LANDING MODEL AIRCRAFT

A basic observation.

Draw a horizontal line. At the left add an arrow and the word “Thrust”. At the other end draw another arrow and mark this one “Drag”. Intersect the line with a vertical one. At the top draw an arrow and the word “Lift”. At the bottom draw another arrow pointing down and mark this one “Weight”. These are the Forces acting on a plane in straight and level flight. Thrust equals Drag. Lift equals Weight.  If any one changes it affects the other parameters and the plane is no longer in S&L flight. FIRST PRINCIPALS....This assume a correctly set up and trimmed model. See “Model aircraft trimming for Sports Flyers”.
  1.  A good landing only comes from a stable approach.
  2. The elevator only trims the aircraft longitudinally, it does not make it climb and dive. Longitudinal trim is only good for one power setting. ie...increase or decrease the power and the aircraft will either climb or descend.
  3. With the throttle closed during the approach adjusting the elevator will give an increase or decrease in airspeed which will result in an increase or decrease in lift generated. This results in the a/c diverging from what is required,ie. a constant, straight line glide path at constant speed.
  4. The landing begins at the base leg of the circuit when, at the appropriate time, which depends on the a/c height (for we model flyers) some power is reduced to cause a decrease in airspeed and therefore a gentle descent. At this time do not adjust the elevator as the a/c will assume its trimmed airspeed and stabilise.
  5. Turn onto the approach, align the a/c with the runway centre line and slowly reduce the power until it is just a tad over idle. (idle is almost as good but doesn`t help if you are a little too high). The a/c will now begin a descent which may seem too steep at first but resist the temptation to pull back on the stick. It will very soon self adjust to its trimmed airspeed which will be stable as long as you DO NOT make an input or re-trim the elevator.
  6. During this stage keep the wings level and keep aligned with the r/w c/l.
  7. When you are committed to land, or at your chosen touchdown point, close the throttle if it was left open a tad.
  8. At about 6 feet off the ground lift the nose gently, (the round-out) to arrest the rate of descent, with the elevator and HOLD IT in that position. The a/c will now slow and, because lift has now reduced, will start to descend again. Lift the nose again and hold. Once you have raised the elevator do not release it, hold it steady. Repeat until you have arrived.....
  9. On the approach and finals DO NOT ADJUST THE ELEVATOR until the round out.
  10. The throttle is a prime control not an on/off switch. Use it to climb and descend, loop and hold the height in a tight turn. After having said that our models are grossly overpowered and a more scale speed can be achieved by reducing the power to approx half and trimming the elevator to maintain a constant height.
  11. Good landings will only really be achieved time after time if circuits, landings and touch and goes are practiced regularly until the above advice comes as a second nature.
  Further notes. A high headwind will give a model a steeper glide path than a lower one so start the descent closer in to the touch down point. Re 5) above. Throttle closed. If you decide that you are too high make the decision to adjust early rather than late. Gently turn off the c/l and describe an `S` until you are in line with the c/l and make another estimate. If still too high do it again. Practicing landings and approaches may save you an expensive u/c, prop or worse,  ....your pride!! E&OE. Mike White