o Open a new spreadsheet document.
o Click in the top left corner, where the row and column headers meet, in order to select the entire sheet.
o Go to Format | Cells... | Font (or right-click | Format Cells... | Font) and select your chosen font - or just use the Font Name box in the Formatting toolbar.
o Repeat for Sheet2 and Sheet3 if desired.
o Go to File | Templates > | Save..., give the template a name, and save it somewhere - probably in My Templates.
o Go to File | Templates > | Organize..., browse to and select the template, and then click Commands | Set As Default Template.
This template will now be used when you create a new spreadsheet (Calc) document, with the font set as you require. But I suspect any new sheets you insert may fall back to Arial.
I trust this helps.
Brian Barker