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To effect a right turn, we actually deflected the right elevon down which created more drag on the right ... The downward deflected right elevon was not causing roll to the left as it would in an airplane.

The reason why deflecting the elevon down created a lot of drag but almost no additional lift as in a conventional subsonic airplane, lies in the particular behaviour of hypersonic aerodynamics.

Since upon impact the particle has changed its speed (the speed perpendicular to the surface has become zero), then by Newton's second law ($F=ma$) all the particles of air bumping into the body generate a force ($N$ in the following picture) which is:

Since upon impact the particle has changed its speed (its speed perpendicular to the surface has become zero), then by Newton's second law ($F=ma$) all the particles of air bumping into the body generate a force ($N$ in the following picture) which is:

The particles of air flowing over the surface of the body do not impact with it and they just keep on flying straight on: the "shadowed" surface do not experience any aerodynamic force and the air there just remains undisturbed: only the surface of the body being directly impacted by the air experiences an aerodynamic force.

That's the all story about hypersonic aerodynamics! Very simple indeed.

The particles of air flowing beyond the surface of the body do not impact with it and they just keep on flying straight on: the "shadowed" surface do not experience any aerodynamic force and the air there just remains undisturbed: only the surface of the body being directly impacted by the air experiences an aerodynamic force.

That's the all story about hypersonic aerodynamics! Very simple indeed.