Steep Turns

Private Pilot License (PPL) Notes

These notes cover the fundamentals of steep turns, including the physics behind them, effects on the aircraft, and how to perform them safely.

Introduction to Steep Turns:

1. Steep turns involve banking the aircraft at 45 degrees or more.
2. They require careful coordination of controls and understanding of aerodynamics.

Newton's First Law and Load Factors:

1. Newton's First Law states that a body in motion stays in motion unless acted upon by an external force.
2. Applying a force to change the aircraft's straight flight path adds stress to its structure.
3. Load factor (expressed in Gs) is the ratio of total aerodynamic force to the weight of the aircraft.
   1. At rest on Earth, the aircraft experiences 1G.
   2. A load factor of 2G means the stress on the structure is twice its weight.

Aircraft Load Categories:

1. Aircraft are designed to withstand specific load factors based on their category:
   1. Normal Category: Non-acrobatic flight; limit load factor of +3.8G to -1.52G.
   2. Utility Category: Limited acrobatics; limit load factor of +4.4G to -1.76G.
   3. Acrobatic Category: Full acrobatics; limit load factor of +6G to -3G.
2. Structures are built to handle 1.5 times the limit load factors for safety margins.
   1. Exceeding these limits can cause structural damage.

Effects of Bank Angle on Load Factor:

1. In level turns, load factor increases with bank angle due to centrifugal force and gravity.
   1. 30° bank: Load factor is 1.15G.
   2. 45° bank: Load factor is 1.41G.
   3. 60° bank: Load factor is 2G.
   4. 70° bank: Load factor is nearly 3G.
2. Increased load factor causes the aircraft to stall at higher speeds.
   1. Example: At 2G, stall speed increases from 44 knots to 63 knots in a Skyhawk.

Maneuvering Speed (Va):

1. The speed below which you can use full control movements without overstressing the aircraft.
2. Maneuvering speed decreases with aircraft weight.
   1. Example: Skyhawk Va is 99 knots at 2450 lbs and 81 knots at 1600 lbs.
3. Do not exceed maneuvering speed in turbulent air or during abrupt control inputs.

Performing Steep Turns:

1. Pre-Turn Checks:
   1. Conduct clearing turns to check for traffic.
   2. Ensure altitude is at least 1,500 feet AGL.
   3. Reduce speed to or below maneuvering speed.
2. Entering the Turn:
   1. Select a cardinal heading (north, east, south, or west) and note a visual reference point.
   2. Begin rolling into a 45° bank turn.
      1. Increase power as needed past 30° bank.
      2. Apply additional back pressure to maintain altitude.
   3. Use coordinated aileron and rudder inputs.
      1. Use right rudder when turning right to counteract left-turning tendencies.
3. Maintaining the Turn:
   1. Keep a consistent 45° bank angle.
      1. Use slight opposite aileron pressure to prevent overbanking.
   2. Maintain altitude within 100 feet.
      2. If losing altitude, reduce bank angle slightly and increase pitch.
      3. If gaining altitude, increase bank angle slightly or reduce back pressure.
   3. Monitor instruments and outside references.
      4. Cross-check attitude indicator, altimeter, and visual horizon.
4. Exiting the Turn:
   1. Begin rollout 25° to 35° before the reference point.
   2. Apply opposite aileron and rudder to level the wings.
   3. Reduce back pressure and return power to cruise setting.

Conclusion:

1. Steep turns develop your coordination and control of the aircraft.
2. Understanding load factors and maneuvering speeds is crucial for safety.
3. Practice steep turns after solo flight to enhance proficiency.

Remember, smooth and coordinated control inputs are key to performing steep turns safely and effectively.