Page 3.12 (4,794)
Trim and Holding the Yoke
Return to Whittsflying Home Page
Trim history; ...Trim; ...Opinion on Trim; ...Trim Opinion2; ...Trim Opinion3;
...Trim Use; ...Cruise-Control; ...Tight Grip vs light touch; ...One Finger and a Thumb Flying; ....Trim Instruction; ...Trimming Cessnas; ...Trim Exercises; ...Trim Demo; Emergency Trim Use; You and Your Autopilot; Trimming as an Art; ...By the Numbers C-150 Landings; ...Now back to Trim; ...Using this Process with a C-172; ...Pinching Won't Work; ....Trim Lesson; ...Talking Points on Trim; (Internet Thread) ...Trim Factors; ...
The trim tab or servo trim was invented by Anton Flettner, a German aeronautical engineer. He started work in 1905 for the Zeppelin Company. Died in 1962.
Most aircraft have single axis trim for the elevator. Airliners have three-axis trim for the elevator, rudder and ailerons. Trim is used to correct for any forces that might tend to counter your selected flight performance. Trim allows the pilot to relax. A pilot who cannot trim will be an exhausted pilot in a short time. It takes only a couple of flights for a pilot to realize the benefits of trim. The best check for proper trim setting for any flight configuration is to let go of the yoke completely and see what the nose does.
The simplest elevator trim uses a wheel, lever, or crank to pull a cable or rod attached to a trim surface bell-crank. Other systems use a jackscrew and rod to set trim. Electric trim is best used for coarse settings. Only the coordination of eye and hand can correctly set fine trim settings. Using the trim control positions the trim and the aircraft for the desired attitude.
If an aircraft is improperly rigged trim is not the fix required. An aircraft that consistently flies one wing low need help only a mechanic can give. The aircraft wings have adjustments that can correct problems detected in using trim.
The controllable trim tabs are required on all aircraft. It is usually on only one side of the elevators since they are both on the same rod (Cessna). It is hinged and can be moved only by use of a cable system connected to the trim control in the cockpit. The direction the tab moves causes an opposite deflection of the control surface. The ground adjustable trim tab is a small surface on the trailing edge of a control surface, most often the rudder, that can be bent to set control forces at cruise speeds. The trim setting creates the aerodynamic forces required to keep the elevator and the airspeed in the desired position.
The three factors affecting trim are the center of gravity, airspeed and configuration (flaps/gear). The passenger load will affect the center of gravity and require unique takeoff and level flight trim settings. Each trim setting has a corresponding speed that the aircraft will seek and hold.
If you are holding any pressure on the yoke against the trim setting a moment of distraction will result in an airspeed change. A stabilized approach to landing is difficult, to impossible, if the aircraft is not well trimmed. The less skilled the pilot the more likely he is to neglect proper trim technique and attempt to maintain control by arm and hand pressures. Good technique requires that the pressures felt on the yoke be from pilot applied input. Any pressures applied otherwise are indicative of improper trim. Trim is the cruise control of flying. Not using trim is equivalent to being able to turn on/off power steering.
Trim makes it possible for the pilot to configure the aircraft to counteract and neutralize the normal nose heavy condition. There is a designed twisting along the longitudinal axis caused by a difference between the weight on the center of gravity and the lift acting through the center of pressure. If the pilot does not trim then control pressure must be held maintain the negative lift value of the horizontal stabilizer and elevator. Trim allows this control pressure to be adjusted for hands-off flight. In a trimmed condition the pilot can feel the control pressures required to a acquire a desired flight attitude. An improperly trimmed aircraft is constantly seeking to relieve any pilot induced control pressure.
The original design of the aircraft sets the shape, position, and size of flying surfaces and controls so that in cruise conditions these would provide least resistance and maximum speed. Outside of this condition a trim control was installed to maintain the aircraft stability required for climb, descent, landings and other flight speeds and configurations. On some aircraft the angle of incidence of the horizontal stabilizer can be changed by a trim control. This is more effective and efficient than a trim tab (Mooney). The stabilator is another way (Piper). It is an airfoil that in one piece acts as both stabilizer and elevator. The trim control of the stabilator acts as both a trim and anti-servo tab (power assist). The yoke applies control forces to the tab to move the entire control. No change in trim technique is required in either case.
Ideally an aircraft would have a three-axis trim; elevator, rudder, and aileron. Without such trim some aircraft just fly crooked. Fixed tabs on the rudder and adjustment screws on the wings can make semi-permanent or even permanent fixes to the aircraft trimmed condition in level cruise. A pilot can, with low-wing aircraft utilize fuel weight/consumption to adjust the aircraft 'trim'. Passenger seating can also make a difference.
The aircraft trim system is used to adjust the aerodynamic center of lift as required to balance the ever-changing center of gravity primarily along the longitudinal axis of the airplane. This relieves the pilot from having to maintain control pressures on the yoke. The pitch can be varied with the trim wheel to adjust for weight, configuration, speed and power. A pilot should be aware that any change in these factors will require a trim change.
The trim system usually consists of a cable from a moveable small surface on the empennage forward to the cockpit. The FARs require that a trim position indicator exist in the cockpit with a takeoff position especially marked and visible to the pilot. Mooney aircraft move the entire empennage. Some of the surfaces called trim tabs are fixed and can only be adjusted on the ground by bending. The trim system is not intended as a primary flight control. Remember, Trim effects will be reversed if the primary control is jammed.
Opinion on Trim
Trimming the airplane is something that comes with practice. Like many others have said here, the best way to learn is to get the airplane relatively stabilized where you want it (climb, cruise, or decent) and trim the forces off. The best way to get it right on is when you think you've got it close, simply let go of the yoke. If the nose comes up or goes down, feed in a little more trim in the right direction. You should eventually be able to trim the airplane to be rock steady in any flight condition (smooth air assumed:)). In fact, you know the trim wheel on the 172 has little bumps on it just for grip? You should get to the point where moving the trim wheel one bump in either direction makes a noticeable difference to the trim.
I tend to be very active with the trim. In fact, I usually retrim for nearly everything I'm doing if I'm going to be doing it for more than a couple of minutes. For example, on climb out, I trim for the climb airspeed and let the airplane fly the climb. In cruise, I do the same. Also on approach, I retrim for each configuration to give me the decent rate I'm looking for. In this way, I'm only ever maneuvering the airplane away from the trimmed condition. In other words, on approach, I don't have to "fly" the airplane for the approach because the trim is taking that workload. That allows me to concentrate on making the correct turns, setting up the approach, watching out for traffic, configuring the airplane, watching my decent rate, all without having to manhandle the yoke. If I need more or less decent rate, I just move the trim a hair.
The trim on the Piper Cub is a great little arrangement that uses a winding handle like a car window. It takes quite a few turns to trim from a climb to level flight, etc. but it also allows you to make really fine adjustments. In fact, when in the glide for approach, I may make adjustments to the trim that are all of about 1/8th of a turn or even less.
