This paper presents some results of experimental investigation on a two-phase pulse detonation engine (PDE) model. Proof-of-principle experiments of this model with liquid C8H16/air mixture were successfully conducted. Efforts were focused on initiation and propagation of detonation waves by means of one-step detonation initiation method, low-energy ignition system (total stored energy of 50 mJ), and effective Schelkin spiral. Three PDE models with different sizes were tested: 30 mm-I.D. by 2 m-length; 56 mm-I.D. by 2 m-length and 50 mm by 1 m, which were operated over a repetition frequency range from 1 Hz to 36 Hz. One-way valves were used to adaptively control intermittent supplies of air and fuel flows. The results of detonation velocity, over-pressure and impulse measurements were presented. The measured pressure ratio of detonation wave was close to that of C-J detonation. The effects of equivalence ratio, PDE diameter, length, and detonation frequency on its performance were experimentally investigated. The obtained results have demonstrated that the averaged thrust of PDE is approximately proportional to the volume of detonation chamber and detonation frequency. For liquid C8H16/air mixture. the PDE operation with as short a length as 1000 mm and detonation frequency up to 36 Hz was successfully realized, which made an important step to practical PDE. (C) 2003 The Combustion Institute. All rights reserved.