Beechcraft T-34C “Turbo-Mentor”
Archive Photos ¹
Beechcraft T-34C “Turbo Mentor” (BuNo 160530, c/n GL-87) on display (4/29/89) at the 1989 MCAS El Toro Air Show, MCAS El Toro, Santa Ana, California (Photo by John Shupek copyright © 1989 Skytamer Images)
Beechcraft T-34C “Turbo Mentor” (BuNo 160631, c/n GL-96) on display (c.1990) at the 1990 MCAS El Toro Air Shows, MCAS El Toro, Santa Ana, California (Photo by John Shupek copyright © 1990 Skytamer Images)
Beechcraft T-34C “Turbo Mentor” (BuNo 161809, c/n GL-204) on display (c.1992) at the 1992 Hawthorne Air Faire, Hawthorne, CA(Photo by John Shupek copyright © 1992 Skytamer Images)
Beechcraft T-34C “Turbo Mentor” (BuNo 164161, c/n GL-341) on display (c.1990) at the 1990 MCAS El Toro Air Show, MCAS El Toro, Santa Ana, California, (Photo by John Shupek copyright © 1990 Skytamer Images)
The Beechcraft T-34 Mentor is a propeller-driven, single-engined, military trainer aircraft derived from the Beechcraft Model 35 Bonanza. The earlier versions of the T-34, dating from around the late 1940's to the 1950s, were piston-engined. These were eventually succeeded by the upgraded T-34C Turbo-Mentor, powered by a turboprop engine. The T-34 remains in service almost six decades after it was first designed.
Design and Development ²
The T-34 was the brainchild of Walter Beech, who developed it as the Beechcraft Model 45 private venture at a time when there was no defense budget for a new trainer model. Beech hoped to sell it as an economical alternative to the North American T-6/NJ Texan, then in use by all services of the U.S. military.
Three initial design concepts were developed for the Model 45, including one with the Bonanza's signature V-tail, but the final design that emerged in 1948 incorporated conventional tail control surfaces for the benefit of the more conservative military (featuring a relatively large unswept vertical fin that would find its way onto the Travel Air twin-engine civil aircraft almost ten years later). The Bonanza's fuselage with four-passenger cabin was replaced with a narrower fuselage incorporating a two-seater tandem cockpit and bubble canopy, which provided greater visibility for the trainee pilot and flight instructor. Structurally the Model 45 was much stronger than the Bonanza, being designed for +10“g” and -4.5“g”, while the Continental E-185 engine of 185-hp at takeoff (less than a third of the power of the T-6s engine) was the same as that fitted to contemporary Bonanzas.
Following the prototype were three Model A45T aircraft, the first two with the same engine as the prototype and the third with a Continental E-225, which would prove to be close to the production version. Production did not begin until 1953, when Beechcraft began delivering T-34A's to the United States Air Force (USAF) and similar Model B45 aircraft for export. In 1955 production of the T-34B for the United States Navy (USN) began, this version featuring a number of differences reflecting the different requirements of the two services. The T-34B had only differential braking for steering control on the ground instead of nosewheel steering, additional wing dihedral and, to cater for the different heights of pilots, adjustable rudder pedals instead of the moveable seats of the T-34A. T-34A production was completed in 1956, with T-34B's being built until October 1957 and licensed B45 versions built in Canada (125 manufactured by Canadian Car and Foundry), Japan (173 built by Fuji Heavy Industries), and Argentina (75 by FMA) until 1958. Beechcraft delivered the last Model B45's in 1959. Total production of the Continental-engined versions in the US and abroad was 1,904 aircraft.
Beechcraft Model 73 Jet Mentor ²
In 1955 Beechcraft developed a jet-engined derivative, again as a private venture, and again in the hope of winning a contract from the US military. The Model 73 Jet Mentor shared many components with the piston-engined aircraft; major visual differences were the redesigned cockpit which was relocated further forward in the fuselage and the air intakes for the jet engine in the wing roots, supplying air to a single jet engine in the rear fuselage. The first flight of the Model 73, registered N134B, was on 18 December 1955. The Model 73 was evaluated by the USAF, which ordered the Cessna T-37, and the USN, which decided upon the Temco TT Pinto. The Model 73 was not put into production.
Beechcraft T-34C “Turbo-Mentor” ²
After a production hiatus of almost 15 years, the T-34C Turbo-Mentor powered by a Pratt & Whitney Canada PT6A-25 turboprop engine was developed in 1973. Development proceeded at the behest of the USN, which supplied two T-34B's for conversion. After re-engining with the PT6 the two aircraft were redesignated as YT-34C's, the first of these flying with turboprop power for the first time on 21 September 1973. Mentor production re-started in 1975 for deliveries of T-34C's to the USN and of the T-34C-1 armed version for export customers in 1977, this version featuring four underwing hardpoints. The last Turbo-Mentor rolled off the production line in 1990.
Operational History ²
The first flight of the Model 45 was on 2 December 1948, by Beechcraft test pilot Vern Carstens. In 1950 the USAF ordered three Model A45T test aircraft, which were given the military designation YT-34. A long competition followed to determine a new trainer, and in 1953 the Air Force put the Model 45 into service as the T-34A Mentor, while the USN followed in May 1955 with the T-34B. The US Air Force began to replace the T-34A at the beginning of the 1960's, while the U.S. Navy kept the T-34B operational until the early 1970's. As of 2007, Mentors are still used by several air forces and navies.
The T-34A and T-34C were used by the Argentine Navy during the Falklands War.
In 2004, due to a series of crashes involving in-flight structural failure during simulated combat flights, the entire US civilian fleet of T-34's was grounded by the Federal Aviation Administration. The grounding has since been eased to a series of restrictions on the permitted flight envelope.
The T-34C is still used as the primary training aircraft for United States Navy and Marine Corps pilots. The T-34C is currently being replaced by the T-6 Texan II but is still the primary aircraft at NAS Corpus Christi and NAS Whiting Field. NAS Pensacola has already completed the transition to the T-6 and the first T-6s are scheduled to arrive at Whiting Field in summer 2009.
NASA Dryden Flight Research Center has operated two T-34C aircraft. The first was previously flown at the Glenn Research Center in Cleveland, Ohio, for propulsion experiments involving turboprop engines, and then came to Dryden as a chase aircraft in 1996. That aircraft was returned to the US Navy in 2002. Dryden obtained its second T-34C in early 2005 from the Navy's Air Warfare Center Aircraft Division at NAS Patuxent River, where it was due to be retired. At Dryden, the T-34C is primarily used for chasing remotely piloted unmanned air vehicles which fly slower than NASA's F-18's mission support aircraft can fly. It is also used for required pilot proficiency flying.
The Mentor is the aircraft used by the “Lima Lima Flight Team” and “Dragon Flight”, both civilian demonstration teams. It is also used by aerobatic pilot Julie Clark, who flies her T-34 “Free Spirit” (N134JC) at air shows.
T-34 Operators ²
Specifications T-34C & T-34C-1 Turbo-Mentor ³
Avionics and Equipment:
Weights and Loading:
Performance (T-34C, at T/O weight of 1,910 kg; 4,210 lb, except where indicated):
Performance (T-34C-1 with 410 kW; 550 shp engine, estimated. [A] with two stores at AUW of 2,222 kg; 4,900 lb. [B] with four stores at AUW of 2,494 kg; 5,500 lb, except where indicated):
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