Wingspan: 18 feet
Speed: 35 mph
Power: 650 watts
Engine: Electric / Fuel Cell Powered
Fuel: Hydrogen

A UAV platform is desired by the Multidisciplinary Flight Dynamics and Control Laboratory (MFDCLab) as well as the Center for Environmental Analysis - Center for Research Excellence in Science and Technology (CEA-CREAST) to perform environmental sampling and to demonstrate a new technology in aircraft propulsion, Fuel Cell Power.In addition, the development of flight control lasws for a fuel cell powered aircraft that is capable of autonomous flight is of intrest to the MFDCLab. Pursuant to these goals, an overall aircraft design that emphasized stability and a high lift-to-drag ratio was employed.
Construction of Fuel Cell Powered Unmanned Aerial Vehicle
The MFDCLab's Fuel Cell UAV is a composite aircraft, made of fiberglass, carbon fiber and aramid (KevlarR). The fuselage has an aramid honeycomb sandwiched by layers of fiberglass and carbon fiber. The wings have a foam core that was hot wire cut into the shape of an Eppler 214 airfoil. Foam core wings are lightweight but strong. The Eppler 214 is a highly efficient shape that allows for a wing with a high lift to drag ratio. With an 18 foot span, the wings have a high aspect ratio and help to provide the most lift with a minimum amount of drag. This was important to the design of the UAV because the fuel cell power plant has a low power to weight ratio. We basically wanted to design the airframe so that a minimum amount of power would be needed from the fuel cell to power the plane.
Taxi Test
On February 24th, 2006, UAV project captain, Christpher Herwerth, project members, Charles Chaing and Shigeru Matsuyama, and senior design project members, David Junus and Chao Nhine Ho, conducted a taxing test. It was conducted at the Whittier Narrows RC Airfield. The purpose of the test was to check the operation of the landing gear's durability and stability, which was designed and constructed by senior design team members, Charles Chiang, David Junus and Chao Nhine Ho. Since a fuel cell propulsion system is still in testing phase for it's power output, we used 18-cell nicke cadium battery packt to power the UAV for this test. Our taxi pilot, Shigeru Matsuyama, powered the Astro Flight electric motor to nearly 50% throttle which resulted in a ground speed slightly slower than the takeoff velocity of 23 mph. The movie clip on the right shows a slow and a fast taxi test. Resulting from this taxi test, we discovered that the landing gear is very stable. However, durability criterion is failed because the tires got flat.

Currently, we are processing for installing all control surfaces and we are hoping to schedule a battery-powered flight sometime soon.

It was a good thing that the UAV didn't take off because the control surfaces on the wing had not been installed yet! Ailerons, elevators and the rudder are currently being fitted onto the UAV by the senior design team.
Fuel Cell Testing
Our fuel cell is a Proton Exchange Membrane type (PEM) manufactured by Horizon Fuel Cell Technologies. It has an efficient cylindrical design and is air cooled which gives it a weight advantage since many PEM fuel cells are water cooled. PEM also stands for Polymer Electrolyte Membrane and these names are used interchangeably. Testing of the fuel cell is ongoing.
Research grade hydrogen was purchased from Gilmore Liquid Air and a series of pressure reducers lower the pressure of the hydrogen from 2300 psi to 5 psi. Positively charged hydrogen ions cross the carbon membranes inside the fuel cell creating the flow of electrons. The "exhaust" of the PEM fuel cell is water and heat. The fuel cell potentially can provide up to 650 Watts of power.
In order to check the actual power output capability and to familiarize the operation of this fuel cell, Captain, Christpher Herwerth, Fuel Cell Specialist, Alan Ko, and other UAV team members have been conducting a series of testing. Initial tests have yielded a maximum of 513 Watts. In order to test the fuel cell, a load bank was designed and built by Alan Ko. The load bank is important because we must dissipate the electrical energy put out by the fuel cell in a controlled manner. The load bank turns the electrical energy into heat. If too much current is drawn, the fuel cell may be damaged. For actual flight conditions, a portable metal hydride tank will store the hydrogen. Our next fuel cell test will check the operation of the metal hydride tank.
Flight Test
Fuel Cell Powered UAV Team planned to do a Flight Test at Rabbit Dry Lake in Apple Valley. We were very excited about going and flying this airplane. All UAV team at the lab, together with Senior Design Team worked hard on the plane to make it happen. Friday, we gathered five ofclock in the morning and left to the lake. Rabbit Dry Lake was about 2 hrs from Los Angeles. Finally about seven thirty, we arrived there and as soon as we got out of cars, we felt very strong wind. For our first flight, we did not want to fly in the gust wind since it could harm our airplane easy. When we measured the wind speed, it was 17 knot at maximum. It was too strong for the plane to take off. We hoped that the wind would calm down so we waited for about two hours c. The wind speed never came down. Instead, it went up to about 20 knots. It was about 09:30, unfortunately we had to cancel our schedule for the day and postpone to the next Friday, June 2nd. We packed everything and left the lake about 10:00.

