Transcript Midterm Presentation

Fuel on Board a General
Aviation Aircraft
THE FUEL ON BOARD TEAM
MELISSA DAVIS
ROBERT FULLING
MICHAEL DREHER-BRYRD
MATTHEW PLOURDE
MENTOR - DR. ROBERT L. ASH
Outline
 Background
 Problem definition
 Progress of the project
 Float
 Capacitance
 LabVIEW/ Data acquisition
 Testing
 Conclusion
 Website/Gantt chart
 Works cited
http://www.iaopa.eu/contentServlet/iaopa-news-july-2014
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
 Single 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
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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
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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:
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Power - 200 micro joules
Current - 100 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.
http://sine.ni.com/gallery/app/ui/page?nodeId=212383&mTitle=NI%20USB6001&mGallery=set_usb-6001_2_3
Testing Apparatus
 A cooler with dimensions of 21X11X5.5 in to
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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: http://dasp.mem.odu.edu:8080/~fuel_fa14/default.html
Work Cited
[1] General Aviation Manufacturers Association (2014). 2013 General Aviation
Statistical Databook & 2014 Industry Outlook. [Online]. Availible:
http://www.gama.aero/files/2013_GAMA_Databook-LowRes02192014.pdf
[2] Joseph E Burnside, “Fuel Totalizers: EI, JPI are top values”, The Aviation
Consumer, Vol. 38, pp. 16-20, Mar. 2008.
[3] National Transportation Safety Board (2012, Oct.). Review of US Civil
Aviation Accidents - Calendar Year 2010. [Online]. Available:
http://www.ntsb.gov/doclib/reports/2012/ARA1201.pdf
[4] Norm Crabill, “Proposed Research Topics for General Aviation, Fuel-OnBoard”, unpublished.
[5] Aviation Maintenance Technician Handbook-Airframe, United States
Department of Transportation, Federal Aviation Administration,
Oklahoma City, OK, 2012, pp 13-22.
[6] Li, Guohua, and Susan P. Baker. "Correlates of pilot fatality in general aviation
crashes." Aviation, space, and environmental medicine 70.4 (1999):
305-309.