Carter PAV
Encyclopedia
The Carter PAV (Personal Air Vehicle
Personal air vehicle
A personal air vehicle or PAV, also personal aerial vehicle, is a class of light general aviation aircraft which meets design and performance goals intended to make flying as commonplace as driving...
) is a two-bladed, compound autogyro
Autogyro
An autogyro , also known as gyroplane, gyrocopter, or rotaplane, is a type of rotorcraft which uses an unpowered rotor in autorotation to develop lift, and an engine-powered propeller, similar to that of a fixed-wing aircraft, to provide thrust...
developed by Carter Aviation Technologies
Carter Aviation Technologies
Carter Aviation Technologies is a privately held aviation research and development company based in Wichita Falls, Texas, United States....
to demonstrate slowed rotor
Helicopter rotor
A helicopter main rotor or rotor system is a type of fan that is used to generate both the aerodynamic lift force that supports the weight of the helicopter, and thrust which counteracts aerodynamic drag in forward flight...
technology. The design has an unpowered rotor mounted on top of the fuselage, wings like a conventional fixed-wing aircraft
Fixed-wing aircraft
A fixed-wing aircraft is an aircraft capable of flight using wings that generate lift due to the vehicle's forward airspeed. Fixed-wing aircraft are distinct from rotary-wing aircraft in which wings rotate about a fixed mast and ornithopters in which lift is generated by flapping wings.A powered...
mounted underneath, and a controllable pitch
Controllable pitch propeller
A controllable pitch propeller or variable pitch propeller is a type of propeller with blades that can be rotated around their long axis to change their pitch...
pusher propeller at the rear of the fuselage. Tungsten
Tungsten
Tungsten , also known as wolfram , is a chemical element with the chemical symbol W and atomic number 74.A hard, rare metal under standard conditions when uncombined, tungsten is found naturally on Earth only in chemical compounds. It was identified as a new element in 1781, and first isolated as...
weights (75 ounces each) are placed in the rotor tips to enhance rotational energy
Rotational energy
The rotational energy or angular kinetic energy is the kinetic energy due to the rotation of an object and is part of its total kinetic energy...
and to reduce flapping.
Development
When the CarterCopterCarterCopter
The CarterCopter is an experimental compound autogyro developed by Carter Aviation Technologies to demonstrate slowed rotor technology. On 17 June 2005, the CarterCopter became the first rotorcraft to achieve mu-1 , an equal ratio of airspeed to rotor tip speed, but crashed on the next flight and...
crashed in 2005, 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. Several changes and development problems occurred along the way; twin boom was deemed unnescessary so a single boom was constructed, and flaws in rotor blades and hub were revealed during testing and then corrected.
On 16 November 2009 the AAI Corporation
AAI Corporation
AAI Corporation is an aerospace and defense development and manufacturing firm in Hunt Valley, Maryland, USA. It is formerly a wholly owned subsidiary of United Industrial Corporation, AAI was acquired by Textron in 2007 and currently is an operating unit of Textron Systems Corporation...
(a division
Division (business)
A division of a business entity is a portion of that business that operates under a different name. It is the equivalent of a corporation or limited liability company obtaining a fictitious name or "doing business as" certificate and operating a business under that fictitious name...
of Textron
Textron
Textron is a conglomerate that includes Bell Helicopter, E-Z-GO, Cessna Aircraft Company, and Greenlee, among others. It was founded by Royal Little in 1923 as the Special Yarns Company, and is headquartered at the Textron Tower in Providence, Rhode Island, United States.With total revenues of...
) signed a 40-year exclusive license agreement with the company concerning all unmanned aircraft systems, one of which is intended to deliver 3000 pounds of cargo similar to the unmanned Kaman K-MAX, but over a future range of 1300 nautical miles compared to the demonstrated 150 nautical miles (277.8 km) or more of the K-MAX. The agreement commits CarterCopters to developing the technology to maturity, in exchange for exclusive rights to develop UAVs for the next 40 years. The first product in the AAI
AAI Corporation
AAI Corporation is an aerospace and defense development and manufacturing firm in Hunt Valley, Maryland, USA. It is formerly a wholly owned subsidiary of United Industrial Corporation, AAI was acquired by Textron in 2007 and currently is an operating unit of Textron Systems Corporation...
agreement is an autonomous
Unmanned aerial vehicle
An unmanned aerial vehicle , also known as a unmanned aircraft system , remotely piloted aircraft or unmanned aircraft, is a machine which functions either by the remote control of a navigator or pilot or autonomously, that is, as a self-directing entity...
slowed rotor/compound (SR/C) aircraft to be based on the Carter Personal Air Vehicle.
"Critical Design Review" (CDR) for AAI Corporation
AAI Corporation
AAI Corporation is an aerospace and defense development and manufacturing firm in Hunt Valley, Maryland, USA. It is formerly a wholly owned subsidiary of United Industrial Corporation, AAI was acquired by Textron in 2007 and currently is an operating unit of Textron Systems Corporation...
was performed around January 2010 when the prototype was already being built. Usually a CDR is performed before a vehicle is built.
