Updated April 25: Vietnamese farmers who built their own helicopter may take to the air within a week, local press reports say. Officials inspected the craft on Wednesday, and are considering approving a limited flight test.
If official approval comes, it will be the end of a 5 year battle for Tran Quoc Hai and Le Van Danh, who have faced arrest and heavy financial losses in their quest to soar aloft in the boxy red chopper they built in Hai's tractor workshop.
Officials who inspected the chopper this week limited it to a low speed engine test, and would not allow pilot Hai to take to the air, according to Saigon's Tiep Thi newspaper.
The Vietnamese inventing duo are often described as farmers by local press because they come from an agricultural background. Hai is also an accomplished mechanic who runs a small agricultural machinery factory. Danh, who has provided much of the $20,000 spent on the project, invests in real estate. The photo below shows then next to their helicopter - Hai is on the right.
Based on an inspection of the chopper and Hai's workshop, defense ministry experts immediately said they were concerned about several aspects of the aircraft. The trial-and-error nature of the design process gives them particular cause for concern in a field which allows little room for error.
Will the home-made metal alloys used in critical parts such as rotor blades be strong enough, one expert asked. The tips of helicopter rotor blades move close to supersonic speeds, producing the craft's characteristic sound.
A ministry pilot questioned the suitability of the Russian truck engine that powers the craft. Light military helicopters have twin 1400 horsepower engines, he said. The light-weight DIY chopper's engine is believed to produce less than 300 horsepower.
The officials said they would decide whether to permit the craft to proceed to a low level hovering flight test, or suggest changes, by next weekend .
The inventors have proposed various uses for their helicopter, including aerial observation, cattle herding, and spraying crops with pesticide.
Update April 13: The Vietnamese Defense Ministry has denied permission for a test flight of the helicopter in its current form, according to the Thanh Nien Daily News.
Update April 25: Tran Quoc Hai has appealed to Vietnam's prime minister, asking him to allow testing to continue. The prime minister intervened in the case late last year, telling government officials to proceed with a review of the helicopter, when it had appeared they might not do so.