Ornithopter: flying robots with historical origins

• What was needed: Lightweight and robust rod ends that are capable of reliably transmitting the high tensile and compressive forces generated by flapping wings.
• Requirements: High load capacity, low weight, maintenance-free, dirt-resistant, free movement of the spherical ball, compact type, long service life
• Industry: Model making
• Success for the customer: igubal ® rod end KBRM-03-MH
  These rod ends fulfil all requirements and contribute significantly to the efficiency and reliability of ornithopters. They consist of a robust plastic housing and a plastic spherical ball with an integrated metal sleeve, which offers a higher tightening torque and can transmit high tensile and compressive forces without impairing the free movement of the spherical ball. The rod ends offer low-friction movement and require no additional lubrication, making them particularly resistant to dirt and dust. Many of the designed flying robots have already flown hundreds of hours without having to replace a rod end.

The development of a realistic and powerful ornithopter places high demands on the materials and components used. A central problem is the bearing of the wings, which must withstand high tensile, compressive and torsional forces. When landing on sand or grass, no foreign bodies must be allowed to penetrate the bearing. Previous solutions made of commercially available plastic or aluminium failed under these conditions: They could not withstand the tensile forces or were susceptible to dirt, which led to rapid wear and loss of performance. Only the steel rod ends met almost all the criteria, but were 5 times heavier than the igubal®-rod end and 4 times more expensive.

After extensive tests and our advice, the developer decided in favour of our igubal® KBRM-03-MH rod end. These rod ends are made of a special polymer that can withstand high tensile and compressive forces and is also very light. A metal sleeve in the plastic calotte ensures a higher tightening torque. They require no additional lubrication and are therefore insensitive to dirt and dust, which is a particular advantage when landing on uneven surfaces. The rod ends are compact, robust and allow the ball to move freely in the housing thanks to the metal sleeve. Thanks to their long service life and high efficiency, they make a decisive contribution to the performance of the ornithopters. The flying eagle V3 thus achieves a remarkable flight time of 26 minutes with minimal energy consumption of just 40 watts for a 0.8 kg bird.