These are some notes and links regarding Pelans who have military records or where there are other accounts of their lives in the military. The list is not complete.
American Civil War
Robert T Pelan, of Irish descent, died from wounds sustained at the Battle of Fredericksburg on the 15th December 1862. He was a member of the 7th Rhode Island Infantry.
The Irish Times newspaper of 18th March 1922 reports the death of Peter Pelan, 86, a Crimean War veteran who died at Lisburn. He had been in the 70th Foot Regiment and served in the Crimean and Afghan wars. He took part in the march from Kabul to Kandahar under the command of Frederick Roberts - another Irishman.
South African campaigns
From  - "The Ulster Museum has an oval wooden food platter with four legs, with the information that this was taken from King Lobengula's kraal (village) by Trooper T. R. Pelan of Royston's Horse during the Zulu war of 1906. The dish was given to the Museum in 1917 by Trooper Pelan's widow, who lived in Lisburn, Co. Antrim." .
First World War
The Tale of Royston's Horse: Connections between the Ulster Museum and Africa in the Nineteenth and Twentieth Centuries, Winifrid Glover, Archaeology Ireland , Vol. 11, No. 3 (Autumn, 1997), pp. 27-29