Really not sure where best to post this, but I am getting totally pissed off with aircraft going non radio. Warwick this morning I was taxiing for runway 27. A warrior had just called departing the circuit and I called “entering and lining up runway 27” when I spotted a PC12 on mid downwind. Now, I know that I had time to enter and roll before he landed, but with nil radio calls from him and a massive difference in performance and no idea of his intentions, I called “traffic downwind at Warwick, I will hold and line up behind you” then I received from him, “have you sighted” which confirms his radio was working and on the correct frequency. Now, a PC12 is not a basic puddle jumper and one would assume a fair degree of qualification and professionalism from someone piloting one, so why no radio calls???? See and avoid is essential!!