Helicopter main rotor blade balance weight retention assembly
A helicopter main rotor blade balance weight retention system and assembly having a base plate ( 105 ), at least one support post ( 107 ) integral with the base plate and extending out perpendicularly from the base plate, a plurality of balance weights ( 109 ), a retaining nut plate ( 111 ), and one or more fastening bolts ( 113 ) for securing the balance weights to the base plate, and the base plate to the rotor blade. The balance weights ( 109 ) include apertures ( 117, 119 ) through which the support posts and the fastening bolts pass. The apertures through which the support posts pass are dimensioned such that the a snug fit is formed between the support posts and the balance weight; but the apertures through which the fastening bolts pass are dimensioned such that the threaded portions of the fastening bolts are not subjected to any shear loads from the balance weights due to the centrifugal force generated by the rotating rotor blades. The weight retention assembly is installed into pockets in the blade tip.
1. A rotor blade balance weight retention assembly comprising:
a base plate adapted for installation within a pocket in a rotor blade having upper and lower airfoil surfaces, the pocket being open to one of the airfoil surfaces;
at least one support post extending up from the base plate;
at least one balance weight stacked upon the base plate;
a retaining plate stacked upon the uppermost balance weight; and
at least one fastener for coupling the base plate, the balance weights, and the retaining plate together, the fastener passing through the other of the airfoil surfaces;
wherein the support post prevents the balance weight from contacting the fastener.
2. The rotor blade balance weight retention assembly according to claim 1 , further comprising:
a fastener receiver coupled to the retaining plate for receiving the fastener.
3. The rotor blade balance weight retention assembly according to claim 1 , further comprising:
a cover adapted to enclose the pocket, the cover being configured to match the contour of the rotor blade.
4. The rotor blade balance weight retention assembly according to claim 3 , wherein the cover is configured to match the contour of the upper airfoil surface of the rotor blade.
5. The rotor blade balance weight retention assembly according to claim 3 , wherein the cover is configured to match the contour of the lower airfoil surface of the rotor blade.
6. A helicopter main rotor balance weight retention system comprising:
a rotor blade having an inboard root end, an opposing outboard blade tip, a leading edge, an opposing trailing edge, an upper airfoil surface, and an opposing lower airfoil surface;
a first pocket disposed within the rotor blade at the blade tip; and
a first balance weight retention assembly disposed within the first pocket comprising:
a base plate coupled to the rotor blade;
at least one support post extending perpendicularly from the base plate;
at least one balance weight stacked upon the base plate, the balance weight having a support aperture aligned with each support post, each support aperture being dimensioned to snugly receive each corresponding support post, and at least one fastener aperture;
a retaining plate stacked upon the uppermost balance weight for preventing movement of the balance weights relative to the base plate, the retaining plate having a support aperture aligned with each support post, each support aperture being dimensioned to snugly receive each corresponding support post, and at least one fastener receiver;
at least one fastener for coupling the base plate, the balance weights, and the retaining plate together, the fastener being releasably received by the fastener receiver; and
a cover releasably coupled to the rotor blade for enclosing the first pocket;
wherein the first pocket is open to the one of the airfoil surfaces, and the fastener passes through the other of the airfoil surfaces.
7. The helicopter main rotor balance weight retention system according to claim 6 , further comprising:
a fine adjustment balance weight retention assembly disposed within the first pocket, the fine adjustment balance weight retention assembly comprising:
a base plate coupled to the rotor blade;
at least one balance weight stacked upon the base plate;
a retaining plate stacked upon the uppermost balance weight for preventing movement of the balance weights relative to the base plate;
at least one fastener for coupling the base plate, the balance weights, and the retaining plate together.
8. The helicopter main rotor balance weight retention system according to claim 6 , further comprising:
a second pocket disposed within the rotor blade at the blade tip, the second pocket being located closer to the trailing edge than the first pocket;
a second balance weight retention assembly disposed within the second pocket, the second balance weight retention assembly comprising:
a base plate coupled to the rotor blade;
at least one support post extending perpendicularly from the base plate;
at least one balance weight stacked upon the base plate, the balance weight having a support aperture aligned with each support post, each support aperture being dimensioned to snugly receive each corresponding support post, and at least one fastener aperture;
a retaining plate stacked upon the uppermost balance weight for preventing movement of the balance weights relative to the base plate, the retaining plate having a support aperture aligned with each support post, each support aperture being dimensioned to snugly receive each corresponding support post, and at least one fastener receiver;
at least one fastener for coupling the base plate, the balance weights, and the retaining plate together, the fastener being releasably received by the fastener receiver; and
a cover releasably coupled to the rotor blade for enclosing the second pocket.
