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EP-4741282-A1 - A ROTARY WING AIRCRAFT WITH A FIREWALL ARRANGEMENT LOCATED ABOVE AN UPPER PRIMARY SKIN THAT COMPRISES A POLYMERIC COMPOSITE

EP4741282A1EP 4741282 A1EP4741282 A1EP 4741282A1EP-4741282-A1

Abstract

The invention relates to a rotary wing aircraft with a fuselage that includes an upper primary skin (2c) which comprises a polymeric composite, and with an aircraft upper deck (6) arranged above the fuselage; wherein the aircraft upper deck (6) comprises an engine accommodating region (7) that accommodates at least one aircraft engine (11b) within a firewall arrangement that comprises at least one lower firewall (30b) arranged above the upper primary skin (2c) of the fuselage and spaced apart from the upper primary skin (2c); wherein the at least one lower firewall (30b) includes at least a lower firewall panel (40) and a high emissivity panel covering layer (43a) that covers the lower firewall panel (40) and comprises a high emissivity of at least 0.7; and wherein the high emissivity panel covering layer (43a) is facing the at least one aircraft engine (11b).

Inventors

  • KEMPF, Manuel
  • FINK, AXEL
  • Walch, Philipp
  • SPECHT, Luca
  • Dosch, Valerie
  • Pritzkow, Walter
  • Gauthier, Loïc

Assignees

  • AIRBUS HELICOPTERS DEUTSCHLAND GmbH
  • Airbus Helicopters

Dates

Publication Date
20260513
Application Date
20241106

Claims (15)

  1. A rotary wing aircraft (1) with a fuselage (2) that comprises an upper primary skin (2c) and forms an aircraft interior region (2a, 2b), the upper primary skin (2c) comprising a polymeric composite, in particular a carbon fiber reinforced polymer, and separating the aircraft interior region (2a, 2b) from an aircraft upper deck (6) arranged above the fuselage (2); wherein the aircraft upper deck (6) comprises an engine accommodating region (7) with a firewall arrangement (10), the engine accommodating region (7) accommodating at least one aircraft engine (11b) within the firewall arrangement (10) such that the firewall arrangement (10) defines a fire proof separation at least between the at least one aircraft engine (11b) and the aircraft interior region (2a, 2b); wherein the firewall arrangement (10) comprises at least one lower firewall (30b) that is arranged between the at least one aircraft engine (11b) and the upper primary skin (2c) of the fuselage (2), the at least one lower firewall (30b) being spaced apart from the upper primary skin (2c) by a first predetermined separation distance (41) and from the at least one aircraft engine (11b) by a second predetermined separation distance (42); wherein the at least one lower firewall (30b) includes at least a lower firewall panel (40) and a high emissivity panel covering layer (43a) that covers the lower firewall panel (40) and comprises a high emissivity of at least 0.7; and wherein the high emissivity panel covering layer (43a) is facing the at least one aircraft engine (11b).
  2. The rotary wing aircraft (1) of claim 2, wherein the high emissivity panel covering layer (43a) comprises at least one of black polytetrafluorethylene, black polyetheretherketone, black ceramic coating, or black paint, coating, or high-temperature resin with carbon particles.
  3. The rotary wing aircraft (1) of claim 1 or 2, wherein the at least one lower firewall (30b) further comprises a low emissivity panel covering layer (43b) that covers the lower firewall panel (40) and comprises a low emissivity of maximally 0.4, and wherein the low emissivity panel covering layer (43b) is facing the upper primary skin (2c).
  4. The rotary wing aircraft (1) of claim 3, wherein the low emissivity panel covering layer (43b) comprises a thickness in a range from 100 nm to 50 µm.
  5. The rotary wing aircraft (1) of claim 3 or 4, wherein the low emissivity panel covering layer (43b) comprises a metallic coating, in particular aluminum, chromium, silver, or gold, or a combination of two or more metallic coatings.
  6. The rotary wing aircraft (1) of claim 5, wherein metallization of the low emissivity panel covering layer (43b) results from application of physical vapor deposition.
  7. The rotary wing aircraft (1) of any one of the preceding claims, wherein the upper primary skin (2c) comprises a low emissivity skin covering layer (43c) that covers the upper primary skin (2c) and comprises a low emissivity of maximally 0.4, and wherein the low emissivity skin covering layer (43c) is facing the at least one lower firewall (30b).
  8. The rotary wing aircraft (1) of claim 7, wherein the low emissivity skin covering layer (43c) comprises a metallic coating, in particular aluminum, chromium, silver, or gold.
  9. The rotary wing aircraft (1) of claim 7, wherein the low emissivity skin covering layer (43c) comprises white paint.
  10. The rotary wing aircraft (1) of claim 7, wherein the low emissivity skin covering layer (43c) comprises a metallic foil, film or tape, in particular a self-adhesive aluminum foil, film or tape.
  11. The rotary wing aircraft (1) of claim 7, wherein the low emissivity skin covering layer (43c) comprises a paint, in particular a metallic paint, or resin with metallic particles.
  12. The rotary wing aircraft (1) of any one of the preceding claims, wherein the lower firewall panel (40) is a monolithic panel that comprises fiber-reinforced ceramics.
  13. The rotary wing aircraft (1) of any one of the preceding claims, wherein the lower firewall panel (40) comprises a thickness in a range from 1 mm to 6 mm.
  14. The rotary wing aircraft (1) of any one of the preceding claims, wherein the first predetermined separation distance (41) amounts at least to 20 mm.
  15. The rotary wing aircraft (1) of any one of the preceding claims, wherein the at least one lower firewall (30b) is funnel-shaped and converges from an outer perimeter (31) to at least one inner collecting point (33).

