The Patakatapaka was a dreadful Númenórean explosive and steam-driven "chain-cannon," after the fashion of later "machine-guns" such as were made by the Men of the Sixth Age. It is not known how long it existed in the Númenórean arsenal, but it is most likely that it was a product of Sauron's teaching. After the drowning of Númenór the secret of its functioning and making was lost to western Men, and while the elite soldiers of the Dark Tower were sometimes reported using like weapons, its cost and inefficiency prevented the dreadful weapon from achieving prominence in Middle-Earth.
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Notes[]
Fantastic fire-weapons used by the Númenoreans were alluded to in the History of Middle-Earth but never described in detail, however Tolkien curiously included Patakatapaka" as a Quenya wird for Machine-gun so it is quite likely the weapon existed.