DC-DC converter not simulating correctly
DC-DC converter not simulating correctly


I think you'll find that the simulation is correct.
The datasheet for the MC3046A shows the schematic (9.1.1) you require when using an external transistor: 



Without the Base/Emitter resistor the capacitance of the Q1 junction (both EB and CB) will cause your Q1 to switch off very slowly. This will decrease the backemf you get from the series inductor so limiting the voltage output.