2 April 2020:The L-39NG, new light jet trainer aircraft has achieved an important milestone by opening the flight envelope during the test flight. The highest speeds achieved during flight tests was 509.4 KTAS (943.4 km / h) and Mach = 0.822.
The test flight was completed in configuration with a full integral tank in the so-called wet wing. Manufactured by the Czech aircraft manufacturer AERO Vodochody AEROSPACE, the L-39NG reached full range of expected heights and speeds during the test flight.
"The L-39NG project team has completed a crucial and very challenging phase of the flight testing. After a series of ground tests, we successfully proved the airframe strength during the flight without any critical case. Thanks to these tests, we confirmed that the L-39NG design has exceptional robustness and stability," said Jaromr Lang, chief designer of the L-39NG.
The Flutter test -
- The opening of the L-39NG envelope was preceded by a set of flutter tests in order to verify the aircraft's resistance and its structure ability to damp spontaneous oscillations induced by external aerodynamic forces in flight.
- During the flutter tests, the aircraft structure oscillations were initiated by small rockets at the wing tips or by impulses to the flight control system caused by the test pilot.
- Later, an analysis of measured vibrations took place.
- For this purpose, the Aero test pilots completed a series of test flights at different altitudes and speeds.
- All those flights were performed by the first flight prototype with manufacturing serial number 7001.
- During the flutter test, a total number of 192 rockets were fired, including 144 rockets fired in flight and 48 rockets in ground tests.
- Total number of 352 measurement cases were made and analysed.
"We achieved significant progress in ground and flight testing so far. With two L-39NG flying prototypes in the air since middle of April plus our technical demonstrator, we are very well prepared for our remaining journey to certify the aircraft in the third quarter of 2020," said Dieter John, President & CEO of AERO Vodochody AEROSPACE.
"Opening the flight envelope of the L-39NG is an important milestone not only for the whole project, but above all for our further dealings with our business partners and potential customers," said Jiri Podpera, President of OMNIPOL, the strategic partner of the L-39NG project with equal 50 per cent participation.