Boeing Skyfox
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The Boeing Skyfox was a twin-engined jet trainer aircraft, a highly upgraded development of the Lockheed T-33. It was designed as a primary trainer to compete with and replace the Cessna T-37 Tweety Bird. Besides its primary role as a trainer, the aircraft was envisioned to have other roles as well, including ground attack. The program was started by the Skyfox Corporation in 1983, and was acquired by Boeing
in 1986.
The program included the replacement of the Allison J33-A-35 turbojet by two Garrett TFE731-3A turbofan
s. It also included an extensive redesign of the airframe. Only one prototype aircraft was built, and the program was later canceled due to lack of customers.
. The "Skyfox" was conceived and developed by Russell O'Quinn. The modification designs were led by T-33 designer Irvin Culver and a number of other former Lockheed
employees formed Flight Concepts Incorporated in 1982, with the intent of modernizing the T-33 design. The company's name was later changed to Skyfox Corporation.
The highly modified and modernized aircraft was expected to cost about half of a new comparable trainer, such as the British Aerospace
BAE Hawk
and the Dassault/Dornier Alpha Jet. With the design work done, Skyfox purchased 80 surplus T-33s.
The first one converted was an ex-Canadian Forces
CT-133
, the Canadian license-built equivalent of the T-33 which were formerly a Silver Star 3AT (Armament Trainer). This particular aircraft was produced in 1958, had construction number T.33-160 and serial number RCAF21160. It was struck-off charge on 10 November 1970 and was sold through Crown Assets Disposal Corporation
to Leroy Penhall/Fighter Imports in 1973. It was then sold to Murray McCormick Aerial Surveys in 1975. Its next owner was Consolidated Leasing in 1977.
It was sold to the Skyfox Corporation, carrying the U.S. civilian registration number of N221SF, on 14 January 1983 and went to the Flight Test Research in August 1983. After conversion to the Skyfox configuration it flew its first flight as the Skyfox prototype on 23 August 1983, nearly 35.5 years after the first flight of the T-33. Race and test pilot Skip Holm
performed the initial flight test at the Mojave Airport, California. The Skyfox prototype was white overall, with black cheat lines, and a very pale blue trim.
The Skyfox Corporation was not able to find any buyers for the aircraft, despite its price and capability. However, in 1986, Boeing Military Aircraft Company saw potential, and purchased the marketing and production rights. Even though Portugal
signed a letter of intent for 20 conversion kits, no other nation signed on, and faced with a lack of customers, Boeing cancelled the project. The prototype aircraft remains the only Skyfox built. As of June 2008, the prototype is parked on the flightline at Rogue Valley International
(MFR) in Medford
, Oregon
without engines.
engines mounted externally. Together, the two TFE731s weighed 17% less than the single original engine, provided 60% more thrust on 45% less fuel.
The engine change provided a large internal volume for fuel storage, eliminating the need for the T-33's tip tanks. Although the tip mountings were retained to provide for optional auxiliary fuel tanks if desired.
Other modifications included inboard wing leading-edge extensions, the replacement of the tip tanks with winglets, new canopy with one-piece windshield, revised nose geometry to improved visibility from the cockpit and to fair into the T-33's lateral intakes, new tail surfaces with a mid-set tailplane, although the original wings were retained, and new avionics.
The Skyfox was designed to be produced entirely from kits of components. The conversion involved the disassembly, the inspection, and the refurbishment of the T-33 airframe as necessary, the installation of the kits and reassembly of the airframe in the Skyfox configuration.
There were two conversion options: to purchase a complete Skyfox from Boeing or to purchase a conversion kit from Boeing and perform the conversion in the country itself.
The standard conversion kit included:
Plus control panels for the cockpit
In addition to the standard conversion kit described above, Boeing also offered a number of options that could further improve the overall capability of the Skyfox:
The two TFE371-3A turbofans that powered the Skyfox together weighed 17 per cent less than the single J33-A-35 turbojet of the T-33, while producing 60 per cent more thrust and consuming 45 per cent less fuel. The TFE371-3A turbofan had a ten-fold increase in time between overhauls (TBO) compared with the J33-A-35 turbojet. The result was a greatly improved maneuverability, range, endurance, payload and the added overwater and hostile terrain safety of the twin powerplant configuration.
The Boeing Skyfox was a twin-engined jet trainer aircraft, a highly upgraded development of the Lockheed T-33. It was designed as a primary trainer to compete with and replace the Cessna T-37 Tweety Bird. Besides its primary role as a trainer, the aircraft was envisioned to have other roles as well, including ground attack. The program was started by the Skyfox Corporation in 1983, and was acquired by Boeing
Boeing
The Boeing Company is an American multinational aerospace and defense corporation, founded in 1916 by William E. Boeing in Seattle, Washington. Boeing has expanded over the years, merging with McDonnell Douglas in 1997. Boeing Corporate headquarters has been in Chicago, Illinois since 2001...
in 1986.
