Hinge Moment Coefficient Given Stick Force Calculator

Formula Used:

\[ C_{he} = \frac{F_s}{G \times 0.5 \times \rho \times V^2 \times c_e \times S_e} \]

Stick Force (F_s):

Gearing Ratio (G):

1/m

Density (ρ):

kg/m³

Flight Velocity (V):

m/s

Elevator Chord (c_e):

Elevator Area (S_e):

m²

Hinge Moment Coefficient (C_he):

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1. What is Hinge Moment Coefficient?

The Hinge Moment Coefficient is a dimensionless parameter that quantifies the moment experienced by a control surface hinge in an aircraft. It represents the aerodynamic forces acting on control surfaces and is crucial for designing aircraft control systems with appropriate force feedback to the pilot.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ C_{he} = \frac{F_s}{G \times 0.5 \times \rho \times V^2 \times c_e \times S_e} \]

Where:

\( C_{he} \) — Hinge Moment Coefficient (dimensionless)
\( F_s \) — Stick Force (N)
\( G \) — Gearing Ratio (1/m)
\( \rho \) — Density (kg/m³)
\( V \) — Flight Velocity (m/s)
\( c_e \) — Elevator Chord (m)
\( S_e \) — Elevator Area (m²)

Explanation: This formula calculates the hinge moment coefficient by relating the stick force felt by the pilot to the aerodynamic properties and geometric characteristics of the elevator control surface.

3. Importance of Hinge Moment Coefficient

Details: The hinge moment coefficient is critical for aircraft control system design as it directly affects pilot workload and aircraft handling characteristics. Proper hinge moment design ensures adequate control force feedback, preventing overcontrol and providing the pilot with a natural feel of the aircraft's response to control inputs.

4. Using the Calculator

Tips: Enter all values in appropriate SI units. Stick force in Newtons, gearing ratio in 1/m, density in kg/m³, flight velocity in m/s, elevator chord in meters, and elevator area in square meters. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why is hinge moment coefficient important in aircraft design?
A: It determines the control forces required by the pilot and affects the aircraft's handling qualities and stability characteristics.

Q2: What factors affect the hinge moment coefficient?
A: Control surface geometry, aerodynamic balance, gap seals, and the location of the hinge line relative to the aerodynamic center.

Q3: How does gearing ratio affect the calculation?
A: The gearing ratio represents the mechanical advantage in the control system, converting stick force to control surface deflection.

Q4: What are typical values for hinge moment coefficient?
A: Values vary significantly depending on aircraft type and control surface design, but typically range from 0.1 to 1.0 for conventional aircraft.

Q5: How can hinge moments be reduced in aircraft design?
A: Through aerodynamic balancing techniques such as horn balances, internal seals, beveled trailing edges, and servo tabs.