9. The helicopter main rotor balance weight retention system according to claim 8 , further comprising:
a fine adjustment balance weight retention assembly disposed within the first pocket, the fine adjustment balance weight retention assembly comprising:
a base plate coupled to the rotor blade;
at least one balance weight stacked upon the base plate;
a retaining plate stacked upon the uppermost balance weight for preventing movement of the balance weights relative to the base plate;
at least one fastener for coupling the base plate, the balance weights, and the retaining plate together.
10. The helicopter main rotor balance weight retention system according to claim 9 , wherein the fine adjustment balance weight retention assembly is aligned with the first balance weight retention assembly.
11. The helicopter main rotor balance weight retention system according to claim 10 , wherein the fine adjustment balance weight retention assembly is located inboard of the first balance weight retention assembly.
12. A helicopter main rotor balance weight retention system comprising:
a rotor blade having an inboard root end, an opposing outboard blade tip, a leading edge, an opposing trailing edge, an upper airfoil surface, and an opposing lower airfoil surface;
a first pocket disposed within the rotor blade at the blade tip; and
a first balance weight retention assembly disposed within the first pocket comprising:
a base plate coupled to the rotor blade;
at least one support post extending perpendicularly from the base plate;
at least one balance weight stacked upon the base plate, the balance weight having a support aperture aligned with each support post, each support aperture being dimensioned to snugly receive each corresponding support post, and at least one fastener aperture;
a retaining plate stacked upon the uppermost balance weight for preventing movement of the balance weights relative to the base plate, the retaining plate having a support aperture aligned with each support post, each support aperture being dimensioned to snugly receive each corresponding support post, and at least one fastener receiver;
at least one fastener for coupling the base plate, the balance weights, and the retaining plate together, the fastener being releasably received by the fastener receiver; and
a cover releasably coupled to the rotor blade for enclosing the first pocket;
wherein the first pocket is open to the upper airfoil surface, the fastener passes through the lower airfoil surface, and the cover is configured to match the contour of the upper airfoil surface.
13. A helicopter main rotor balance weight retention system comprising:
a rotor blade having an inboard root end, an opposing outboard blade tip, a leading edge, an opposing trailing edge, an upper airfoil surface, and an opposing lower airfoil surface;
a first pocket disposed within the rotor blade at the blade tip; and
a first balance weight retention assembly disposed within the first pocket comprising:
a base plate coupled to the rotor blade;
at least one support post extending perpendicularly from the base plate;
at least one balance weight stacked upon the base plate, the balance weight having a support aperture aligned with each support post, each support aperture being dimensioned to snugly receive each corresponding support post, and at least one fastener aperture;
a retaining plate stacked upon the uppermost balance weight for preventing movement of the balance weights relative to the base plate, the retaining plate having a support aperture aligned with each support post, each support aperture being dimensioned to snugly receive each corresponding support post, and at least one fastener receiver;
at least one fastener for coupling the base plate, the balance weights, and the retaining plate together, the fastener being releasably received by the fastener receiver; and
a cover releasably coupled to the rotor blade for enclosing the first pocket;
wherein the first pocket is open to the lower airfoil surface, the fastener passes through the upper airfoil surface, and the cover is configured to match the contour of the lower airfoil surface.
14. A helicopter comprising:
a fuselage;
a drive means carried by the fuselage for actuating a drive mast;
at least one rotor yoke coupled to the drive mast;
a plurality of rotor blades coupled to the rotor yokes, each rotor blade having an inboard root end, an opposing outboard blade tip, an upper airfoil surface, and an opposing lower airfoil surface;
a pocket disposed in the rotor blade at the blade tip, the pocket being open to one of the airfoil surfaces;
a base plate disposed within the pocket and coupled to the rotor blade;
at least one support post extending perpendicularly from the base plate;
at least one balance weight stacked upon the base plate, the balance weight having a support aperture aligned with each support post, each support aperture being dimensioned to snugly receive each corresponding support post, and at least one fastener aperture;
a retaining plate stacked upon the uppermost balance weight for preventing movement of the balance weights relative to the base plate, the retaining plate having a support aperture aligned with each support post, each support aperture being dimensioned to snugly receive each corresponding support post, and at least one fastener receiver;
at least one fastener for coupling the base plate, the balance weights, and the retaining plate together, the fastener passing through the other of the airfoil surfaces and being releasably received by the fastener receiver; and
a cover releasably coupled to the rotor blade for enclosing the pocket, the cover being configured to match the contour of the upper airfoil surface.