My instructor recommended the following and it works for me;-)
--First NEVER fly the plane with trim wheel, always establish your attitude (level, climb or descend) with Yoke and power
--When you're stable trim off heavy yoke pressure first and resettle
--Then fine trim until you just have your hand on the yoke but you aren't inputting any effort at all.
--Let go for a second or two and check and check that it doesn't climb or descend is the final proof.
--Retrim for every change in attitude. I got to practice this in the circuit under the lashing tongue of my instructor... Trim
for climb out before and after raising the flaps, trim on crosswind after leveling, trim after every flap setting and throttle setting on downwind, base and final. You really get the hang of it then I can tell you!
Should you ever be in a situation where the elevator is jammed and will not move, you should be aware that this causes the movement of the trim to give reverse effects in so far as directing the nose up or down.
Trimming takes some practice but once mastered will make every aspect of your flying easier. First thing is you can't trim the plane until it is where you want it to be. If it's climbing you can't just throw in nose down trim, that would be trying to fly the plane with trim and even though that's not that uncommon, it won't work. You have to hold the plane in whatever attitude you are trying to hold, let the plane settle up, determine whether you are pushing/pulling on the yoke and then trim those forces off. Of course if the forces are excessive trim most of it away, wait for the plane to settle and then finish trimming. The test is being able to let go of the plane at any time and the plane is still doing what it was doing before you let it go. Students never seem to see the importance of trimmed, hands-off flight until they have to either triangulate their position during a lost procedure or divert to an airport other than the one flight planned. Trying to fold and unfold those damn sectionals without being able to take your hands off the yoke can be a handful. On my private checkride the DE expected me to let go of the yoke, check for traffic, draw and compute to my diversion, check for traffic, maintain a shallow turn as I held altitude and check for traffic.
Correct use of the trim requires that control pressures be applied to hold the desired flight attitude. Then the trim is adjusted to relieve present control pressures. Some initial change in trim should always be made since it reduces drag. If the aircraft is in an accelerating or decelerating mode anticipatory trim changes may be desired. Proper trim is a necessary part of flying from both operational and safety standpoints. The skill of the pilot is proportional to ability to trim.
Being able to trim the aircraft for any attitude requires that the pilot adjust the amount of download on the horizontal tail surfaces. It is this downwload that overcomes the nose weight of an aircraft. Download is 'lift' of the tail surfaces directed opposite to the lift of the wing. Refer to the Flight Training Handbook, AC 61-21 Page 277.
The important thing in using trim is always to be able to keep track of where it is. This is the reason I urge you to use a finger tip rather than a pinch. The fuel/pilots location in the c-150/152 are so near the CG that the trim movement will be rather constant. Any variation will be corrected if everything is predicated on beginning at a constant. The constant that I use has always been: Level cruise at 2400 rpm and hands off.
This constant works just a well if using C-172 or C-182. The presence of a rear-seat passenger will be corrected for using this constant. Pipers trim differently. Flaps change pitch attitude significantly but require very little trim adjustment. As you know the indicator markings are often illegible or not calibrated. A slipping trim cable is a frequent problem.
Learning to trim for level flight requires that you think in terms of setting as many constants as possible for a given flight situation. First, get a constant level attitude. Using the nose/horizon reference is more difficult than using the wing. The wing level with the horizon works best with the high-wing types. Second, get a constant speed at cruise speed or lower. If you exceed cruise speed without reducing power your trim setting will set for the higher speed. You should practice reducing power to 75% power setting as cruise. 2450 rpm is a good set. Third, trim off the pressure.
Is their only one way to trim? No. With experience you may just give a few flips and make a fine adjustment as required. You can even make numerous small changes. Doing it differently does not make it wrong. There is no one way to do anything in flying. Different aircraft and different trim systems require different techniques. The aim of my following suggestions is that it gets the beginner into anticipating trim movements as may be required for every change of configuration. Trim then becomes another constant.
Trimming off pressure is a search for the trim position that allows the aircraft to be flown with only one finger and the thumb. Which ever one you are using to hold altitude tells you which way to move the trim. Most students tend to move the trim more than required. You might do well as a student to use half as much movement as you think is required. You are trimmed when both finger and thumb need only to lightly brush the yoke. Getting trimmed to this point makes flying enjoyable and relaxing. Unlike an automobile, a correctly trimmed airplane can be flown hands-off. Once this sense of 'feel' is acquired you will not want to fly any other way. Every pilot has a slightly different 'feel' of an aircraft so changing pilots usually involves changing trim.
Every student and pilot should use trim to create opportunities to fly with rudder. Training aircraft usually have a rudder tab that has been set by prior pilots so that very little rudder is required in straight-and-level cruise. You can make slight turns using just the rudder with little difficulty. Steeper turns with the rudder will cause a loss of altitude. Much of this altitude is regained when using hard rudder to level the wings. Practice flying with just the rudder when copying the ATIS, using the sectional, or just for fun.
Once an aircraft is trimmed for a particular airspeed in level flight, additional power or a reduction in power will cause the aircraft to climb and descend at that airspeed. You must exercise some yoke control and rudder to correct for any transitional oscillations. Trim remains the same. Trim is the cruise control of flying an aircraft. I very much recommend not changing trim when descending from cruise to pattern altitude. Descend by reducing power. Enter downwind at cruise speed until abeam the numbers. The deceleration in airspeed while holding altitude on downwind will allow you to trim for the approach speed while reaching the appropriate 'key' position for turning base.
Airplanes should be trimmed for every condition of flight except during times you may be turning or changing airspeeds. Flying an aircraft out of trim makes control difficult and wearisome. Initial trim settings should be just 'close'. Fine trim when the power and airspeed has stabilized. The check of trim setting is confirmed by letting go of the controls.
Every control system has inherent frictions that tend to keep them in position. In some cases this internal aircraft factor may make an aircraft seem out of trim. Occasionally an aircraft may be affected by atmospheric conditions. In turbulence a tight grip will only accentuate the bumps. Single finger control is best in choppy conditions.
If your aircraft has rudder trim, you adjust it only after
elevator trim has been fine-tuned. Rudder is trimmed in wings-level
flight with a nose-on reference point. Use rudder pressure to
maintain the reference point and then trim off the pressure.
Confirm rudder trim setting by letting go of all the controls.
Aileron trim, if there, is set much the same way.
Once an aircraft is completely trimmed it can be neatly controlled with small brief rudder input. Pitch changes can be controlled with VERY small power changes. Flying with just the rudder is a very useful experience. Even in instrument conditions the rudder can be used. Step on the high wing of the attitude indicator and the turn coordinator. Step on the heading desired of the heading indicator. Such flying removes flying as a problem part of the IFR equation.
