TP400 nears Fadec trials, certification
Engine consortium Europrop International (EPI) is now just 300 test hours away from certification of its 11,000-shp TP400 turboprop for the Airbus A400M military transport. According to technical director Karsten Muehlenfeld, the final software of the full authority digital engine control (Fadec) is to be delivered to the Toulouse iron bird late this month, allowing flight trials to at last begin. Problems with the Fadec have been at the heart of the serious delays suffered by the aircraft program.
The Fadec has to be civil certified, as has the rest of the engine. Therefore, exhaustive documentation is needed, which the previous release of the software failed to have. Muehlenfeld emphasized the program has 50 percent more input and output interactions than that of A380 engines.
The remaining 300 hours are included in a total 800 to 900 test hours that are still necessary to have full engine capabilities at entry into service. For example, interaction with the propeller, air intake and wing have to be measured. The first 300 hours involve only the engine–without its propeller, nacelles and so on. EPI uses six testbeds over Europe. The consortium is also using data from the C-130 flying test bed that has flown 35 hours so far. However, it is insisting these tests are under Airbus Military’s responsibility.
Regarding the high-pressure compressor, executive vice president Jacques Desclaux told AIN that the new version has passed tests that will translate into it being soon cleared for flight. “Aerodynamically, there is no change. We just made it more robust, thus adding a bit of weight,” he said. He stressed the surge margin is unchanged. As for engine weight, Muehlenfeld said he is confident plans to shave an extra 65 pounds will succeed by entry into service.
He gave some details of the design, noting that EPI has applied more new technology (as opposed to proven technology) than expected. In the intermediate compressor, a casing treatment takes care of surge margin without the usual complex stator variable vanes. In the high-pressure compressor, a four-stage blisk rotor cuts the part count and is 10 percent lighter. In the combustor, a very thin flame tube saves weight as well. In the low-pressure combustor, each pair of blades has a common root, which reduces the part count again.