Extra 300/SC, Руководство по обслуживанию

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CHAPTER 51
PAGE 25
MAINTENANCE MANUAL EXTRA 300/SC
PAGE DATE: 12. February 2019
The damaged area of the inner laminate has to be taken out as
well. Make sure not to increase the disbond area by preparing
the hole. Preferably use a hand held milling machine. In case
of cutting with a saw, the pulsation stress may peel of the
inner laminate (secondary damage). If the extent of the
disbonded area on the inner laminate exceeds the prepared
cut out, increase the cut out of material and upper laminate.
Prepare a scarfed overlap of laminate around the circular cut
out. Overlap lenght of inner laminate should not be less than
20 mm.
I M P O R T A N T Overlap lenght of the upper laminate should not be less
than 1/50; (ratio: laminate thickness / overlap lenght).
Prepare a replacement block of core material (foam or
honeycomb) with equivalent diameter and thickness. Cut it
to fit snuggly in the trimmed hole. In case of foam core, coat
one side with a mixture of resin and microballoons (ratio
100:15). Apply prelaminated fabric layers required for the
inner laminate on this side of the core filler block. Ensure
correct style and direction of fabric. After precuring the
laminate at elevated room temperature (30°C), scarf the
overlap and sand the upper overlapping core material down,
up to the surrounding core material.
Subsequently clean the repair area thoroughly as follows:
- Remove the sanding dust with a pneumatic vacuum
cleaner
- Clean the scarfed overlaps with carbon-tetrachloride or
acetone in case of dirt or grease was introdued during the
preparation.
W A R N I N G Carbon-tetracloride or Acetone used for cleaning re-
pair areas are flamable liquids and should be used with
proper ventilation and safety equipment.
I M P O R T A N T Repair area must be free of dirt and grease.
Wet all surfaces of the backing plate and the scarfed area with
resin mixture. Lay on prelaminated fabric layer in accord-
ance to the layer sequence plan. Ensure correct style and
direction of fabric.
REPAIRS
Repair of Sandwich Material