Grip vs light touch
The left hand has only two useable digits while flying. The forefinger is behind the yoke for back pressure and the thumb is for forward pressure. You cannot feel the pressures requiring trim if a heavier touch is used. Tension is the greatest single cause of a full tight grip. Note how a beginning driver grips the wheel. The sooner the student learns that a light touch with proper trim gives more positive control, the better. There is a safety factor in this. Any distraction or movement of the body will affect yoke pressure. This is especially true if the pressure is being held tightly against the trim. The pilot with a light touch can let go of the yoke and the plane will fly as trimmed. The tight grip increases fatigue as a factor. Easy to say; difficult to do. IFR pilots do it better with a light touch. A full grip on the yoke seems to result in inadvertent climbs and turns. Tension is the greatest single cause of the tight full grip on the yoke. The best analogy is the differences between student and experienced drivers in holding the steering wheel of a car.
Finger and a Thumb Flying
Over controlling is a symptom. A student or pilot who is heavy, reactionary, or hesitant on the controls is not yet a believer. The proficient pilot has faith in the airplanes ability to perform in a particular manner. All proficient flying is an act of faith just as is having the runway disappear during a landing.
Students do not begin as believers. The instructional process is supposed to turn students into believers. I had to fly 200 hours before I began to believe. Prior to that point I controlled with a tight grip on both the yoke and the seat cushion. I tore two seat cushions out of the C-150 I learned in, because I could not accept the fact that the plane could fly without my firm hand on the control. Occasionally, after a flight I would need to unwind my fingers off the yoke with my right hand. My instructors told me to relax but never showed me how to do it.
Now, I think I know how to show a student how to avoid over-controlling. I nag at them for the way they trim, apply and take off power, hold the yoke, and see what is happening. Most of all, I insist that they let go of the yoke and try to SEE what the airplane does without their input. Initially, students lack the faith necessary to believe that the plane will actually fly without their help. In time, they will learn that the plane, properly trimmed will perform better without their meddling.
Turbulence is one of the best opportunities for the pilot to see this. The natural, normal reaction of a student pilot in turbulence is to grip the yoke more firmly. This is what you do going over chuckholes in an automobile. In an airplane a firm grip gives you a two-for-one bump. A light touch will reduce the extent of light to moderate turbulence significantly. When students turn the plane over to me in turbulence they always contend that it stopped just as I take the controls. The real difference is that I have faith in the planes ability to do a better flying job than I can.
If, from the very first moment of sitting in an airplane, a student is required to limit his touching of the yoke to just forefinger in back and thumb in front a considerable amount of instructional time and money could be eliminated from learning to fly. Unfortunately, the student usually gets off on the wrong foot (hand). The design of the yoke with its scallops for the full fist grip leads to the belief that it is designed that way for a purpose. A student has probably been on several demo-rides where the idea is to suck the student into a flight program. The initial acceptance of a full fist grip on the demo-rides means that unlearning is going to be necessary. There is enough unlearning required in learning to fly as it is. To add the way you hold the yoke to the mix just makes the process more difficult.
I once had a student come to me with a few hours in the C-150. He had never used the trim wheel. He could fly quite well without using the trim wheel. He just set it at a level flight setting and left it there. Reducing the power to 1500 and adding full flaps brought him down to a fine approach and landing. Remove the flaps and a bit of backpressure he could climb reasonably well. No problem except that he was usually exhausted after a flight from the constant strain of holding the yoke during maneuvers. There are still pilots flying C-150s this way because it can be done and you dont mess with the trim. These pilots probably soled in ten hours or so. The shock came when they tried to transition to a more complex or powerful aircraft.
I do not teach students to fly the C-150. I teach students to fly the C-150 as though it were a complex powerful aircraft. We trim for every configuration to hands-off flight. We fly only with forefinger and thumb, and preferably only one or the other until neither are required. To fly this way the student must be taught to SEE ahead of the airplane. (See Budd Davissons article in Dec. 1997 of Flight Training magazine pg 28-31) My first ten hours of flight training are devoted to teaching the student to SEE and TRIM the plane for hands-off flight. Not all are proficient in the ten hours but I dont solo them until they trust the plane to stay at the selected airspeed and flight path.
I once facetiously suggested that a student sandpaper his finger tips to force him to lighten up on the controls. Next flight he showed up with red, raw fingers. Didnt help all that much but Im more careful in my suggestions now. Just finished checking him out in the C-182RG, he remarked about how stable the plane was. Interesting, how he gave the plane credit for his ability to fly hands-off. A universal comment that comes back to me from my students who progress into instrument flying, is that the instrument instructors are always pleasantly surprised how my students all have a light touch. As a school teacher, the highest praise I ever received was when a student would thank me two years after leaving my classroom.
So, what does all this have to do with over-controlling? Pilots
over control because they have not learned to SEE,
TRIM and LET GO. To a degree, I
cannot tell a student just when and where to look out the windshield.
It is a
very individual problem and solution. I can point out the necessity,
and by repetition help the student anticipate the
nose position, trim setting, and power for the most difficult
of these configurations. Im talking about level cruise.
With practice you can do it with your eyes closed. You will need to SEE only to confirm. Then just for fun you can move your arms forward and back to initiate shallow climbs and descents. Notice I havent mentioned the rudder. Thats desert.
I you find that you are consistently having to correct for climb or descents, change from two finger flying to appropriate one finger flying. until you find the pressure required for level flight at this configuration and power setting. THEN make your slight trim adjustment.
Cruise Control for Airplanes
Learning to trim for level flight requires that you think in terms of setting as many constants as possible for a given flight situation. First, get a constant level attitude. Using the nose/horizon reference is more difficult than using the wing. The wing level with the horizon works best with the high-wing types. Second, get a constant speed at cruise speed or lower. If you exceed cruise speed without reducing power your trim setting will set for the higher speed. You should practice reducing power to 75% power setting as cruise. 2450 rpm is a good set. Third, trim off the pressure.
Is their only one way to trim? No. With experience you may just give a few flips and make a fine adjustment as needed. You can even make numerous small changes. Doing it differently does not make it wrong. There is no one way to do anything in flying. Different aircraft and different trim systems require different techniques. The aim of my following suggestions is that it gets the beginner into anticipating trim movements as may be required for every change of configuration. Trim then becomes another constant.
Trimming off pressure is a search for the trim position that allows the aircraft to be flown with only one finger and the thumb. Which ever one you are using to hold altitude tells you which way to move the trim. Most students tend to move the trim more than required. You might do well as a student to use half as much movement as you think is required. You are trimmed when both finger and thumb need only to lightly brush the yoke. Getting trimmed to this point makes flying enjoyable and relaxing. Unlike an automobile, a correctly trimmed airplane can be flown hands-off. Once this sense of feel is acquired you will not want to fly any other way. Every pilot has a slightly different feel of an aircraft so changing pilots usually involves changing trim.
