flight evaluations, conducted from May to July 1959, noting that despite the deficiencies of the design, the "fixed-wing tilt-prop," or tiltrotor, was a practical application for rotorcraft. [5]

Following the completion of the joint service testing, the aircraft was returned to the Ames facility, where on 12 August 1959, Fred Drinkwater became the first NASA test pilot to complete the full conversion of a tiltrotor to airplane mode. On 8 August 1961, Army Major E. E. Kluever became the first Army pilot to fly a tiltrotor aircraft.[ citation needed ] [6] Testing would continue through July 1962 as NASA and Bell completed wind tunnel testing to study pitch-flap coupling exhibited by the tiltrotor in an effort to predict and eliminate the aeroelastic dynamic rotor instability (referred to simply as pylon whirl) that had caused problems throughout the program.

In April 1966, Bell Helicopter aerodynamicist Dr. Earl Hall published an analysis of the XV-3 program data explaining the tiltrotor aircraft pylon whirl instability. In order to establish Hall's findings and develop a computer model, NASA agreed to conduct wind tunnel testing at the Ames 40 × 80 wind tunnel. As the engineers were completing the last planned test, a wingtip failure caused both rotors to fail, resulting in severe damage of the XV-3 and damage to the wind tunnel. [7] On 14 June 1966, NASA Ames Research Center announced the completion of XV-3 testing. The XV-3 had accomplished a total of 250 flights, accumulated 125 flight hours, and completed 110 full conversions. [6]

Survivor

XV-3, 54-148, on display at the National Museum of the USAF (2012) Bell XV3 at Nat Museum USAF.jpg
XV-3, 54-148, on display at the National Museum of the USAF (2012)

In late 1966, the sole remaining XV-3, serial number 54-148, was moved to outside storage at Davis-Monthan AFB in Tucson, Arizona. [8] In 1984, the Bell XV-15 flight test team discovered the aircraft stored outside the Army's Aviation Museum during the XV-15 visit to Fort Rucker, Alabama, as part of a demonstration tour. [9] 54-148 was repaired by December 1986, with Army support and the leadership of former Bell XV-3 engineer Claude Leibensberger, but the aircraft was disassembled and placed into indoor storage. [10] On 22 January 2004, the XV-3 was delivered to Bell Plant 6 in Arlington, Texas. [8] [11] In 2005, Bell Helicopter employees began work to restore 54-148 to museum display condition, this time led by former XV-3 engineer Charles Davis. [8] Following a two-year restoration, the XV-3 was transferred to the National Museum of the United States Air Force in Dayton, Ohio. It was placed on display in the museum's Post-Cold War Gallery in June 2007, [12] and as of 2011 is on display in the Research & Development Gallery. [13]

Specifications (XV-3)

Starboard tiltrotor, Alliance Airshow, Fort Worth, Texas (2006) Xv3-5.jpg
Starboard tiltrotor, Alliance Airshow, Fort Worth, Texas (2006)
Restored XV-3 at an air show, showing the side-door open Xv3-4.jpg
Restored XV-3 at an air show, showing the side-door open
Hatch open showing the Wasp radial piston engine Xv3-6.jpg
Hatch open showing the Wasp radial piston engine

Data from NASA Monograph 17 [14] and Aerophile, Vol. 2, No. 1. [15]

General characteristics

Performance

See also

Related development

Related lists

Related Research Articles

<span class="mw-page-title-main">VTOL</span> Aircraft takeoff and landing done vertically

A vertical take-off and landing (VTOL) aircraft is one that can take off and land vertically without relying on a runway. This classification can include a variety of types of aircraft including helicopters as well as thrust-vectoring fixed-wing aircraft and other hybrid aircraft with powered rotors such as cyclogyros/cyclocopters and gyrodynes.

<span class="mw-page-title-main">Bell Boeing V-22 Osprey</span> Military transport tiltrotor

The Bell Boeing V-22 Osprey is an American multi-mission, tiltrotor military aircraft with both vertical takeoff and landing (VTOL) and short takeoff and landing (STOL) capabilities. It is designed to combine the functionality of a conventional helicopter with the long-range, high-speed cruise performance of a turboprop aircraft. The V-22 is operated by the United States and Japan, and is not only a new aircraft design, but a new type of aircraft that entered service in the 2000s, a tiltrotor compared to fixed wing and helicopter designs. The V-22 first flew in 1988 and after a long development was fielded in 2007. The design essentially combines the vertical takeoff ability of a helicopter, but the range of a fixed-wing airplane.

<span class="mw-page-title-main">Tiltrotor</span> Aircraft type

A tiltrotor is an aircraft that generates lift and propulsion by way of one or more powered rotors mounted on rotating shafts or nacelles usually at the ends of a fixed wing. Almost all tiltrotors use a transverse rotor design, with a few exceptions that use other multirotor layouts.

