During a coordinated level 45° banked turn, if airspeed increases from 89 knots to 98 knots, what happens to the turn radius?

During a coordinated level 45° banked turn, if airspeed increases from 89 knots to 98 knots, what happens to the turn radius?

• A. Radius decreases
• B. Radius remains the same
• C. Radius increases
• D. Load factor decreases

Answer: (C)

In a coordinated level turn, with the bank angle fixed, the turn radius is set by speed and bank. The relationship is R = V^2 / (g tan φ). So when the speed V increases while the bank angle φ stays the same, the radius grows with the square of the speed. That means going from 89 knots to 98 knots makes the path larger, not smaller. Numerically, the radius increases by about (98/89)^2 ≈ 1.21, roughly a 20% longer radius. The load factor for a fixed bank in a level turn stays determined by the bank (n = sec φ) and doesn’t drive the change in radius with speed, so the main effect is the larger radius.

In a coordinated level turn, with the bank angle fixed, the turn radius is set by speed and bank. The relationship is R = V^2 / (g tan φ). So when the speed V increases while the bank angle φ stays the same, the radius grows with the square of the speed. That means going from 89 knots to 98 knots makes the path larger, not smaller. Numerically, the radius increases by about (98/89)^2 ≈ 1.21, roughly a 20% longer radius. The load factor for a fixed bank in a level turn stays determined by the bank (n = sec φ) and doesn’t drive the change in radius with speed, so the main effect is the larger radius.