Rotary wing aircraft airframe

Patent metadata

Field	Value
Publication number	US-9517831-B2
Application number	US-201414546325-A
Country	US
Kind code	B2
Filing date	Nov 18, 2014
Priority date	Nov 20, 2013
Publication date	Dec 13, 2016
Grant date	Dec 13, 2016

Abstract

A rotary wing aircraft airframe ( 2 ) with a longitudinal axis comprising: a subfloor structure ( 15 ) for supporting cabin floor panels ( 13 ) and/or at least one fuel tank bladder ( 12 ). Said subfloor structure ( 15 ) has a bottom shell ( 16 ), longitudinal support beams ( 21 ), ribs ( 20 ), main frames ( 23 ) and floor panels ( 13 ). The bottom shell ( 16 ) has a flat shell portion ( 17 ) and two lateral shell portions ( 18 ) extending integrally from said flat shell portion ( 17 ) along its longitudinally oriented sides and being curved towards respective front edges of said ribs ( 20 ) and main frames ( 23 ). The longitudinal support beams ( 21 ) are provided with attachments for the floor panels ( 13 ), the longitudinal support beams ( 21 ) are attached at least partially to the ribs ( 20 ) and/or the main frames ( 23 ) and the longitudinal support beams ( 21 ) are featuring along at least ⅔ of their longitudinal extension a height 2 to 20 times smaller than any distances of any of the floor panels ( 13 ) to the bottom shell ( 16 ).

First claim

What is claimed is:

1. An airframe for a rotary wing aircraft, the rotary wing aircraft having a longitudinal axis and comprising:
a subfloor structure for supporting cabin floor panels, the subfloor structure having a bottom shell, ribs, main frames and floor panels, the ribs and main frames extending essentially in planes perpendicular to the longitudinal axis on one side of the bottom shell and the floor panels being in an essentially horizontal plane essentially parallel to the longitudinal axis on the same side of the bottom shell as the ribs and main frames and mounted on flat top edges of the ribs and of main frames; the flat top edges being opposite in position to the bottom shell, the bottom shell having an essentially flat shell portion including longitudinally oriented sides and two curved lateral shell portions extending integrally from said flat shell portion along the longitudinally oriented sides and being curved towards respective lateral borders of said ribs and main frames;
longitudinal support beams along at least a longitudinal section of the subfloor structure along the longitudinal axis, the longitudinal support beams provided with attachments for the floor panels, the longitudinal support beams being attached to at least one of the ribs and the main frames and featuring along at least ⅔ of their longitudinal extension a height 2 to 20 times smaller than a corresponding adjacent distance between the floor panel and the bottom shell; and
at least a pair of membrane elements of bulgy shape; each membrane element laterally protruding to the outside of the longitudinal support beams one each side of the subfloor structure; each membrane element being provided with an upper longitudinal hem attached to said longitudinal support beams and a lower longitudinal hem attached to the bottom shell; the membrane elements being attached to the longitudinal support beams for purely two-dimensional loading of the membrane elements.

2. The airframe according to claim 1 , wherein each membrane element laterally extends beyond the upper longitudinal hem and a lower longitudinal hem into a free volume; each membrane element of bulgy shape having an upwardly transversal C shape having a hollow side turned towards an interior of the subfloor structure.

3. The airframe according to claim 1 , wherein the membrane element is made of a flexible or semi-rigid material, the material comprising at least one one of fabric, cloth, mesh, plastic, and fiber reinforced plastic, the material featuring a thickness of 0.1 mm to 3 mm.

4. The airframe according to claim 1 , wherein the planes of the ribs and/or the main frames extending essentially perpendicular to the longitudinal support beams are orthogonal or slanted with regard to the essentially horizontal plane of the floor panels.

5. The airframe according to claim 1 , wherein end panels are provided in the essentially horizontal plane of the floor panels essentially longitudinally along a top end of the two lateral shell portions.

6. The airframe according to claim 5 , each end panel being integral respectively with one of the two lateral shell portions and pointing towards an inside of the subfloor structure.

