Forces on a Sailplane: Study of Flight Dynamics

[alchemist]

i am doing a study on the flight dynamics of a sailplane. How does the downward motion of the glider gives rise to lift and the forward thrust.

the free http: //www.yorksoaring.com/whatissoaring/wis3.html

So the question that has been bothering me is that whether the direction of drag is directly opposite to the the thrust acting on the plane, or is it opposite to the resultant vector from the thrust and lift on the plane, and in this case not parallel to the thrust?

In this diagram, the flight path is taken to be in the same direction as the thrust force, i just want to clarify the correctness of such a diagram, as it will affect the answer to my first question.

Lastly, i would like to affirm that the thrust force arises from the parallel weight component of the plane right? or is it otherwise?

 

[russ_watters]

The drag vector is always directly opposite the direction of motion in aircraft. In the case of a glider, the direction of motion is the direction of the thrust.

And yes, thrust is the component of the weight parallel to the direction of motion.

 

[ravenprp]

Thank you for your question and for sharing your study on the flight dynamics of a sailplane. The downward motion of a sailplane, also known as a glider, is essential in creating lift and forward thrust. This is because the glider's wings are designed to produce lift when air flows over them at a certain angle, and the downward motion helps to create this angle of attack.

To answer your first question, the direction of drag on a sailplane is indeed opposite to the direction of thrust. This is because drag is caused by air resistance, which is always in the opposite direction of motion. In the case of a sailplane, the motion is in the direction of the thrust force, so drag will be in the opposite direction.

In regards to the flight path and the direction of thrust, it is correct to have them in the same direction. This is because the thrust force is the force that propels the sailplane forward, and the flight path is the path that the sailplane takes as a result of this force. The lift force, on the other hand, is perpendicular to the flight path, as it is responsible for keeping the sailplane in the air.

Lastly, the thrust force does arise from the weight component of the sailplane, as the weight of the sailplane is the force that needs to be overcome in order for the sailplane to move forward. This is why the thrust force is often referred to as the "opposing force" to weight in flight dynamics.

I hope this helps to clarify your questions and provides a better understanding of the forces acting on a sailplane in flight. Best of luck with your study!