(2) Layout and Mask. Layout and mask off main rotor blades fo r polyurethane tape application as shown in figure
(3) Cut tape. Cut tape to the dimensions in table 3-30.
Surface preparation and cleaning are the most important steps to insure proper
(4) Surface Preparation. Remove dark green paint down to light green primer in the area shown in figure 3-47
with MEK or sandpaper. Scuff the masked off area with 120 grit sandpaper. Only sand in a spanwise direction as shown
in figure 3-1, sheet 1. Use of a power polishing sander is permitted for this procedure.
Do not sand the bare metal skin of helicopter rotor blades. Sanding bare metal
skin on helicopter rotor blades reduces the structural integrity and fatigue life of
(5) Cleaning. Wipe the masked area several times with cheesecloth or machinery towel dampened with
isopropyl alcohol or denatured alcohol, then wipe with a clean, dry cloth.
Perform Steps (6) through (8) for one blade at a time.
(6) Application of Adhesive Promoter. Apply a thin coat of No. 86 adhesive promotor to the area covered by the
first piece of tape, shown in figure 3-48. Allow to dry at least five minutes, but not more than one hour before applying
tape. Promoter can extend beyond end of tape. Apply promoter in tape length segments to avoid contamination of
(7) Tape Application, 4 in. Apply alignment marks to outside of tape in the appropriate position obtained from
piece of tape to area shown in figure 3-48 per tail rotor procedures. Trim tape to outline of stainless steel guard and
remove tape from over inboard attachment screw holes (see figure 3-49). With backing strips on and against the blade,
hold 20 inch long piece of 4 inch wide tape in position on the tip leading edge per figure 3-50 and mark where tip and
bottom inboard edge mates with existing tape. Repeat this procedure with a second piece of 20 inch long piece of 4 inch
wide tape for the outboard edge (see figure 3-50). Cut tape at the mark lines. Apply No. 86 promoter and place tape in
position as shown in figure 3-50. Any bubbles encountered during the application process may be removed by continuous
squeegee stroking towards the edge of tape or by puncturing the bubbles with a needle and applying pressure to wet