Every student and pilot should use trim to create times to fly with just rudder. Training aircraft usually have a rudder tab that has been set by prior pilots so that very little rudder is required in straight-and-level cruise. You can make slight turns using just the rudder with little difficulty. Steeper turns with the rudder will cause a loss of altitude. Much of this altitude is regained when using hard rudder to level the wings. Practice flying with just the rudder when copying the ATIS, using the sectional, or just for fun.
Once an aircraft is trimmed for a particular airspeed in level flight, additional power or a reduction in power will cause the aircraft to climb and descend at that airspeed. You must exercise some yoke control and rudder to correct for any transitional oscillations. Trim remains the same. Trim is the cruise control of flying an aircraft. I very much recommend not changing trim when descending from cruise to pattern altitude. Descend by reducing power. Enter downwind at cruise speed until abeam the numbers. The deceleration in airspeed while holding altitude on downwind will allow you to trim for the approach speed while reaching the appropriate key position for turning base.
Cessna has engineered its trim so that certain changes in trim can be anticipated to correspond to flight path changes in different models. For example, in the C-150 from level cruise abeam the numbers, a power reduction to 1500 can be trimmed off by holding heading and altitude to 60 knots. It will take three full top-button to the full travel bottom to do this. Pinching between the buttons will leave you short. 10 degrees of flaps while holding sixty with the yoke can be re-trimmed to a 60 knot descent by undoing one of the previous three turns. Bottom button all the way to the top. Let go and if the nose begins to change pitch make the slight trim adjustment required. 10 more degrees of flap while holding 60 knots can be locked there by taking off another full turn of trim. Full flaps while holding sixty can be set by taking off the last turn. You, every student and pilot, should learn a count or feel system for applying and removing flaps. Learn to use the flaps without looking at the indicator during application. A four count works well for 10 degrees on a Cessna.
Removal of the flaps during the go-around finds you trimmed for level cruise. One full trim down will give Vy climb at 65 knots. This same procedure can illustrate why, when making a short approach, reduction of power to 1500 and application of full flaps at the white arc will give you a hands-off approach speed of 60 knots.
The same process works with the C-172 except you use 70 knots for downwind and final adding two ten-degree notches of flaps while taking off two full turns of trim. On final you put in full flaps and no trim change. You are on a stabilized approach hands-off at 60 knots. For the go-around, on bringing up the flaps you will be trimmed for a 75 knot climb. The hard part of flying the C-172 is leveling off. The old joke about how long does it take a student to level off a C-172 is answered with, "Thirty-five hours". It will take about one and one-third turns of trim and a close eye on the altitude while the plane accelerates. The trick is to reduce to 2450 as soon as you reach 100 knots. Otherwise, you will be jockeying airspeed and trim for quite a while. The cause of this problem is that the C-172 has less power for its weight than the C-150. The time to accelerate to 100 knots seems to take forever. Initially you will be holding backpressure and then forward pressure on the yoke while the airspeed gets sorted out. Due to deceleration the C-172 power should only be reduced to 1700. At approach speed the power will have dropped to 1500 rpm.
Cessna ruined a terrific engineering design when they built the C-152. The trim/flap ratios of the C-152 are there but not at 1 to 1. You can develop the procedure for stabilized airspeeds by using the suggested procedure of the C-150 and keeping track of the amount of trim required for each ten degrees of flap. It can be done but the neat engineering isnt there. Abeam the numbers the C-152s power should be set at 1600. By the key position it will be at 1500.
The direction to move the trim and the proper instructional words to use are a common source of confusion. Raising the trim wheel lowers the nose. It is better to have the student think of touching the trim wheel as touching the tail of the aircraft. Moving the trim wheel up will cause air flow over (under) the elevator to move the tail up. Thus, raising the trim wheel raises the tail while lowering the nose. Lowering the trim wheel lowers the tail and raises the nose. By agreement, I make a practice of telling the student the direction to move the trim wheel. I also advise against pinching or flipping the wheel. I suggest use of the index finger on the knobs of the wheel. A full turn and count system seems to have been deliberately engineered by Cessna. All full movements of the trim should be with the forefinger getting the very top or bottom button of the trim wheel and moving it as far as possible. Always start at the very top button or the very bottom button with the finger tip. Grasping the trim wheel between the fingers prevents the full movement needed thus making necessary more trim adjustment. Pinching the wheel always leaves the turn one button short.
Cessna has engineered its trim so that certain changes in trim can be anticipated to correspond to flight path changes in different models. For example, in the C-150 from level cruise abeam the numbers, a power reduction to 1500 can be trimmed off by holding heading and altitude to 60 knots. It will take three full top-button to the full travel bottom to do this. Pinching between the buttons will leave you short. 10 degrees of flaps while holding sixty with the yoke can be re-trimmed to a 60 knot descent by undoing one of the previous three turns. Bottom button all the way to the top. Let go and if the nose begins to change pitch make the slight trim adjustment required. 10 more degrees of flap while holding 60 knots can be locked there by taking off another full turn of trim. Full flaps while holding sixty can be set by taking off the last turn. You, every student and pilot, should learn a count or feel system for applying and removing flaps. Learn to use the flaps without looking at the indicator during application. A four count works well for 10 degrees on a Cessna. Flaps that have indent settings will work only if calibrated for trim movement.
Cessna ruined a terrific engineering design when they build the C-152. The trim/flap ratios of the C-152 are there but not at 1 to 1. You can work out the procedure for stabilized airspeeds by using the suggested procedure of the C-150 and keeping track of the amount of trim required for each ten degrees of flap. It can be done but the neat engineering isn't there. Abeam the numbers the C-152's power should be set at 1600. By the 'key' position it will be at 1500.
Authorized Cessna dealers are required to teach flying the C-152 in such a manner as to not require trim except to the slightest degree in the pattern.. A C-152 with the trim set for climb on takeoff is supposed to fly slightly faster than Vy. On reaching 50 feet below pattern altitude the power is reduced to 2000 rpm which causes the nose to fall and the plane to fly level at 80 knots. On reaching the numbers the power is reduced to 1600 and 10-degrees of flaps are put in. The plane will descent at 70-knots. The turn to base is made as another 10-degrees are put in. The plane now will fly at 65-knots with no trim change required. The turn to final is made while adding flaps and the aircraft will fly at 60 knots. The plane is flown into the flare at 60-knots and allowed to decelerate for the landing with a pitch attitude that will not cover the far end of the runway as the throttle is gradually reduced for touchdown. Seems that the C-152 was the first aircraft designed around a specific method of teaching landings. Anton Flettner must be turning lengthwise in his grave.
I have given this procedure considerable thought and feel that it is designed for this specific type of aircraft. I question if any other aircraft type or manufacture could be flown in this manner. Cessna must be growing its own brand of instructor to fly this aircraft in this manner. I can only suspect that an ulterior commercial motive exists, and the hell with the consequences.
