New Name Leads Slew Of Announcements At Sun-N-Fun 2003

By ANN Correspondent Juan Jimenez

What's in a name? In the case of CarterCopters LLC, it was too much of a reference to the aircraft and not enough to the business of the company. Hence, it was announced today at Sun-N-Fun 2003 that the company now has a new name which more closely reflects what the company actually does for a living: Carter Aviation Technologies.

According to company spokesperson Ms. Anita Infante, the new name was chosen because it matches the company's emphasis on research and development of technologies with the intention of licensing them to aircraft manufacturers, rather than the direct production of aircraft. The prototype aircraft that the company is currently developing and flying will still be called CarterCopters, said company founder Jay Carter Jr., "but our company is much more than a unique aircraft. We are developing new, global impact technologies for aviation as a result of creative engineering and thinking outside the norm."

In a press conference that covered a wide range of subjects, the company also made several other announcements. A new prototype of the CarterCopter, which the company has christened the Next Generation CarterCopter (NxCC), is now under construction. The design incorporates a number of changes, including:

• The fuselage will be extended by over three feet to reduce drag caused by airflow separation.
• The wingspan will be increased.
• The booms will be placed at a wider stance.
• An additional vertical stabilizer will be added.
• A new, high-Mu rotor and spinner will be installed.
• The new interior will feature an expanded cabin offering a choice of seating for six or seven - one option will even include a small lavatory!
• A 2,000 shp turboprop engine

The projected performance for this new prototype, if achieved, should impress even the staunchest non-believers.

• 2,500 lbs empty weight
• 5,000 lbs gross weight while retaining VTOL capability
• 6,000 lbs gross weight with 200 ft rolling takeoff
• 350 mph top speed
• 30,000 ft cruise altitude in a pressurized cockpit
• 2,000 mile range with 1,000 lb useful load

No completion schedule has been announced as of yet for this iteration of the CarterCopter. However, one thing was made clear, and that is that in tune with the company's emphasis on R&D, the prototype will be shown in non-aviation venues as well as in the traditional aviation industry trade shows and fly-ins.

Mentioned as well during the conference was the importance of the use of Laminar Research's X-Plane simulation software during the development of the CarterCopter. Mr. Carter put it in simple words - without Austin Meyer's product, it is very likely that the company would not exist. Carter talked about one particular instance during a flight test in which the CarterCopter suddenly went nose-high and climbed nearly 2,000 feet for no apparent reason. The aircraft lost nearly all airspeed during the excursion. It turned out, however, that the test pilots had been using X-Plane to "fly" the prototype through the same tests on the ground, and had run into the exact problem while in the sim. Because they had seen the behavior in the sim, they immediately recognized what was going on and executed a smooth, uneventful recovery.

Thanks to an agreement between CarterCopters and Austin Meyer, the model developed by the company for the prototype is included with X-Plane, and in the near future the model developed for the new NxCC prototype will also be made available to the public.

One of the more interesting modifications incorporated into the NxCC is a change to the rotor tips which is expected to allow the company to come that much closer to break the Mu-1 barrier. This barrier refers to the long-standing belief that the ratio of the forward speed of the aircraft to the tip speed of the rotors can never exceed a value of one without destroying the rotors. When a helicopter is hovering, the value of Mu (represented by the Greek symbol  ) is zero. In the CarterCopter, as the forward speed of the aircraft increases, lift is transferred from the rotors to the wings. This allows the rotor RPM to be reduced, which obviously reduces the rotor tip speed, in the same way that the tip speed of a conventional aircraft propeller is reduced when RPM is reduced.

However, as RPM slows and speed increases, airflow over the retreating blade of the rotor is reversed. Previous research had shown that long before the ratio of Mu could reach a value of one, the rotor would become unstable and flap uncontrollably, leading to a catastrophic failure. The only two rotorcraft to achieve Mu values approaching a value of one were the Cheyenne (0.8) and the McDonnell XV-1 (0.95). Neither of these rotorcraft went into production.

On March 22, 2002, the CarterCopter reached a forward speed of 173 mph and an Mu of 0.87. One of the results of this flight test was the conclusion that the company engineers still needed to work on stability of the rotor blade at high Mu values. Carter theorized that the way to prevent the rotor system from destabilizing was to overcompensate on the advancing rotor blade in order to negate the instability of the retreating rotor blade. Because the CarterCopter rotor incorporates a single spar, it is somewhat easier to control this instability. One of the modifications that Carter is incorporating into the rotor design is something that could not be done without composites - the addition of 55 lbs of lead ballast to the rotor tip. Carter estimates that this modification will allow the blade to reach an Mu of 0.9 or higher, and still remain within the 5 to 1 safety factor that he demands of all systems on the aircraft.

All of this activity has not gone unnoticed by the military establishment. Carter argues that the reason for the development of tilt-rotor aircraft is the belief that the Mu=1 barrier could not be broken. According to him, this has led to over $50 billion being spent on tilt-rotor technology. Now that Carter is making progress in proving the belief wrong, this is creating some doubt about where future funding should be directed. Nothing would please the military more than the development of an aircraft with features such as what the CarterCopter is demonstrating or plans to show on NxCC. For example, current production rotorcraft cannot nose up or down in a hover and at the same time maintain a fixed position over the ground, a ship, or some other object. The CarterCopter's tilting rotor mast can be incorporated into a design that would allow exactly such a maneuver to be accomplished.

Another interesting announcement at the conference was the development of a new propeller system for an unnamed UAV. The propeller developed for this aircraft is unique in that it has been tested at tip speeds over Mach 1.0. The prop, which weighs all of eight tenths of a pound, required a 100-hp powerplant to accomplish this feat. Most of the power, however, was expended as noise during testing.

Finally, Carter pointed out that in the middle of the celebrations of the anniversary of the first flight of the Wright Flyer, no one was paying much attention to the 80th anniversary of the first flight of the Cierva C.4 in 1923. Juan de la Cierva's aircraft, the first autogyro, flew in January of that year. Five years later, in 1928, Harold Pitcairn made history when he flew the first autogyro in the US under a license from de la Cierva. Working together, they later developed the first articulating rotor head, which Igor Sikorsky later licensed for use on the world's first production helicopter.

FMI: www.carteraviationtechnologies.com