Between August 1986 and February 1987, tests were carried out of the new starter called "Unducted Fan" (UDF). In the Mojave desert of the USA. This new engine reuses the propellers. A Boeing 727 has been used for these tests. This boeing has been replaced by a UDF. It has been very good, especially at 0.84 matx and 11,000 m high.
Through the UDF, commercial aircraft will circulate at the same speed as turboreactors, but with lower fuel consumption. In the tests the fuel consumption of two normal engines has been 49% higher than that of the UDF.
New sessions will soon be held in the Douglas MD-80 model. In addition, despite his doubts, Boeing has selected UDF engines to equip the new B7J7. The first commercial flight of this new B7J7 is now available for 1992.