4. LESSON 6 - FLYING STRAIGHT, WINGS LEVEL
- Airspeed is the result of pitch attitude
- Use the trim to maintain your pitch attitude
- Use the airspeed indicator for cross-checking only
- Keep the wings level; for directional corrections: use the stick and rudder simultaneously
You instructor will ask you to maintain a certain airspeed throughout this exercise. First set a certain pitch attitude (the distance between your glider’s nose and the horizon) and make only small corrections to get to the desired airspeed. Now use the trim lever to ease off any pressure on the control stick. If you are flying too slowly, push the stick forward a little to get a lower pitch attitude and a higher airspeed. It will take a few seconds for the higher airspeed to be displayed by the airspeed indicator. This shows how important it is to observe the horizon.
USING THE TRIM
We practise straight flight at a constant airspeed. You adjust the trim lever until you feel no control pressure. It makes sense to set the trim shortly after releasing from the winch or aerotow and whenever you want to make airspeed changes (e.g. fast straight flight, thermal flying, approach and landing).
USING THE AIRSPEED INDICATOR
Your airspeed indicator is only there for cross-checking. If you try and keep up with the airspeed indicator without looking at the horizon, you will probably find that your airspeed varies between being too high or too low. Don’t ‘chase’ the indicator.
COORDINATED CONTROL INPUTS DURING A STRAIGHT GLIDE
First choose a notable landmark on the horizon and fly towards it. If you have trouble finding a landmark, your instructor will help you. You will then practice steering coordinatedly by using stick and rudder simultaneously for every correction. It will take some practise to find the right balance between both control inputs. Luckily the cheapest and most important flight instrument will assist you: the yaw string.
When the yaw string is pointing straight at you, you are flying without skidding or side-slipping. The fuselage of the glider points straight into the airflow.
When the wings are level but the yaw string is at an angle, the airflow is pushing the glider to one side. You can correct this situation by moving the rudder pedals in the opposite direction of the deflected string until it is straight again. The yaw string is a very sensitive and precise instrument to measure whether you are flying coordinated.
If a disturbance in the airflow makes one wing go down, the aircraft will start a turn. Do you remember from Lesson 4 how the side effect of roll is adverse yaw? The yaw string will now point to the higher wing. To return to coordinated flight, you need to move your stick in the direction of the string. The glider will then fly wings level again.
When flying straight, you have to make sure that the horizon also looks straight from the canopy. Have a look at the position of the wingtips as well. The better you are able to keep the wings level, the easier it will become to fly straight. In the beginning, you will notice it isn’t easy to fly straight, but you will soon learn to “feel” when the glider is adopting the right position in relation to the horizon.
If you have to adjust your direction when flying straight towards your landmark on the horizon: use the stick and rudder simultaneously. If you forget to use either the rudder or the stick, your nose will keep moving back and forth around your landmark.In summary:
- Wing low: correct by using the stick and check the yaw string!
- Wings level / yaw string deflected: use opposite rudder.
- Directional corrections: use stick and rudder simultaneously.