鸭子设计；Design trade-off; 目标不一样

不同鸭翼战斗机的气动设计

战机	鸭翼特点	影响
歼-20	大型固定鸭翼，提升敏捷性，同时优化隐身设计	兼顾隐身与机动
台风	近距鸭翼布局，提高瞬时盘旋能力	适合格斗战
阵风	小型鸭翼，提高低速控制和高迎角机动	适合多任务作战
苏-57	采用前翼设计，无传统鸭翼，但部分机动原理相似	兼顾隐身与机动

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Types of Canard Positions on Fighter Jets

1. Close-Coupled Canards (Near the Main Wing)

   • Example Jets: Dassault Rafale (France), Eurofighter Typhoon (Europe)

   • Position: Located very close to the main wing, usually just ahead of it.

   • Effects:

     • Enhances lift by interacting with wing vortices, improving high-angle-of-attack stability.

     • Boosts instantaneous turn rate, useful in dogfights.

     • Helps with short takeoff and landing (STOL) capabilities.

     • Has some impact on radar cross-section (RCS), but can be mitigated through design.

2. Far-Forward Canards (Ahead of the Cockpit or Nose)

   • Example Jets: Sukhoi Su-30MKI (India, Russia, Variant), JAS 39 Gripen (Sweden)

   • Position: Located farther ahead of the main wing, usually near or ahead of the cockpit.

   • Effects:

     • Improves nose authority, making it easier to achieve high angles of attack.

     • Enhances post-stall maneuverability.

     • May cause increased drag in some flight conditions.

3. Large, Mid-Position Canards (Blended with the Fuselage)

   • Example Jet: Chengdu J-20 (China)

   • Position: Medium-sized canards positioned midway along the fuselage, optimized for both stealth and maneuverability.

   • Effects:

     • Provides additional lift and control while minimizing drag.

     • Designed to reduce RCS compared to traditional canards by aligning them with stealth shaping principles.

     • Likely aids in high-speed stability and supercruise performance.

4. Dynamic or Retractable Canards

   • Example Jet: No modern operational fighters use fully retractable canards, but some experimental designs have explored them.

   • Concept:

     • Canards that retract or move dynamically to balance stealth and aerodynamics.

     • Could be useful for stealth-first designs where canards are deployed only when needed.

Conclusion

The best canard placement depends on mission priorities:

• Close-coupled (Typhoon, Rafale): Best for agility and lift at high angles of attack.

• Far-forward (Gripen, Su-30MKI): Enhances nose control and maneuverability.

• Blended stealth (J-20): Balances agility with stealth considerations.

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