The secret is out - what the Sentry's rotordome is really for...

[Lima Juliet]

DARPA/Boeing DiscRotor - YouTube

All right, the thread title is tongue in cheek, but the video is genuine DARPA. :ok:

[CoffmanStarter]

Leon ... Now that's an interesting engineering challenge to overcome I'll bet :ooh:

[MightyGem]

Interesting concept, but the blades appear to be longer than the diameter of the disc.

[Spanish Waltzer]

MG,

It's called the Tardis concept

[LT Selfridge]

I love the way that DARPA always portrays its concepts as being helpful to people.

[West Coast]

Wouldn't it be helpful to some?

[SASless]

Based upon the home yard Weed Eater!