Heli-torch. Essentially a helicopter-mounted drip torch for prescribed burns. 3:21 video:
https://www.youtube.com/watch?v=u1kpobfCgAk
Previously:
https://www.homemadetools.net/forum/...3557#post78292
https://www.homemadetools.net/forum/...3746#post78672
https://www.homemadetools.net/forum/...486#post104356
https://www.homemadetools.net/forum/...7085#post84989
https://www.homemadetools.net/forum/...3122#post98114
https://www.homemadetools.net/forum/...3312#post98673