I am busy studying engineering and I have a subject that requires us to design and build a working instrument using strain gauges. We have a workshop at our disposal and all necessary materials and electronics. At this moment my group and I are stuck with coming up with an idea for an instrument we can make using strain gauges that will not be too simple or generic. So far, we have come up with several ideas, but only two seemed to be viable with our limited time and knowledge. Idea 1: We would like to measure the torque produced by different propellers by mounting an electric motor to a fixed shaft. The strain gauges would then be placed on this shaft at 45 degree angles to measure the shear caused by the motor trying to twist the shaft. But, since we will only be using relatively small electric motors (with +- 3kg pulling force) we may have a problem with the sensitivity of the system. One idea was to use a tube of some type of aluminium alloy to try get decent strain. However, I have no idea if a tube can be used instead of a solid shaft. Another thing I am unsure of is what type of torque would we be measuring, dynamic or static ? (if say for instance we measure the strain produced at max rpm for each propeller). I know that in industry the strain gauges are mounted on the rotating shaft, and not on a fixed shaft attached to the motor firewall, to measure the strain. Also what else would we need to take into consideration with this design ? Design 2 of idea 1: The second design involves mounting the motor between two cantilever beams. The torque caused by the rotating motor and propeller at max rpm would result in the one beam deflecting upwards, and the other deflecting downwards. Is this idea even viable for measuring max torque of a rotating object ? Idea 2: The second idea is to make an accelerometer to measure the acceleration of different propellers on a motor. The idea is to make a vertical cantilever with a certain mass at the top together with a mounted motor and propeller and to measure acceleration from zero to max rpm.The strain gauges would then be placed on the beam near to the fixed end. I was told that I may need to consider practical aspects of the design such as damping and the systems natural frequency if I am to design an accelerometer. However, I have no idea how to design it to take these into consideration, or if I even need to even worry about it for the stated purpose. The golden question is, will I be able to get either of these two ideas to work ? We have a limited time to design and build a strain gauge instrument, we have other subjects that also require a lot of attention. I would like to get a final viable design asap. I would highly appreciate any advice or any additional information. If you think any of these two ideas can work, please help me to fully understand what I need to take into consideration to make a precise and accurate final instrument.