Any simulations of four-winged dinosaur flight? (microraptors)
Note nowhere in the article does it mention the rear wings flapping. The rear wings do not provide lift, they are acting as control surfaces to improve stability and maneuverability. (think of the tail of a plane).earlier/proto flies have far more demand for control surfaces than developed/derived fliers due to lacking more precise control of flight surfaces.

They basically take off just like any other bird, if they could fly. Flight in dinosaurs likely did not even evolve from gliding as we commonly think of it but instead from raptorian pouncing, the sprawled posture of microraptor you sometimes see, with its hind legs spread wide, is anatomically impossible, you literally have to dislocate both legs to do it. Dinosaur hip joints do not allow for much lateral extension unlike mammalian or varanid ones, more like a hinge than a ball and socket. 

The animal in flight would have looked like this.



Hall, Justin, et al. "A new model for hindwing function in the four-winged theropod dinosaur Microraptor gui." JOURNAL OF VERTEBRATE PALEONTOLOGY. Vol. 32. 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA: TAYLOR &amp; FRANCIS INC, 2012.