Once you trim and let go, the trim may not be capable of holding the aircraft where you place it. Many trim controls have a trim-speed band. This band is a range of speeds that the plane will fly at the same trim setting. This band is due to friction in the trim cable system. This friction does not become noticeable until some yoke maneuver is made that the yoke does not return to where it was. The new trimmed speed depends on where the friction resistance stops when pressure is released. The allowable FAR 23.173 trim-speed band is 10% either way from selected speed. I could not comfortably fly a plane with such a range.
To teach the effectiveness of trim try the following exercise. The instructor should demonstrate how to hold the nose in one fixed position while the student varies the trim wheel for several turns in each direction. From level cruise, have the student lock his left elbow on the door. First the instructor varies the trim up and down while the student holds the nose in a fixed position against all pressure. Then let the student move the trim. This clearly shows the control pressures as affected by trim. The function of trim on control pressure should be shown on initial climb-out on the very first lesson. Skill in moving the trim and keeping track of these movements is an essential skill for what is to follow.
An additional exercise, once some skill in leveling off is acquired, is to have the student trim the plane for level flight. Then watch the nose attitude change as the arms are held forward or back over the head. Show the student that, in a correctly trimmed aircraft, even head movement will have an effect. This is a good reason not to keep sectionals where you must look down to read them. Move the sectionals up to panel level. Further, if the plane is placed into a 30 degree bank with about 2/3 if a trim down (direction of wheel movement) the aircraft maintain both bank and altitude. These are good confidence maneuvers and illustrations of the aircraft stability and should be used to encourage the student to maintain a light, trim sensitive, touch on the controls. The student should be trained to keep track of trim turns, the indicator position, and verbalize trim movements.
The next element in maintaining speed is knowing where the trim is, in the first place, and knowing how much movement is required for each power setting. From a hands-off trimmed climb at 60 knots, the C-150 will be level with a full fingertip trim turn of the trim wheel bottom to top. The C-172 takes one and a third turns. If you pinch the wheel you will always come up short. Some fine adjustment may be needed for hands-off level flight but you will be very close. To initiate the speed reduction required at the numbers for landing, the trim is moved with full finger-tip turns top to bottom three times while holding heading and altitude. The C-150 is now hands off at 60 knots and the C-172 is hands off at 70 knots.
Because of patent laws the nose gear geometry of different
manufacturers was forced to develop different mechanisms for
flaps, gear, and trim. Pipers trim differently, the addition
of flaps changes attitude and airspeed without requiring much
trim change. Cessnas require trim change for changes in airspeed
and flaps. The same factors exist in both cases. It is the interrelationships
between the factors that require pilots to adapt their skill
to the design requirements. The finger tip technique that works
so well on the Cessna must be changed to the pinch and flip,
palm roll, and electric assist of the Piper. In my mind, the
greatest skill difference in making manufacturer type transition
lies in the use of trim.
Here is a demonstration I do with trim. Have your instructor take you up and set the trim all the way one way or the other (up or down it does not matter) and then let you slowly take the airplane after that's done. Don't be surprised if you need both hands. Then slowly take the trim and move it to the other extreme feeling the pressure change. Then finally back to a hands-off condition.
After that you will be convinced on one thing for sure. Trim
is either your best friend or worst enemy. grin
Emergency Trim Use
If the elevator is locked as with a control lock, the use of trim will be backwards. Any use of the trim will be as an elevator. To raise the nose of the aircraft you must raise the trim tab. Confusing but true.
and Your Autopilot
--Is the autopilot only an emergency device?
--Is it an aid for the incompetent?
--Is it a copilot to assist the pilot in need?
--The autopilot has built-in complexity that is a potential hazard if not understood.
--The autopilot is not a substitute for instrument competency.
--Poor instrument skills and reliance on the autopilot can kill.
--Some autopilots must be turned off rather than overridden.
--Autopilots should be turned off in turbulence
--Do not takeoff or land with the autopilot.
--The autopilot probably has a minimum operating speed.
--Altitude hold is not 'altitude return'.
--It is up to the pilot to become an expert systems manager.
--A pilot must be able to disconnect the autopilot without hesitation.
--The autopilot can fly the approach while the pilot watches for the airport.
--Autopilots do not have the capability to make a go-around or a missed departure procedure.
--The autopilot allows a rested pilot to be there at the end of a long flight.
--Cockpit housekeeping and planning is easier when on autopilot.
--For every coupled approach you should make a hand-flown approach for skill maintenance.
Trimming as an Art
I teach trimming from the first flight. The learning law of primacy certainly applies to the way you were first taught to trim. Of all the ways there are to trim, under stress you will revert back to the way you were first taught. Thus the initial instruction is of critical importance. What follows is my thinking about it.
There are as many ways to trim as there are pilots and airplanes. As one of my internet friends advised me, trim is the cruise control of flying. We have trim by way of electricity, pinching, fingertip, counting, knobs, pressure, flipping, guessing, chasing and watching. One of the more interesting has been trim by a thousand adjustments. What we are seeking is hands-off control of the aircraft after each configuration transition.
The engineering of the aircraft can be designed around the trim wheel, crank, or lever in conjunction with flaps and/or power. Some trim differences are wedded into the patents for the aircraft. Cessna, Piper and Mooney have different ways of accomplishing the same flying result. Cessna's trim wheel is not intuitive when looking over the nose. Moving trim up to lower the nose often results in a movement in the wrong direction. Piper's is intuitive. Rolling wheel forward lowers the nose.
I am presently teaching a dyslexic with occasional conflicting results. The 40-degree flaps of the C-150 and earlier 172 were engineered for coordination with the trim wheel. The C-152 and 30-degree flap C-172s have made it possible to fly patterns using a set power and flaps without any trim changes. I can do it but I don't like it. What is possible is not necessarily a wise introduction of skills needed for higher performance aircraft. Most a Cessnas require a significant change in trim for every notch of flaps in order to maintain desired approach speeds. Pipers, once approach power and appropriate past the numbers airspeed has been set by trim, make changes using flaps with little trim adjustments and incrementally decreases in airspeed to final approach speed required. Individual preferences reign supreme.
My first instructor was associated with Cessna Corporation for many years. In the C-150 he taught me that there were a series of 1 to 1 relationships engineered into the Cessna. These relationships only existed if I set the power precisely, I moved the trim wheel using my finger tip, and accurately positioned my flaps. The critical aspect of these relationships working depended upon my always starting from the same critical situation. Level cruise at 2450 rpm and trimmed for hands-off level flight.
By the numbers
--The yoke is held lightly between the thumb and forefinger, throughout, use pressure rather than movement.
--Hands-off possible except during configuration transitions.
--At the numbers, reduce power to 1500 rpm while holding heading and altitude as airspeed falls to 60 knots.
--As it slows and extends the downwind smoothly put in three full down-turns of trim using the fingertip.
--Get the trim knob just under the slot at the top and take it all the way down to the bottom. Do this three
times. Don't hurry, just hold your altitude and watch the nose. Check for hands-off. At 60 knots clear the direction of your turn.
