Ram door assemblies

1. A ram door assembly for an intake opening of an intake duct of an auxiliary power unit of an aircraft; comprising:

a ram door hingeably mounted adjacent to the intake opening and moveable between an open position and a closed position, the ram door having an interior surface and an exterior surface; and

a fairing positioned on the interior surface of the ram door.

2. The ram door assembly of claim 1 , wherein the fairing is configured to smoothly direct air into the intake duct when the ram door is in the open position.

3. The ram door assembly of claim 1 , wherein the interior surface has an inner area adjacent an aft edge and an outer area adjacent the forward edge, and wherein the fairing is positioned on the inner area of the interior surface of the ram door.

4. The ram door assembly of claim 1 , wherein the forward section extends generally at a first angle from the ram door and the aft section extends generally at a second angle to the ram door, the second angle being greater than the first angle.

5. The ram door assembly of claim 1 , wherein the forward section is generally concave.

6. The ram door assembly of claim 1 , wherein the fairing is generally asymmetrical about a longitudinal axis.

7. The ram door assembly of claim 1 , wherein the fairing is configured to reduce drag on the ram door.

8. The ram door assembly of claim 1 , further comprising first, second, and third side plates extending from the interior surface of the ram door, the fairing comprising a first portion arranged between the first and second side plates and a second portion arranged between the second and third side plates.

9. An assembly for an aircraft, comprising:

an auxiliary power unit;

an intake duct configured to deliver an airflow to the auxiliary power unit, the intake duct having a first end coupled to the auxiliary power unit and a second end defining an intake opening;

a ram door assembly comprising a ram door hingeably mounted adjacent to the intake opening and moveable between an open position and a closed position, the ram door having an interior surface and an exterior surface; and

a fairing positioned on the interior surface of the ram door,

wherein the fairing has a forward section that extends up from the ram door, a generally arcuate transition section, and an aft section that extends down to the ram door, and

wherein the forward section extends generally at a first angle from the ram door and the aft section extends generally at a second angle to the ram door, the second angle being greater than the first angle.

10. The assembly of claim 9 , wherein the fairing is configured to smoothly direct air into the intake duct when the ram door is in the open position.

11. The assembly of claim 9 , wherein the interior surface has an inner area adjacent an aft edge and an outer area adjacent the forward edge, and wherein the fairing is positioned on the inner area of the interior surface of the ram door.

12. The assembly of claim 9 , wherein the forward section is more tapered than the aft section.

13. The assembly of claim 9 , wherein the forward section is generally concave.

14. The ram door assembly of claim 9 , wherein the fairing is generally asymmetrical about a longitudinal axis.

15. The assembly of claim 9 , further comprising first, second, and third side plates extending from the interior surface of the ram door, the fairing comprising a first portion extending between the first and second side plates and a second portion extending between the second and third side plates.

16. A ram door assembly for an intake opening of an intake duct of an auxiliary power unit of an aircraft; comprising:

a ram door hingeably mounted adjacent to the intake opening of the auxiliary power unit and moveable between an open position and a closed position, the ram door having an interior surface and an exterior surface; and

a fairing positioned on the interior surface of the ram door,

further comprising first, second, and third side plates extending from the interior surface of the ram door, the fairing comprising a first fairing portion arranged between the first and second side plates and a second fairing portion arranged between the second and third side plates.