<span class="mw-page-title-main">Bell XV-15</span> American experimental tiltrotor aircraft

The Bell XV-15 is an American tiltrotor VTOL aircraft. It was the second successful experimental tiltrotor aircraft and the first to demonstrate the concept's high speed performance relative to conventional helicopters.

<span class="mw-page-title-main">Leonardo AW609</span> Twin-engine tiltrotor VTOL aircraft

The Leonardo AW609, formerly the AgustaWestland AW609, and originally the Bell/Agusta BA609, is a twin-engined tiltrotor VTOL aircraft with an overall configuration similar to that of the Bell Boeing V-22 Osprey. It is capable of landing vertically like a helicopter while having a range and speed in excess of conventional rotorcraft. The AW609 is aimed at the civil aviation market, in particular VIP customers and offshore oil and gas operators. It has progressed from a concept in the late 1990s, to development and testing, and is working towards certification in the 2020s.

<span class="mw-page-title-main">Bell X-22</span> 1960s American V/STOL aircraft

The Bell X-22 is an American V/STOL X-plane with four tilting ducted fans. Takeoff was to selectively occur either with the propellers tilted vertically upwards, or on a short runway with the nacelles tilted forward at approximately 45°. Additionally, the X-22 was to provide more insight into the tactical application of vertical takeoff troop transporters such as the preceding Hiller X-18 and the X-22's successor, the Bell XV-15. Another program requirement was a true airspeed in level flight of at least 525 km/h.

<span class="mw-page-title-main">Lockheed AH-56 Cheyenne</span> Canceled US helicopter program

The Lockheed AH-56 Cheyenne is an attack helicopter developed by Lockheed for the United States Army. It rose from the Army's Advanced Aerial Fire Support System (AAFSS) program to field the service's first dedicated attack helicopter. Lockheed designed the Cheyenne using a four-blade rigid-rotor system and configured the aircraft as a compound helicopter with low-mounted wings and a tail-mounted thrusting propeller driven by a General Electric T64 turboshaft engine. The Cheyenne was to have a high-speed dash capability to provide armed escort for the Army's transport helicopters, such as the Bell UH-1 Iroquois.

<span class="mw-page-title-main">Canadair CL-84 Dynavert</span> Canadian experimental tiltwing VSTOL aircraft

The Canadair CL-84 "Dynavert", designated by the Canadian Forces as the CX-131, was a V/STOL turbine tiltwing monoplane designed and manufactured by Canadair between 1964 and 1972. Only four of these experimental aircraft were built with three entering flight testing. Two of the CL-84s crashed due to mechanical failures, with no fatalities occurring in either of the accidents. Despite the CL-84 being successful in the experimental and operational trials carried out between 1972 and 1974, none of the prospective customers placed any orders for the type.

<span class="mw-page-title-main">Tip jet</span> Jet nozzle at the tip of some helicopter rotor blades

A tip jet is a jet nozzle at the tip of some helicopter rotor blades, used to spin the rotor, much like a Catherine wheel firework. Tip jets replace the normal shaft drive and have the advantage of placing no torque on the airframe, thus not requiring the presence of a tail rotor. Some simple monocopters are composed of nothing but a single blade with a tip rocket.

A convertiplane is defined by the Fédération Aéronautique Internationale as an aircraft which uses rotor power for vertical takeoff and landing (VTOL) and converts to fixed-wing lift in normal flight. In the US it is further classified as a sub-type of powered lift. In popular usage it sometimes includes any aircraft that converts in flight to change its method of obtaining lift.

<span class="mw-page-title-main">Sikorsky S-72</span> US experimental compound helicopter (hybrid helicopter/fixed-wing aircraft)

The Sikorsky S-72 was an experimental Sikorsky Aircraft compound helicopter developed as the Rotor Systems Research Aircraft (RSRA) for the National Aeronautics and Space Administration (NASA) and the United States Army. The RSRA was a testbed for rotor and propulsion systems for high-speed.

<span class="mw-page-title-main">Bell Boeing Quad TiltRotor</span> Proposed four-rotor derivative of the V-22 Osprey

The Bell Boeing Quad TiltRotor (QTR) is a proposed four-rotor derivative of the Bell Boeing V-22 Osprey developed jointly by Bell Helicopter and Boeing. The concept is a contender in the U.S. Army's Joint Heavy Lift program. It would have a cargo capacity roughly equivalent to the C-130 Hercules, cruise at 250 knots, and land at unimproved sites vertically like a helicopter.

<span class="mw-page-title-main">Powered lift</span> VTOL capable fixed-wing aircraft

A powered lift aircraft takes off and lands vertically under engine power but uses a fixed wing for horizontal flight. Like helicopters, these aircraft do not need a long runway to take off and land, but they have a speed and performance similar to standard fixed-wing aircraft in combat or other situations.

