What he neglects to mention is both studies raise concerns about simulations of helicopters. From the abstract of the first study: "The simulators which exhibi

What he neglects to mention is both studies raise concerns about simulations of helicopters. From the abstract of the first study: "The simulators which exhibited the highest incidences of sickness were helicopter simulators with cathode ray tube (CRT) infinity optics and six-degrees-of-freedom moving base systems. Of those studied, fixed-wing, fixed-base, dome displays had relatively low incidence of simulator sickness." If you read the second study, the VR environments tested we're exclusively those of piloting helicopters. Since helicopters have a lot of lateral and rotational acceleration, its plausible that this is why the simulation sickness is so great.