Wichita Falls, Texas: Saturday, February 16, 2002

By Jay Carter and Paul Smith

CarterCopter Technology Demonstrator (CCTD) flight testing continued in Olney, Texas on February 7th and 8th.

FLIGHT ENVELOPE EXPANDS TO A MU OF .69

Three new CarterCopter flight records were established:

* The Greek letter "u" (Mu) is used to designate the ratio between the forward speed of the rotorcraft to its rotor tip speed relative to the aircraft. No other manned aircraft has ever flown at a Mu of 0.55 let alone broken the "Mu 1 barrier" in sustained, stabilized flight.

Flight control concept working:

Our concept for controlling rotor flapping and rpm as the aircraft accelerates and Mu approaches 1 (Mu 1 barrier) is working perfectly. This concept was patented before we flew for the first time. We have another patent pending on a method to better control flapping and prevent it from becoming excessive. This control has proven its value on several occasions. Our constant success in achieving higher Mu values validates our approach in achieving a Mu greater than 1 - a goal that has eluded all other helicopter companies.

A deciding factor in the time it has taken to make these milestones is our cautious approach and risk mitigation strategy. During the course of this rigid test and development cycle we have found the control system was not rigid enough to provide adequate control as we expanded the Mu region. The origin of the softness in this control system lies in the push-pull cables and the direct cyclic control system. The system is not boosted in spite of an aircraft test weight of 3500 lbs. This was done to keep the system simple. The rotor system is designed to be inherently stable - something most helicopters do not have and certainly not ones that fly at high speeds & relatively high Mu's. The CCTD is not inherently more difficult to fly. However, flying the CCTD requires a significant learning curve not unlike other revolutionary aircraft designs such as the Harrier or the V-22.

Flight notes:

At 140 rpm, 150 mph and a Mu of .69 the CCTD was stable. A modification to keep the blades from popping out of track has thus far worked and the blades are tracking so closely that the pilots did not report any vertical bounce.

During several test flights we have noted a condition whereby the rotor plane of rotation diverged rearward, causing the aircraft to pitch up. This is caused in part by the soft control system which allows the spindle to continue to tilt back even after the pilot pushes forward on the stick. At the higher speeds, once the rotor tilts back beyond a certain point, the loads (indirectly caused by flapping) increase rapidly and the cable stretch allows the rotor to tilt back even further. The last flight on Friday was the most severe. The pilots were able to get out of a potentially dangerous situation by pushing the collective to a minus 2 degrees, which immediately unloaded the rotor. The aircraft pitch up was more severe on this flight because the rotor had been trimmed back more than before to keep the rotor rpm and lift up. This was performed to maintain a more responsive control until the aircraft had obtained a higher forward speed where the airplane flight controls are much more responsive. The rotor trim is also controlled with a push-pull cable and at the high rotor trim settings, the mechanical advantage changes such that this cable sees a much higher load. The corresponding and accumulative stretch of this control cable was a factor of the soft control system. We will incorporate a redesign to increase the stiffness of the rotor control before we fly again.

Safety First:

Although the CarterCopter project seems to be progressing slower than anticipated, we continue to maintain our primary focus on safety. We take small calculated steps to isolate problems and make appropriate changes before proceeding further into a potentially dangerous situation where we cannot safely back out. We have to sometimes remind ourselves that we are doing what the major helicopter companies gave up on and what most helicopter engineers said could not be done. After noting our recent successes, it is comforting to know that some of them are beginning to understand and appreciate our achievements. We are doing everything reasonable to reduce risks and continue to safely test the CCTD, but we have to assume some level of manageable risk. This project has been a true team effort, including our test pilots who take the greatest risk.

On the horizon:

Jay Carter, Jr. recently met with several senior aerospace executives where we presented an outline of the steps it will take to finally achieve the goal of flying at a Mu of 1. There are also two government Unmanned Aerial Vehicles (UAV) contractors interested in our propellers. Additionally, we think our aircraft has great potential as a competitor in the VTOL UAV market and we are gaining some recognition in that area from major UAV designers.