<span class="mw-page-title-main">Proprotor</span>

A proprotor is a spinning airfoil that function as both an airplane-style propeller and a helicopter-style rotor. Several proprotor-equipped convertiplanes, such as the Bell Boeing V-22 Osprey tiltrotor, are capable of switching back and forth between flying akin to both helicopters and fixed-wing aircraft. Accordingly this type of airfoil has been predominantly applied to vertical takeoff and landing (VTOL) aircraft.

<span class="mw-page-title-main">McDonnell XV-1</span> American experimental gyrodyne

The McDonnell XV-1 is an experimental Convertiplane developed by McDonnell Aircraft for a joint research program between the United States Air Force and the United States Army to explore technologies to develop an aircraft that could take off and land like a helicopter but fly at faster airspeeds, similar to a conventional airplane. The XV-1 would reach a speed of 200 mph, faster than any previous rotorcraft, but the program was terminated due to the tip-jet noise and complexity of the technology which gave only a modest gain in performance.

<span class="mw-page-title-main">AgustaWestland Project Zero</span> 2010s Italian electric tiltrotor aircraft

The AgustaWestland Project Zero is a hybrid tiltrotor/Lift fan aircraft. It has been developed by AgustaWestland as a technology demonstrator, and is used to investigate all-electric propulsion and other advanced technologies. It is the world's first electric tiltrotor aircraft.

<span class="mw-page-title-main">Transcendental Model 1-G</span> 1950s American prototype tiltrotor aircraft

The Transcendental Model 1-G was an experimental American tiltrotor prototype of the 1950s. It was a single-seat aircraft powered by a piston engine, and was the first tiltrotor to fly. A single example was built, which was destroyed in a crash in 1955.

<span class="mw-page-title-main">Bell V-247 Vigilant</span> Unmanned military tiltrotor concept

The Bell V-247 Vigilant is a concept by Bell Helicopter to develop a large tiltrotor unmanned aerial vehicle.

<span class="mw-page-title-main">Leonardo Next-Generation Civil Tiltrotor</span> Twin-engine tiltrotor aircraft demonstrator

The Leonardo Next-Generation Civil Tiltrotor is a tiltrotor aircraft demonstrator designed and developed by the Italian aerospace company Leonardo S.p.A. Studies for a two times larger tiltrotor than the AgustaWestland AW609 started in 2000. Since 2014, its development is sponsored by the European Union's Clean Sky 2 program. By May 2021, major components were under production By 2023, the maiden flight had been pushed back to 2024, from a 2020 initial plan.

References

  1. Kiley, Don. "The Tiltrotor. Aviation's square peg?". Flight Safety Information Journal Archived September 7, 2008, at the Wayback Machine . Special Edition, July 2003. Accessed on 26 October 2008.
  2. 1 2 3 Whittle, Richard. "The Dream Machine: The Untold History of the Notorious V-22 Osprey" pp. 36, 41, 48. New York: Simon & Schuster, 2010. ISBN   1-4165-6295-8.
  3. Maisel et al., 2000, p. 4.
  4. Ristine, Jeff. "Obituary: Robert G. Ferry; Air Force veteran was record-setting test pilot" U-T San Diego , Feb. 2, 2009. Accessed: April 9, 2014.
  5. Maisel et al., 2000, p. 14.
  6. 1 2 Maisel et al., 2000, p. 141.
  7. Markman and Holder, 2000
  8. 1 2 3 Miller, Jay. "World's First Tilt-Rotor Under Restoration". Flight Journal. November/December 2004. Accessed at findarticles.com on 26 October 2008.
  9. The Bell XV-15 was flown over Fort Rucker's Nap-of-the-Earth (NOE) flight course from 10–13 September 1984. (Maisel et al., 2000, p. 145.)
  10. Maisel et al. 2000, p. 17.
  11. "XV-3, world’s first tiltrotor aircraft returns to Texas A half century after being built in Fort Worth". Press release from Bell Helicopter. 22 January 2004. Accessed at helis.com on 26 October 2008.
  12. "BELL HELICOPTER TEXTRON XV-3" Archived September 25, 2008, at the Wayback Machine . National Museum of the USAF. Accessed on 26 October 2008.
  13. "www.nationalmuseum.af.mil". Archived from the original on June 28, 2011.
  14. Maisel et al. 2000, pp. 121–2.
  15. Miller, Jay. Aerophile. San Antonio, Texas, June 1979. Volume 2, Number 1. pages 13–14.
  16. Lednicer, David. "The Incomplete Guide to Airfoil Usage". m-selig.ae.illinois.edu. Retrieved 16 April 2019.
  17. Pelletier, Alain J. (1992). Bell aircraft since 1935 (1st ed.). London: Putnam Aeronautical. p. 259. ISBN   1557500568.

Further reading