When theCarterCopter was damaged in 2005 due to a gear-up landing caused by pilot error, the cost of repair was deemed higher than the cost of making a new aircraft with the added benefit of incorporating lessons learned from the first aircraft. Design of the PAV was begun during 2005.[4][5] Several changes and development problems occurred along the way; twin boom was deemed unnecessary, so a single boom was constructed, and flaws in rotor blades and hub were revealed during testing and then corrected.[6][7]
On 16 November 2009, theAAI Corporation (adivision ofTextron) signed a 40-year exclusivelicense agreement[8][9] with the company concerning allunmanned aircraft systems, one of which was intended to deliver 3,000 pounds (1,400 kg) of cargo similar to the unmannedKaman K-MAX, but over a future range of 1,300 nautical miles (2,400 km)[8][10][11] compared to the demonstrated 150 nautical miles (280 km) or more of the K-MAX.[12] The agreement committed CarterCopters to developing the technology to maturity, in exchange for exclusive rights to develop UAVs for the next 40 years. The first product in theAAI agreement[10] was to be anautonomous slowed rotor/compound (SR/C) aircraft based on the Carter Personal Air Vehicle.[13][14][15]
"CriticalDesign Review" (CDR) for AAI Corporation was performed around January 2010 when the prototype was already being built. Usually a CDR is performed before a vehicle is built.[3]
In 2014, Carter said they bought back the license from AAI[16] and is seeking production partners outside USA,[17][18] hoping for production 3–5 years later.[19]
The first flight occurred on 5 January 2011 at Olney without wings and lasted 36 minutes, which qualified Carter for a milestone payment.[25][26][27]
Carter stated that the PAV performed its first zero-roll jump take-off on 18 January 2011,[22] to a height of 120 feet (37 m). Eight jump take-offs were performed.[22] There are some electrical issues with the aircraft, and it is not involume production.[28][29]
The PAV flew traffic patterns with wings at Olney in January 2012,[30] and has since flown winged test flights. It flew a few hours at a time, but itsflight certificate restricted it to within 5 miles (8.0 km) of Olney.[31]
As of June 2012, development of the PAV is a year behind schedule[32] due to various technical problems,[33] and a delay of a further year was caused by rotorRPM software control issues.[34] Carter received funding from theWichita FallsEconomic Development Corporation in 2010 to complete the PAV.[35][36][37][38] Carter views the lack of a PAVflight simulator as a mistake, and attempts to build one. The previous CarterCopter was designed using a flight simulator.[33]
According to Carter, the PAV reached Mu-1 on 7 November 2013. It also achieved a speed of 174 kn (322 km/h; 200 mph), and the rotor was slowed down to 113 rpm.[42][43] The PAV flew its first public show flight outside Olney when it flew to Wichita Falls later that month.[44] Carter says the PAV has achieved a speed of 204 miles per hour (328 km/h) at an altitude of 16,000 feet (4,900 m), a Mu of 1.13[34][45] and anL/D of 11.6[46]-15. Carter has applied to the FAA to change the PAVs certificate from research and development to demonstration.[47]
The second PAV (called PAV-II, registration N210AV) was flight approved in March 2014,[48][49] and demonstrated atSun 'n Fun air festival andMacDill Air Force Base in 2014, both in Florida.[50] In July 2014, it was displayed atOshkosh Airshow. Carter says it has flown 186 kn (344 km/h; 214 mph) at 18,000 feet (5,500 m).[17] The first non-Carter pilots flew the aircraft in 2015.[51]
Helicopter rotors are designed to operate at a fixedRPM[56][57][58] (within a narrow range of a few percent),[59][60] whereas Carter uses RPM ranges between 100 and 350.[61] Most aircraft have two energy parameters (speed and altitude) which the pilot can trade between,[62] but Carter technology attempts to use rotor rotation as a third energy parameter.[63][64]
The PAV has traditional airplane-like controls (Vernier type[3]), but thestick also controls the rotor.[19] Most controls were automated in 2011,[21][67] and jump-takeoff is performed at the push of a button.[19]Materials used include glass fiber, aluminum, titanium, and steel, as well asautoclaved carbon/epoxy prepreg witharamidhoneycombcore on the PAV-II.[68] The tip weights had been made oftungsten, while the current (2013) are made of steel.[69]
Suppliers for the aircraft include Blue Mountain Avionics foravionics and air-to-ground video andtelemetry, and Sky Ox Oxygen Systems as the PAV is not pressurized.[55]60 channels of information convey sensor measurements from the aircraft to a ground computer, and 4 video cameras tape the flights.[22] The engine is equipped with a performance enhancement system byNitrous Express.[70]
ThePAV has flight characteristics similar to other Carter aircraft. When stationary on the ground, the engine powers up the flat pitch rotor to 370 RPM,[3] and the engine is then disengaged from the rotor to provide full power to the propeller.[61][67]
The rotor now has substantialrotational energy due to the tip weights (usable temporaryeng1 equivalent to 1,000 horsepower or 750 kilowatts),[71] and the rotor blades are pitched to push air down and lift the aircraft in ajump takeoff.[61][72]While altitude is reached, the aircraft transitions into forward flight using the pusher propeller, and the rotor shifts toautorotation (windmilling) with air flowing up through the rotor.As speed increases, the air flow increases rotor RPM like other autogyros. Once sufficientairspeed is reached (around 70–85 miles per hour or 113–137 kilometres per hour)[73] for the small wings to provide lift, rotor blades are feathered to reduce rotor speed to 100 RPM[61][74] and minimize drag, and lift is provided mostly by the wings[1] when speed reaches 150 miles per hour (240 km/h).[73] Rotor lift is reduced to 10%, and flight efficiency is somewhat below that of acommercial jet plane.[75]
^"Archive 2006"Carter Aviation, 2 January 2006.Mirror. Retrieved: 7 August 2010. Quote: "For the past several months, Carter has been designing a new aircraft"
^John M. Seddon, Simon Newman.Basic Helicopter Aerodynamics p216,John Wiley and Sons, 2011. Retrieved: 25 February 2012.ISBN1-119-99410-1.Quote: The rotor is best served by rotating at a constant rotor speed
^Robert Beckhusen. "Army Dumps All-Seeing Chopper Drone"Wired 25 June 2012. Retrieved: 12 October 2013.Archived on 22 April 2015.Quote:The number of revolutions per minute is also set at a fixed rate
PAV in flight 12
PAV jump take-off, with wings