After one week delay of flight, June 2nd 2006 Friday, we came back to the Rabbit Dry Lake for another flight test attempt. This time, wind was calm about 8 knots at maximum. We also modified our airplane to make it more stable. We had confident that this airplane would fly. About 7:53AM, ASTRO Flight electric motor started winding and running down the grunwayh. At 7:53AM and 13 second, we had the first successful take off. FCUAV flew for about 20 second and it landed. The plane had a hard landing and hit the tail and broke off the vertical tail and one of the right horizontal tails. Other than that, there was no damage to the plane.
2nd Battery Powered Flight
Fuel Cell Powered UAV Team went to APOLLO XI Airfield in Van Nuys on July 21st (Friday) for our the second battery flight. Since we had many modifications from the last flight, we planned another battery flight before we fly with a Fuel Cell.

3nd Battery Powered Flight with New Pilot, Jay
Velocity Mapping Altitude Mapping

Fuel Cell Powered Flight
On August 25th, 2006, the team flew the UAV powered by Fuel Cell. We had very successful flight.

* press play to start video *
* double click to play in full screen *



With the successful flight of the Fuel Cell UAV on August 25, 2006, the MFDCLab became one of few groups in the nation to demonstrate fuel cell powered flight in a UAV platform. The MFDCLab at California State University, Los Angeles was the third University group in the world and the second in the United States to power a UAV with a hydrogen fuel cell. Including private corporations, the MFDCLab was the fifth entity to achieve such a flight. Other fuel cell flights were demonstrated by FH Wiesbaden in Germany, Georgia Tech, AeroVironment Inc., and the Naval Research Laboratory with a 100 Watt fuel cell flight. Since March 2006, the UAV team conducted four flight tests, three under battery power and one fuel cell powered flight. Flight video can be viewed at the MFDCLab website. Additionally, several news media organizations reported on our flight including KFWB radio, KABC Channel 7 news and NASA website Life on Earth. California State University, Los Angeles also published our success on the university website. Links to those websites are listed below.

The UAV team has continued to explore the use of fuel cell powered unmanned vehicles on a smaller scale. A second fuel cell UAV project has started in January of 2007. A polymer electrolyte membrane fuel cell powered unmanned air vehicle using compressed hydrogen storage, has been developed in collaboration with Oklahoma State University (OSU) and Horizon Fuel Cell Technologies. The major advantages in using fuel cell technology are energy density, efficiency, pollution, and reliance on foreign oil. Energy densities for fuel cell systems using compressed hydrogen are still not as high as combustion engines. However, the advantage is that fuel cell systems are much more efficient and cleaner. If compared to lithium based batteries, which are also as efficient and clean, the energy density of fuel cell systems are typically twice as much. A 150 Watt PEM fuel cell, augmented by a lithium polymer battery powers an aerodynamically efficient composite airframe constructed mainly of fiberglass and balsa wood. The battery provides additional power for takeoff and climb while the fuel cell powers cruise conditions. With an overall weight of 5 kg and a 4.4 meter wingspan, the UAV has an energy density of 450 W-h/kg. A range test flight was performed and achieved a record of 74 miles in roughly over 3 hours. An endurance flight is scheduled for June 2008 with the goal of achieving flight time of 16 hours. Oklahoma State Universityfs main role involved the design and construction of a highly efficient airframe. OSU conducted a successful battery powered long endurance flight of over 12 hours in duration so their experience in designing highly efficient airframes has shortened the time to complete a long endurance fuel cell powered UAV. Images of OSUfs Dragonfly aircraft is shown in Figure A.1.1 below. During the design process, both parties have visited each other at each others respective university. As the UAV team has experience in fuel cell integration and fuel cell powered UAV flight, input into the design process was critical. Additionally, the UAV team has made many inputs into the configuration of the fuel cell system manufactured by Horizon Fuel Cell Technologies.

Copyright © 2004 Multidisciplinary Flight Dynamics & Control Laboratory
Cal State University, Los Angeles