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by DebtDeflation 552 days ago
I've been following the story and this has been discussed on the local Reddit subs. They are almost certainly PteroDynamics XP-4 drones flying from and to the military bases in question for testing purposes. There literally was a public demo of them on the USNS Burlington in Philadelphia a year ago.
2 comments

I really like that it switches off the outer pair of propellers in level flight, that's a nice feature.

Changing the vertical alignment of the wings to horizontal after takeoff is also really cool, an interesting alternative to 4 vertical propellers with a separate pair of wings. It seems to eliminate the extra moving parts to control those vertical propellers.

The linkage system is pretty cool I will say that.
Something actually patent-worthy.
How? it's just a UAV, quad version of a V-22 Osprey. Maybe I'm missing something peculiar about it?

https://en.wikipedia.org/wiki/Bell_Boeing_V-22_Osprey

"just" is doing a lot of work there. Everything is "just" an evolution of something else. Doesn't mean it's not novel or clever.
The wing folding mechanism is pretty novel as far as I'm aware. The idea of quad hover to forward flight isn't new or unique but the specific configuration is something I haven't seen before. NASA was working on some that tilted the whole wing not this folding design which uses fewer motors compare to the old NASA Greased Lightning test article.

https://www.youtube.com/watch?v=kXql26sF5uc

Osprey has a common power shaft between the engines for fault tolerance, constraining the structure's design, such as the lack of dihedral. This has a different set of design constraints and a different solution to propulsion failure.
The hinge mechanism and the control dynamics.
HN is yet again amazed that military technology is in fact used to carry out secret operations.