Socata has just unveiled its new light weight, single-engine and high-performance airplane, the TBM-900 on March 12, 2014. It is a more-powerful successor to the successful variant TBM-850. For four years, the manufacturer put in lots of efforts to improve the design concept of the TBM series of airplanes. This project, known internally as the "Century Project", mainly focused on improving the aerodynamics of the TBM-900 using computational fluid dynamics. With the help of a computer model named Fluent, the engineers found possible areas which can be improved so that the airplane can lower the drag and gain speed.
A major change was made to the plenum and the engine's air intake. It was discovered that turbulent air flow is present towards the right of the plenum, slightly behind the air intake lip. Upon making the air intake narrow and canted, and bringing the propeller 4-inches towards it, the TBM 900 gained significant drag reduction that is equivalent to six knots of speed. It was also found that the main landing gear doors in TBM-850 were causing a drag equivalent to three knots. So, thy were replaced by just one pair of doors.
Two more major changes were made which contributed to a quicker takeoff and better climb performance. The first one was the inclusion of a Hartzell propeller that had five 5 blades made from carbon fiber. The second change is making available all of the 850 shaft horsepower (shp) generated by the TBM-900's PT6A-66D turboprop engine - this contributed to a 15% increase in the initial climb rate. In the TBM 850 and 700 models, the shp for takeoff was limited to 700. Some minor modifications enable the TBM 900, which uses the same engine as the 850, to produce of 850 shp. This enables the airplane to climb to the maximum altitude it may reach in just 17 minutes and 15 seconds under International Standard Atmospheric (ISA) conditions. This is a 14% improvement over TBM 850's performance. In case of take-off distances below the sea level, TBM 900's needs only 2,380 feet for clearing the FAA-standard fifty-foot obstacle, the 850 needs 2,840 feet for this. The 950 also manages better takeoff at high altitudes even in hot conditions; in this case, it's performance is 16 - 23% better than that of the 850 variant. Daher-Socta claims that at an altitude of 8,000 feet and in atmosphere ISA+30 degrees, the TBM 900 requires a runway of 4,185 feet while the 850 needs 5,450 feet.
Another change in TBM 900's aerodynamics is its winglets with come more effective ailerons that help maintaining the balance along the airplane's longitudinal axis while rolling. The winglets also create a "rail effect" for improving directional stability, which is also provided by an improvised dorsal fin. There are Whelen LEDs provided on the winglets - the lights blend in perfectly with other external lighting of the airplane. Also, the manufacturer says that Forward Looking Infrared Sensors (FLIR) can be accommodated in the winglets.Β
Coming to the performance, the TBM 900 boasts a maximum cruise speed of 330 Knot True Air Speed (KTAS) at FL280 which drops a little to 326 KTAS at FL310 - these speeds are higher than those of 850 by ten and 6 knots, respectively. When the power settings are set to maximum, the 950 can go over 100 nm farther when compared to 850. It was officially announced that the maximum range of TBA 900 with maximum fuel and NBAA is 1,582 nm, which is 132 nm or 9% better than 850. A 45-minute, standard IFR reserves can help the 900 go 1,730 nm. For the range equivalent to that of 850, the speed of 900 is 40 KTAS higher. Or at the same speed as the 850, the 900's range is increased by 120 nm or 8%.
Changes to Cockpit and Systems:
The TBM 900's cockpit is also subjected to radical changes. A center pedestal that is made narrow with a rounded base makes entering and exiting the cockpit more comfortable. The width of the front seats is slightly decreased, and they come with lateral supports as in many high-end cars. Unlike before, when the pilot door used to be an option, now it (pilot door) has became a standard on TBA 900. Not having the door is optional now.
There is no control level or propeller control on the center pedestal. A new power lever combines both the propeller and power control functions. The propeller can be electrically governed through a system made by Czech manufacturer Jihostroj that help maintaining the propeller rpms close to a redline of 2,000 rpms. A gate arrangement looking like the lower-case "h" is provided so that you can move the lever from the fuel cutoff to low-idle and high-idle positions (the right half of the gate run), and the left part of the gate run deals with power control whenever you bring the power lever towards the left. This arrangements makes sure you control forward, beta and reverse thrusts in a conventional manner.
The TBA 900 also includes a new electrical system. Its new 300-amp generator, unlike the 200-amp systems found in 700 and 850, comes with a starter that shuts off automatically at 50% NG at the start sequence. According to Daher-Socata, a battery start will now take only 30 seconds.Β
Still, there are so many new features in the TBM 900 some of which are discussed in the following sections.
1. It has the latest version of the Garmin G1000 suite software that includes hold-in place functions and radar images superimposed over the map view.
2. The landing gear controls are totally redesigned, and a light, easy-to-use handle is provided to announce gear unsafe and gear-in-motion warnings.
3. The de-icing control panel is completely redesigned.
4. Preselect positions of the flap and asymmetry detection system.
5. Automated control of Pressurization. Simply setting the field elevation of the destination will do; the system does the job on its own.
6. Control yokes that are ergonomically accurate and come with thumb rests.Β
7 Switches and a comfortable yoke design.
Overall, the TBM 900 is the most advanced, well-optimised airplane of the TBM series. It is also the the fastest and highly capable variant that comes with a large price tag - $3.71 million for the basic variant. The 900 is slowly gathering momentum in the marketplace. Daher-Socata has already began the production and there is an order for 40 airplanes, which is more than than the number of 850s sold in 2013 (the company ceased to make 850 at the serial number 684).
