Landing Gear Technology on CarterAviationTechnologies.com

Landing Gear Technology

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Landing Gear Picture

Carter has invented and patented an ultra-high-energy-absorbing landing gear system, which has been flying on the CCTD prototype since 1998. The gear was designed to greatly improve safety margins during landings and should be scaleable to fit any aircraft. The gear uses a special "Smart Strut," a hydraulic cylinder with a mechanical smart valve. During the first inch of travel, the valve determines the impact velocity, and automatically adjusts the pressure to provide a near constant deceleration for the remainder of the travel, with no rebound. This is the most efficient way to absorb the impact energy of the landing. The landing gear has another noteworthy feature in that should the impact velocity in a crash be much higher than the design limit, then the max pressure is kept below that which would cause yield until the gear bottoms out, which keeps the gear from failing until the max energy possible has been absorbed.

The prototype system being flown on the CCTD uses an 18-inch stroke. It has been proof tested to absorb a 1200 feet-per-minute (fpm) landing impact with no damage to the aircraft or occupants. It will absorb a 25 fps impact with only minimum damage. The prototype weighs 125 lbs total (50 lbs for each main and 25 lbs for nose) but can be engineered to weigh a total of 100 lbs when in production. This technology is fully developed.

We have completed drop testing of our next generation aircraft landing gear design. We tested one gear to an impact velocity of 24 ft/s (1440 fpm) with a 3000 lb test weight. The drop height was 134" (107" until first impact + 27" of landing gear stroke). The landing gear did not exceed the design limits, which were themselves only 2/3 of the load applied during the static proof test. The peak decceleration during the 24 ft/s test was 5g. Depending on the weight being supported by the gear, the impact velocity could be varied accordingly, as long as the total energy being absorbed by the gear remains the same. For a 2000 lb weight, that would be an impact velocity of 30.4 ft/s (1824 fpm) and a drop height of 197". The total weight of the gear, including the rim, tire, brake, and attachment hardware, but not including the pump used for retraction/extension, was less than 70 lbs. Note that these tests were for one gear supporting 3000 lbs. For a typical airplane with two main gear, this translates to a 6000 lb gross weight.

An improved version has been designed that uses a hydraulic fluid that changes viscosity based on an applied electrical charge. Using a 3-ft stroke, the new gear should absorb up to 2000 fpm landing impacts with no damage to the aircraft or occupants. The FAA standard for certified aircraft is 7-10 fps (600 fpm).

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