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Statement of Work

Design. Test. Fly.

Proposals with a statement of work are normally prepared in cooperation with the prospective client. Your proposal will include cost and calendar schedule and are based on estimated man-hours per task.

DARcorporation's success as a leading provider of contractual technical services usually results in long-term partnerships that go far beyond the initial assignment. A typical design and analysis task will include:

  • Sizing of the airplane to a given mission specification.
  • Continue work on definition of the following parameters: Take-off Weight, Empty Weight, Mission Fuel Weight, Take-off Power, Wing area and Maximum Lift Coefficients. Class I Drag.
  • List comparative airplanes with similar mission performance:
    • Overall Configuration Selection
    • Fuselage Layout
    • Propulsion System Integration
    • Wing and Empennage Planform Parameters
    • Type and Size of High Lift Devices
    • Landing Gear Type
    • Class I Weight and Balance
    • Preliminary arrangement drawings
    • Class I Stability and Control
    • Iterations on weights and L/D
  • Dimensioned Three-view Drawings
  • Major Systems. General system arrangements and location in the airframe.
  • Landing gear tires and struts sizing. Verification of landing gear disposition.
  • Initial structural arrangement drawings
  • V-n diagrams
  • Class II weight calculations with center of gravity locations.
  • Engine inclination determination
  • Calculation of hingemoment derivatives and coefficients for elevator, aileron and rudders. Elevator, rudder and aileron sizing, including horn balance and tabs.
  • Lift versus angle of attack curves for power-off, power-on, clean, take-off and landing condition.
  • Verify trimmed maximum lift coefficients for the defined flight conditions and flap size verification.
  • Calculation of zero angle of attack pitching moment, lift coefficients and stability & control derivatives for the defined flight conditions at forward and aft center of gravity.
  • Trim diagrams for the defined flight conditions.
  • Stick force, stick-force-gradients and stick-force-per-g gradients for the defined flight conditions at aft and forward center of gravity. DARcorporation will determine whether down-spring and/or bob-weight installation are required. Where necessary, design adjustments will be suggested. Lateral-Directional trim. Control forces will be calculated for different flight conditions for several different bank angles and sideslip angles. Control forces will be compared with applicable FAR regulations.
  • Class II (detailed) drag calculations for several flight including power effects:
  • Performance calculations for:
    • Cruise (maximum speed, range, endurance and payload-range diagram)
    • Climb (Rate of climb)
    • Take-off
    • Landing
    • Stall speed
    • Maneuver
  • Dynamics:
    • Calculation of the moments of inertia of the airplane at three different weights.
    • Determination of the longitudinal and lateral-directional transfer functions of the airplane.
    • Calculation of the damping ratios, frequencies and time constants of the airplane, compare with FAR requirements. This will determine short period, phugoid, spiral, roll and dutch-roll behavior.
    • Where necessary, design adjustments will be suggested.
  • Preliminary layout drawing for all essential airplane systems.
  • Preliminary manufacturing breakdown
  • List maintenance and accessibility requirements.
  • Preliminary cost analysis
  • Detailed loads analysis
  • Detailed structural design
  • Wind tunnel testing and program management

Please Contact DARcorporation for additional information.