Embraer/FMA CBA 123 Vector
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| CBA 123 Vector | |
|---|---|
| Type | Light business aircraft or 19 seat regional airliner |
| Manufacturer | Embraer/Fábrica Militar de Aviones |
| Maiden flight | July 18, 1990 |
| Status | Retired |
| Number built | 2 |
| Unit cost | >USD$5 million |
The Embraer/FMA CBA 123 Vector is a 1990 turboprop aircraft designed for regional flights, carrying up to 19 passengers. The program arose from a partnership between the Brazilian company Embraer and the Argentine company Fábrica Militar de Aviones (FMA) (now named Lockheed Martin Aircraft Argentina SA), thus the name "CBA", "Cooperación Brasil-Argentina" "Cooperação Brasil-Argentina" (Brazil-Argentina Cooperation). The project was an advanced turbopropeller aircraft for its time, including advanced technology in avionics, aerodynamics, and propulsion.
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[edit] Development
By 1985, economic integration of South America seemed to be in progress with advances in the negotiations of Mercosur between the Brazilian and Argentine governments. In 1996, as a way of encouraging partnership between both countries, an agreement to develop a a Brazilian-Argentine aircraft was signed between Embraer and FMA.
The costs and workload of the project were divided between Embraer (67%) and FMA (33%). The aircraft was designed as a high technology turboprop, fully certified under USA FAR 25, including propellers in pusher configuration to increase passenger comfort, wings with supercritical airfoils, FADEC system for engine control, plus EICAS and EFIS avionics systems. The "Vector" name was chosen by an international competition including more than 6,000 proposals.
The first prototype of the Vector flew on July 18, 1990, and the flight occurred with no problems. The official presentation on July 30, 1990 was attended by Brazil President Fernando Collor de Mello and Argentine President Carlos Menem.
[edit] Program Cancellation
There were several reasons for cancellation of the 123 Vector program:
- The publicly announced reason was the high projected unit cost (US$5,000,000). A significant reason for this high cost was the expense of certifying the new technologies (FADEC/EICAS/EFIS). These technologies are now more common in the airline industry, but in the early 1990s they represented unproven factors, and the FAA required more testing, and more backup systems, than had been envisioned at the program outset.
- Placing the propellers at the aircraft tail created several problems:
- It required that the engines be mounted high (to avoid propeller strike during landing flare). The resulting nose-down moment when power was applied required significant tailplane download, which increased the induced drag of the aircraft.
- It greatly increased the risk of propeller damage during ground operations, especially takeoff. This would have been a significant sales barrier.
- It meant that more of the fuselage had to be located forward of the wings (in order to maintain the proper weight balance), which meant that streamlining of the tailcone was more abrupt, with slightly greater drag than expected.
- It meant that more of the payload (i.e. passengers) would be placed ahead of the loaded center of gravity. Thus when passengers deplaned, the empty aircraft would be tail-heavy, and since it was a tricycle configuration, would fall onto its tail. To counteract this possibility, the main landing gear wheels were set farther aft than on other aircraft, and a much larger elevator force was required to rotate the aircraft in the takeoff run, or to hold the nosewheel aloft during the landing flare.
- Placing the propellers aft of the engine pylons caused them to operate in disturbed airflow, which increased their noise level and caused higher material stresses in the blades and engine shafts. Although no fatigue-related problems were noted in the the 123 Vector prototypes during their relatively brief lives, the knowledge of previous failures in similar configurations (e.g. Convair B-36) would have been a significant sales obstacle. In addition, this configuration was chosen to reduce noise and vibration levels as perceived by passengers. However, the "buzzsaw" sound resulting from the propellers as they chopped through the pylons' wake was more unpleasant in the cabin (although further from most of the seats) than a wing-mounted propeller would have been, and the greater pylon vibration (caused by one propeller blade slicing the wake while the other blades operated in undisturbed air) was transmitted to the aft fuselage, resulting in an unpleasant vibration in the rear portion of the cabin.
- Choosing a supercritical airfoil seemed fitting, given the advanced nature of the proposed aircraft. However, since the projected cruising speed was well below transonic, the supercritical aspect was unnecessary, and only added problems: lower maximum lift coefficient, unfamiliar fore-aft distribution of pressures compared to more common airfoils (leading to more resesarch and calculations required to properly size load-bearing components of the wing panels), scarce research data for flap loadings in combination with this airfoil, pilots were not familiar with the wing's responses at high angles of attack.
The final unit cost of the aircraft — US$ 5 million — was too high to be absorbed by the market. Also, new investments from the Brazilian Government became unavailable due to the political crisis caused by the impeachment of Collor de Mello.
The CBA 123 Vector project, which cost US$ 300 million, was therefore cancelled, with only two prototypes built. Although a failure, the project gave Embraer maturity to work with new technologies, which led to the development of the successful Embraer ERJ 145 family of jets.
[edit] Specifications
General characteristics
- Crew: Two pilots
- Capacity: 19 passengers
- Length: 18.5 m (60.67 ft)
- Wingspan: 16.46 m (54 ft)
- Height: 5.6 m (18.37 ft)
- Empty weight: 4,900 kg (10,800 lb)
- Max takeoff weight: 7,711 kg (17,000 lb)
- Powerplant: 2× Garrett Systems TPF351-20A, 1,219 hp (909 kW) each
Performance
- Maximum speed: 593 km/h (368.25 mph)
- Range: 1,610 km (1,000 mi)
- Service ceiling 12,192 m (40,000 ft)
[edit] References
- Embraer history on Jetsite.com.br
[edit] External links
- Embraer
- Lockheed Martin Aircraft Argentina
- CBA 123 Vector photos on Airliners.net.
[edit] See also
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