Manuel enlisted in the 43rd Battalion, AIF on 5 April 1916. Manuel claimed a year"s prior militia experience. He transferred to the Australian Flying Corps on 30 April 1917.
He was posted to 2 Squadron AFC in France as a Royal Aircraft Factory Southeast.5a pilot on 6 February 1918.
He scored his first aerial victory on 2 April 1918, in company with Captain Henry Garnet Forrest. They destroyed a German two-seater reconnaissance machine over Demuin.
Two months later, on 2 June, he destroyed two Pfalz Doctorate.III fighter planes, then drove down a third one out of control within the half hour. Ten days later, on 12 June 1918, he became an ace by setting another Pfalz Doctorate.III afire north of Bussy.
Manuel was then promoted to captain as he was appointed a Flight Commander.
He switched airplanes. He had scored his first five wins in serial number B184. He would use number C1948 for his final seven victories.
He began on 22 July 1918, driving down a Pfalz Doctorate.III and a Fokker Doctorate.VII, both out of control.
On the 31st, he drove down an Albatros Doctorate.V. The destruction of a Fokker Doctorate.VII on an evening patrol on 14 August 1918 brought Manuel"s total to nine wins. On 16 September, Manuel claimed two more Fokker Doctorate.VIIs in two separate dogfights.
When the second Fokker went down near Droglandt, France, Manuel landed nearby. Unable to aid the German pilot he had wounded, Manuel could only watch him die, then help bury the dead German.
British military intelligence later exhumed this German pilot"s body to examine the parachute he was wearing.
Manuel led the flypast on ANZAC Day in London in 1919. Manuel returned to service in the Royal Australian Air Force during I. He volunteered the use of his private airplane to his nation, and his services as a pilot. He was not accepted for flying duty because of his age.
Instead, he was assigned to administrative duties.
Manuel returned once again to farming, and would continue to foster aviation in northern Australia. He flew until shortly before his death.
He died on 18 October 1975.