Flight – forces that act on an airplane in flight

• weight
• lift
• drag
• thrust

Flying encompasses two major problems; overcoming the weight of an object by some opposing force, and controlling the object in flight. Both of these problems are related to the object’s weight and the location of the center of gravity. During a flight, an airplane’s weight constantly changes as the aircraft consumes fuel. The distribution of the weight and the center of gravity also changes.

Experiments, simulations

• Wright brothers were the first to understand how the lift from the aerofoil changes in flight, and the first to design their propellers as a form of aerofoil.
• lift balance allowed the Wrights to measure the lift coefficient directly
• drift balance – directly measure the drag to lift ratio.
• simulation – based on Hooven’s dynamic model, experience just how difficult it was to control the 1903 Flyer.

What’s the problem?
“Orville and Wilbur Wright” (video 4:00) – explaining how the four forces of weight, lift, drag and thrust affected the flight of their aircraft.

• Ask – What are the forces acting on the object that is flying? How is this different than the forces on the same object sitting on the ground? What has to change for the object to fly?
• Imagine – How can you change the forces on the object? What do you need to make that happen?
• Design, Build – What are all the components needed to make the changes so the object can fly?
• Improve – How well will it fly? What are some of the things that could be changed to make it fly better?

That’s engineering

• force may be thought of as a push or pull in a specific direction. A force is a vector quantity so a force has both a magnitude and a direction. When describing forces, we have to specify both the magnitude and the direction.

Engineering ideas

• lift, drag, thrust, gravity, aerodynamics, aviation

Do It
Challenges for you to work on…

• Aero! (interactive simulation, app, free) – Enjoy learning about the dynamics of flight, as you control a beautiful albatross soaring over the ocean. Directly control the angle of an albatross’s wing, causing changes in lift forces and allowing the bird to ascend or descend.

• First Flight simulation – experience just how difficult it was to control the 1903 Flyer. They require very fast reactions and leave you full of admiration for the skilled flying of the Wright Brothers.

• design a glider Make sure it is functional. Use the Worksheet during the process of testing your glider.