The flight of Auk XIII was very similar to that of its predecessor, Auk XII, launched just a little while earlier. Upon ignition, it "jumped from the pad...leaned over, puffed a big cloud of smoke, and sped off into the sky." When it reached its highest point and fell back it disappeared into a dense thicket of trees. The boys could hear it hit the branches of a large oak as it approached the ground on its descent.
Since O'Dell had knocked over Quentin's theodolite in his excitement at the rocket's launch, the boys were unable to get a reading of its altitude, but it was clear that Aux XIII had not reached the height of Aux XII. When the boys recovered the rocket, they found that, like Aux XII, its nozzle was completely worn through. Billy suggested that maybe the heat created by the rocket candy was too intense for the nozzle as it was created, but, upon closer examination, Sonny noticed that the nozzle actually appeared to be corroded. From this observation, Quentin was able to deduce that the problem was caused by rapid oxidation; heat combined with a steady flow of oxygen had worked together to destroy the rocket's nozzle. It was evident that the next step in the experiments would have to be the discovery of a material that would be capable of withstanding both heat and oxidation (Chapter 11).