The Bell HSL-1 was a tandem-rotor antisubmarine warfare helicopter built by Bell for the US Navy in the 1950s.
https://diqn32j8nouaz.cloudfront.net...helicopter.jpg
Previously:
https://www.homemadetools.net/forum/...617#post159170
https://www.homemadetools.net/forum/...170#post157685
https://www.homemadetools.net/forum/...822#post152381
https://www.homemadetools.net/forum/...219#post149989
https://www.homemadetools.net/forum/...414#post142609
