Washers on Tail Rotor Pitch Links

Although I have never experienced such an event on the tail rotor pitch links, it is possible for the rod end bearing retainer to fail allowing the rod end outer casting to slip over the bolt head that secures it to the tail rotor mechanism. A simple safety modification is to install a washer under the head of each of the four bolts with a large enough diameter to prevent the rod end casting from being able to totally come off the bolt. If the bearing retainer should fail then the pilot would feel a vibration from the tail rotor area but the rod end should remain functional for enough time to allow an emergency descent and landing

The above photo is typical and you can see that the washers are not installed under the bolt heads.   The tail rotor pitch pins above have the washers installed.

• It has been suggested that the builder install a large enough washer that the washer OD will not fit through the outer casing of the rod end should the rod end bearing keeper fail
• The bolt's safety wire will pass around washer

The Slider rails on the Rotorway helicopter will wear with use and can become quite sloppy. I have seen them worn to the point of failure on at least one Rotorway helicopter. The factory plans direct the builder to drill a hole through the slider and the slider rail once the belts were stretched to firmly secure them from movement. I have seen this done and when I checked the tail rotor belt tension it was way on the loose side. The builder did not think that he needed to make any more adjustments after the initial stretch—Wrong! If this method is followed it is possible to end up with a series of holes drilled on the slider from multiple adjustments over the life of the belts. It is not a bad method but it takes additional time to remove the screws and nuts in order to adujust the tail rotor belt tension.

One of my students had what he felt was a better solution that is pictured below. This aviation cable turnbuckle was purchased from Aircraft Spruce and Specialty and has forks on each end. The forks slip onto the rail and are bolted on beyond the 1” furthest adjustment mark. To adjust the belt tension he clips the safety wire that passes through the hole in the turnbuckle and is wrapped around the all thread rod. He then loosens the turnbuckle, tightens the belts, tightens the turnbuckle to clamp the rails against the slider firmly, installs new safety wire to prevent the turnbuckle from rotating.

In the photo above you can also see that the builder installed a tubular bushing on the rear portion of the all thread rod behind the jam nut. This gets the jam nut out in front of the rear aluminum angle where it can be easily reached with your 1/2" wrench each time you adjust the tail rotor belt tension. You will be glad you installed this simple modification. Below is a photo of the Aircraft Spruce and Specialty catalog where he ordered the turnbuckle. It is an AN 150-8S turnbuckle assembly. You can click on this link that I have provided to go directly to their order page for this turnbuckle. Remember that each builder is responsible for any alterations that he makes. I am simply sharing what others have done on their own helicopters.

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The material on each page is the opinion of the author only and any actions taken by the reader relating to information on this site is the responsibility of the builder.