Equivalent Airspeed Given Static Pressure Calculator

Equivalent Airspeed Formula:

\[ EAS = a_o \times M \times \left( \frac{P_{static} \times 6894.7573}{P_o} \right)^{0.5} \]

Sonic Speed at Sea Level (a₀):

m/s

Mach Number (M):

Static Pressure (P_static):

Static Sea Level Pressure (P₀):

Equivalent Airspeed (EAS):

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1. What is Equivalent Airspeed?

Equivalent Airspeed (EAS) is calibrated airspeed corrected for the compressibility of air at a non-trivial Mach number. It represents the airspeed at sea level that would produce the same dynamic pressure as the true airspeed at the actual flight altitude.

2. How Does the Calculator Work?

The calculator uses the Equivalent Airspeed formula:

\[ EAS = a_o \times M \times \left( \frac{P_{static} \times 6894.7573}{P_o} \right)^{0.5} \]

Where:

\( EAS \) — Equivalent Airspeed (m/s)
\( a_o \) — Sonic Speed at Sea Level (m/s)
\( M \) — Mach Number (dimensionless)
\( P_{static} \) — Static Pressure (Pa)
\( P_o \) — Static Sea Level Pressure (Pa)
6894.7573 — Conversion factor

Explanation: The formula accounts for compressibility effects at higher Mach numbers and provides the equivalent speed at standard sea level conditions.

3. Importance of EAS Calculation

Details: Equivalent Airspeed is crucial for aircraft performance calculations, structural load analysis, and flight testing. It provides a standardized measure of airspeed that accounts for compressibility effects at different altitudes.

4. Using the Calculator

Tips: Enter sonic speed at sea level in m/s, Mach number, static pressure in Pa, and static sea level pressure in Pa. All values must be positive and valid.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between EAS and CAS?
A: EAS is CAS corrected for compressibility effects, while CAS is IAS corrected for instrument and position errors.

Q2: Why is compressibility correction important?
A: At higher Mach numbers, air compressibility affects pressure measurements, making EAS a more accurate representation of dynamic pressure.

Q3: What is the typical value of sonic speed at sea level?
A: Approximately 340 m/s (1115 ft/s or 661 knots) at standard atmospheric conditions.

Q4: When is EAS most important?
A: EAS becomes increasingly important at higher altitudes and speeds, particularly when Mach number exceeds 0.3.

Q5: How does EAS relate to structural loads?
A: EAS directly correlates with dynamic pressure, making it essential for structural load calculations and aircraft design.