Machining the Trunnion

the first operation

The first stage, after surfacing a block of aluminum flat and parallel on both sides and adding some hold down slots, was to clamp it down on a scrap piece and machine the first side profile, using standard carbide endmills for roughing and ball endmills for finishing. The picture shows after this first operation is complete. We’ve added four bosses outside the actual part profile for hold down capscrews and dowels. They will be cut off in a later operation.

3 thoughts on “Machining the Trunnion

    • Hi,
      The basic principle is that of an air/oil spring. The air, under some pressure, acts as a spring, and hydraulic fluid forced through orifices acts as the damper. So we can absorb the energy of landing efficiently and without much rebound. The valve through which the fluid is forced has different flow rates in the up versus the down direction, so it greatly minimizes any tendency to bounce on landing. Also, this unit has to steer the airplane, so the steering bellcrank on top is connected through the unit with a stainless steel bar that drives the moving stanchion (cylindrical part) and thereby turns the nose wheel. I’ll post a cutaway of the CAD model to show the internal parts.

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