Over on the DotPhysics blog, Rhett Allain confronts the technical impossibility presented by the flying R2D2 as depicted in the prequel trilogy. This is what physics degrees are for:

If I assume that R2 is flying horizontally at a constant velocity, and the the "thrust" is at an angle theta from the vertical then:





I guess I should say I am using g as the local gravitational field for whatever planet he (R2) is on. Is R2 even a he? Maybe R2 is a she. I don't know. The point is that the vertical component of the thrust must equal the vertical component of the gravitational force. So what you say?