posted on Aug, 18 2016 @ 11:49 AM
a reply to: DinobotIV
Seen demo of Osprey at airshow in "airplane" mode and that wasn't it last night.
It was like a deep deep hum with turbine sound in it, but definately not turbo prop sound.
Going by FA-18 flyover at treetop and guessing their speed at 350ish knots and comparing doppler change to last night's flyover I'd guess speed was
Mentioned in beginning post that I can identify 99.9% of both civilian and military aircraft just on sound alone, makes no difference if they are in
climb, cruise or descent, I do this all the time.
What I heard last night was nothing in the "normal" inventory.
Need some conjecture so I can go in right direction in identifying as I'm stumped.