Description

The present invention relates to a rotary wing aircraft with a fuselage that forms an aircraft interior region, the fuselage comprising an upper primary skin that separates the aircraft interior region from an aircraft upper deck arranged above the fuselage, wherein the aircraft upper deck comprises an engine accommodating region with a firewall arrangement, the engine accommodating region accommodating at least one aircraft engine within the firewall arrangement such that the firewall arrangement defines a fire proof separation at least between the at least one aircraft engine and the aircraft interior region. In a rotary wing aircraft, such as a small or medium-size helicopter, an associated fuselage typically comprises an upper primary skin that separates an aircraft interior region, which is formed by the fuselage, from an aircraft upper deck arranged above the fuselage. The aircraft interior region usually accommodates at least a cockpit and may further accommodate a cabin for passengers and/or cargo. The aircraft upper deck generally includes an engine accommodating region that accommodates one or more engines, typically air breathing gas turbines, and that is, therefore, also referred to as the "engine deck". The one or more engines are adapted for driving the rotary wing aircraft, e. g. by providing power to an associated power distribution unit, such as a gear box, which then provides this power to a suitable propelling unit, such as e. g. a rotor, propeller or other. Typically, the engines are arranged outside of the aircraft interior region, on top of the fuselage and close to the other main components of a respective powerplant, the main gear box and the main rotor. This is crucial for the entire aircraft performance, safety and reliability. According to airworthiness certification regulations, the engine deck of a given rotary wing aircraft must be fire proof in a fire event. Basically, each engine has to be isolated from the rest of the rotary wing aircraft and the engine deck has to be designed such as to prevent corrosion and to prevent hazardous substances passing from a respective engine compartment to other parts of the rotary wing aircraft. Moreover, an associated primary structure enclosed within the engine compartment has to be capable of sustaining limit load during a fire event of 15 min of duration. Adequate assumptions have to be made regarding a possible size and location of damage on the primary structure of the rotary wing aircraft. No burn through or backside flame ignition is acceptable and respectively employed materials must behave self-extinguishing after flame exposure. These measures are independent of additional fire extinguishing systems. In particular, the engine deck must be capable of sustaining service temperatures without deterioration of load carrying or fire proof capabilities. Respective operating temperatures acting on the aircraft upper deck as a whole are a result of the heat radiation of the engines and are essentially a function of the location within the engine compartment, the engine proximity, the compartment design and the engine characteristics among others. Typically, higher temperatures are present at the rear section of the engine compartment close to an associated engine combustion chamber and an associated exhaust. In fact, typical operating temperatures of the engine deck range from about 70 °C to 300 °C. As a result, each engine compartment and, more generally, the engine deck as a whole is equipped with a suitable firewall arrangement which forms a fire protection zone. The fire protection zone accommodates the engines within the firewall arrangement such that the firewall arrangement defines a fire proof separation between the engines, towards the forward and aft regions of the engine deck and the aircraft interior region formed by the fuselage of a given rotary wing aircraft. More specifically, a firewall arrangement in an engine deck may be delimited by a lower firewall located above the upper primary skin of the fuselage, as well as by a front firewall, a rear firewall, and a cowling that represents an upper loft of a given rotary wing aircraft and covers the engine deck. If the rotary wing aircraft is a twin-engine aircraft, both engines are usually separated from each other by a center firewall protecting both engines from each other. In any case, the engines are attached to the upper primary skin and corresponding framework members such as beams or frames by means of several engine mounts. The front firewall and the rear firewall represent a barrier to respective front and rear portions of a given aircraft upper deck. The cowling is usually at least partially removable to provide access to the engines. An illustrative firewall arrangement is described in the document EP 3 932 801 B1. More generally, the document EP 3 932 801 B1 describes a rotary wing aircraft with a fuselage that forms an aircraft interior region, the fuselage comprisin