hi.,

When airplanes appear to be landing sideways it is to keep the aircraft lined up with the runway centerline during their final approach. Depending on the wind strength, the airport's location, the type of aircraft, and the pilot's skill will dictate which technique they will use.

porpoising is usually caused by a tail-heavy condition. It is indeed a SA Micro Stik 26in wingspan..

The phugoid or long period motion is a characteristic oscillations of the aircraft after a small disturbance of the steady flight (ie. due to small horizontal control surface motion or the air gust). The airplane is traveling along the sinusoidal trajectory with small changes of the air speed and pitch angle.

Best wishes..