The Effects of Controls
Ask a dozen people why the sky is blue and you will get a dozen woolly answers about refraction and reflection but not one honest, I don’t know. So nobody learns anything.
And now ask a dozen pilots why Madame Beech or Mr Piper put a rudder on their aircraft and you will hear all sorts of bull – but very few will answer, it’s mainly to counteract design problems like aileron drag and P factor. Much more on this later.
Back in the days when Pilate was only a student, I wrote a slender document called “Patter for Instructors”, or something. It worked well – instructors liked it and so did the DCA (which later became the CAA). So I updated it a bit and most of the flying schools in South Africa copied it – which was fine – actually quite flattering. I was trying to make a living from training pilots – not selling bits of paper.
Forty years later, when I sold my flying school, three of the instructors cosied up to the CAA and decided to turn this little ten-page book into something really impressive. They formed committees and sub-committees to advise each other. They were determined to improve my slender guide and make it so comprehensive that no one would ever use it.
They turned it into an AIC – 333 pages of dense text with the impressive name DOC NO: DP/FTD/TS/05/009 Flight Instructor’s Training Procedures, Revision No: 07. DATE AMENDED: 26 October 2009.
Imagine coming back to your bachelor pad, after a hard day at the office, to study this by candlelight during load-shedding. I believe this boring document, with its paragraphs and sub-paragraphs, sub-sub-paragraphs and roman numerals, has single-handedly caused our terrible shortage of Instructors.
The exercise – Effects of Controls – from a single page, now takes up 30 pages and includes things like the effects of carb-heat. Why not chuck in cabin-heat and the door handle as well? They both have just as much potential to kill you if you get them wrong.
They missed the point of the whole thing. The document was meant to teach new instructors the best way of training pedestrians in the art of handling basic aeroplanes.
Which reminds me – a pupe did indeed try to kill me by getting the cabin-heat wrong. So perhaps I should revise my thinking on the whole thing. Anyhow, here’s what happened.
CRUISER CRISIS
I was training a bunch of enthusiasts at Swellendam. They were a good bunch of people and we were having huge fun playing with rudimentary aeroplanes away from controlled airspace. Honest flying.
But I need to tell you about this one pupe who simply wasn’t hacking it. His name was Hendrik. He was a hell of a decent guy so I am doubly reluctant to speak ill of him – but facts is facts. If I describe the classic village idiot sitting on a wall with straw in his hair, taxi-door ears, rabbit teeth and the puzzled demeanour of a sheep who has found his path impeded by a mangelwurzel, you will have a picture of Hendrik.
Poor guy – not his fault, that’s simply the way they had kitted him out at birth. Those who constructed him, both mentally and physically, did not have aeroplanes in mind at the design stage.
Anyhow I am doing circuits and bumps with him in a delightful little Piper Cruiser, and they are not going well. While Hendrik’s body was in the aircraft, his mind was sitting on a stone in the sun, chewing a piece of grass.
We were doing a glide approach on runway 33 (the uphill one) when all the cheese-holes became aligned with the planets. In those days, most training landings were from glide approaches that started at 1000 ft on base.
In the last few seconds Hendrick had done two things wrong. He had started the glide too early, and he had forgotten to use carb-heat.
Now before going on, I should tell you that the Cruiser has fore-and-aft seating – like a Cub. The instructor sits in the rear and has access to only three controls – the stick, the rudder and the throttle. Apart from this, you can see little more than the back of the pupe’s head unless you loosen your seat-belt and move forward to peer over his shoulder.
So although a Cruiser is huge fun, it’s not the ideal training aeroplane.
Anyhow, there we are in a glide with no carb-heat – so the engine is going to stop fairly soon. This would be fine if we were able to make it to the field – but we weren’t.
“Carb heat,” I say.
Nothing happens, so I repeat my request a little louder. We didn’t use head-sets – we just shouted. But the comparative silence of a glide approach made comms pretty easy. It wasn’t that he couldn’t hear me – it just wasn’t getting through. His mind was still sitting in the sun chewing grass.
“Carb heat!” I shout, and tap him on the shoulder.
He is made of rubber. His head twists round 180 degrees, like a turkey, and he seems surprised to find someone else in his vicinity.
I point at the panel and repeat my instruction slowly as if talking to a snotty infant.
He faces ahead again and yanks out the mixture.
The engine noises cease, and the prop slows to a gentle windmill.
“Not that one,” I screech. So he pulls another knob that works the cabin-heat. But leaves the mixture out.
I seldom shout at a pupe, but this calls for decisive action, so I bellow at him to push the red knob – the mixture – in.
There is only one other red knob in the cockpit – it’s the throttle on the left sidewall, just below the window. So that’s what he goes for. The only thing that changes is the expression on his face as he again swivels his head round to give me a helpless look. Of course the throttle makes not a damn of difference, because the mixture has killed the engine.
I grab the controls and we skim over the dirt road and plonk down in a boulder-strewn area 50 yards short of the runway. And stop almost immediately.
There is no damage, but I have to get out and swing the prop to get us to the numbers – and thence to the hangar.
THE EFFECTS OF THE CONTROLS
Sorry about the side-track. I was just letting you know that under the ‘Effects of the Controls’ we will not cover all the controls – like that ridiculous AIC. We only do the three main flying controls. We cover the flaps separately, and the rest as they come up during the training.
This exercise is both critically important, and boringly obvious. It’s like learning to swim – you had better get it right, but once you have the basics of flying, or swimming, you may never need to give them another thought unless you go in for instruction, aerobatics or aquatic sport.
Ask the average commercial, or even airline pilot, to describe the effects of the controls, and you will get an old-fashioned look and some vague muttering. Or they might laughingly tell you about “the houses”. Push the stick forward and the houses get bigger. Pull it back and the houses get smaller. Pull it further back, and the houses get bigger again.
