A model of "parallel" metal-graphene quantum FET nanotransistor with a gate on the Coulomb blockade in the "magic" Ir55 nanocrystals is proposed and designed. This nanotransistor will have a speed of about 2.5 * 1011 Hz and size of 32x32x12 nm3. It is shown that in this model of nanotransistor a source-drain potential is equal to 1.2 V, the threshold for the opening of the gate UG is equal to 0.4 V and the total current in parallel connected 250 elementary single-electron nanotransistors - crystals of Ir55 is 1.5 * 10-5 A. This current is approximately equal to the current in experimental terahertz semiconductor nanotransistors. It is shown that gain coefficient for charge is Kq = 1, and the power gain is equal to KP ~ 3. Such nanotransistor at using inductive-capacitive load could be an element of the integrated circuit - the generator of electro-magnetic waves with a wavelength of 1.2 mm and power density ~ 104 W/cm2.