The engineering team at Gap-Tallard, France-based Beringer Wheels & Brakes has devised a new tailwheel design to help prevent ground loops in tailwheel-equipped airplanes. The patented “tailwheel with double pivot” essentially is a lockable tailwheel that is steerable while in the locked position. Beringer also announced that it has received a supplemental type certificate for a complete Cirrus SR20/22 replacement wheel and brake system with Beringer’s anti-lock inline regulator (ALIR) anti-skid braking feature.
The double pivot tailwheel is a replacement for current Scott designs and weighs the same, while incorporating other features such as a tubeless wheel and sealed bearings that require no maintenance. Beringer plans to certify the new tailwheel first on a Piper Super Cub.
On normal tailwheel designs, the pivot axis of a steerable tailwheel is offset from the wheel axis, and the distance between the two is called the trail, according to engineer Claire Beringer. “When you increase this [trail], the maneuverability increases but stability decreases.” While pilots appreciate the trail feature that allows the tailwheel to pivot for improved ground handling, if there is a disturbance during landing, such as a crosswind gust, the force on the tail wheel tends to cause the wheel itself to turn just when it would be more helpful for the pilot if the wheel were to remain straight. “The [tailwheel] spring is not strong enough to retain the tailwheel in its axis,” she said.
The Beringer double pivot tailwheel has two different pivot axes, one for the wheel itself and one forward of that for the full pivot needed to maneuver in tight spaces on the ground (in other words, adding trail to the wheel). With the wheel in the locked position, the wheel can’t pivot but can still be used to steer a certain amount right or left. By pulling a cable in the cockpit, the pilot adds the trail to the tailwheel assembly, which can then pivot in any direction.
On a typical lockable tailwheel found on airplanes such as the P-51 Mustang or DC-3, Beringer said, “When locked, there’s not [any] path correction; it is impossible to steer. With the double-pivot mechanism, the wheel is locked but you still can steer. Then you increase the trail on the tailwheel by pulling the cable, and you can make a U-turn and get in the hangar more easy.”
The double pivot tailwheel should receive TSO approval in about six months, Beringer said, then it will be STC’d on the Super Cub. A price has not yet been set.
The Cirrus SR20/SR22 wheel and brake system costs $7,559 and includes tubeless wheels with sealed no-maintenance bearings (6.00 by 6 main wheels and 5.00 by 5 nosewheel), dual-caliper brakes, pilot and copilot master cylinders, brakes lines and Beringer’s ALIR system. The Cirrus system saves 4.5 to 7.5 pounds compared with existing brakes, depending on which type is installed. Beringer’s sintered metal brake pads last 500 cycles and discs for 2,000 cycles. Landing rolling distance is 40 percent lower with the Beringer brakes, according to the Beringer.
The ALIR system includes a regulator, which prevents the brake pressure from exceeding a set limit (which is adjustable for each installation), no matter how hard the pilot pushes on the pedal. This means that the pilot can use differential braking, for example in the Cirrus, to steer on the ground, but it prevents one brake from being actuated harder than another during the landing roll, thus helping keep the airplane straight but also allowing application of full braking power. The system’s pressure limiter also helps prevent brakes from locking up. This is very useful in a tailwheel airplane to help avoid locking the wheels and flipping over onto the nose when maximum braking is needed.
One of the most popular Beringer wheel and brake conversions is for Pilatus’s PC-6 utility single-engine turboprop. According to general manager Véronique Beringer, the maintenance costs for the original PC-6 brakes average $25 per hour. The Beringer brakes average $4 per hour. “We have sold 120 kits for the PC-6,” she said.
For quicker service in the U.S., Beringer has an office in Chicago staffed with technical experts and assemblies and parts for all of its products.