Aircraft with a fuselage that comprises at least one hollow beam element

1. An aircraft with a fuselage, the fuselage comprising at least one hollow beam element, wherein the at least one hollow beam element accommodates at least one hollow duct element that comprises a tubular duct element wall, wherein at least one protective spacer is arranged between the tubular duct element wall and the at least one hollow beam element such that free space is available between the tubular duct element wall and the at least one hollow beam element.

2. The aircraft according to claim 1 ,

wherein the tubular duct element wall and the at least one protective spacer are integrally formed as a single piece.

3. The aircraft according to claim 2 ,

wherein at least the tubular duct element wall comprises polyvinylidene fluoride.

4. The aircraft according to claim 3 ,

wherein the at least one protective spacer comprises polyvinylidene fluoride.

5. The aircraft according to claim 2 ,

wherein the at least one protective spacer is provided as an external protrusion of the tubular duct element wall.

6. The aircraft according to claim 2 ,

wherein the at least one hollow beam element is a blow molded composite structure that is integrally formed as a single piece.

7. The aircraft according to claim 1 ,

wherein the at least one protective spacer is attached to the tubular duct element wall.

8. The aircraft according to claim 1 ,

wherein the at least one protective spacer is attached to the at least one hollow beam element.

9. The aircraft according to claim 8 ,

wherein the at least one hollow beam element comprises at least first and second wall members, which are rigidly attached to each other.

10. The aircraft according to claim 9 ,

wherein the at least first and second wall members are rigidly attached to each other via associated plate-shaped elements.

11. The aircraft according to claim 10 ,

wherein the at least one protective spacer is attached to one of the associated plate-shaped elements.

12. The aircraft according to claim 1 ,

wherein the at least one protective spacer comprises a polyethylene foam.

13. The aircraft according to claim 12 ,

wherein the at least one protective spacer is a foam stripe.

14. The aircraft according to claim 12 ,

wherein the tubular duct element wall comprises polyvinylidene fluoride.

15. The aircraft according to claim 1 ,

wherein the at least one hollow duct element is adapted for guiding ventilation air in the aircraft.

16. The aircraft according to claim 1 ,

wherein the at least one protective spacer comprises a closed-cell polyethylene foam.

17. An aircraft comprising a fuselage, the fuselage comprising a hollow beam, the hollow beam accommodating a hollow duct comprising a tubular duct wall, wherein a protective spacer is disposed between the tubular duct wall and the hollow beam such that free space is between the tubular duct element and the hollow beam.

18. The aircraft according to claim 17 ,

wherein the tubular duct wall is made of a polymeric material.

19. The aircraft according to claim 17 ,

wherein the protective spacer is made of a polymeric material.

20. An aircraft comprising a fuselage, the fuselage having a hollow beam, the hollow beam accommodating a hollow duct comprising a tubular duct wall and a plurality of solid protective spacers spaced from each other and disposed between the tubular duct wall and the hollow beam such that a plurality of free spaces extend between the tubular duct wall and the hollow beam.