Fuselage airframe

Patent metadata

Field	Value
Publication number	US-9623950-B2
Application number	US-201514613685-A
Country	US
Kind code	B2
Filing date	Feb 4, 2015
Priority date	Feb 6, 2014
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

A fuel tank and a differential frame in a fuselage airframe of a helicopter, the fuel tank being installed between the fuselage lower cover shell and the floor panel. The differential frame separates the fuel tank into two individual compartments, the differential frame having a web below the floor panel with a variable-height with a minimum height at the symmetry axis of the fuselage cross-section and a maximum height at lateral frame roots regions. A transversal beam is attached at each of its both ends to the differential frame bridging the entire variable-height of the differential frame and the fuel tank with two front and rear fuel bladders covering both individual tank compartments with a middle bladder installed between the transversal beam and the variable-height web of the differential frame.

First claim

What is claimed is:

1. A fuselage airframe of a helicopter comprising a subfloor compartment for a fuel tank, encompassed by a concave cover shell, standard frames and a floor panel covering the subfloor compartment above the concave cover shell, wherein at least one differential frame is mounted to the concave cover shell, the at least one differential frame being perpendicular and symmetric with regard to a longitudinal axis and having an upper section above the floor panel and a lower section below the floor panel and respectively lateral frame root regions merging the upper and lower sections, the at least one differential frame partitioning the subfloor compartment between the standard frames, wherein the lower section of the at least one differential frame has a web with variable-heights with respect to the cover shell between a minimum height at the longitudinal axis and a maximum height at the lateral frame root regions, and wherein at least one transversal beam is provided, bridging the entire web portion of the lower section with the variable-height of the at least one differential frame and being hingedly attached at its both lateral ends to the lower section of the at least one differential frame by means of at least one bolt.

2. The airframe according to claim 1 , wherein the at least one bolt is a shear bolt.

3. The airframe according to claim 1 , wherein the portion of the web of the lower section with variable-height of the at least one differential frame covers the fuselage width less the width of the lateral frame portions a floor plane level.

4. The airframe according to claim 3 , wherein the portion of the web of the lower section with variable-height of the at least one differential frame covers 20% to 80% of the fuselage width.

5. The airframe according to claim 1 , wherein at least two additional shear or tension attachments are provided between respective metallic fitting shear bolt joints, connecting the at least one transversal beam to the lower section with variable-height of the at least one differential frame.

6. The airframe according to claim 1 , wherein the minimum height of the lower section of the at least one differential frame is flush with an inner surface of the concave cover shell at the longitudinal axis.

7. A fuel tank for integration within the subfloor compartment of a fuselage airframe of a helicopter airframe according to claim 1 , wherein the fuel tank comprises at least one front fuel bladder and at least one rear fuel bladder connected by a middle bladder with a reduced cross section relative to the at least one front fuel bladder and/or the at least one rear fuel bladder, wherein a bottom part of the middle bladder is adapted to a V-shape of the web of the lower section of the at least one differential frame, covering an opening between the web with variable height and the transverse beam with a lowest level of the middle bladder being flush with a lowest level of the front fuel bladder and the rear fuel bladder.

8. A procedure for an integration of the fuel tank within the subfloor compartment of the fuselage airframe according to claim 1 , the procedure having the following steps:
putting the fuel tank with two fuel bladders connected by a middle bladder with a reduced cross section from inside of the fuselage airframe on the concave cover shell of the subfloor compartment between the standard frames and with the reduced cross section of the middle bladder on the web with variable-heights of the differential frame;
attaching the transversal beam across the middle bladder and the differential frame by means of installing the at least one bolt; and
attaching the floor panel on top of the standard frames, the web with variable-heights of the differential frame and on top of the transversal beam with the fuel tank below.

9. A fuselage airframe of a helicopter comprising a subfloor compartment for a fuel tank, the subfloor compartment comprising a concave cover shell, first frames, a floor panel disposed above the subfloor compartment and the concave cover shell, and a second frame mounted to the concave cover shell, the second frame being perpendicular and symmetric with regard to a longitudinal axis and having an upper section above the floor panel and a lower section below the floor panel and respectively lateral frame root regions merging the upper and lower sections, the second frame partitioning the subfloor compartment between the first frames, the lower section of the second frame having a web with variable-heights with respect to the cover shell between a minimum height at the longitudinal axis and a maximum height at the lateral frame root regions, and the air frame further comprising a transversal beam bridging the entire web portion of the lower section with the variable-height of the at least one differential frame and being hingedly attached at both lateral ends to the lower section of the at least one differential frame.

10. The airframe according to claim 9 , wherein the transversal beam is hingedly attached to the differential frame by at least one bolt.

11. The airframe according to claim 10 , wherein the at least one bolt is a shear bolt.

12. The airframe according to claim 9 , wherein the portion of the web of the lower section with variable-height of the second frame covers the fuselage width less the width of the lateral frame portions at a floor plane level.

13. The airframe according to claim 12 , wherein the portion of the web of the lower section with variable-height of the second frame covers 20% to 80% of the fuselage width.

14. The airframe according to claim 9 , wherein at least two additional shear or tension attachments are provided between respective metallic fitting shear bolt joints, connecting the transversal beam to the lower section with variable-height of the second frame.

15. The airframe according to claim 9 , wherein the minimum height of the lower section of the second frame is flush with an inner surface of the concave cover shell at the longitudinal axis.

Assignees

• Airbus Helicopters Deutschland GmbH

Inventors

• Fink Axel
• Rack Andreas
• Hoefer Philipp

Classifications

• Y02T50/44

  Cross-Sectional Technologies · mapped topic

• B64D37/04

  Arrangement thereof in or on aircraft · CPC title

• B64D37/06

  Constructional adaptations thereof · CPC title

• B64C1/062 Primary

  specially adapted to absorb crash loads · CPC title

• B64C1/061 Primary

  Frames · CPC title