Kevin P. Ford

Experimental Investigation of the Decomposition Preceding Cookoff in a Composite Propellant

The decomposition preceding autoignition of an ammonium-perchlorate-based composite propellant was experimentally investigated. Autoignition temperature is measured for a selected heating rate. At that same heating rate, differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared spectroscopy, and hot-stage microscopy are employed to study the propellant behavior leading to reaction. These experiments are conducted on both cured composite propellant and individual ingredients, including neat ammonium perchlorate and a cured binder. For a heating rate of 2 °C/min., it is determined using thermogravimetric analysis/Fourier transform infrared that ammonium perchlorate and the binder begin to react together near 150°C, whereas differential scanning calorimetry shows initial exothermic behavior after the orthorhombic-to-cubic phase transition near 240°C. This disparity is discussed and further investigated using larger-scale cubes of propellant heated in ovens at the same heating ...

Design of a Robust High Altitude Rocket Motor Igniter

In order to ensure reliable high altitude ignition of the improved Black Brant Mk 1 sounding rocket, a new igniter was designed and tested. Since traditional theoretical methods for calculating the required igniter charge size gave widely varying requirements, an empirical method was instead utilized. Various igniter models were fired in an enclosed chamber and heat flux and pressure outputs were measured. These data were compared to laser ignitability results obtained for the Black Brant solid propellant to ensure that sufficient igniter output was provided. A static test and flight test demonstrated that the redesigned igniter performed well to ignite the rocket under near vacuum conditions.