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.


Ship 2 is in the Smithsonian National Air and Space Museum (Udvar-Hazy Center).

Source: AHS V/STOL Wheel

Overview

Data on design, manufacture and status

Design authority: Bell Helicopter Textron, Inc.

Primary manufacturer: Bell Helicopter Textron, Inc.

Parent type: Bell XV-15

Aircraft status: No longer flying

Configuration

Primary flight and mechanical characteristics

VTOL type: Convertiplane

Compound type: N/A

Lift configuration: Tilt rotor/prop/duct (x2)

Crew required: 2

Crew seating: Side-by-side

Landing gear: Wheels (all retractable)

Layout and Dimensions

Data on aircraft size

Overall Dimensions
Overall Height: 4.67 m 15.3 ft
Overall Length: 12.83 m 42.1 ft
Overall Width: 17.43 m 57.2 ft
Airframe Dimensions
Airframe Length: 12.83 m 42.1 ft
Airframe Width: 9.80 m 32.2 ft
Airframe Height: 3.86 m 12.7 ft
Landing Gear Dimensions
Landing Gear Base: 4.80 m 15.8 ft
Landing Gear Track: 2.95 m 9.7 ft
Cabin Dimensions
Cabin Internal Height:  
Cabin Internal Length:  
Cabin Internal Width:  

Weights and Performance

Data on aircraft weight and flight characteristics

Weights
Max Gross Weight (ground): 6,009 kg 13,248 lb
Max Gross Weight (airborne):  
Max Take-off Weight: 6,009 kg 13,248 lb
Empty Weight: 4,574 kg 10,083 lb
Useful Load: 1,436 kg 3,165 lb
Empty Weight Fraction: 0.761
Climb Performance
Max Rate of Climb:  
Hover Performance
Hover Ceiling IGE:  
Hover Ceiling OGE:  
Limitations
Max Level Flight Speed: 482 km/h 260 kts
Never Exceed Speed:  
Service Ceiling:  
Range and Endurance
Max Range:  
Max Endurance:  

Engine Details

Aircraft powerplant (lift and/or propulsion)

Provided powerplant data is for uninstalled, sea level, static operations.

Powerplant
Number of engines: 2
Designation: Lycoming LTC1K-41K turbine
Manufacturer: Lycoming Engines
Normal Ratings
Max continuous: 933 kW 1250 hp
Take-off / rated: 1156 kW 1550 hp
Intermediate:  
Maximum:  
OEI Ratings
OEI contingency: 1344 kW 1802 hp
OEI continuous:  
OEI 30-second:  
OEI intermediate:  

Primary Lift Device

Data on primary lift devices such as main rotors

Cruise mode RPM=517, Airfoil section=NACA 0009, 'Delta 3'=-15 degs (i.e. pitch increases as flapping increases)

Main Rotor Characteristics
Diameter: 7.62 m 25.00 ft
RPM: 589.0 rpm 589.0 rpm
Direction of Rotation: Counter-rotating
Hub Type: Gimballed in helicopter mode; rigid in airplane mode
Main Rotor Blade Characteristics
Blade Construction: Blades had a stainless steel spar, aliminum skin with aluminum honeycomb core
Blade Chord: 0.356 m 1.17 ft
Blade Tip Geometry: Conventional
Blade Twist: -0.628 rad -36.000 deg
Number of Blades: 3
Main Rotor Derived Characteristics
Disc Area: 45.60 m² 490.9 ft²
Disc Loading: 65.89 kg/m² 13.494 lb/ft²
Solidity: 0.0891
Main Rotor Blade Derived Characteristics
Blade area per blade: 1.35 m² 14.6 ft²
Tip Speed: 235.00 m/s 771.0 fps

Primary Control Device

Data on primary control devices such as tail rotors

Tail Rotor Characteristics
Diameter:  
Configuration: Unknown
Direction of Rotation: Unknown
RPM:  
Tail Rotor Blade Characteristics
Number of Blades:  
Blade Construction: N/A
Blade Chord:  
Blade Twist:  
Tail Rotor Derived Characteristics
Disc Area:  
Solidity:  
Tail Rotor Blade Derived Characteristics
Tip Speed:  
Blade Area (per blade):  

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