--Put in a notch of flaps (4-count) while keeping nose from pitching up and taking off one turn of trim. Fly 60 knots and fine trim if required for hands-off stabilized approach.
--Anticipation is the key element of this method. If you wait for the nose to rise on putting in flaps before applying forward pressure you will begin a series of altitude oscillations. If you are too slow taking off trim
you will have undesirable yoke pressure.
--Maintaining a constant airspeed indication in a turn is also a matter of anticipation. On initiating the turn (Right rudder in right turns and a tap of left in left turns) apply a slight forward pressure and then increasing back pressure during the 30-degree bank and turn. Come out of the bank with another touch of forward pressure with the thumb. Check for hands-off.
--Put in the second notch of flaps and take off the second turn of trim using the fingertip to get it all.
--Base is flown at 60 knots and cut, squared or widened to adjust altitude. Clear and turn final as before.
check for hands-off airspeed control.
--Watch the nose and the space over it to the runway threshold while hands-off.
--If the space is flattening the only solution is to add full throttle while holding forward pressure for 60 kts
--Adding power and holding 60 will cause the aircraft to intercept the proper glide path and the runway
will disappear. Don't try to see the runway. A high approach is much safer than a shallow one. You will
have more engine-out options and can aim your touchdown better.
--Leave power in from 10 to 20 seconds and then back to 1500 rpm. Repeat as required. Add full flaps
and take off the third turn of trim. Remember a partial flap landing leaves you trimmed for climb.
--If the space is getting smaller put in full flaps immediately and take off one turn of trim.
--Diving for the runway is a self-defeating exercise. To get down, slow down.
--A full flap approach that requires a slip to make the runway is best turned into a go-around.
--Keep 1500 until reaching the runway is certain and then reduce power in small increments.
--The round-out brings the aircraft parallel to the runway for slowing up and getting down in ground effect.
--As you raise the nose be sure to apply right rudder to keep the nose from gradually swinging left.
--Look at the far end of the runway and using back pressure gently cover it with the nose of the aircraft.
You will need to gradually increase the back pressure needed to keep the nose covering the runway end
while making incremental reductions of power. Watch the nose and horizon to catch any movement to the
--The ideal is to hear the stall warner, have the power off, and touch down simultaneously. The actual touchdown should be a surprise to you.
--Continue to hold the yoke back and up with sufficient pressure to keep the nose wheel from touching. Bringing up the flaps will assist in keeping the nose wheel off the ground. This is the ideal I seek when
doing touch-and-go's. Check clime speed with hands-off and right rudder.
--The proof of the pudding is the ability to fly the airspeeds not only hands-off but with the airspeed
indicator covered. The other day I had a pre-solo student chasing the airspeed needle. I proved to him that he could fly the proper airspeeds with the indicator covered. He could and did.
Now back to Trim:
In the 150 we initially put in three turns of trim down. In the process of landing we took off three turns so the aircraft is trimmed for level. Therefore, before we takeoff again we want to put in one full turn down for takeoff and climb. This turn will give you very close to Vy climb. Hands-off check of trim but using right rudder.
On reaching altitude, lower the nose; hold altitude with pressure while taking off a full turn of trim for level cruise. Leave the power in until reaching over 80-knots, holding altitude to allow acceleration and then reduce the power to 2450 rpm. We are now back to our initial approach point. Hands-off.
with the C-172
--With modified C-172s having at or above 200 hp, this process must be adjusted to fit the individual aircraft.
--The national standard for a person to learn how to level off at C-172 is said to be thirty-five hours.
--Begin from level cruise
--Apply Carb heat and reduce power to 1700 rpm while holding heading and altitude. As aircraft slows
the rpm will drop to 1500.
--Trim down three full fingertip turns behind the topmost trim button seen.
--Hold pattern altitude and heading until aircraft reaches 80 knots.
--At 80 knots put in 10-degrees of trim and take off one full fingertip turn of trim. Speed will fall to
--70-knots and descent will begin while base turn is made using appropriate forward-back-forward yoke
pressures to maintain 70-knot airspeed.
--On base the second 10-degrees of flap are added and another turn of trim is removed via the fingertip. The
speed is unchanged at 70 knots
--After the turn to final full flaps are added and airspeed allowed to fall to l60 knots. No trim is removed so that
on touchdown after a properly trimmed 60-knot full flap landing, the C-172 will be trimmed for a Vy takeoff.
Pinching Won't Work
--Those who habitually pinch the trim wheel will always be applying too little trim to make this work.
--You must learn to read the nose and anticipate its rise and fall as to
how much pressure is required to stop at a
--Then, based upon the pressure you need to hold a given airspeed, make an adjustment of one or two buttons
using the fingertip.
--Once you get close adjust accordingly.
Trim Lesson (11-03)
Flew with pre-solo student and setting him up to make some mistakes that he had not already learned from. Part of my teaching process is to cover as many mistakes along with avoidance and correction procedures as I can.
Student had taken off from a touch-and-go without resetting the trim. He proceeded to run the trim back and forth seeking the Vy speed without success. Time for a lesson.
You can but should not fly the plane with the trim. Chasing the airspeed indicator with the trim wheel is a no-win situation. You must first focus on the nose attitude and lock your arm against the side panel to hold it still.
Once you have the nose 'locked' trim off the pressure so you can hold the airspeed. That said, here is how you teach the required skill.
The instructor agrees to hold the nose in position at a Vy airspeed while the student runs the trim several full turns in each direction. Then let the student hold the yoke and run the trim-wheel on himself. Go both directions several times and each time the pressure reduces at Vy have the student let go of the yoke.
Ideally, this teaching lessons is done early on in the four basics instruction. However, expect it to be forgotten by a student under the onslaught of so much new material early on. It never hurts to review all the potential mistakes just before solo.
Talking Points on Trim
Some of you might remember when I posted a question about trimming out the airplane which I posted while I was under instruction for my PPL.
The situation was that the CFI appeared a bit irritated at my relatively frequent fiddling with the trim wheel to get us to level flight. This conversation occurred during the first few training flights.
He wanted me to concentrate on flying the airplane not fiddling with the trim wheel, I guess. His technique involved reaching the desired altitude and shoving the yoke forward (this usually happened while climbing out from the airport, as opposed to leveling off after descending) until level flight was achieved and then trimming to relieve the pressure on the yoke and be done with it.
I tended to be fussy, trying to adjust and readjust, which could be a longish process because the trim needs changed as the aircraft wound up to cruise speed.
So I learned to fly the airplane the way he wanted me to, sometimes accepting some nominal yoke pressure in order not to seem obsessed with the trim wheel.
But I never really understood what the problem was, I always want to fuss with the trim wheel, no matter how often I need to, in order to stay in trim. I consider it just an aspect of flying the airplane:
Trim as necessary and as often as necessary. It sure doesn't bother me any to fiddle with it, and now that I have my license, I do what I think is necessary.
