Challenger Ultralight Aircraft Maintenance

Tip #7 – Tightening Landing Gear Drag Wires

The drag wires are the wires the stretch from the fuselage to the main landing gear legs. These stranded wires support the landing gear legs by transmitting some of the forces encountered in landing and taxing to the fuselage body. They prevent the gear legs from bending to far. It is therefore important to keep these drag lines fairly tight. They tend to stretch with use and need to be tightened up from time to time.

There are two ways to tighten drag lines. The hard way is to disassemble the wire from the eye loop that connects it to the eye bolt at one end. Then you will need to shorten the effective length of the wire and recrimp the wire in place. It is a real good idea to mark the wire with a black magic marker first to indicate the original stretched length of the wire before disassembly. It is a bit of a guessing game to get the length right.

However, if the drag wire is not too stretched out it may need only a small adjustment in overall length. This can be done quickly and easily by rotating the stranded wire so as to tighten the wire twist. Remove the eye bolt that connects the drag line to the fuselage. Rotate the wire a couple of turns in the same direction as the wire twist. This will shorten the overall length just enough to tighten a bit of slack in the wire. Reinstall the eyebolt to the fuselage. The job only takes a few minutes and requires no fancy crimping tools or new parts.

Another tip is to do this job with the plane resting on its tail and with someone sitting in the back seat. This will push the gear legs forward ever slightly. When the plane is returned to a nose down position it will tighten the wires a little more.

The same procedure can be followed with the two drag wires that run between the two gear legs across the belly. A good tip for installing or tightening these wires is to do it with the plane lifted off the ground do that the legs are not bearing any load. When the plane is returned to sitting on the landing gear the wires will further tighten up. These two wires should be about the same tightness. This can be determined by strumming the wires and comparing the sound produced. They should sound about the same. If they don’t, give the looser wire (lower note) a twist as shown in method two above and reinstall.

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