Our intrepid student aviator and artist, John Ewing, continues his flight training and is hit with academic work that challenges his semi-retired brain. Attitude flying, however, is a bit more intuitive, although we catch him making engine noises in a silent airplane.
September 23, 2004
|About the Author ...
The immensely talented Johnny Ewing was born at a very, very early age, and almost immediately demonstrated a talent for drawing. The attempts to find his cute little mouth with his tiny spoon often left quite a large array of wet food puddles on his end of the dinner table, and he would smear his chubby little arms around in these puddles, making, uh, interesting designs. I was reluctant to remove the designs and would leave them until the flies became bothersome.
I often predicted that one day Johnny would make his mark in the art world, just as he had left marks on the dinner table, and I am utterly happy that I can now say, "I told you so," to those crass neighbours that held critical opinions of my Johnny.
The only part I do not understand is all this business about flying an airplane.
(signed) My Mother
This is the second in a series of excerpts that began with Chapter One.
Chapter 2: Notes on Lesson One -- Effects of Controls
|Cessna & Cartoonist
This will be a short chapter because, unfortunately, I did not make full notes on the lesson. No doubt I was excited and over-exuberant, and possibly incoherent, after this flight. I jotted down only a couple of sentences, and am therefore a bit blank as to the finer points. It will not be difficult to reconstruct the situation, however; I am good at that sort of thing.
What things I do not remember I will construct from my own fertile imagination; if they happen not to fit some preconceived notion you may have, that is not my fault. You shouldn't allow yourself preconceptions (check the 'Human Factors' section in the manual).
Alastair escorted me into a tiny little room with an overhead projector, a whiteboard, and a wooden model of something I took to be a replica of an airplane, identical to the things I constructed when I was eight years old. This was the lecture room. I learned that in these early days of my training there would always be a lecture conducted just prior to the flight. This was the common routine.
We would spend perhaps twenty minutes going over slides and diagrams, have a few questions and answers, before going out to the plane.
I hadn't been in this sort of environment since my pathetic efforts at university years ago. I knew what to bring, though; I had pencil and note pad in hand. What I didn't know, until later, was that my brain had gone into semi-retirement.
Alastair set about doing his duty, and I've no doubt that, considering the situation, he did it well. He was clear in his speech and authoritative in manner. And, to be fair, the lecture contained some material that seemed quite reasonable.
Unfortunately it also contained "theorems" and "mathematical formulas," and these things will always leave me floundering in their wake, for they are mainly gobbledygook. Listen to this: "The sum of pressures in an ideal fluid is always constant, i.e., Ke + Pe = K."
It is clearly Greek. What is the average person supposed to make of that? I got no clue from Alastair's expression, for he pretended to be serious.
Here is another one: "Ke (airspeed) incr, Pe decr." That is pure gibberish. All I can assume is that the page we were studying from was choc-a-block with typographical errors. But if not, then it is a wonderful example of the vast gulf separating the egghead in his ivory tower from some poor slob trying to learn to fly an airplane. I defy anyone to quote me an example of when it is vital that the symbols "Ke + Pe = K" should flash into a pilot's brain. It is a continuing source of despair to me that plain language is so out-of-fashion in imparting knowledge.
But that's another issue completely............
You study the chart showing air flowing through something called the Venturi Tube and it made sense, sort of, although I wondered who Venturi was and why he had left his tube lying around where idle theorists could get their hands on it.
The demonstration with the Venturi tube suggested strongly that air molecules do not like being separated, and when they are separated they work like crazy to rejoin each other back at the point where they were separated. How does this apply to creating lift on an airplane wing? Simple. Pay close attention: The wing comes barging through a cluster of air molecules, splitting them into two groups.
The lower group remains more or less static as the flatter bottom surface of the wing zips through. But the upper group, full, obviously, of indignation at being thus treated, grit their teeth and fire up to rejoin their comrades below.
And here's the rub: the upper surface of the wing is curved, so, because they are forced to follow the curved upper surface of the wing, the upper molecules have to travel further. And by traveling further, they travel faster, and by traveling faster they are in touch with the surface less and create lift. Get it?
Well, neither did I at first, and I still haven't proved it personally; I'm content to take Alastair's word.