Well on Saturday, I was going up for a little staying current flight and invited a friend of mine, who is a high time pilot and owns a Waco UPF-7, to come along.
I knew he hadn't flown in a long time because he doesn't fly the biplane in the winter. So shortly after we lifted off and were climbing out, I asked him if he'd like to fly. He immediately grabbed the controls saying "sure". "Your airplane" I told him. He started looking down at the instrument panel and I touched the trim wheel saying "here it is". He immediately grabbed it and spent the next few minutes making many little adjustments as we leveled off and reduced power. In fact he fiddled with it a lot.
Some of that was his unfamiliarity with the airplane: I find myself coming very close to the trim setting I need with just a tug or two on the wheel these days, but I sure don't mind fussing some more if I need to.
I recall hearing about some guys who level the airplane *using* the trim! As they approach their desired altitude, they begin to level off using the trim wheel to bring the nose down, rather than shoving the yoke forward and trimming off the pressure.
But it sure did my heart good to see this vastly experienced pilot having absolutely no problem reaching for the trim wheel frequently.
I'd disagree with your CFI, the trim is your best buddy! Of course the more proficient you get the quicker you can trim it out nicely but trim away the forces as they appear, don't wait until level flight and then trim everything at once.
Using the trim to fly the airplane is a no-no however. Remove the forces on the stick/yoke with the trim, but don't use it to fly the airplane.
The exception would be practicing a simulated "yoke failure". I've tried an approach to land using only power, the rudder and elevator trim in a 172 without touching the yoke. It works better than you might think. I wouldn't recommend modeling yourself after "vastly experienced" pilots, but only the best ones.
You should always fly the airplane trimmed, of course, but some pilots are more efficient trimmers than others. Fiddlers are inefficient. Some are trying to fly the airplane with trim, which is a no-no, but others just haven't developed an idea of how much trim it's going to take to do the job, or else they have a hard time feeling when the pressure goes away on the yoke.
Take a hint from your CFI that there may be a higher level of skill in this area than you currently possess, and spend some time seeing if you can achieve it before you dismiss his critique
<<You are the second person to say: "flying with the trim wheel is a no no." But I'm at a loss as to why this might be. Can someone enlighten me? Thanks.>>
My observation is that it leads to "fiddling". :-) Putting the nose where you want it and trimming off the pressure is very quick, once you develop the knack. Fiddling distracts the pilot from other piloting tasks, such as not crashing.
<<Eventually it became a non issue, either because I got to proper trim quickly or he just gave up commenting. ;-)>>
Probably a little of both. Sometimes I wonder if a student is really getting better, or he's caused me to lower my standards. :-)
<<Until someone in this group mentioned that it's perfectly ok to trim to hold altitude in a 360, I didn't even know it was an option.
It is perfectly ok, though I don't teach that method.
<<I prefer to nose over and add nose down trim at roughly the same time thus relieving the pressure on the yoke. Then I hold altitude gradually trimming as necessary while the airplane builds it's speed. >>
That's the method that I teach, so I don't have a problem with it either. I strongly disagree with using pure muscle power until the desired airspeed is reached. In higher performance aircraft, that's a long time and lots of yoke pressure. I noticed that Dudley described trimming in this situation as "not optimal". That's such a vague
criticism that until it's defended, it has no meaning.
<<Who cares if you touch the trim wheel now and then? How could it possibly hurt?>>
It doesn't hurt at all. But when you use a subjective word like "fiddling", everyone conjures up a different idea of the frequency of trim adjustments. If people assume that you fiddle more than you really do, well, that's part of this very imperfect communication medium. Take what you can use and ditch the rest.
If you try to fly with the trim wheel there is too much delay between the
trim adjustment and its effect, so you are always playing catch-up as compared
to direct movement of the elevator.
Two things; first; the sequence for trimming out the airplane is NOSE; POWER; TRIM. You put the nose where you want it and HOLD it there, while the airspeed and power are in transition; you adjust the power to where it should be as the airspeed stabilizes; THEN you trim off the pressure. Trimming the airplane while it's in ANY transition is not optimal, especially when you get into flying high performance airplanes.
Second; hand the airplane over to ANY pilot worth the title and the first
thing they'll do is re-trim it :-) It's the way they personally feel the
airplane. A secondary aspect of this is psychological and of little aerodynamic
consequence, but for some pilots, it's an unwritten and unspoken superiority law
that establishes in their minds that they, and not you, have a slightly
"better" feel of where the trim should be :-)) It completes mentally,
their "taking over" command of the airplane. Don't be misled by the
hidden humor in these factors. They indeed exist in the real world and are a
part of the advanced data base for the more "aware" CFI.:-)
Or it may simply be the result of 2 pilots altering their position in the airplane. Resulting in a slight shift of the weight and balance. I've caught my CFI and these days CFII leaning forward or back just to screw up my trim and mess with my head and sometimes my altitude. I caught this one day when the pattern of re-trimming was a bit to obvious in smooth air. He's sitting in the right seat just grinning ear to ear. Had me wondering if the throttle slipped or we had an engine problem with similar tricks. I've flown the same C-172 solo long enough to know that normally this doesn't happen. On an XC in smooth air only slight trim changes as the fuel burns.
I'm having a hard time putting your advice together with my experience in the 172. Not using any trim until at attitude and speed means a lot of yoke pressure. Even in a small plane like a 172, this pressure shifts you from
flying with your fingertips to gripping the yoke. The PTT is usually operated with the same hand. It is probably different with a stick but the off center grip on the yoke makes it hard to push, talk, and make smooth roll corrections. It's distracting and the 172 takes so long to speed up that it goes on for a while.
I agree that you don't want to fly with the trim but I have found that a hybrid approach works very well. I start giving the trim wheel small nudges about 300 feet below the target altitude. My right hand usually isn't doing
anything at this point and I don't have to hunt for the trim wheel. These don't create much noticeable attitude or speed change by themselves and the plane has plenty of time to re-stabilize after each nudge, maybe a half-dozen in all. The cumulative effect gets me to the point where I can perform the level off pretty much as you describe but without so much pressure that I have to change my grip on the yoke or have a bobble if I move my thumb to talk to ATC. It makes for a very smooth transition without all the fiddling after the nose over that I used to do.
The problem comes from trying to trim the airplane before you have set your pitch and power. Any adjustment to pitch and power will cause temporary instability. You have to hold the airplane where you want it until
everything has worked itself out, then trim for no pressure. Otherwise your changing the trim will change the pitch, causing you adjust the other way, etc. Using trim to fly the airplane will cause pilot induced oscillations
and make it very difficult to hold altitude and heading.
Cause of the trimming problem:
A stock C-172 is relatively more under-powered than the C-150 or C-152.
Every C-172 will fly and trim a bit differently every time due to loading and power (speed)..
Your trim solution will be unique to you.
Solution from Vy Climb to Level Cruise
Begin by being trimmed to Vy climb
Determine your aircraft's speed in level flight at cruise setting.
