Pitch to Altitudeand Power to Airspeed?
… or Power to Altitude and Pitch to Airspeed?
Several years ago, a pilot examiner of my acquaintance would askhis private applicants one question and one question only during the oral portion of aflight test. The question was, “Which control makes the airplane go up?” If theapplicant answered, “The throttle makes it go up,” he passed the oral part ofhis check ride, but if he said the elevator makes the airplane go up, he failed the oraland thus the entire flight test!
Sooner or later, every student pilot becomes aware of the age-old controversy regardingwhich controls what: pitch for speed and power for rate of climb, or vice versa. Flightinstructors often demonstrate one method or the other, depending on which the individualinstructor favors. The power-to-control-airspeed demonstration goes like this: Theinstructor says to his student, “You think the elevator controls airspeed? Come on,let’s see.” They then taxi out, line up on the runway and the instructor starts tofuriously pump the yoke (or stick) back and forth with the airplane remaining in place.Eventually, the student asks, “What on earth are you doing?” The instructorreplies, “I’m trying to get up enough speed to take off!”
When asked the question of which does what, one prominent air race pilot responded,”All I know is, when I lose a race, I go out and get a bigger motor!” (I know,all you old Army Air Corps and Air Force guys are going to jump on this and tell me it isan engine, not a motor, but I was directly quoting the original.)
To demonstrate the power-controls-altitude approach, the instructor will take a studentup to a nice safe altitude, retard the throttle to idle and say, “OK, you’ve got it.Now pull back on the yoke (or stick) and make it go up.” Sure enough the airplanewill do just that, briefly, as it zooms up until it runs out of poop. Then, it will quitflying altogether and start to descend. Obviously, there is an overlapping function ofthese controls and they both do both jobs in varying degrees, depending on thecircumstances. In other words, a pilot can make either control perform either function atany given time. It is simply a matter of juggling the two controls to achieve a desiredresult.
Trim for Speed
Did you ever notice that when two pilots are occupying the front seats of an airplaneand the one flying says to his companion, “OK, you take it for a while,” thatthe very first thing the new guy at the controls does is reach for the elevator trimcontrol and make a minor adjustment? Happens every time.
We adjust the elevator trim for a specific airspeed. This can be demonstrated quiteeasily. First, attain a nice, safe altitude. Then, in level cruise, adjust the pitch trimfor hands-off flight at cruise speed and in cruise configuration. Now, reduce power toidle and watch what happens: The airplane will pitch down and speed up, pitch up and slowdown, pitch down and speed up, pitch up and slow down; repeating this process throughseveral (perhaps as many as half a dozen) oscillations until it stabilizes in a glide atthe original airspeed .
Next, leave the trim where it is, apply climb power and again observe what happens. Theairplane will pitch up and slow down, pitch down and accelerate (slightly above itsoriginal speed), and repeat this process through a few oscillations, each excursionbecoming smaller until it once again stabilizes at the original airspeed , only thistime in a climb.
Because most training airplanes are so light that they can be left in a sort of neutraltrim and very little force is required to operate the controls, many instructors fail toteach their students proper trimming technique. And proper trim technique is particularlyimportant when leveling off from the initial climb to set up the cruise configuration. Theway it should be done is quite simple. First, level off at the desired altitude, then wait.After the airspeed builds up to cruise, reduce the power to the desired setting, trim forhands-off, and you’re all set. Most pilots attempt to level off by rolling in downelevator trim until a level attitude is reached, simultaneously reducing power. Thistechnique requires several adjustments until hands-off level flight at cruise speed isreached.
That it is easier to juggle one variable than two or more should go without saying. Whythen do pilots continue to play with both pitch and power on a VFR final approach? If theairspeed is set with pitch, then all that is required is to adjust the power to controlthe descent. Believe me, if you sight down the runway (not directly ahead, but slightlyoff to the side for better depth perception), bring the airplane down to a couple ofinches off the runway and then hold it off the ground with the elevator as long as youcan, your passengers will look around and say, “When did we land?” It will be sosmooth you simply can’t feel it.
An old instructor had an expression that has stuck with me for over 50 years. He said,”Take the slack out of the stick.” In other words, maintain a steady pressure asyou bring the elevator up. If you are abrupt, the airplane will zoom up a few feet and goTHUNK, and possibly bounce. If you don’t use enough back pressure, you will surely landnosewheel first and possibly bounce (or worse). By taking the slack out of the stick, theold guy meant that as the speed bleeds off, the stick (or yoke) will tend to become slack.Don’t let it do this. Simply maintain a constant pressure until you are rolling on theground. But don’t forget to “fly” the airplane to ramp.
