Abstract: The invention relates to a horizontal tail of a catapult launched glider which can change angles during flight.

Abstract: The invention is related to a swimming teaching apparatus which provides user to make a complete swimming like action on land. The special technical features are a body rotation mechanism, arms guide, a breathing sink and a kick pad for legs, all together to perform on land swimming exercise. All strokes can be skilled with a precise instruction by the coach when the user is stationary on the invention. The invention allows user to do continuous practice of the swimming movements without be interrupted by a breathing problem, when the arms and legs are well coordinated, breathing sink then add to exercise, user can do combined actions slowly to ensure the correctness. The invention is tried to substitute the buoyancy of water as a pre-training machine for those schools which have no swimming pools can still carry out swimming courses for their students to reduce drowning incidents.