The program included the replacement of the Allison J33-A-35 turbojet by two Garrett TFE731-3A turbofan
Turbofan
The turbofan is a type of airbreathing jet engine that is widely used for aircraft propulsion. A turbofan combines two types of engines, the turbo portion which is a conventional gas turbine engine, and the fan, a propeller-like ducted fan...
s. It also included an extensive redesign of the airframe. Only one prototype aircraft was built, and the program was later canceled due to lack of customers.
Development
Over 6,500 Lockheed T-33 trainers were built, making it one of the most successful jet trainer programs in history. However, technology passed the "T-Bird" by, and by the 1980s, it was clear that the world's air forces needed a more modern training aircraftTrainer (aircraft)
A trainer is a class of aircraft designed specifically to facilitate in-flight training of pilots and aircrews. The use of a dedicated trainer aircraft with additional safety features—such as tandem flight controls, forgiving flight characteristics and a simplified cockpit arrangement—allows...
. The "Skyfox" was conceived and developed by Russell O'Quinn. The modification designs were led by T-33 designer Irvin Culver and a number of other former Lockheed
Lockheed Corporation
The Lockheed Corporation was an American aerospace company. Lockheed was founded in 1912 and later merged with Martin Marietta to form Lockheed Martin in 1995.-Origins:...
employees formed Flight Concepts Incorporated in 1982, with the intent of modernizing the T-33 design. The company's name was later changed to Skyfox Corporation.
The highly modified and modernized aircraft was expected to cost about half of a new comparable trainer, such as the British Aerospace
British Aerospace
British Aerospace plc was a UK aircraft, munitions and defence-systems manufacturer. Its head office was in the Warwick House in the Farnborough Aerospace Centre in Farnborough, Hampshire...
BAE Hawk
BAE Hawk
The BAE Systems Hawk is a British single-engine, advanced jet trainer aircraft. It first flew in 1974 as the Hawker Siddeley Hawk. The Hawk is used by the Royal Air Force, and other air forces, as either a trainer or a low-cost combat aircraft...
and the Dassault/Dornier Alpha Jet. With the design work done, Skyfox purchased 80 surplus T-33s.
The first one converted was an ex-Canadian Forces
Canadian Forces
The Canadian Forces , officially the Canadian Armed Forces , are the unified armed forces of Canada, as constituted by the National Defence Act, which states: "The Canadian Forces are the armed forces of Her Majesty raised by Canada and consist of one Service called the Canadian Armed Forces."...
CT-133
Canadair T-33
|-See also:-References:NotesBibliography* "Canada's Fab Four". Air Forces Monthly. Stamford, Lincolnshire, UK: Key Publishing Limited, August, 2003. ISSN 0955-7091....
, the Canadian license-built equivalent of the T-33 which were formerly a Silver Star 3AT (Armament Trainer). This particular aircraft was produced in 1958, had construction number T.33-160 and serial number RCAF21160. It was struck-off charge on 10 November 1970 and was sold through Crown Assets Disposal Corporation
Crown Assets Distribution
The Crown Assets Distribution handles moveable Crown assets that a federal department or agency has declared as surplus.The Public Works and Government Services Canada operates eight Crown Assets Distribution Centres located across the country which manage the disposal of moveable federal...
to Leroy Penhall/Fighter Imports in 1973. It was then sold to Murray McCormick Aerial Surveys in 1975. Its next owner was Consolidated Leasing in 1977.
It was sold to the Skyfox Corporation, carrying the U.S. civilian registration number of N221SF, on 14 January 1983 and went to the Flight Test Research in August 1983. After conversion to the Skyfox configuration it flew its first flight as the Skyfox prototype on 23 August 1983, nearly 35.5 years after the first flight of the T-33. Race and test pilot Skip Holm
Skip Holm
Skip James Holm is a retired pilot who lives on the eastern slope of the Sierra Nevada.Holm claims to hold the world record for combat flight hours: 1,172. He retired from the U.S. Air Force Reserve in 1992, with the rank of Lieutenant Colonel. He logged his combat hours flying F-105s and F-4s in...
performed the initial flight test at the Mojave Airport, California. The Skyfox prototype was white overall, with black cheat lines, and a very pale blue trim.
The Skyfox Corporation was not able to find any buyers for the aircraft, despite its price and capability. However, in 1986, Boeing Military Aircraft Company saw potential, and purchased the marketing and production rights. Even though Portugal
Portugal
Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...
signed a letter of intent for 20 conversion kits, no other nation signed on, and faced with a lack of customers, Boeing cancelled the project. The prototype aircraft remains the only Skyfox built. As of June 2008, the prototype is parked on the flightline at Rogue Valley International
Rogue Valley International-Medford Airport
Rogue Valley International-Medford Airport is a public airport located 3 miles north of downtown Medford in Jackson County, Oregon, USA. In addition to Jackson County, the airport serves seven nearby counties in southwest Oregon. It is owned and operated by Jackson County's Aviation Authority...
