1. Basic Aeronautics and Aerodynamics

2. Explain difference between aeronautics & aerodynamics.
Understand properties of air that are important to flight.
Define airfoil & know the parts of an airfoil.
Describe the concepts of relative wind, angle of attack & streamlines.
Describe Bernoulli’s principle.
Describe the four forces of flight.
Give examples of aircraft characteristics that can improve each force.
Explain how the loss of one force affects the other 3 forces.
Describe the real world effects of viscosity & compressible airflow.
Name two effects wings have on airflow not accounted for by airfoils.
Unit Objective: Blue already discussed. Red today

3. Composition and Properties of Air
Know and understand the terms:
Pressure
Temperature
Density
Viscosity
Laminar flow
Speed of sound (in air)

4. Atmosphere is like a layer of blankets
Air Pressure
Intro Chapter 7 by going over objectives in book
higher altitudes is like the top blanket of the pile; it is under much less pressure than the air at the lower altitudes.
Atmosphere is like a layer of blankets

5. Air pressure is the force put on you by the weight of air molecules.
15 # / in2
air pressure is always pushing on us from all sides - about 15 lbs/ every square inch
but at the same time our bodies push back against the air pressure with people force
so it balances out and we don't get crushed
Do water/card demo before next slide

6. Explain the teacher demo in your notes: What’s going on?
Show how much more force air pressure exerts than water. Do water tube with card demo.

7. Something like this??? Show balloon from fridge, put in hot water.

8. Ear Discomfort in Higher Altitudes
When you fly in a plane (or drive up into the mountains), what happens to your ears?
Your ears pop because the air pressure is different as you go higher.  When the air inside your body changes so that it will be the same as the new pressure outside your body, your ears pop.
Do you ever get a bloated feeling when you fly?

9. What is Temperature?
Atoms and molecules in a substance do not always travel at the same speed.
Range of energy (the energy of motion) among the molecules.
In a gas the molecules are traveling in random directions at a variety of speeds
some are fast and some are slow.
What is Temperature?

10. Temperature
Measure of the average heat or thermal energy of the particles in a substance.
Does not depend on the number of particles in an object.
Does not depend on the size of it.
Temperature is a measure of the average heat or thermal energy of the particles in a substance. Since it is an average measurement, it does not depend on the number of particles in an object. In that sense it does not depend on the size of it. For example, the temperature of a small cup of boiling water is the same as the temperature of a large pot of boiling water. Even if the large pot is much bigger than the cup and has millions and millions more water molecules.
Make sure you understand what happens to air temp as altitude increases. Under no contract to follow rules!

11. What is density? How many molecules are squeezed into a given volume
What would be the density of air at higher altitudes? Why?
Density is related to temperature.
As air heats, molecules move farther apart

12. What is viscosity? Fluid’s resistance to flow
Compare water & honey
Which is more viscous?
Air is a fluid & has resistance to flow
Attraction b/t molecules of air
Attraction b/t air & molecules of whatever it touches
What is the relationship b/t density of air and resistance?
If a F is applied to air, its molecules resist a tendency to flow. >density=>resistance

13. Viscous Drag

14. What is laminar flow? Who has an easier time swimming:
A whale or a water flea?

15. Laminar vs. Turbulent Flow
Smooth streamlines
Highly ordered
Turbulent
Velocity fluctuations
Highly disordered
Involves smooth streamlines and highly ordered molecules
A lot of Velocity fluctuations b/t the molecules
Highly disordered

16. Reynold’s Number
In fluid mechanics, the Reynolds number (Re) is a dimensionless quantity that gives a measure of the ratio of inertial forces to viscous forces and consequently quantifies the relative importance of these two types of forces for given flow conditions.

18. Low Reynold’s Number: Viscous forces dominate Inertial forces
In this type of flow, Viscous F dominate inertial Forces (# is low)

19. High Reynold’s Number: Inertial forces dominate viscous forces
Fluid flow is characterized as being turbulent