Hello everybody, I'd like to share with you an article I had recently posted on the IAFTP website. My thoughts are meant to be associated with light single prop training A/C. Please comments ... but don't be too cruel
Abstract: Thanks to the fact that small SEPs are light, there’s no a real need for trimming all the time for every speed or flap setting. In this way the student has the chance to gain a “control/muscle memory” throughout the pattern, starting from the last time he trimmed the aircraft. He understand that now, the force he’s applying is due to the fact he is controlling the speed during the descent, managing the energy, instead of letting simply the nose down; in the same way he understand more easily how to control his rate of descent with power.
Details: Once in downwind, memory items/flow are performed, entering slow flight condition at the required speed with the 1st notch of flaps, then a/c is trimmed to obtain a neutral feeling on the control column for that airspeed.
We are in a situation that require the a/c to cooperate with us and fly almost by itself, so we can spend a couple of seconds giving a glance to the checklist, deal with communications and stay focused on traffic avoidance, so trimming here is important.
When it’s time to turn on base, power is reduced to initiate a positive nose down tendency and base turn is started at max 20° of bank; during this maneuver the nose dipping movement is seconded applying a minimum back pressure on the elevator, this in order to obtain an initial deceleration to, lets say, 70 kts while descending.At this stage no trim is required, it’s an energy management phase therefore feeling how the airflow act on the elevator is very important, as well as maintain sensitivity over load changes.
Once on base the rate of descent is adjusted and flaps are set as required; even if 2nd notch of flaps is added no trim is really needed, as pitch changes are neglectable and flaps induced movements are absorbed with the joke while speed is kept constant, the attention is focused on final turn planning and height and energy management.
Final turn is achieved in the same way using the 20° bank and 70kt limitation, and then as soon as the a/c is stable and wings leveled, speed and flaps are set as required. Once on final trim is finally used to lighten up a little bit the loads on the elevator, but not to a neutral feeling.
Summary of Effectiveness: In my opinion this practice help the trainees that tends to over control, and those who use too much trim in the wrong way, as it were a flight control.
Thanks to the fact that small SEPs are light, there’s no a real need for trimming all the time for every speed or flap setting. In this way the student has the chance to gain a “control/muscle memory” throughout the pattern, starting from the last time he trimmed the aircraft. He understand that now, the force he’s applying is due to the fact he is controlling the speed during the descent, managing the energy, instead of letting simply the nose down; in the same way he understand more easily how to control his rate of descent with power.
At the same time this help in dealing with go-arounds especially unexpected ones, where an excess of nose-up trim associated with flaps at slow speeds, can produce unhealthy climbing attitudes if power is suddenly applied; this is maybe not a problem for a seasoned pilot, but can be scary and hard to manage for a beginner.In addition, to give precise and simple parameters to comply with ( max bank, min airspeed) and avoid messing with the trim, will help in achieving a better initial stick&throttle feeling, while keeping him in a safe speed/attitude envelope.