Rate One Turn Calculation

Rate One Turn Calculator

Calculation Results

Required Bank Angle: 0°

Turn Radius: 0 Nautical Miles

Turn Diameter: 0 Nautical Miles

Time for 360° Turn: 120 Seconds (2 Minutes)

Rate of Turn: 3° Per Second

function calculateRateOne() { var tas = parseFloat(document.getElementById('trueAirspeed').value); if (isNaN(tas) || tas <= 0) { alert("Please enter a valid True Airspeed."); return; } // A Standard Rate Turn (Rate One) is 3 degrees per second. // Bank Angle (approx) = (TAS / 10) + 7 // Accurate Formula: tan(bank) = (velocity * angular_velocity) / gravity var velocityFeetPerSec = tas * 1.68781; var angularVelocityRadPerSec = (3 * Math.PI) / 180; var gravity = 32.174; var bankAngleRad = Math.atan((velocityFeetPerSec * angularVelocityRadPerSec) / gravity); var bankAngleDeg = bankAngleRad * (180 / Math.PI); // Radius R = V / omega var radiusFeet = velocityFeetPerSec / angularVelocityRadPerSec; var radiusNM = radiusFeet / 6076.1; var diameterNM = radiusNM * 2; document.getElementById('bankAngleResult').innerText = bankAngleDeg.toFixed(1); document.getElementById('radiusResult').innerText = radiusNM.toFixed(2); document.getElementById('diameterResult').innerText = diameterNM.toFixed(2); document.getElementById('turnResults').style.display = 'block'; }

Understanding the Rate One Turn

In aviation, a Rate One Turn (also known as a Standard Rate Turn) is defined as a turn where the aircraft changes its heading at a rate of 3° per second. This is a critical concept for instrument flight rules (IFR) because it allows pilots to calculate exactly how long a turn will take without relying solely on visual cues.

The 2-Minute Turn

Since a full circle consists of 360 degrees, and a Rate One turn proceeds at 3 degrees per second, a complete 360-degree orbit will always take exactly 120 seconds (or 2 minutes). Similarly, a 180-degree turn takes 60 seconds. This predictability is vital for holding patterns and air traffic control vectoring.

The Bank Angle Rule of Thumb

While physics provides an exact trigonometric formula, pilots often use a common rule of thumb to estimate the bank angle required for a standard rate turn:

Bank Angle ≈ (TAS / 10) + 7

For example, if you are flying at a True Airspeed (TAS) of 120 knots, the calculation would be (120 / 10) + 7 = 19°. Our calculator uses the precise aerodynamic formula for higher accuracy, especially at higher speeds where the rule of thumb begins to deviate.

Factors Affecting the Turn Radius

It is important to note that as your airspeed increases, the radius of your turn also increases if you maintain a standard rate. This is why faster aircraft require much larger chunks of airspace to complete a turn compared to slower training aircraft. In high-speed flight, a standard rate turn might require an excessively steep bank angle; in such cases, pilots often limit their bank to 25° or 30° for passenger comfort and safety.

Practical Example

• Airspeed: 150 Knots
• Required Bank: ~22.6°
• Turn Radius: ~0.82 Nautical Miles
• Time to Turn 90°: 30 Seconds