Actually, this is so important (as was your first swimming lesson) that I am going to walk you through the pre-flight briefing and patter – before we look at the actual flying exercise.
Remember the golden rule:
Tell me and I will forget
Show me and I will remember
Involve me and I will understand
So you are going to do all three. You will tell her about the effects of the three main flying controls, using a model aircraft in your briefing room. Next, you are going to demonstrate how they work, in the real aircraft. And finally you are going to involve her by letting her fly herself and try out the controls one at a time.
By the way, patter means the words you use in the air, as you talk her through the exercise. For some exercises you need to learn it pretty much by heart otherwise the aircraft is likely to complete the exercise while you are stumbling along behind it groping for the right words.
Remember that the aeroplane is a terrible classroom – because of the noise, the distractions and the lack of face-to-face contact. For this reason – try to avoid teaching in the cockpit. Most of the teaching and learning should happen in the classroom or the briefing room.
PATTER
This warrants a bit of discussion. Mr Chambers’ splendid dictionary claims that patter is: chatter, gabble, jabber, line, pitch, jargon, monologue.
Madame Merriam-Webster is a little more verbose on the subject, she thinks ‘patter’ means:
- a specialized lingo: especially: the jargon of criminals (such as thieves)
- the spiel of a street hawker or of a circus barker
- empty chattering talk
- the rapid-fire talk of a comedian
- the talk with which an entertainer accompanies a routine
Well they are both wrong – you don’t need to be a thief, a street hawker, circus barker, comedian or entertainer to use patter – you need to be a top-line flying instructor.
Effects of Controls Briefing
Remember to have the model pointing away from the pupe, and to start each control response from straight and level flight.
The stuff in blue is a reminder of what to say in the briefing and is also the actual patter you will use in the aircraft.
We will start with the PRIMARY effects of the three main flying controls.
The elevator
- When I ease the stick back – like this, the elevator on the tail moves up, this decreases lift there, so the tail moves down and the nose moves in the direction of the cabin roof.
- When I ease the stick forward – like this, the elevator on the tail moves down increasing the lift there, so the tail moves up and the nose moves in the direction of the undercarriage.
- This movement is known as pitching.
- The aircraft pitches about its lateral axis – which runs from wingtip to wingtip.
The ailerons
- When I ease the stick to the right – like this, the right aileron moves up, decreasing the lift on the right wing, while the left aileron moves down, increasing the lift there. So the aircraft ‘banks’ to the right, with the right wingtip moving in the direction of the undercarriage. Obviously, if you move the stick to the left the aircraft ‘banks’ that way.
- This ‘banking’ movement is known as rolling.
- The aircraft rolls about its longitudinal axis which runs from the spinner, between our seats to the tail.
The rudder
- When I press on the right rudder pedal – like this, the rudder on the tail moves to the right. This causes the tail to move to the left and the nose moves in the direction of the right wingtip. Using left rudder causes the tail to move to the right and the nose moves in the direction of the left wingtip.
- This movement is known as yawing.
- The aircraft yaws about its vertical axis which runs from the undercarriage, up between our seats and to the cabin roof.
Notice that I use rather clumsy terms about the nose moving ‘in the direction of’ the undercarriage, the cabin roof or a wingtip. This is necessary because the controls always have the same effect relative to the aircraft.
For instance, if you are banked in a turn and you ease the stick back, the nose will not move vertically up – it will still move in the direction of the cabin roof. In other words, it will tend to pull the aircraft into the turn.
If you venture into aerobatics one day and you have the aircraft inverted, easing the stick back will still move the nose in the direction of the cabin roof – which will be down.
Also, if you are banked, say to the right, and you use right rudder, the nose will move in the direction of the right wingtip – in other words it will move down and cause you to lose height.
Finally, in defence of the clumsy phrase, it would be more elegant to say that the nose moves towards the undercarriage, or the wing tip. But that’s not strictly correct – it doesn’t move one millimetre towards anything.
So remember – the PRIMARY effects of the controls are all relative to the aircraft – not relative to your main reference – the horizon.
Unfortunately the ailerons and the rudder both have FURTHER effects, meaning an additional effect that’s not necessarily desirable – it’s just a fact that you must be aware of and make corrections for.
The further effects of the ailerons
Remember that if you move the stick to the right, the right aileron moves up – reducing the lift on the right wing, and also reducing the drag. At the same time the left aileron moves down, causing more lift and more drag. This differential drag will cause the nose to move to the left.
So, although you have moved the stick to the right – the nose will move in the direction of the drag on the left wing.
But this only happens when the ailerons are deflected, so if you centralise the ailerons, as you do once established in a turn, then that differential drag disappears.
Don’t worry too much about it at the moment – we will deal with it again later under a coordination exercise.
The further effects of the rudder
Remember that the right rudder moves the nose in the direction of the wingtip – so the nose yaws to the right. This means the right wing slows down and the left wing, on the outside of the turn, speeds up and gets more lift. The result is that as the aircraft yaws to the right it also banks to the right.
All a bit tough to get your head around? So here’s a table to make it easier:
| CONTROL | NORMAL EFFECT | AXIS | FURTHER EFFECT |
| Right Aileron | Roll to the Right | Longitudinal | Nose yaws Left |
| Up Elevator | Pitch towards cabin roof | Lateral | None |
| Right Rudder | Yaw to Right | Vertical | Roll to Right |
Okay – so that’s what you teach in the lecture hall, and in your briefing. Once you are in the air you just need to remind her by using key words as you patter her through the exercises.
Do it properly and it works beautifully.
And I haven’t yet explained properly why aeroplanes need a rudder. That, and some more patter next time.
