The Trike Xenit has a belt drive and sometimes it`s possible a sliding of this belt with an increasing of rpm and a loss of trust. The rpm must be included between 7000-7200 with propeller L-M-07 and 6600-6800 with propeller L-M-08. For this reason, we suggest to use a revolution counter during the flight.
You can test the Xenit on the ground bringing the rpm at max. If you hear a whistle during the acceleration, and above all, an increasing of rpm not like above descripted, you must regulate the belt.  The regulation of the belt tension is a very easy operation that it`s descriped in the manual instructions.