Abstract: A fluid energy convertor comprising a turbine having a cylindrically shaped interior whose exterior surface is exposed to a fluid front which is naturally accelerated while flowing around same creating a current of fluid which is contained only within a portion of a cylindrically shaped passageway, located around the outside of said cylindrically shaped interior, where contact is made between said current of fluid and a series of turbine vanes causing their movement and providing an active force on same which is transmitted by way of the turbine's structure to a centrally rotating spindle and other means for providing useful work. Multiple automatically controlled adjustable louvers assist in directing the fluid front into said passageway and in containing said current of fluid within said passageway with said louvers being adjustable to either speed-up or throttle said current of fluid as required for maximum work within limits dictated by the fluid velocity, turbine size and convertor structural strength.