 Credited with one more victory during August 1917 , and another four the following month , Pentland 's score stood at ten when he was injured on 26 September after an artillery shell struck his SPAD and forced him to crash land . Following his recovery , he again spent time instructing before being posted back to a front @-@ line unit , this time No. 87 Squadron , operating Sopwith Dolphins . Promoted captain , he returned to France in April 1918 , having transferred the same month with the rest of the RFC to the newly formed Royal Air Force ( RAF ) . Pentland went on to achieve thirteen victories with No. 87 Squadron , where his aggressive tactics saw him dubbed the " Wild Australian " by colleagues . Appointed commander of ' B ' Flight , he also frequently acted as a " lone wolf " , actively seeking dogfights with enemy aircraft on his own . On 18 June , he was alone on patrol when he engaged a flight of four Rumpler high @-@ altitude reconnaissance aircraft , forcing down three of them . This action earned him the Distinguished Flying Cross , gazetted on 3 August : 
