Piper Altaire

PA-47 PiperJet
The prototype PA-47 PiperJet at Lakeland, Florida, in April 2009
Role	Very light jet
National origin	United States
Manufacturer	Piper Aircraft
First flight	30 July 2008
Status	Cancelled
Number built	1
Unit cost	$2.199M (in 2006 USD)

The Piper PA-47 PiperJet was a single-engined very light jet (VLJ) that was intended to be developed and built by Piper Aircraft. However, following a change of ownership at Piper, it was decided to redesign the aircraft into the PiperJet Altaire. Despite being technically successful, the Altaire project was cancelled in October 2011 due to economic conditions.

The PiperJet was announced in October 2006, as a competitor to the twin-engined Eclipse 500 and Cessna Citation Mustang. The aircraft's fuselage was the same cross section as the propeller-driven Piper PA-46 series, with a 4 feet (1.2 m) increase in length. It was to be capable of carrying up to 7 passengers and cruise at 360 knots (666.7 km/h), at a maximum altitude of 35,000 feet (10,668.0 m). Maximum range was expected to be 1,300 nautical miles (2,407.6 km), with a full-fuel payload of 800 pounds. Piper selected Williams International to supply its FJ44-3AP turbofan engine for the PiperJet.

Due to the engine being mounted above the center of gravity, power was highly stabilizing (addition of power would push the nose down), which could have been disconcerting to pilots. Initially, Piper designers incorporated an automatic pitch trim system to coordinate horizontal stabilizer angle of incidence with power setting. This system was later replaced by a vectored thrust nozzle, developed by Williams International, which resulted in reduced weight and simplified manufacturing processes.

A design feature of the aircraft was the use of a straight duct air intake design for the vertical stabilizer (tail) mounted engine, similar in engineering design concept to a McDonnell Douglas DC-10, rather than the s-duct arrangement of most trijet aircraft designs such as the Dassault Falcon 900.