Gas Gen Base Mount


With an entirely different mounting scheme from print, I was faced with devising a method to support the gas gen. turbine without interfering with any side rail mounted devices and plumbing. Most of the thrust is absorbed with the two aluminum upright mounting stems which are connected via a sturdy plate to the back of the gearbox... thus, the gas gennie mount need be nothing more than a support to alleviate the strain between the power turbine NGV and the turbine tunnel, mating gearbox to the remainder of the turboprop.

  The first step was to turn and drill a ring with a bolt pattern exactly matching the spider to gas gen attachment point. A 1/8" thick section of the ring was parted after the holes were drilled.
A mild steel plate forms the lower base. Two 5/16" mild steel squares were turned round at the ends and TIG welded as shown. This picture shows the mount upside down, as viewed from the bottom. The bead is filed flush with the surface. Good penetration ensures a strong joint regardless.
In the mill, the far ends of the 5/16" square uprights were bored to develop a mating surface with the parted ring. This is then carefully TIG welded in place. The ring is split with a hacksaw to provide a 3-hole mounting pattern.
Mounted to the turbine in a test-fit manner. The holes were drilled a bit loose to allow just a touch of movement for final alignment.
Shown here mounted with the rest of the turboprop. The rails on either side are stiffened with 1/32" aluminum sheet cross-members, and to one of these will be bolted the mount. To prevent corrosion, the mount was spray-painted with BBQ grill black enamel, good to 1200 degrees f.

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