Conceptual Structure & Analysis

Here are the steps your team can follow when brainstorming the structure of the UAV.

Step 1:

Fixed-wing UAVs or Rotorcrafts?

• What is the operation scenario of the UAV?
  • Limitations on takeoff and landing sites?
  • Requirements on flight time and distance?
  • Payload restrictions?

• Rotorcrafts
  • Pros
    • Flexibility & Maneuverability (hover, vertical takeoff and landing (VTOL))
    • Easy operation
    • Portable
    • Easy to install, disassemble, and repair
    • Mature techniques at present
  • Cons
    • Not suitable for long-journey missions
    • Very limited load weight, small internal space
    • Relatively low speed

• Fixed-wing UAVs
  • Pros
    • Suitable for long-journey missions
    • Can achieve high speed
    • Better aerodynamic performance
    • Less energy consumption (electrical batteries)
    • Large payload capacity, large internal space
  • Cons
    • Strict takeoff and landing runway limitations
    • Weak flexibility, cannot manage missions like accurate mapping
    • Complex operation

Plus, sometimes, hybrid drones can be the optimal option.

Step 2:

Analyze the Layout/ Configuration

Fixed-wing

• Straight wing
  • Pro: structure simple; lightweight; large lift
  • Con: large drag and unstable under high-speed
  • Applications: model aircraft; (early) subsonic aircraft

• Delta wing
  • Pro: little drag; large fuel tank; lightweight
  • Con: poor maneuverability under low speed; difficult to land
  • Applications: High-speed aircraft

• Trapezoidal wing
  • Pro: structure simple; large lift; high structural strength
  • Con: limited wingspan
  • Applications: Low-speed aircraft

• Flying wing
  • Pro: high aerodynamic efficiency
  • Con: difficult to manipulate; poor stability
  • Applications: Fighters

• Forward-swept wing
  • Pro: good low-speed performance; large lift; high wing aerodynamic efficiency
  • Con: prone to bending and deformation; relatively complex structure; requires higher material quality and manufacturing costs
  • Applications: Fighters

• Swept wing
  • Pro: little drag; suitable for high-speed flight
  • Con: poor low-speed performance (little life)
  • Applications: high-speed aircraft

Rotary wing

• Single-rotor
  • Pros:
    • Simple structure, easy maintenance
    • Longer flight endurance
    • Capable of carrying heavier payloads
    • Better stability in strong winds
  • Cons:
    • Noisy due to large rotor
    • Large rotor poses safety risks
    • Complex design requiring tail rotor for stabilization
  • Applications:
    • Agricultural spraying
    • Transporting heavy loads
    • Long-duration surveillance missions

• Dual rotor
  • Pros:
    • Vertical take-off and landing (VTOL) capabilities, offering helicopter-like flexibility
    • Fixed-wing efficiency during high-speed flight
    • Superior performance in range and speed
  • Cons:
    • Complex design and manufacturing, higher maintenance cost
    • Potential instability during mode transitions
    • Requires advanced piloting skills
  • Applications:
    • Military reconnaissance and transport (e.g., V-22 Osprey)
    • Search and rescue missions
    • Long-range cargo transport

• Multirotor
  • Pros:
    • Easy to control, ideal for hovering and precise flight
    • Relatively simple structure, lower cost
    • Can operate in tight spaces
  • Cons:
    • Short flight endurance, limited payload capacity
    • Less stable in strong winds
    • Slower flight speeds
  • Applications:
    • Aerial photography and videography
    • Surveying and mapping
    • Package delivery

Step 3:

(Fixed-wing) Wing Position

• High-wing: Wing positioned above the fuselage
  • Pro: high stability; good runway adaptability; little drag; large fuselage capacity; wide vision (camera position)
  • Con: poor flexibility; large drag; complex structure

• Mid-wing: Wing positioned in the middle of the fuselage
  • Pro: little drag; high flexibility and maneuverability
  • Con: limited fuselage space (wing box occupies volume)

• Low-wing: Wing positioned below the fuselage
  • Pro: high flexibility; easy-to-place landing gears
  • Con: relatively low stability; limited fuselage space (wing box occupies volume); not suitable for low-altitude flights

Step 4:

Tail Design

Here are some major types of tails, and the common ones are discussed in the following:

• Conventional tail
  • Pros:
    • High structural stability and reliability
    • Avoid wing wake flow interference
    • High control efficiency
    • Easy fuselage rear opening, easy for cargo loading and unloading
  • Cons:
    • Require high material strength and lightweight
    • Special aeroelastic problems exist
• V tail
  • Pros:
    • Improves the aircraft’s control performance and longitudinal stability under high-speed
    • Helps reduce drag and increase speed
    • May serve the functions of both the vertical and horizontal stabilizers
  • Cons:
    • Complex design with high material requirements
    • May generate additional aerodynamic drag in certain flight conditions