A 73-year-old retired general who shook up the military organization and the communist movement in the 1970s is now a full-fledged inventor who talks about ‘maximum angle of attack’ for a wind turbine design that can potentially revolutionize the Philippine power industry.
Victor Corpus, who became famous in 1970 as the rebel soldier, now spends most of his time tinkering with wind turbines. An early experiment on a tidal power project became the basis of his vertical-axis design for a wind turbine that can capture the full force of the wind to produce electricity at a rate much lower than the prevailing cost, he says.
“Our target is to bring down the cost of electricity. We have one of the highest power rates in Asia and in the world, second only to Japan. It costs P12 per kilowatt-hour in Cagayan province, compared to P4.16 per kWh in China. If we can use a more efficient turbine to provide clean and sustainable energy, then foreign investors will come to us,” Corpus says during the presentation of his improved Nautilus wind turbine innovation in Pasay City before technical experts from the Department of Science and Technology and major universities.
“If China can produce electricity at P4.16 per kWh, we can produce it at a lower price because labor cost in China is now double our labor cost. Then, we have a more efficient vertical-axis wind turbine which has at least three ‘maximum angles of attack’ compared to China’s horizontal axis which has no maximum angle of attack,” says Corpus, who served in the board of PNOC Alternative Fuels Corp. before pursuing his invention.
The ‘maximum angle of attack’ refers to the angle between the oncoming wind and the spokes of a vertical-axis wind turbine that can produce the strongest torque.
Corpus says the Nautilus wind turbine is much cheaper to build and install because it is ground-based. The turbine is designed to control the velocity of the wind through ‘weirs’ or ‘funnels’ which redirect the flow of the wind for maximum torque and capture the spilled wind energy by channeling its flow into a series of ‘Venturi’ chambers which also has the effect of accelerating wind velocity.
Before becoming an inventor, Corpus, who obtained his elementary and high school education from De La Salle College in Manila, graduated from the Philippine Military Academy in 1967 where he was heavily exposed to engineering courses. He was a lieutenant and an instructor at PMA when he defected to the New People’s Army, the armed wing of the communist movement in the country in 1970.
He became active in the communist movement as a training officer of NPA Northern Luzon command from 1971 to 1976 and was based in Sierra Madre mountain range where he nearly died. He later became disillusioned in the movement and surrendered to his former PMA classmates. He was imprisoned for 10 years until he was among the political prisoners freed by former President Corazon Aquino in 1986. A film was made about Corpus’ life in 1987.
He returned to the military in 1987. He was appointed chief of the Intelligence Service of the Armed Forces of the Philippines in 2001 and received the rank of brigadier general in 2003.
He retired from the military in 2004 and was appointed to the board of state-run Philippine National Oil Corp.- Alternative Fuels Corp. in 2005, when he started his research on renewable energy.
While working for PNOC- Alternative Fuels Corp., Corpus became interested in tidal energy. “Because of our so many islands, we are one of the richest countries in the world when it comes to tidal energy. It taps current as a result of ‘Venturi’ effect between islands. We can just tap the current from the islands that are close to one another to produce enough energy to supply the whole country. The problem we saw is that we would need $7 million per kilometer of submersible cable to bring the output from the sea back to land. It is very costly,” he says.
A typhoon destroyed one of their early prototypes for a tidal power plant and blew it to the South China Sea. “We were forced to go back to the table model,” he says.
A new model for the tidal power project used weirs and ‘Venturi’ chambers to redirect the flow of water and remove the counterflow effect. “After experimenting with the model, we brought it ashore and on the beach where you could feel the breeze. It turned out to be our ‘eureka’ moment. On the beach, the turbine rotated continuously,” he says.
This became the basis of the Nautilus design for a vertical-axis wind turbine. Even long after leaving the government service, Corpus pursed the development of the project at his home.
“To tell you the truth, it took us 12 years to define the problem, just to come up with the definition of the problems for wind turbines,” says Corpus. His improved Nautilus vertical-axis wind turbine apparatus, which he developed along with wife Germelinda, daughter Cynthia, chief engineer Mark Anthony Nillo and chief technician Daryl Carl Rebadomia, is awaiting an official patent. Corpus also joined the Filipino Inventors Society Producers Cooperative led by Francisco ‘Popoy’ Pagayon to push for local inventions and innovations.
“Basically, it is an improvement of a vertical-axis wind turbine that addresses all the basic weaknesses of a traditional wind turbine. We identified seven basic weaknesses,” Corpus says of his innovation. “We have eliminated all the weaknesses and enhanced its strength.”
Corpus’ design addresses the issues of negative headwind, lack of maximum angle of attack, inability of traditional wind turbines to manipulate wind velocity, spilled wind kinetic energy, wasted wind kinetic energy, gravitational stress limits and need for towers.
“We have corrected these seven problems, removed the negative headwind or counterflow and converted it into a positive wind flow with maximum angle of attack. We also tapped the wasted energy by diverting them into the turbine. So the wasted energy turns into positive energy,” says Corpus.
About 40.7 percent of the wind flow escapes between the blades of traditional horizontal-axis wind mills which have sprouted in Ilocos Norte, Rizal and Guimaras. The same volume of wind is not harnessed by existing vertical-axis wind turbines.
Corpus’ innovative design using weirs harnesses the wasted energy and recyles the spilled energy. Negative headwind is converted into positive tail wind, adding one maximum angle of attack at 225 degrees.
The design uses weirs to add maximum angles of attack. The Nautilus also increases wind velocity by incorporating a series of ‘Venturi’ chambers.
Corpus says unlike the horizontal axis wind turbine which requires tall towers, the apparatus for a vertical axis wind turbine is ground-based with relatively low profile. This eliminates high gravitational stress.
He says it is also much cheaper to fabricate and install the vertical-axis wind turbine using local materials and facilities, compared to horizontal axis blades that are manufactured abroad.
The Engineering Department of De La Salle University is set to evaluate the capacity of the improved Nautilus vertical-axis wind turbine and compare it with existing wind turbines.
Jose Patalinjug III, regional director of DOST in the National Capital Region, agreed to support the further development of Corpus’ Nautilus design. “If we need further R&D on this, we are willing to fund this. If we need further testing to collect the necessary data, we will do that, until finally we can say that this invention, this innovation is commerciable,” Patalinjug says.
“If we can install the Nautilus in Sierra Madre which faces the strong wind from the Pacific Ocean, our people will benefit from much cheaper electricity. It will not only reduce the cost of electricity, it will also make it cleaner,” says Corpus.