- TaxiTaxiingTaxiing refers to the movement of an aircraft on the ground, under its own power, in contrast to towing or push-back where the aircraft is moved by a tug...
run in Autumn 2010http://www.cartercopters.com/weekly_update_archive_2010_1.html http://www.cartercopters.com/pr_2010-10-24.html at Olney AirportOlney, TexasOlney is a city in Young County, Texas, United States. The population was 3,236 in 2008.-Geography:Olney is located at ....
after FAA Special Airworthiness CertificateSpecial Airworthiness CertificateA special airworthiness certificate is an airworthiness certificate that is not sufficient to allow an aircraft to be used in commercial passenger or cargo operations.-United States:...
on 27 July 2010, and traffic patternAirfield traffic patternAn airfield traffic pattern is a standard path followed by aircraft when taking off or landing, while maintaining visual contact with the airfield....
movement on 2 December 2010, piloted by Larry Neal at the controls and co-pilot Robert Luna. Larry Neal was also one of the pilots of the CarterCopter at Olney in 2005.
The first flight occurred on 5 January 2011 at Olney without wings and lasted 36 minutes, which qualified Carter for a milestone payment.
Carter claims that the PAV performed its first zero-roll jump take-off on 18 January 2011, to a height of 120 feet. 8 jump take-offs were performed. There are some electrical issues with the aircraft, and it is not in volume production
Mass production
Mass production is the production of large amounts of standardized products, including and especially on assembly lines...
.
Design
Computer aided design and X-plane flight simulation were used during development.
Unlike the twin-boom CarterCopter, the PAV has a single tailboom. A tilting mast allows the rotor to be tilted 15 degrees forward and 30 degrees aft to allow different centres of gravity
Center of gravity of an aircraft
The center-of-gravity is the point at which an aircraft would balance if it were possible to suspend it at that point. It is the mass center of the aircraft, or the theoretical point at which the entire weight of the aircraft is assumed to be concentrated. Its distance from the reference datum is...
and wing angle-of-attacks.
Helicopter rotors are designed to operate in a narrow range of RPM.
Most aircraft have two energy parameters (speed and altitude) which the pilot can trade between, but Carter technology attempts to use rotor rotation as a third energy parameter.
The purpose of the Slowed Rotor/Compound aircraft is to enhance the flight envelope
Flight envelope
In aerodynamics, the flight envelope or performance envelope of an aircraft refers to the capabilities of a design in terms of airspeed and load factor or altitude. The term is somewhat loosely applied, and can also refer to other measurements such as maneuverability...
compared to airplanes, helicopter
Helicopter
A helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...
s and traditional autogyro
Autogyro
An autogyro , also known as gyroplane, gyrocopter, or rotaplane, is a type of rotorcraft which uses an unpowered rotor in autorotation to develop lift, and an engine-powered propeller, similar to that of a fixed-wing aircraft, to provide thrust...
s, by minimizing the dangerous areas of the stall speed diagram/Height-velocity diagram
Height-velocity diagram
The Height-Velocity diagram or H/V curve is a graph charting the safe/unsafe flight profiles relevant to a specific helicopter. As operation outside the safe area of the chart can be fatal in the event of a power or transmission failure it is sometimes referred to as the dead man's curve or Coffin...
as well as moving the speed limit up.
It uses Vernier type controls, and most controls are now automated.
Materials used include glass fiber, aluminum, carbon, titanium, and steel.
Suppliers for the aircraft include Blue Mountain Avionics for avionics
Avionics
Avionics are electronic systems used on aircraft, artificial satellites and spacecraft.Avionic systems include communications, navigation, the display and management of multiple systems and the hundreds of systems that are fitted to aircraft to meet individual roles...
and air-to-ground video and telemetry
Telemetry
Telemetry is a technology that allows measurements to be made at a distance, usually via radio wave transmission and reception of the information. The word is derived from Greek roots: tele = remote, and metron = measure...
, and Sky Ox Oxygen Systems as the PAV is not pressurized.
60 channels of information convey sensor measurements from the aircraft to a ground computer, and 4 video cameras tape the flights.
Operation
The PAV has flight characteristics similar to other Carter aircraft. When stationary on the ground, the engine powers up the flat pitch rotor to 370 RPM, and the engine is then disengaged from the rotor...alternative.. The engine accelerates the rotor in no-lift pitch until the rotor speed required for flight is achieved. The engine is then declutched from the rotor and it has maximum power for the propeller.
The rotor now has substantial rotational energy
Rotational energy
The rotational energy or angular kinetic energy is the kinetic energy due to the rotation of an object and is part of its total kinetic energy...
due to the tip weights, and the rotor blades are pitched to push air down and lift the aircraft in a jump takeoff.
While altitude is reached, the aircraft transitions into forward flight using the pusher propeller, and the rotor shifts to autorotation
Autorotation (helicopter)
Autorotation is the state of flight where the main rotor system of a helicopter is being turned by the action of air moving up through the rotor rather than engine power driving the rotor...
(windmilling) with air flowing up through the rotor.
As speed increases, the air flow increases rotor RPM like other autogyros. Once sufficient airspeed
Airspeed
Airspeed is the speed of an aircraft relative to the air. Among the common conventions for qualifying airspeed are: indicated airspeed , calibrated airspeed , true airspeed , equivalent airspeed and density airspeed....
is reached for the small wings to provide lift, rotor blades are feathered to reduce rotor speed to 100 RPM and minimize drag, and lift is provided mostly by the wings.