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 1-G in 1951. The 1-G suffered from dynamic stability problems that were determined to be fundamental to the tilting rotor concept, so the Air Force funded research on rotors in transition including gyroscopic effects and oblique airflow.

The 1-G 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) 1-G had a 26 ft long fuselage and a wingspan of 21 ft. The height was only 7 ft; in fact, the 1-G was so small, the pilot's head rose above the windscreen (see photo).

The 1-G 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.

Source: AHS V/STOL Wheel


Data on design, manufacture and status

Design authority: Transcendental Aircraft Corporation

Primary manufacturer: Transcendental Aircraft Corporation

Parent type: No type defined

Aircraft status: No longer flying


Primary flight and mechanical characteristics

VTOL type: Convertiplane

Compound type: N/A

Lift configuration: Tilt shaft (x2)

Crew required: 1

Crew seating: Single seater

Landing gear: Wheels (non-retractable)

Layout and Dimensions

Data on aircraft size

Overall Dimensions
Overall Height:  
Overall Length:  
Overall Width:  
Airframe Dimensions
Airframe Length: 7.92 m 26.0 ft
Airframe Width: 6.40 m 21.0 ft
Airframe Height: 2.13 m 7.0 ft
Landing Gear Dimensions
Landing Gear Base:  
Landing Gear Track:  
Cabin Dimensions
Cabin Internal Height:  
Cabin Internal Length:  
Cabin Internal Width:  

Weights and Performance

Data on aircraft weight and flight characteristics

Listed Max Speed as Helicopter; As Aircraft: 160 mph (257 km/h)

Max Gross Weight (ground): 794 kg 1,750 lb
Max Gross Weight (airborne):  
Max Take-off Weight: 794 kg 1,750 lb
Empty Weight: 658 kg 1,450 lb
Useful Load: 136 kg 300 lb
Empty Weight Fraction: 0.829
Climb Performance
Max Rate of Climb:  
Hover Performance
Hover Ceiling IGE:  
Hover Ceiling OGE:  
Max Level Flight Speed: 185 km/h 100 kts
Never Exceed Speed:  
Service Ceiling: 1,524 m 5,000 ft
Range and Endurance
Max Range:  
Max Endurance: 2 hrs 2 hrs

Engine Details

Aircraft powerplant (lift and/or propulsion)

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

Number of engines: 1
Designation: Lycoming O-290-A reciprocating
Manufacturer: Lycoming Engines
Normal Ratings
Max continuous:  
Take-off / rated: 119 kW 160 hp
OEI Ratings
OEI contingency:  
OEI continuous:  
OEI 30-second:  
OEI intermediate:  

Primary Lift Device

Data on primary lift devices such as main rotors

633 RPM in helicopter mode, 240 RPM in prop-rotor mode

Main Rotor Characteristics
Diameter: 5.18 m 17.00 ft
RPM: 633.0 rpm 633.0 rpm
Direction of Rotation: Not applicable
Hub Type: Articulated
Main Rotor Blade Characteristics
Blade Construction:
Blade Chord: 0.102 m 0.33 ft
Blade Tip Geometry:
Blade Twist:  
Number of Blades: 3
Main Rotor Derived Characteristics
Disc Area: 21.09 m² 227.0 ft²
Disc Loading: 18.82 kg/m² 3.854 lb/ft²
Solidity: 0.0374
Main Rotor Blade Derived Characteristics
Blade area per blade: 0.26 m² 2.8 ft²
Tip Speed: 171.75 m/s 563.5 fps

Primary Control Device

Data on primary control devices such as tail rotors

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

Related VFS Resources

Resources related to the Model 1-G , provided by the Vertical Flight Society.
Forum Proceedings
Vertiflite articles
Enter a search term in the box above.
Web files from
Enter a search term in the box above.
Webpages from
Enter a search term in the box above.

Related Public Resources

Resources related to the Model 1-G , provided by public sources across the internet.