7. The airframe according to claim 1 , wherein the longitudinal support beams are functionally and physically integrated within the curved lateral shell portions of the bottom shell without any interruptions.

8. The airframe according to claim 1 , wherein the ribs are continuous and extend from the flat shell portion of the bottom shell to the floor panels and laterally enclose the whole width of the bottom shell being attached to their lateral curved shell portions.

9. The airframe according to claim 1 , wherein the main frames are continuous and extend from the flat shell portion of the bottom shell to the floor panels and laterally enclose the whole width of the bottom shell being attached to their lateral curved shell portions.

10. The airframe according to claim 1 , wherein intermediate lateral ribs are provided supporting end panels, lateral curved shell portions and/or the longitudinal support beams.

11. The airframe according to claim 1 , wherein at least one flat tank separation web is provided extending from the flat shell portion of the bottom shell to the floor panels and longitudinally between the ribs and/or the main frames.

12. The airframe according to claim 1 , wherein seat rails are provided allocated coincident to the longitudinal support beams and are integrated to the longitudinal beams.

13. A rotary wing aircraft including an airframe according to claim 1 , wherein at least a longitudinal section of the structure is longerons free.

14. A rotary wing aircraft including an airframe according to claim 1 , wherein the structure is longerons free all along the length of the structure, in the longitudinal axis of the airframe.

15. An airframe for a rotary wing aircraft comprising:
a bottom shell having a flat shell portion and two curved lateral shell portions, each lateral shell portion extending outwardly from the flat shell portion;
a series of ribs and main frames extending in planes perpendicular to a longitudinal axis of the rotary wing aircraft and on one side of the shell, each rib and main frame having a flat top edge positioned on an end of the rib and main frame opposite to the bottom shell, wherein the two lateral curved shell portions are curved towards respective lateral borders of the series of ribs and main frames;
floor panels in a horizontal plane parallel to the longitudinal axis and on the one side of the shell, the floor panels mounted to the flat top edges of the ribs and main frames, wherein the bottom shell, the series of ribs and main frames, and the floor panels cooperate to form a subfloor structure to support cabin floor panels;
first and second longitudinal support beams, each longitudinal support beam extending along the longitudinal axis and along at least a longitudinal section of the subfloor structure, each longitudinal support beam having an upper region with attachments for the floor panels, each longitudinal support beam having a series of front flanges spaced apart from one another and extending from the floor panels to the bottom shell, each longitudinal support beam having a height between adjacent front flanges being 2 to 20 times smaller than a height of an adjacent front flange such that an opening is defined within the region, each longitudinal support beam being connected to at least one of the ribs and main frames;
first and second membrane elements, each membrane element having an upper longitudinal hem connected to the upper region of a respective longitudinal support beam and a lower longitudinal hem connected to the bottom shell for purely two-dimensional loading of the membrane element, each membrane element having a C-shaped cross sectional shape with a concave hollow side, the concave hollow sides of the first and second membrane elements facing one another, each membrane element protruding towards an adjacent lateral curved shell portion.

16. The airframe according to claim 15 wherein the first and second membrane elements are disconnected from adjacent ribs and main frames.

17. The airframe according to claim 15 wherein a fuel tank compartment is defined between the first and second membrane elements, the bottom shell, and the floor panels; the airframe further comprising:
a fuel tank bladder positioned within the fuel tank compartment, the fuel tank bladder resting on the flat shell portion of the bottom shell and on the first and second membrane elements.

Assignees

• Airbus Helicopters Deutschland GmbH

Inventors

• Fink Axel
• Steindl Christoph

Classifications

• B64C1/18 Primary

  Floors · CPC title

• B64D37/04

  Arrangement thereof in or on aircraft · CPC title

• B64D37/06

  Constructional adaptations thereof · CPC title

• B64C27/04

  Helicopters · CPC title

• Y02T50/44

  Cross-Sectional Technologies · mapped topic