KR2S Neutral Point Prediction with a Wireless String Potentiometer

KR2S Neutral Point Prediction with a Wireless String Potentiometer

The Mojave Experimental Flyin is always a great place to walk around and bump into people smarter than you, and one of the recurring themes amongst this group of awesome folks was a need for instrumentation of surface positions to complete the AirDAQ architecture as a flight test tool. Diane Barney had taken an interest in the KR2S' "quirky" longitudinal stability, so I got to work on an elevator position string pot and she got to work on a test plan for a neutral point prediction. A couple of days later, I was calibrating the PotDAQ on the KR2S's hstab. It turned out to be a pretty cool piece of hardware. It uses the same temporary attachment scheme as the air data boom, an industrial-grade string potentiometer, and a repurposed air data computer from a Featherweight boom. It's still a little bit bulky, but it provides repeatable measurements of surface position down to about 0.15 degree.

Using X-Plane to Visualize INS Data

Using X-Plane to Visualize INS Data

Getting data to the finish line is always tricky. Acquisition is one part of that equation, but the part that more often puts me in front of a laptop with my headphones on and a weird look on my face is the reduction. It's very engaging to find ways to look at data that are intuitive and useful, and I work pretty hard to build a "toolbox" of scripts that get data into a usable format in time to brief the next sortie. Usually this takes the form of the plots that show up elsewhere on this site, but the introduction of the INS as a data acquisition tool meant that I had a ton of data and needed a better way to look at it.

Testing the BoxDAQ

Testing the BoxDAQ

The BoxDAQ project has been a whirlwind of excitement so far. It started in December of 2016, when I bought a VectorNav VN-200 Rugged INS to use for improving the accuracy of our air data calibration maneuvers. I was really impressed with the data, but it wasn't long before Wasabi called me up and said they had an Extra 300L with an empty front seat that was going to be spending some time upside down in the near future.