As for judging just where you will touch down, the old saw works quite well. You simplyeye the spot you want and, if it appears to be moving toward you, you will land beyond it.If it appears to be moving away from you, you will undershoot. If, however, it seems to bemotionless, that’s where you will touch down. This has worked for me as I have wonnumerous spot landing contests. My basic policy has always been to never tell anyone howto fly. I simply tell ’em what I do and WHY. If they like what they hear, they can adoptthe same procedures; if not, they may do as they please.
The “sight picture” technique works equally well on takeoffs. The modernapproach to teaching takeoffs favors holding the airplane on the ground on the takeoffroll until the magic number appears on the airspeed indicator and then ROTATE. Unless aprecise airspeed is required for the climb (to clear an obstacle or get out of a tightplace) this is totally unnecessary in a light fixed-gear, fixed-pitch-prop airplane. Isuppose that some of the large flight schools, assuming that all their students are futureairline pilots, started teaching this way ab initio so there would be no transitionrequired. Then the FAA started recommending this teaching technique because theyunderestimate the intelligence of pilots. The Feds assume that a few years down the road,the student pilot will be flying a high-performance single or a twin in which thistechnique is required. Since the FAA believes pilots are too stupid to make the transitionwhen the time comes, “we’d better teach em to do this now.”
I was taught – and I gave many thousands of hours of dual to primary students – usingthis procedure: Line up with the runway, apply full power and track straight down therunway using the feet to steer the airplane. As speed builds up, apply back elevatorpressure until the nose of the airplane cuts the horizon, and then wait. When the airplaneis ready, it will fly off the ground.
No Airspeed Indicator
A student pilot, working solo in the pattern at the airport where I am based, had beentaught the “modern way” – to depend on the airspeed indicator. On the initialclimb-out after a takeoff, he lost his airspeed indicator. (A spider had made a nest inthe pitot tube.) The poor fellow declared an emergency and disrupted a busy airport whilehe made his way ’round the patch. He was thoroughly shaken by the incident, which shouldhave been purely routine.
When I was trained in the old Army Air Corps, an experiment was undertaken with myclass of Cadets. Throughout our primary training (sixty-five hours during which we weretaught to do everything that can be done with an airplane) we never saw the face of anairspeed indicator. They had been physically removed from the airplanes. We survived byflying by sight picture and feeling (and otherwise sensing) the necessary speeds for eachmaneuver (including aerobatics).
Today, my policy is to not solo a primary student until he/she has twice flown thepattern with the airspeed indicator covered up. It’s no big deal. Remember the formulathat ALWAYS works: Power plus attitude equals performance. Apply this formula, fly bysight picture and I guarantee you’ll enjoy your flying more, and be a better pilot for it.Although airspeed is critical in both instances, glider pilots and aerobatic pilots flyalmost entirely by utilizing the sight picture technique. It is really the only thing thatworks for them, and you’d better believe their flying is much more precise than that ofthe average private pilot.
The term “flying by sight picture” refers not only to sight, but to all thesenses. Hearing plays an important part in this technique. Of course, in an open cockpitairplane it is even more important as the wind rushes by, but a pilot can hear the changesin engine sound as the pitch changes even in a closed-cabin airplane. All kinds of subtlenoises give one cues as to what’s happening.
And the sense of touch is vitally important in this kind of flying. The tension on theyoke (or stick) and rudder pedals, and the amount of force required to move them tells thepilot a lot about what is being experienced: A lot of pressure indicates high speed andlittle (or no) pressure indicates the imminence of a stalled condition.
All the senses taken together create a genuine “seat of the pants” flyer, anddespite all the modern technology and modern theories regarding flying “by thenumbers,” it is the seat-of-the-pants guy who has the most fun and enjoys aviationthe most. If you’ve never experienced this kind of aviating, I urge you to try it. You’lllike it!
Following the publication of my last column on “Who Needs an InstrumentRating?” I received over forty email comments and criticisms sent directly to me, andI answered every one of them. I do wish, however, that if you have a comment regarding oneof my columns, you would post it here in the comments section so that others might shareyour input.