title: Hiller Ten99
text: # Hiller Ten99
  
  The Hiller Ten99 (also known as the Hiller 1099) was an American 1961 experimental helicopter, created by Hiller Aircraft.
  
  ## Design and development
  
  The helicopter seated six and was similar to other helicopters by Hiller, but featured a larger, box-shaped cabin. It has four doors, and a set of clamshell doors on its aft side. The aircraft was powered by a Pratt & Whitney Canada PT6, and in July 1961, was the first aircraft to have been powered solely by a PT6 engine. The Ten99 was developed for a United States Navy Assault Support Helicopter program. However, the Navy eventually selected the Bell HU-1 instead. A civilian model was proposed, but not produced, and the project was eventually abandoned.
  
  ## Specifications
  
  Data from Jane's All The World's Aircraft 1965–66
  
  General characteristics
  
  * Capacity: 6 people
  * Length: 41 ft 3 in (12.57 m) (overall length)
  * Height: 10 ft 5 in (3.18 m)
  * Empty weight: 1,900 lb (862 kg)
  * Max takeoff weight: 3,501 lb (1,588 kg)
  * Powerplant: 1 × Pratt & Whitney Canada PT6 Turboprop, 550 hp (410 kW)
  * Main rotor diameter: 35 ft 8 in (10.86 m)
  * Main rotor area: 997 sq ft (92.6 $m^2)$
  