Fail-safe engine support system
An engine support mount including an airframe structure having a first anchor surface and a length extending along an x-axis, with a second axis defined perpendicularly to the x-axis. A support member is fixed to the airframe structure and defines a first aperture and a second aperture. A mounting assembly includes an elongated arm and first and second primary attachment assemblies respectively attaching the arm to the support member at the first and second apertures, the arm having a second anchor surface. A moment arm reduction feature includes a lug fixed to one of the anchor surfaces and a corresponding fastener fixed to the other of the anchor surfaces. The first anchor surface is positioned on the airframe structure outside of the first and second apertures, and the second anchor surface is positioned on the arm outside of the first and second attachment assemblies.
1. An engine support mount for supporting an engine having a casing, the mount comprising:
an airframe structure having a length that extends along an x-axis, with a second axis being defined perpendicularly to the x-axis, the airframe structure comprising a first anchor surface;
a support member fixed to the airframe structure and comprising a first lug spaced from the first anchor surface along the second axis;
a mounting assembly comprising an elongated arm and a primary attachment assembly attaching the arm to the first lug, the elongated arm comprising a second anchor surface spaced from the primary attachment assembly along the second axis; and
a moment arm reduction feature comprising a second lug and a corresponding fastener, the second lug being fixed to one of the anchor surfaces and the fastener being fixed to the other of the anchor surfaces,
the fastener having a diameter,
the second lug defining an aperture having a diameter,
the fastener extending through the aperture,
the diameter of the aperture being over-sized so that a load-bearing path is not established between the fastener and the second lug during normal operation.
2. The engine support mount of claim 1 , wherein the diameter of the aperture is over-sized to a pre-determined degree.
3. The engine support mount of claim 1 , further comprising—
a thrust assembly comprising: (A) a thrust load link fixed to the arm and to the airframe structure, (B) a thrust pin comprising a main shaft and a flange head and having a length extending perpendicularly to the x-axis, (C) a fitting fixed to the casing, and (D) a resilient interface fixed to the fitting and defining a second aperture therethrough,
the thrust pin being fixed to the arm,
the main shaft extending through the second aperture to restrict movement of the thrust pin relative to the casing along the x-axis,
a first gap being defined between a first face of the flange head and an opposing surface of the casing,
a second gap being defined between a second face of the flange head and an opposing surface of the resilient interface.
4. The engine support mount of claim 3 , wherein the first gap and the second gap are of pre-determined sizes.
5. The engine support mount of claim 1 , wherein—
the first lug defines a second aperture,
the arm comprises spaced third and fourth lugs respectively defining third and fourth apertures aligned along the x-axis with the second aperture,
the primary attachment assembly comprises a fastener having a length extending along the x-axis and through the aligned second, third and fourth apertures to attach the arm to the first lug,
the third lug is spaced from the first lug along the x-axis by a gap of pre-determined size so that a thrust load-bearing path is not established along the x-axis between the third lug and the first lug during normal operation.
6. The engine support mount of claim 5 , wherein the gap is of pre-determined size.
7. The engine support mount of claim 1 , further comprising an engine link assembly comprising a second fastener and a link comprising a first portion, a second portion and a third portion defining a second aperture, wherein—
the first portion is attached to the arm and the second portion is attached to the engine casing,
the engine casing defines a third aperture,
the second fastener extends through the second aperture and the third aperture,
the second aperture is over-sized so that a load-bearing path is not established between the second fastener, the engine casing and the third portion of the link during normal operation.
8. An engine support mount for supporting an engine having a casing, the mount comprising:
an airframe structure having a length that extends along an x-axis, with a second axis being defined perpendicularly to the x-axis, the airframe structure comprising a first anchor surface;
a support member fixed to the airframe structure and defining a first aperture and a second aperture spaced from the first aperture along the second axis;
a mounting assembly comprising: (A) an elongated arm comprising a second anchor surface, and (B) first and second primary attachment assemblies respectively attaching the arm to the support member at the first and second apertures; and
a moment arm reduction feature comprising a lug and a corresponding fastener, the lug being fixed to one of the anchor surfaces and the fastener being fixed to the other of the anchor surfaces,
the first anchor surface being positioned on the airframe structure outside of the first and second apertures along the second axis,
the second anchor surface being positioned on the arm outside of the first and second attachment assemblies along the second axis.
