Please visit the Technical Data portion of our website to find our articles on best cleaning practices.

Tempest currently manufactures only 18mm spark plugs.

Please refer to the Tempest application chart. There are several things you will need to know as most engines have several different spark plugs approved.

1. You will need to know your harness B-nut size. This is the nut that screws onto the spark plug. It will be either a 5/8-24” or ¾-20 thread. Be aware that a 5/8-24 utilizes a 3/4” wrench and a ¾-20 utilizes a 7/8” wrench.
2. Long reach v. short reach will be determined by the specific engine.
3. Heat rating is indicated by the numeric value of the spark plug part number. The lower the numeric value the colder the heat rating. Best practice is to use the same heat rated plug you have removed.
4. Massive electrode or fine wire is a personal choice. Massive plugs will generally operate 400-500 hours. Fine wires can last 1500 hours. This choice is usually determined by number of annual hours flown and the size and performance of the specific engine.

Removing the flanged bushings from the torque link forging can be difficult as there is not a good surface to press against or grab onto. An easy way to remove them is to thread them with a tap, screw a bolt in the thread you made, and then drive or press against the bolt. The thread does not have to be a full depth thread for the bolt to hold securely in the bushing. The bushing material is somewhat hard, but not so hard that a standard hardware store tap will not do the job. Use cutting oil on the tap to prevent tap damage. Normally the bushing will then come out easily.

For stubborn bushings, soak the link assembly in boiling water before pressing the bushing. The heat will expand the aluminum forging more than the steel bushing. This helps loosen the press fit while limiting the temperature to prevent from overheating and harming the heat treat of the aluminum forging. A controlled oven can be substituted for boiling water as a heat source, but do not exceed 350° F. Do not use flame or other non-controlled heat sources.

An alternate method is to put dry ice in the bushing before driving or pressing on the bolt you threaded into the bushing. Do not over-press or hammer as the aluminum can gall to the bushing and leave a damaged bushing bore. If the bushing does not come out with light to moderate force take the time to use some heat or cold to help.

There are many components all connected to keep the nose gear in line. If one component is worn or out of tolerance it can cause shimmy problem. Reference Dave McFarlane’s article: Can You Stop Nose Gear Shimmy instructions and suggestions.

Overlooked items also include the rod ends, shimmy dampener mounting and attachment, shimmy dampener, and steering collar. The steering collar is where the steering rod tubes connect and the upper torque link is attached to, along with the shimmy dampener on most aircraft. If the steering collar has play vertically and laterally and is allowed to tilt; that will cause excessive wear and force on the torque links, steering, and strut components. There are three different thicknesses of shims to help get the collar in place.

Ensure that the shimmy dampener is working properly with no dead spots in dampening action. The cylinder could be worn on the inside or on a piston that warrants replacement of components. All of the nose strut components are tied to each other and any movement is transmitted through to the tire and back through the dampening system, which if remedied will continue to be more pronounced.

It is very important to maintain proper torque for the bolts that clamp the chrome bushing/spacer at the upper attachments to the steering collar and the lower attachment to the nose gear strut. It is commonly thought that the chrome bushing/spacer is kept in position by the bolt filling the center bore of the bushing/spacer. This is not correct as the inner bore of the chrome bushing/spacer and the bolt are a loose non-precision fit. The bushing/spacer is secured by the bolt end, clamping the spacer so that it is tight between the arms of the aluminum forgings. Any looseness of this end clamp will allow movement of the chrome bushing/spacer. This movement will erode the aluminum forgings and create more free motion of the torque link.

All shimming of the torque links must be done with proper torque on the bolts. Periodically and during nose gear inspections, check the torque on the upper and lower torque link bolts. If the chrome bushing/spacer is allowed to move, the resultant wear can require replacement of the expensive aluminum forgings. McFarlane is working on a repair for the worn aluminum forgings. Unlike our competitors, extra care is given to the machining of the McFarlane chrome bushing/spacers to give the largest possible bearing surface to the ends that bear against the aluminum forgings. Chamfers or bevels are kept very small.

The torque link stop lugs are more important than you would think. Overextension of the nose strut due to a worn out stop lug can lead to a cascade of problems. McFarlane A&P mechanics have seen struts over extend to the point where the metering pin comes out of the orifice. This results in loss of damping action and the pin hammering the orifice every landing and distorting and enlarging it. Over time, the excess nose strut travel and lack of damping can result in fatigue cracks in the torque link arms. McFarlane recommends thoroughly inspecting all nose strut components when replacing a severely worn stop lug.

The stop lug also acts as a centering device aligning the nose wheel and wheel pant straight with the airplane and slip stream after it has left the runway. Worn stop lugs can allow the nose wheel to lock in a turned position in flight that will require holding rudder for coordinated flight. Retractable gear aircraft depend on the stop lug to properly center the nose gear steering before it retracts into the wheel well.

Our Vertical Fin Fitting kits include all the hardware needed for installation. You may receive NAS1149 hardware with the kit, which supersedes AN960 hardware (referenced in our ICA).