At this stage at least.
But then Alastair gave an example that was simply mind staggering: according to him, the force that lifts a 747 into the air is equivalent to six-month-old babies sucking through a straw.
"Haw haw haw!" I laughed, slapping my knee in appreciation. I love a guy with a kooky sense of humor.
But he was serious. "No, no," he said, "Enough babies sucking upwards on the wing surface of a 747 will keep it in the air."
I worked my chair closer to the door. At the first sign of foam around Alastair's mouth, which seemed likely at any moment, I was out of there. My momma back in Texas wouldn't want her boy listening to that kind of talk.
I sat through the lecture, absorbing as much as I could, trying to quell the recurring thought that flying an airplane was going to be at least as impossible as trigonometry had been.
As Alastair continued I became convinced that he was sincere, just as my trigonometry teacher had been, and that he and she had both been forced by unknown dark and dire circumstances into the realms of witchcraft and black magic. By and large I simply had to trust that what Alastair was feeding me was true and would really work once I was in the airplane.
Because there certainly is no disputing the facts he produced. Air rushing over the surfaces of various flaps and tabs will cause that particular area of the plane to react, so the pilot, by maneuvering these various flaps this way and that, can make the plane do basically what he wants it to.
Say for instance the pilot presses with his right foot. This causes the rudder flap to swivel to the right, creating a larger, curving area on the left-hand surface over which the air must flow. So now, instead of the air rushing straight back, it is deflected over this curved area, traveling further and creating a sideways lift which pulls the whole rudder area to the left, relative to the longitudinal axis of the plane, which means the plane goes to the right.
Got all that? And the same principle applies to all the control surfaces. If it is a wing flap the direction is up on one side and down on the other, which makes the plane tilt up on one wing and turn.
If it is the elevator flap the whole tail assembly goes up or down. And if the tail, or wing, goes up or down the plane must follow, mustn't it? Of course it must, and there you have it.
There are other terms in vogue to describe such motions as 'pitch' and 'roll' and 'yaw', all of which indicate a direction the plane will move towards when certain flaps are used. Also it seems good in certain situations to use the flaps in combinations. This, according to Alastair, ensures that the plane stays 'balanced.' One good example is that when I want to turn I not only use the wings, I supplement the action of the wings by using rudder as well. Using wings only causes an unbalanced turn; but if I throw in a bit of rudder the tail gets into the act and makes the turn neater.
See? I'm already speaking pilotese. But I'm sure you get my meaning.
After the lecture Alastair and I strolled out into the parking area. It was time to put the theory into practice. As I mentioned earlier, I don't recall any specifics for this flight. We obviously went through the preflight routine, patting and rubbing the airplane, peeking and peering here and there; then inside we flirted once again with the long list of things that had to be done before we could fly. I hope one day to know what they are.
Once airborne we inventoried the things we wanted to make the plane do, checking them off one by one; I suppose they were managed passably well. I obviously survived, else someone other than me would be writing this.
One cryptic sentence from the notes I made was that the takeoff had been 'obscene.' I can't imagine what I must have meant by that. I've always tried to live a decent life and if I participated in an obscene takeoff all I can suppose is that Alastair made me do it.
Chapter Three: Notes on Lesson Two -- Flying Straight and Level
I arrived early at the air club so as to spend some time sitting in the plane staring at the instrument panel. I knew of a guy once who did the same thing before setting out on a long ride on a horse, thinking a little extra practice would be useful. He was wrong. The extra hour astride his mount only gave a headstart to the rawness of the inside of his legs. It was many days before he could wear Levis again.
I was reasonably certain, however, that sitting in the airplane would be less stressful on my legs than sitting on a horse; at least I hoped so, because I'm not sure how I would go about explaining raw legs at home. Still, I was determined to go through with the exercise, sure that it would help me.
I did a few mental dry-runs, pretending to know what I was doing. One of the knobs on the instrument panel looked familiar. I put my hand on the throttle lever and noted how satisfying it felt.
The temptation to go, "Vrooom, vrooomm" was strong and I almost resisted it.
I gave the plane one last reassuring pat and went inside where Alastair did the theory lecture.
