Five component strain gauge balance
AssigneeMcDonnell Douglas Corporation
InventorRoy L. Jones
Life of this patent
Estimating the term…
Abstract
A five-component strain gauge balance for measuring the forces and moments exerted on a reflection plane model aircraft in a subsonic continuous-duty or blow down wind tunnel. The balance beams are arranged in a diamond pattern so that the rolling moment reactions are concentrated in the side beams making the axial force, normal force and yawing moment felt by the forward and aft beams more accurately measurable. The entire balance is machined from a single piece of material, ensuring maximum repeatability of measurements. This design also simplifies fabrication and provides better access for gauging.
Claims8
A balance for measuring forces and moments exerted on a test article in a fluid flow field comprising:
- an upper member having a first upper surface and an opposite first lower surface attached to said test article, the plane of attachment of said upper surface of said upper member and said test article being generally in the plane of said fluid flow field lower boundary,
- a lower member having a second upper surface and an opposite second lower surface attached to a fixed structure, said first upper surface and said second lower surface being symmetrically disposed about a plane parallel thereto,
- a forward beam, an aft beam, and two side beams arranged in a diamond pattern in relation to the direction of fluid flow, connecting said upper and lower members, said forward and aft surfaces of said beams being perpendicular to the direction of fluid flow and wherein the side surfaces of said beams are parallel to the direction of flow to form beams of rectangular cross section when viewed from the top,
- a strain gauge attached to each beam for measuring the strain of each beam, and
- at least one flexure forward of, and at least one flexure aft of each side beam, each flexure connecting said upper and lower members.
A balance for measuring forces and moments exerted on an aircraft model in a wind tunnel wherein half of a model is mounted with the wing in the vertical plane, and with the fuselage half in close proximity to the wind tunnel floor and attached to the top of said balance, comprising,
- an upper member rigidly attached to said model,
- a lower member attached to the wind tunnel structure,
- a forward beam, an aft beam and two side beams arranged in a diamond pattern in relation to the direction of air flow in said wind tunnel rigidly connecting said upper and lower members,
- at least one strain gauge attached to each beam for measuring the strain of each beam, and
- at least one flexure forward of, and at least one flexure aft of, each side beam, each flexure rigidly attached to said upper and lower members.
Dependencies are inferred from the claim text.