21. The nosewheel casters; there is a small tailskid for rudder protection. 22. Full-span hydraulically operated trailing-edge nosewheel undercarriage. 23. On the ground the aircraft has foot pedal-controlled nosewheel steering. 24. The small tailwheel is much lighter and much less vulnerable than a nosewheel . 25. The nosewheel is friction castering and the aircraft is steered with differential braking. 26. The nosewheel is free castering and the aircraft is steered with differential braking. 27. The Challenger was a low-winged nosewheel undercarriage. 28. It had a fixed-wheel tricycle landing gear with a castering nosewheel . 29. A tricycle landing gear with steerable nosewheel was envisioned. 30. In 1941 he worked for Farner AG in Grenchen on nosewheel undercarriage design.