Great Planes Yak-54 1.60 ARF - GPMA1411 - Manual (Page 24)

washer and prop shaft may be required and it is up to the
modeler to do so. We suggest reading through the entire cowl
preparation section before building the cowl ring so you
understand how it works and will be able to modify the ring if
necessary while assembling it to match your engine.
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2. Glue the three smaller rings together, being careful to
align them flush. Test fit this assembly into the front of the
cowl. It should be able to pass through the opening. If not,
sand the edges until it can.
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3. Glue the two larger rings together, being careful to align
them flush. Note that one large ring has a small hole in the
center, and the other large ring has a large hole in the center.
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4. Glue the two cowl ring assemblies together with the
center holes all flush. Be sure that the large ring with the
small hole in the center is at the bottom.
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5. Test fit the cowl ring onto the firewall to determine its
correct orientation. The holes in the cowl ring will only line up
with the holes in the firewall one way.
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6. Sand the inside perimeter of the cowl approximately 1"
[25 mm] from the aft end to prepare it for glue. Clean the
sanded area with compressed air and wipe it down with
denatured alcohol.
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7. Temporarily secure the cowl ring to the firewall using a
few 4-40 x 1/2" [13 mm] socket head cap screws. Slide the
cowl over the cowl ring, aligning the colors on the cowl with
the colors on the fuselage. Overlap the fuselage with the
cowl by 1/4" [6 mm]. This step has positioned the cowl ring
inside the cowl so the colors will align when the cowl is
permanently glued to the cowl ring.
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8. Use the included cowl ring to accurately set the depth
and angle of the cowl so that it is centered over the spinner.
The ring fits onto the engine crankshaft with the round recess
fitting over the engine drive washer as shown. Slide the ring
onto the crankshaft until it touches the front of the cowl. While
maintaining even pressure around the ring, use it to push the
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