Climb 100' above selected altitude and dive to level at selected level cruise speed and reduce power to cruise setting
Note time in seconds from beginning dive to hands-off level.
Keep track of how much you must move the trim in one direction to
Begin turning trim by putting fore-finger under the bottom button and rotate it as far to the top as you can push. (Pinching makes it harder to keep count.
Depending on available power from 1/3 to another full turn will be required.
Regardless, keep track of how much you put in until hands-off level..
Descent to Level from Level
Note time in seconds
Initiate descent to selected altitude
Plan power and rate of descent so as to be at cruise airspeed on reaching level and adjust power for cruise before aircraft can slow.
Repeat this climb and descent process always noting the time required to
reach level cruise flight. In each successive timing interval try to reduce the
duration required to reach level. You will improve your smoothness in the use of
power, anticipation, and time required in each situation. The time you save will
be with you the rest of your flying life. Now you should begin training for
Climb 100' above selected altitude and dive to level at selected level
Ah, surely you're not teaching this as a normal level-off technique
The #2 solution to leveling off a C-172 is entirely dependent upon its power/speed capability
To level off at the selected altitude by leading with 10% of the climb rate will work if you are patient.
The 145 h.p. C-172, partially loaded, would take forever to get to cruise speed. The usual pilot would wind up a couple of feet high because he would start doing other things and the aircraft would gradually climb instead of going faster. Waiting for this aircraft to accelerate could make pilots older. Hence the dive to altitude.
In the trim wheel I did mention that the required trim after the first full turn could vary. Corky later indicated that he has 180 h.p. That will take two full turns and then small adjustments. It accelerates rather well but requires anticipation to prevent gaining altitude instead of speed.
My C-172 has 180 h.p. and a power-flow exhaust. Will climb but not go much faster. Friend has same as my power installation but with speed mods. Claims 135 kts.
Still a good thread.
As uncomfortable as it might seem, pinning the nose with yoke pressure while trimming off that pressure is the optimum method to make the transition. It's the only way it can be done to a single point instead of multiple trim points. It saves time, and it's correct control usage. There's something I think you've missed in your post: wait time.
Depending upon the transition occurring and the aircraft, it may take some time for the final effect of the pitch/power change to be achieved. For example, I've been playing with the delay involved in a level-flight power reduction of my club's 182RG. It can take a fair bit of time for the speed to finally stabilize at the lower level.
Should I be holding the yoke against pressure the entire time? I prefer to trim as the pressure grows. I'm trimming a few times along the way, but each time in the same direction and each time to zero out the pressure. And, of course, the nose stays fixed during the entire process.
It's not just my comfort that's at issue. An out-of-trim airplane is more likely to drift in one direction or another if my attention wanders (i.e. I look at a chart, need to change a frequency, or some such). A quick scan *corrects* for this, but better to avoid it as much as possible. At least, that's my 1/2-cent worth of opinion on the matter.
Wait time = transition time, and yes, holding the yoke against the trim as the airplane stabilizes at the new nose attitude and power setting is the optimum method. Your concentration being broken with charts etc. isn't an issue in the correct procedure equation. In fact, in my opinion you shouldn't be looking at charts during a pitch and power transition :-) Do that after the airplane is stabilized.
It's true also that experienced pilots will lead in some trim and it's not written in stone that this can't be done, but holding the yoke against the trim while the airplane transitions is absolutely the correct method. What it boils down to is this. You learn to do it using nose -power -trim in that order because when you're learning to handle transitions, you are in the early stages of training.
This method is the optimum method for learning to make these transitions. Then as you gain experience, and you are in effect way ahead of your airplane as should be the case with added experience, you are perfectly free to use any means that's comfortable to you to accomplish the task. The fact is that nose-power-trim will still remain the optimum method, but experienced pilots will often "cheat" with the trim as it suits their fancy. Certain airplanes are difficult to hold through transitions. The 182 is a good example of this. I've found the Skylane to be very heavy out of trim. It's quite natural to want to cheat a bit; but make no mistake about it, a 182 can be held against the trim through a pitch/power transition, and doing it one time is still the optimum way to do it. Pin the nose....adjust the power....then trim off the pressure. Read the chart and tune the radio 5 seconds later. they'll still be there!! :-))
There's no problem with feeding off the trim after the power is adjusted back to cruise and the airplane is stabilizing down to the increased airspeed. I'm not saying you have to wait until the airspeed increases all the way to cruise before you begin trimming out the pressure, just that trim comes AFTER nose attitude and power. Done correctly, it's a smooth flowing transition that isn't a sharp 1-2-3 scenario.
It's in fact, very much like you have been describing it. In a climb to cruise transition, you lead the cruise target altitude and begin the transition with forward pressure on the yoke. You play the target round out and PIN that altitude with pressure against your climb trim. Then you make the power adjustments to cruise settings. By this time the airplane is beginning to accelerate. At this point you can start feeding off that trim pressure, and do it as the airspeed is increasing. The ideal scenario is to reach a null pressure in pitch at the exact moment you reach cruise airspeed.
Not everyone does this exactly the same way. You can vary this any way you
like as to when you begin the trim pressure release from the climb setting, but
all the time you are doing this, you must PIN the nose with yoke pressure and
HOLD IT THERE!!!
I think the only thing that might be confusing between what I'm saying and what you are getting out of what I'm saying, is that you might think I'm asking you to wait the entire time it takes for the airspeed to come up to cruise before you begin getting rid of that climb trim. You don't have to do that; and in fact, I wouldn't want you to do that.
The entire advantage of climbing 100’ high and diving is to reach the selected altitude at cruise speed before reducing power to cruise setting and fine trimming. Eliminates wait time. I am the living proof that waiting is what makes you old.
---Stability of an aircraft may be judged by how well it holds a trimmed situation.
---Static stability exists when an aircraft is trimmed for a condition and then moved will return as trimmed.
---A statically stable aircraft is easier to fly.
---A statically unstable aircraft is harder to fly.
---A statically stable aircraft exists when the CG is forward of the wing lift.
---the closer the center of wing wing lift gets to the center of gravity the more unstable the aircraft
---FARs require aircraft to be statically stable with respect to speed changes
----Lift is commonly close to 25% aft of wings chord from the leading edge.
---Trim is used to adjust the tail to counter wings lift forward of the center of gravity by giving down-load.
---The forward C.G requires a tail download as any reduction in speed will lower the nose as a recovery
---About one pound of pressure on the yoke is required for every six knots to prevent a change in airspeed
---Friction of control and connections is a constant difference related to aircraft speed.
---You must overcome this designed-in friction before the controls move
---FRSR is a term meaning free return speed range
---The FRSR is the range of speeds that can be stabilized with a single trim setting.
---Aft CG conditions lower the FRSR speed ranges.
Return to whittsflying
Continued on Page 3.13 Flying Surfaces and Controls