The Stengel Angle

This is the last post of a 3-part series covering the technical visits I made during my study abroad program in France (see Part 1 and Part 2). The last two companies we visited were Safran Herakles, a rocket nozzle manufacturer, and ATR, a regional turboprop aircraft manufacturer.

SAFRAN HERAKLES

The Safran Group is a large multinational that specializes in aerospace propulsion, aircraft equipment, defense, and security. It was the result of a merger between Snecma, the propulsion and aircraft equipment manufacturer, and Sagem, the defense conglomerate, in 2005 and is headquartered in Paris. In the commercial aviation world, Safran is most famous for its Snecma and Turbomeca subsidiaries, who make aircraft engines. Snecma currently works with General Electric in a joint venture on the CFM56 engine for the Airbus A320 and Boeing 737 aircraft along with the GE90 turbofan for the Boeing 777. Turbomeca makes helicopter engines, like for the Eurocopter AS350.

Ariane V, one of the applications of rocket nozzles produced by Safran Herakles

Our tour, however, would take us through a different subsidiary, Safran Herakles, formerly Snecma Propulsion Solide, which designs, develops, and manufactures rocket motors, nozzles, propellants, and thermostructural materials. The division employs 3,000 employees on a turnover of 700€ million. Some of the concepts championed by Safran Herakles include the rotating rocket nozzle (allows for greater trajectory control), the use of Tungsten in hot sections of a rocket, the 3-stage submarine missile, and the development of flexible composite bearings. Furthermore, some of Safran’s achievements in the automobile industry evolved into aerospace applications, like the carbon fiber brakes. Lastly, Safran believes that a key part of their strategy is the development and manufacture of ceramic parts for aviation applications, particularly in the hot turbines of jet engines.

The main part of our tour took us through the rocket nozzle production facility, which is about the size of the Airbus A330 production line (surprising since the whole building is devoted to the nozzle alone). Our guide took us through the facility in chronological order of the manufacturing process, which started with the curing of the composite material in an autoclave. This makes the material tougher under a pressure of about 33 megapascals (about 330 times the standard air pressure at sea level). Next, the nozzle goes through a lathe in order to make the entire surface smooth. Also, small holes are drilled into the nozzle in order to allow pressurized gases to escape and avoid damage during combustion. As with any manufacturing process, the nozzle also undergoes non-destructive testing through x-ray and ultrasonic tests to detect any defects. If any are found, the entire nozzle is scrapped.

The next step is to bond the metal and composite materials, likely the most tedious and time consuming step in the process. First, the material is sand-blasted and then de-greased with organic solutions, which prepares it for bonding. Then, in a white room (a controlled environment where temperature, humidity, and air quality are constantly monitored), highly trained technicians manually apply about 6kg of glue to bond the materials together. Again, if any defects arise, the entire nozzle will be scrapped since it will not perform as needed. Finally, the nozzle is shipped to the operator in two pieces and final assembly typically takes place near the launch pad.

ATR

ATR, or Avions de Transport Régional, is a joint venture between EADS and Italy’s Alenia Aeronautica that produces turboprop regional aircraft. The company was founded in 1981, and has been best known for producing the ATR-42 and ATR-72 aircraft, of which there are over 1,200 orders since the program launched. Currently, ATR dominates the turboprop regional aircraft market with 45% of sales. Their primary competitor is the Canadian aircraft manufacturer Bombardier, who produces the Dash 8 turboprop in addition to the CRJ series of regional jet aircraft. Against the Dash 8, the ATR-42 and ATR-72 hold a 64% share of orders against the Dash 8’s 36%.

ATR’s main French production facility is located on the grounds of Blagnac Airport in Toulouse, France, alongside the other EADS subsidiaries like Airbus. At the ATR facilities, 900 employees conduct the final assembly of all aircraft. The fuselage and tail assemblies arrive from Alenia Aeronautica’s Italian plants and are fitted together with the wing (it weighs 2.7 tons), which is produced by EADS in Bordeaux. Also, the two engines are produced by Pratt & Whitney Canada, and the propellers come from Hamilton Sundstrand. In fact, the final assembly consists of two lines: Line A and Line B. Line A conducts the integration, installation, and testing of all parts and systems, along with installing pre-furnishings and engines. Line B consists only of customization work, such as painting the aircraft and outfitting the interiors to the customer’s specifications. In addition to the standard passenger model, the ATR aircraft can also serve missions for VIP, cargo, research, and maritime/anti-submarine warfare flights.

The ATR-42 holds some operating advantages over the CRJ-200 while carrying the same number of passengers (click for large version)

Although ATR has been around for quite a while, the outlook for the company is looking especially bright. Due to high fuel prices, air operators have been paying a premium for their 50-100 seat regional jets, which saw plenty of orders back in the 1990s. As a result, ATR has seen a surge of orders since 2002, with 70% of their current backlog devoted to turboprop aircraft with less than 90 seats. The company is also forecasting in the next 20 years that 42% of new regional aircraft deliveries will be turboprops and that the aircraft will dominate the 30-90 seat market. Furthermore, ATR will be boosting production from 75 per year to 80 per year in 2013, and then once again to 90 per year in 2014. Some advantages that turboprops hold over regional jets is that they are more fuel efficient, can operate into smaller airports since they don’t use up as much runway for takeoff and landing, are cheaper, and can operate many of the same routes as regional jets. On the other hand, turboprops fly at slower cruise speeds (longer flights), fly at lower altitudes (might be a bumpier ride), and are louder.