(MFR) in Medford
Medford, Oregon
Medford is a city in Jackson County, Oregon, United States. As of the 2010 US Census, the city had a total population of 74,907 and a metropolitan area population of 207,010, making the Medford MSA the 4th largest metro area in Oregon...
, Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
without engines.
Portugal
To replace the T-33A, Portugal signed a letter of intent with the Skyfox Corporation in the middle of the 1980s for twenty conversion kits. The Força Aérea Portuguesa (FAP) proposed that Oficinas Gerais de Material Aeronautico (OGMA) in Alverca would undertake the conversions, but insufficient orders were obtained from other nations to motivate Boeing to continue with the project.USA
Even the USAF was interested in the Skyfox. It was originally planned to demonstrate the Skyfox at Farnborough International 1986, but the aircraft was tested at the time by the USAF. Eventually, the USAF did not purchase the Skyfox.Design
The Skyfox was marketed either as a complete converted aircraft from Boeing, or as a conversion kit, with the customer providing the T-33 airframe. The conversion incorporated about 70% of the existing T-33 airframe, but replaced the existing internal single Allison J33 turbojet engine with two Garrett TFE731-3A turbofanTurbofan
The turbofan is a type of airbreathing jet engine that is widely used for aircraft propulsion. A turbofan combines two types of engines, the turbo portion which is a conventional gas turbine engine, and the fan, a propeller-like ducted fan...
engines mounted externally. Together, the two TFE731s weighed 17% less than the single original engine, provided 60% more thrust on 45% less fuel.
The engine change provided a large internal volume for fuel storage, eliminating the need for the T-33's tip tanks. Although the tip mountings were retained to provide for optional auxiliary fuel tanks if desired.
Other modifications included inboard wing leading-edge extensions, the replacement of the tip tanks with winglets, new canopy with one-piece windshield, revised nose geometry to improved visibility from the cockpit and to fair into the T-33's lateral intakes, new tail surfaces with a mid-set tailplane, although the original wings were retained, and new avionics.
Conversion options
There were two conversion options: to purchase a complete Skyfox from Boeing or to purchase a conversion kit from Boeing and perform the conversion in the country itself.
The standard conversion kit included:
- Two Garrett TFE371-3A turbofans, the nacelles, and the propulsion support system.
- Nose and tail assemblies.
- Single-point refuelling.
- Aerodynamic refinement kit.
- Structural refinement kit.
- Nose wheel steering.
- Anti-skid power brakes.
- Single-piece windscreen.
- Hydraulic components kit.
- Generator control and distribution system.
- Throttle quadrants and control system.
- Fire extinguishing system.
Plus control panels for the cockpit
In addition to the standard conversion kit described above, Boeing also offered a number of options that could further improve the overall capability of the Skyfox:
- Avionics upgrade.
- Basic rewiring of the aircraft.
- Tactical, reconnaissance, and electronic warfare (EW) training mission packages.
- Zero-zero ejection seat.
Operation and support costs
The operating and support costs of the Skyfox were less than that of the T-33 and could compete with the costs of the Hawk and the Alpha Jet. Structural improvements, avionics upgrades, electrical rewiring, airframe and systems refurbishment, and powerplant modifications resulted in low cost, low maintenance hours and low spare parts consumption.The two TFE371-3A turbofans that powered the Skyfox together weighed 17 per cent less than the single J33-A-35 turbojet of the T-33, while producing 60 per cent more thrust and consuming 45 per cent less fuel. The TFE371-3A turbofan had a ten-fold increase in time between overhauls (TBO) compared with the J33-A-35 turbojet. The result was a greatly improved maneuverability, range, endurance, payload and the added overwater and hostile terrain safety of the twin powerplant configuration.
Specifications
| T-33A Shooting Star | Boeing Skyfox | |
|---|---|---|
| Empty weight | 15095 lb (6,847 kg) | 16235 lb (7,364 kg) |
| Rate of climb at Sea Level | 3,400 ft/min (1,036 m/min) | 4,300 ft/min (1,490 m/min) |
| Time to 9,144 m | 15 min | 8 min and 12 sec |
| Operating range | 2,315 km | 3,630 km (Internal fuel) 4,815 km (Internal and external fuel) |
| Operating endurance | 2 hours | 5.1 hours (Internal fuel) 7 hours (Internal and external fuel) |
| Takeoff distance | 4,600 ft (1,402 m) | 2,600 ft (793 m) |