During World War I, it branched out into ammunition, military aircraft engines (the first Rolls-Royce aircraft engines were Renault V8 units) and vehicles such as the revolutionary Renault FT tank.
Selama Perang Dunia I, Renault juga memproduksi amunisi, mesin pesawat (bahkan, mesin pesawat pertama rakitan Rolls-Royce memakai unit V8 dari Renault) dan juga kendaraan seperti tank Renault FT yang revolusioner.