Piasecki PA97 Helistat Accident Crash - helicopter helium blimp hybrid air vehicle heavy lift

The Piasecki PA-97 Helistat was an American experimental heavy-lift aircraft, built by Piasecki by fastening four obsolete helicopters to a framework beneath a helium blimp. The PA-97 was built under a 1980 U.S. Navy contract for the Forest Service to demonstrate a heavy vertical air lifter for harvesting timber from inaccessible terrain. The single demonstrator used a Navy ZPG-2W blimp and four H-34J helicopters. The combination of a large blimp with powered lift made the 343 feet ( m) long helistat the largest dynamic lift aircraft in the world.