We won't be focusing on learning to fly the plane in this lesson (though we will do some of that), that will start in earnest next lesson. Instead, in this lesson, we'll be learning what the effects of each of the aeroplane's controls are. Later on today we'll be experimenting (in a safe way) and experiencing those effects in the aeroplane. Understanding the effects of the aeroplane controls will be the basis of all our safe flying into the future. Question: Have you ever done this...
Have you ever felt the force of the air flowing around your hand when sticking your hand out the car window?
What did you notice?
The **forces on your hand** are not too strong at normal speeds, but you definitely feel your hand being pushed up or down as you change the angle of your hand. But what would it be like when your hand is moving much faster through the air?
We'll find out later!
Key point: the forces you feel on your hand as you change the angle are the same forces which the aeroplane controls experience as we manipulate them.
Outline the lesson plan based on the image: Pitch, roll and yaw will give us the vocabulary to talk more about aeroplane controls.
The bulk of our time will be learning the primary and secondary effects of the main controls.
Recap what we've learned, revisiting our objectives.
Use a prop such as the physical 3d model of the aeroplane to walk through each of these objectives, visually introducing each.
Click Direct-To when ready to advance to waypoint 1.
Start with rolling along the longitudinal axis, as that's "along" the length of the plane — easier to remember. Use the physical 3D model first, then support with the viewer's visual axis. Use the physical 3D model with random movement, so student can name/call out "pitch", "roll" etc. Next "pitch around lateral axis" etc. Finish by using the random movement to have a bit of fun testing our use of the vocabulary.
Click Direct-To when ready to advance to waypoint 2.
Earlier we talked about the feeling of your hand being pushed gently up and down like a wing, when holding your hand outside the car window. But what do you think would happen if you did the same thing out the window of something moving much faster, like an aeroplane?
Well don't try this at home, but here's someone who tried the similar trick by sticking their hand out the window of an aeroplane at 10,000 feet. Notice the forces on their hand as they change the angle of their hand (the angle of attack). It is the very same forces that you feel on your hand as you change the angle of your hand in the wind, that enable us to control a plane!
Clearly sticking our hands out of the cabin window does not give us much control of the aeroplane! Let's look at our physical model and first learn where they are. Once the student knows which of the three control surfaces is which, play a quick "game" of I point, you say. Again, just like the experiment with your hand in the wind, with a sufficient air flow you can: push the elevator up or down, pitching the aeroplane to rotate around the lateral axis, or push the ailerons of one wing down and the other wing up, rolling the aeroplane to rotate around the longitudinal axis, or push the tail of the plane to the left or right, yawing the aeroplane to rotate around the normal axis. Let's look at those one at a time.
Start with the physical model again, showing how with the elevator pitched up, the tail will be pushed down, and vice-versa, before showing the NASA graphic. (Image originally produced by Nancy Hall at the NASA Glenn Research Center — still used on Wikipedia today.)
While on the flat road, the car maintains constant speed because thrust exactly balances the drag on the car from friction. When the car encounters the hill, it not only has the friction to contend with, but it's also pushing against gravity up the slope — so the speed drops. 50% throttle cruises at around 90 kts and slows down to around 60. 35% throttle cruises at around 60 kts and slows down to around 25. 30% stalls — it just can't pull anywhere. DON'T go into stalling or even make a point of it — leave it for later.
Leave the throttle at 60% and just show that as we climb, the speed slows down, which then generates less lift. Pitching forward causes the speed to increase (and lift to increase too). NO NEED to talk about stalling here or anything more technical. So the key point is that the secondary effect of the elevator is our airspeed — and our airspeed is very very important for us to monitor. Just like a car going up a hill that slows down without adding more power or throttle, the aeroplane behaves in the same way, the main difference being that when the aeroplane stalls on a hill, it doesn't have a road beneath it.
Start with the physical model again, showing how with the elevator pitched up, the tail will be pushed down, and vice-versa, before showing the NASA graphic.
Use the physical 3D model again to show this tendency once reaching the end here. Also, it may be worth mentioning that there's actually another more interesting secondary effect of the ailerons, called adverse yaw, which we'll learn about another time as it's actually much harder to notice these days as most planes are designed to counter the adverse yaw. If the student is very on top of the theory already, we could talk about adverse yaw too.
So again, the secondary effect of using the ailerons to roll the plane around the longitudinal axis is: slip and yaw in the direction of the lower wing — and (very slowly!) potentially entering into a spiral dive.
Using the physical 3D model to demonstrate the rudder and yaw through these points.
The skid is the mirror of the slip from aileron-alone use. Both uncoordinated sequences (aileron alone, rudder alone) end in a spiral descent. This is the safety message: cross-coupling of controls, if ignored, leads to the same dangerous outcome. Use gentle rudder inputs only — large inputs are not needed to demonstrate the effect.