Final Assembly - TurboProp


With the base rails assembly complete, I began the final assembly of the turboprop itself.

  This elaborate setup was made to drill a single hole for the EGT probe. By the time I had decided on probe location, which was dependent upon the rails, the power turbine NGV and support mount were firmly secured onto the gas gennie, and I had no desire to detach it. Chucked in the vertical mill, I am able to make a clean spot face and drill through without problems. At the other end of the chuck drawtube is a shop vac, hooked up to suck any hint of swarf which might fall into the NGV area.
The special gearbox mount was secured tightly with thread-lock compound using 8 4-40 FHCS. You can see the tubes which deliver lube and air to the power turbine tunnel.
The tunnel itself is wrapped with the provided ceramic blanket, and wrapped in a thin sheet steel cover. I used nichrome wire to secure. The tape is protecting the ceramic race from any stray fluff from the blanket.

A good source of nichrome wire are the coils found inside a scrapped hair dryer.

The exhaust is mounted, using the two fiber disks and a stainless steel pressure disk.

And the power turbine is secured. Mike mentions an inability to immobilize the shaft, hence the need to cut flats in the end of the shaft which protrudes beyond this turbine. I found that if I delayed mounting the front cover of the gearbox, I could easily sneak a spanner into the gearbox to secure the shaft using the pinion nut. In this manner, I was able to secure it very thoroughly.

Time to mount the cover and prop assembly, shown here assembled separately from the rest of the turboprop.

A good coat of gasket sealant (permatex) was first applied and allowed to set for a few minutes. Don't skip this messy step. Even if you think your surfaces mate perfectly, without it the oil will leak out!

Pressed into place, the front of the turboprop is secured with SHCS. All that remained at this point is to mate the spider to the gas gennie NGV, and the turboprop was complete!

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