Wind Tunnel Balance Correction for Structural Motion Effects

ABSTRACT: M4 Engineering proposes to develop a method for accurately correcting dynamic wind tunnel force measurements by removing components due to inertia and aeroelasticity. This effort will effectively utilize novel sensors to determine inertial loads due to excitation of multiple structural dynamic modes resulting from a broadband loading environment. Methods for system identification and optimal estimation will be included within this development. This work will include demonstration of the proposed technology on a hardware prototype CTS system. The proposed development will create an excellent compliment to modern test and analysis methods. BENEFIT: The new technology developed in this Phase II SBIR will be hardware and software for correcting wind tunnel data for balance motion. The hardware component of the product will be a balance assembly including additional sensors such as accelerometers and gyroscopes in addition to conventional strain gauges. M4 Engineering has initiated discussion with Triumph Aerospace Systems regarding the fabrication of such unique balance hardware. The software that will be developed consists of methods that will be used to accept the output from the hardware and compute the model motion and the associated inertial, aeroelastic, and rigid aerodynamic loads. The first product that this new technology will go into will be wind tunnel instrumentation that measures forces and moments. This type of instrumentation is usually defined as sting balance assemblies. Initial customers will be the Defense Agencies and its contractors. Defense Agencies would include Air Force, NASA, and Navy; and contractors will include Boeing, Lockheed Martin, and Northrop Grumman. These customers are those involved in developing, testing, and/or certifying aerospace vehicles. There are numerous universities performing aerodynamic research and development which are also our potential customers. Customer interaction will ensure development of capability which industry needs. M4 Engineering has begun discussion of this technology with Boeing, Lockheed Martin, and Northrop Grumman. Because this technology will be used in wind tunnel instrumentation, other customers will be those who develop and manufacture wind tunnel instrumentation. While it is important to target customers who are interested in using this technology, it is also important to understand the number of facilities available to conduct wind tunnel testing. While there are certainly wind tunnels worldwide, our initial market research focuses on the United States and Canada. As our technology matures, there will be opportunities to market to the rest of the world. There are 97 major wind tunnels in the United States and Canada. Discriminators are size, accuracy, and other considerations such as whether the balance is a 3-component (normal force, axial force, and pitching moment) or a 6-component (normal force, axial force, pitching moment, side force, yawing moment, and rolling moment). These market size numbers are conservative because there are many other facilities not accounted for since they are not considered major. And there are many other universities conducting aeronautical research. This technology is capable of being used in all wind tunnels not just those considered major. Our technology enhances existing balance capability and the market size estimate is based on figures for existing balances.