THE FUEL ON BOARD TEAM MELISSA DAVIS ROBERT FULLING MICHAEL DREHER-BRYRD MATTHEW PLOURDE MENTOR - DR. ROBERT L. ASH Fuel on Board a General Aviation Aircraft

Outline Background Problem definition Progress of the project  Float  Capacitance  LabVIEW/ Data acquisition  Testing Conclusion Website/Gantt chart Works cited

Background Fuel management is a long standing issue for General Aviation, as current fuel measurement systems are often inaccurate, so fuel management predominantly relies on the pilot’s records and calculations[3][4] In 2010, there were 36 accidents and 5 deaths caused by fuel mismanagement in GA aircraft [1][3]. The Federal Aviation Administration (FAA) requires general aviation aircraft to display zero after all usable fuel is gone [2][5]

Current Fuel Management Systems S ingle position floats and capacitor probes are used in most GA aircraft, however both can be extremely inaccurate because they only measure fuel height at a single location inside the tank [5][4]. Fuel totalizers are the most accurate fuel monitoring devices used today, as they are relatively accurate in measuring the flow rate of the fuel leaving the tank however there is still room for error because the totalizer doesn’t directly measure the volume of fuel in the tank [2].

Problem Statement/Purpose Current fuel measurement systems for GA aircraft are often inaccurate, and have been the cause of stressful flying situations for pilots, crashes, and even death. The purpose of the fuel on board project is to design an economical fuel measurement system for general aviation aircraft that will measure and display the mass of usable fuel inside a tank within ± 3% error.

Progress of the project The designs are finished and most of the parts for the whole system have been collected The potentiometer float has begun assembly The capacitive tube is assemble Research into how to use LABVIEW and connect it to a data acquisition card has been completed The testing apparatus has begun assembly

Multi-Potentiometer Float: Theory Three float arms, each connected to its own float, will be connected to potentiometers inside a single sender unit at the top of the tank. The potentiometers contain resistors and wiper arms. The resistance changes as the wiper moves across it, and can be measured. The resistance of each potentiometer will be measured, and all three will be averaged together to give an accurate measurement of fuel remaining.

Multi-Potentiometer Float: Design ¼ in aluminum rods will be used as the float arms, each connected to a foam float that will rise and fall with fuel surface Each aluminum rod end will be bent at 90 degrees, and then fastened to a potentiometer arm by a rigid coupling. The potentiometers will be secured and protected in a PVC cap, and holes will be drilled in the side of the cap to allow the potentiometer arms to protrude into the tank

Multi-Potentiometer Float: Why it’s different Current float available on the market:  One unit consists of a potentiometer connected to a single, short float arm, and float. Installed in the side of the tank This project’s Potentiometer Float:  Three potentiometers per installment unit, each connected to a 6 in long aluminum float arm and float, Installed in the top center of the tank

Multi-Potentiometer Float: Equations

Capacitive Tube: Theory A capacitor behaves according to coulomb's law, made up of two metal plates (conductors) separated by a dielectric (insulator), and holds a charge depending on the dielectric. Every dielectric substance is given a permittivity constant to account for its chemical makeup and insulation ability GA fuel and air are both dielectric substances, each with its own permittivity value. When permittivity values and the distance between two plates are known, the charge of the capacitor can be measured and used to find the surface area of the dielectric acting throughout the capacitor.

Capacitive Tube: Design Two capacitance tube’s will be built and installed into a tank. Each capacitance tube will be made of an aluminum rod, an aluminum tube, and small lengths of polyethylene tubing Either air or fuel will act as the dielectric insulator, depending on how much fuel is in the tank, and will flow between the aluminum rod and tube. As the fuel level changes, the capacitance will change The change of capacitance between the two tubes will be measured and will ultimately be converted to fuel height

Capacitive Tube: Why It’s Different Current capacitor probes available on the market:  Single, or multiple capacitor probes are installed at different locations in the tank, and let the pilot know whether or not the fluid level is at that capacitor. These probes don’t cover the whole vertical length of the tank This project’s Capacitive tube:  Two tubes will be installed inside the tank away from the tank walls, where the tubes will cover the whole vertical height of the tank where installed, and will dampen the fluid flow in and out of the capacitor

Capacitive Tube: Equations

Fuel Properties Since aviation fuel (Avgas 82) that is commonly used in GA aircraft is flammable, it can only take so much voltage, current and power before it ignites Flammability Limits:  Power micro joules  Current mill amperes  Temp – 400 degrees fahrenheit

LabVIEW and Data Acquisition The DAQ card will read voltage from the potentiometers and the capacitance tubes The DAQ will send the voltage readings into LabVIEW LabVIEW will record the readings as the experiment progresses LabVIEW will act as the microcontroller, converting voltage into liquid height for each concept, and then output the volume of fuel as a display &mGallery=set_usb-6001_2_3

Testing Apparatus A cooler with dimensions of 21X11X5.5 in to represent a fuel tank Wheel barrow base to allow for pitch and roll Accelerometers Deionized water Wiring and installing the prototypes Measuring the liquid that has left the tank

Conclusion The multi-potentiometer float or the capacitive tube could revolutionize fuel management for general aviation aircraft. Not only are these designs affordable, but if they are within the ± 3% error margin, they could reduce the GA aircraft crash rates and reduce pilot stress and workload. Website:

Work Cited [1] General Aviation Manufacturers Association (2014) General Aviation Statistical Databook & 2014 Industry Outlook. [Online]. Availible: pdf [2] Joseph E Burnside, “Fuel Totalizers: EI, JPI are top values”, The Aviation Consumer, Vol. 38, pp , Mar [3] National Transportation Safety Board (2012, Oct.). Review of US Civil Aviation Accidents - Calendar Year [Online]. Available: [4] Norm Crabill, “Proposed Research Topics for General Aviation, Fuel-On- Board”, unpublished. [5] Aviation Maintenance Technician Handbook-Airframe, United States Department of Transportation, Federal Aviation Administration, Oklahoma City, OK, 2012, pp [6] Li, Guohua, and Susan P. Baker. "Correlates of pilot fatality in general aviation crashes." Aviation, space, and environmental medicine 70.4 (1999):