|RFB Fantrainer 600|
|First flight||27 October 1977|
|Developed into||Rockwell Ranger 2000|
The RFB Fantrainer (or Fan Trainer) is a two-seat flight training aircraft which uses a mid-mounted ducted fan propulsion system. It was developed by Rhein-Flugzeugbau GmbH (RFB) in Germany in the late 1970s and used by the German and Thai air forces. It won a competition in Germany beating the Pilatus PC-7 and Beechcraft Mentor as the best solution to the Luftwaffe's Basic Trainer Requirement. However, no orders were forthcoming as Germany had committed to buying US Fighters (F4 Phantom and F-104 Starfighter) which included a deal for pilot training in the United States. Lufthansa was also interested in the aircraft due to its jet-like handling. Users confirm it is very fuel-efficient and provided a true "jet feel" for a reasonable price. The Royal Thai Air Force used the FT400 and FT600 versions to train ab initio pilots who then went on to fly the Northrop F-5E fighter aircraft.
Design and development
In the 1960s the German company Rhein Flugzeugbau developed an interest in aircraft powered by ducted fans integrated into the fuselage, flying two modified gliders as testbeds in 1969 and 1971. In 1970 it announced a new project for a two-seat ducted-fan military trainer, intended to offer jet-like handling at low cost. In March 1975, RFB received a contract from the German Defence Ministry for two prototype Fantrainers for evaluation as replacements for Piaggio P.149s used as initial trainers by the Luftwaffe.
The first prototype (registration D-EATJ), powered by two EA871 110 kW (150 hp) NSU Wankel engines, made its maiden flight on October 27, 1977. This engine installation proved troublesome, and the second prototype (D-EATI), fitted with a single 310 kW (420 shp) Allison 250-C20B turboshaft engine, flew on May 31, 1978. The second prototype crashed on September 7, 1978, which resulted in the first prototype being modified to Fantrainer 400 standard, with an Allison engine and revised air intakes. The Fantrainer was evaluated by the Luftwaffe against the Beechcraft T-34C and Pilatus PC-7 turboprop powered trainers, but although it was considered to be the most suitable of the three aircraft, being cheaper both to purchase (at DM 1 million per aircraft) and to operate, no orders resulted as it was decided that the Piaggio P.149 was still adequate for the Luftwaffe's needs.
The aircraft was finally produced in two models, the Fantrainer 400, powered by a 545 shp (406 kW) Allison 250-C20B, and the Fantrainer 600, which was powered by a 650 shp (480 kW) Allison 250-C30. In both, the turboprop engine drives a pusher fan. The wings are swept 6° forward to ensure the rear pilot’s view is not obscured by the wing-root. The four 96-litre capacity fuel cells are integral with the wing structure.
In August 1982, the Royal Thai Air Force signed a contract with RFB to buy 47 aircraft, 31 of the model 400 and 16 of the 600. They were assigned to the 402 Squadron and used as a step-up trainer for their future F-5 Freedom Fighter pilots. The step-up characteristic of the Fantrainer generally covers one of its main advantages. The training ability for pilots through a Fantrainer is almost fully covered and only supplemented by an Advanced Trainer for the purpose of getting a high performance jet training and experience. The first two aircraft were built in Germany, and the remaining aircraft were assembled in Thailand from kits shipped from RFB. After an initial period of operation, the RTAF elected to replace the aircraft's glass fiber wings with locally produced aluminium wings, even when the original fiber glass wings proved to endure well in the hot and humid Thailand weather, which was a main concern of the manufacturer.
- First prototype of the Fantrainer family. First flight in 1977 powered by two 150 shaft horsepower (110 kW) Wankel engines - 300 shaft horsepower (220 kW) in total, changed in 1978 to Allison engine.
- Second prototype.
- Fantrainer 400
- Stretched fuselage version with metal wings, powered by a 545-HP Allison 250-C20B turboshaft engine.
- Fantrainer 600
- Improved version, powered by a 485-kW (650-hp) Allison 250-C30 turboshaft engine.
- Fantrainer 800/1000/1200/1500
- Upgraded versions, planned but not produced yet.
In the early 1990s RFB and Rockwell International developed in a joint venture a jet-powered variation of the Fantrainer under the denomination Ranger 2000, which was evaluated as a trainer aircraft in the JPATS contest by the USAF and the U.S. Navy, but no orders were placed as the aircraft lost to the T-6 Texan II. One of the two prototypes crashed during evaluation. The Ranger 2000's turbofan engine was a Pratt & Whitney Canada JT15D.
Specifications (Fantrainer 600)
Data from Jane's All The World's Aircraft 1988–89
- Crew: 2
- Length: 9.20 m (30 ft 2 in)
- Wingspan: 9.74 m (31 ft 11 in)
- Height: 3.16 m (10 ft 4 in)
- Wing area: 14.00 m2 (150.7 sq ft)
- Aspect ratio: 6.8:1
- Airfoil: Eppler 502
- Empty weight: 1,160 kg (2,557 lb)
- Max takeoff weight: 2,300 kg (5,071 lb)
- Powerplant: 1 × Allison 250 C30 turboshaft, 480 kW (650 shp)
- Propellers: 5-bladed constant-speed ducted fan, 1.2 m (3 ft 11 in) diameter 
- Maximum speed: 417 km/h (259 mph; 225 kn) at 5,490 m (18,010 ft)
- Cruise speed: 230 km/h (143 mph; 124 kn) at 3,050 m (10,010 ft)
- Never exceed speed: 555 km/h (345 mph; 300 kn)
- Range: 1,037 km (644 mi; 560 nmi)
- Endurance: 4 hr 6 min
- Service ceiling: 7,620 m (25,000 ft)
- g limits: +6/-3 G
- Rate of climb: 15.0 m/s (2,950 ft/min)
Aircraft of comparable role, configuration and era
- Fricker Air International February 1986, pp. 70–71.
- Fricker Air International February 1986, p. 72.
- Aircraft Production in Thailand from Aeroflight
- Taylor 1988, pp. 95–96.
- Fricker Air International February 1986, p. 75.
- Fricker, John. "Flying the Fantrainer". Air International, Vol. 30 No. 2, February 1986. Bromley, UK: Fine Scroll. pp. 70–76. ISSN 0306-5634.
- Taylor, John W. R.. Jane's All The World's Aircraft 1988-89. Coulsdon, UK: Jane's Defence Data, 1988. ISBN 0-7106-0867-5.
- "Concept Aircraft" by Jim Winchester, ISBN 978-84-662-1370-7, MMV International Master Publications BV
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