Alastair introduced me to such things as Lift, Thrust, Weight, and Drag. Also Angle of Attack, which I liked the sound of, being a keen rugby fan. But then Alastair got off on some sort of tangent, insisting that on some occasions, for some reason, I would "stand on the ball." I felt that with all the other things I would be required to do in flying an airplane, trying to do some sort of weird balancing act with a ball was asking too much. That is for seals, and I am not a seal. I made a mental note to refuse if ever I was told to do it. One must be firm in the face of a patently ridiculous request. Although it does depend, to some degree, on the amount of fish they toss my way.
Alastair then allowed me to do the preflight inspection before joining me at the aircraft. Confusion again over those darn seat belts. I couldn't see behind me, again, and consequently got the straps crossed. Also I wanted the headphones lead to go over my left shoulder instead of the right, so I put the headphones on that way. That put the microphone up above my left eye, which was OK by me, but Alastair pointed out that I wouldn't be able to talk to anyone using that method. Good point, I thought; Alastair is sharp. A born instructor.
He also allowed me to go through the Engine Start check-off list. It felt good to be allowed to exert that little bit more control over my fate.
Starting the engine, taxiing towards the runway, I felt I controlled the plane much better than last time. I also had control of the throttle, which felt good.
The takeoff was marginally better than the previous one. Well, by that I mean we were not quite as near to getting into the grass as we had been previously, and up until the last few seconds I kept the weaving back and forth down to an almost acceptable level.
I went up too steeply. Alastair suggested I keep the horizon closer to the rim of the instrument panel. In my version I had nothing but blue sky on the windscreen. Alastair's request seemed reasonable so I agreed to it.
We headed straight for approximate north, the eastern edge of the North Shore Training Area. We climbed to two thousand feet then practiced staying level. The idea was to keep the plane in a steady attitude.
What follows makes little sense -- at least to the uninitiated, which is me -- but I will go through it anyway. We decide what speed we wanted to fly at, then set the attitude of the airplane to be consistent with that speed. I hope I've got it right. The drill consisted of flying at our normal speed, about 90 knots (2300 rpm), then setting the attitude (which for 90 knots is about four inches of horizon above the rim of the panel).
We stay in that attitude for a moment, to determine whether I had to hold pressure forward on the control column, or hold pressure back on the control column, to maintain the desired attitude. Once I determined which it was, I jiggled the trim tab accordingly until I could take my hands off and the plane would sit more or less steady. Once that was accomplished we crosschecked; that is, we checked the altitude to see that we stayed level, checked the speed and found that it was just what we predicted.
Then we changed the speed to 2500 rpm (100 knots), set the attitude, which was about 8 inches of horizon showing above the rim of the panel, then trimmed, just like before. We crosschecked and found our altitude stayed steady and our new speed was 110 knots.
The neat little diagram shows you why: it is because we are going downhill. And it is a technical fact that if you go downhill you go quicker and with less effort than if you go uphill. I've known that for, well, a long time. What I'm not too clear on is how we maintain altitude even when we are going downhill, but it may have something to do with the trim.........
Anyway, we repeated the process at 1900 rpm (70 knots), set the attitude, which was about 2 inches of horizon, etc., and the speed was 70 knots. This one should be easy for you; the nose is pointing up -- an uphill attitude -- so you shouldn't be surprised when the airspeed drops off a bit.
I tell you, it was immensely reassuring to see that when the rigmarole was followed correctly the results were predictable. Would that all the other things in flying were as predictable.
For a diversion during the drill Alastair would arbitrarily take the controls and change the speed. Changing the speed, of course, put the whole attitude off. Then he handed the controls to me and I had to get the correct attitude back, and trim, etc. Good fun. I made the usual number of fumbles and miscues.
A few turns and we were on our way back to the club runway. I had a closer look at the air club this time, trying to become familiar with the area. It seemed a good idea to become good at locating a few landmarks, because, as Alastair explained, I might want to return to the same airfield I left from. Well, any fool knows that. I know it.
(The story continues in Chapters 4 and 5 ...)
Editor's Note: AVweb is serializing several sections of John Ewing's book, "The Cessna, The Sky ... and the Cartoonist," starting with Chapter One
. If you want to read the whole book, you can order it from John's Web site