The theory of total heat transfer to cylindrical collectors in collisionless plasma flow with no magnetic field is presented. The treatment has been done for orbit‐motion‐limited conditions (Debye length sufficiently large), for the speed ratioS=U/(2kT/m)1/2of the flow velocity to the most probable ion thermal velocity from 0 to 10, and for various values of the nondimensional collector potential &khgr;p=qVp/kT.