9. The engine support mount of claim 8 , wherein—
the fastener has a diameter,
the lug defines a third aperture having a diameter,
the fastener extends through the third aperture,
the diameter of the third aperture is over-sized to a pre-determined degree so that a load-bearing path is not established between the fastener and the lug during normal operation.
10. The engine support mount of claim 8 , further comprising—
a thrust assembly comprising: (A) a thrust load link fixed to the arm and to the airframe structure, (B) a thrust pin comprising a main shaft and a flange head and having a length extending perpendicularly to the x-axis, (C) a fitting fixed to the casing, and (D) a resilient interface fixed to the fitting and defining a third aperture therethrough,
the thrust pin being fixed to the arm,
the main shaft extending through the third aperture to restrict movement of the thrust pin relative to the casing along the x-axis,
a first gap being defined between a first face of the flange head and an opposing surface of the casing,
a second gap being defined between a second face of the flange head and an opposing surface of the resilient interface.
11. The engine support mount of claim 10 , wherein the first gap and the second gap are of pre-determined sizes.
12. The engine support mount of claim 8 , wherein—
the support member includes a second lug that defines the first aperture,
the arm comprises spaced third and fourth lugs respectively defining third and fourth apertures aligned along the x-axis with the first aperture,
the primary attachment assembly comprises a fastener having a length extending along the x-axis and through aligned first, third and fourth apertures to attach the arm to the second lug,
the third lug is spaced from the second lug along the x-axis by a gap of pre-determined size so that a thrust load-bearing path is not established along the x-axis between the third lug and the second lug during normal operation.
13. The engine support mount of claim 12 , wherein the gap is of a pre-determined size.
14. The engine support mount of claim 8 , further comprising an engine link assembly comprising a second fastener and a link comprising a first portion, a second portion and a third portion defining a third aperture, wherein—
the first portion is attached to the arm and the second portion is attached to the engine casing,
the engine casing defines a fourth aperture,
the second fastener extends through the third aperture and the fourth aperture,
the third aperture is over-sized so that a load-bearing path is not established between the second fastener, the engine casing and the third portion of the link during normal operation.
15. An engine support mount for supporting an engine having a casing, the mount comprising:
an airframe structure comprising a first anchor surface and having a length that extends along an x-axis, with a second axis being defined perpendicularly to the x-axis;
a support member fixed to the airframe structure and defining an aperture;
a mounting assembly comprising: (A) an elongated arm comprising a second anchor surface, and (B) a primary attachment assembly attaching the arm to the support member at the aperture;
an engine link assembly comprising a link comprising a first portion and a second portion, the first portion being attached to the arm and the second portion being attached to the engine casing; and
a moment arm reduction feature comprising a lug and a corresponding fastener, the lug being fixed to one of the anchor surfaces and the fastener being fixed to the other of the anchor surfaces,
at least a portion of each of the anchor surfaces being positioned closer to the link than to the primary attachment assembly along the second axis.
16. The engine support mount of claim 15 , wherein—
the fastener has a diameter,
the lug defines a second aperture having a diameter,
the fastener extends through the second aperture,
the diameter of the second aperture is over-sized to a pre-determined degree so that a load-bearing path is not established between the fastener and the lug during normal operation.
17. The engine support mount of claim 15 , further comprising—
a thrust assembly comprising: (A) a thrust load link fixed to the arm and to the airframe structure, (B) a thrust pin comprising a main shaft and a flange head and having a length extending perpendicularly to the x-axis, (C) a fitting fixed to the casing, and (D) a resilient interface fixed to the fitting and defining a second aperture therethrough,
the thrust pin being fixed to the arm,
the main shaft extending through the second aperture to restrict movement of the thrust pin relative to the casing along the x-axis,
a first gap being defined between a first face of the flange head and an opposing surface of the casing,
a second gap being defined between a second face of the flange head and an opposing surface of the resilient interface.
18. The engine support mount of claim 17 , wherein the first gap and the second gap are of pre-determined sizes.
19. The engine support mount of claim 15 , wherein—
the support member includes a second lug that defines the first aperture,
the arm comprises spaced third and fourth lugs respectively defining second and third apertures aligned along the x-axis with the first aperture,
the primary attachment assembly comprises a fastener having a length extending along the x-axis and through aligned first, second and third apertures to attach the arm to the second lug,
the third lug is spaced from the second lug along the x-axis by a gap of pre-determined size so that a thrust load-bearing path is not established along the x-axis between the third lug and the second lug during normal operation.
20. The engine support mount of claim 19 , wherein the gap is of a pre-determined size.