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Europa #435 G-RODO Build Journal - 2002 04

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1 Mark the hinge position on the edge of the tailplane. Start to think about cutting out the BID for the port tailplane closeout, but before marking out, check measurements given in manual as the proportions look wrong. The rear face of the exposed foam measures about 650mm from the trough at the tab-tip end to the face that forms the root rib. The manual calls for BID 65cm x 10cm (I wish they'd stick consistently to mm, I find that much easier for some reason) and also says that all overlaps must be on the fore-and-aft surfaces, with none on the trailing edge face. So, to allow the desired 20-30mm overlap, the rear closeout piece should be 710mm x 100mm (ie 2x30mm longer). The root rib area does not seem to need the 80cm length called for, and I would be happy with 770mm here (ie, 30mm shorter). (Yes, I remembered the edges go right to the TE of the glass, and there's enough for the LE flange too.) Could it be that the dimensions given were perhaps for a previous layup scheme where the overlaps were on the rear face? Then when they discovered that made things a bit tight for hinging the tab, they changed the words but forgot to change the sizes. The only evidence against this deduction is that the tip rib is already pretty nearly correctly dimensioned for no overlap onto the rear closeout. Cross-checking the dimensions called out for the trim tab itself a few pages later shows that I have made no gross errors in any of my measurements or cutting lines. When I open the glass cupboard to start marking out, several pieces of loose glass offcuts fall out and I decide now is the time to make a proper offcut box. Look out some bits of faced chipboard, ply, hardboard, etc and decide on some dimensions. 207.7
2 Finalise dimensions of glass offcut box and confirm which bits of material to use. Cut to size and assemble base, ends, and central division. Cut piece of ply for front and sand smooth.
3 Cut piece of hardboard for rear of glass offcut box and fit.
6 While waiting for hard disc repairs to finish, cut aluminium angle to length for legs of offcut box, drill, countersink, smooth edges & corners and fit.
15 Using dimensions I worked out as correct (ie 2 off 710x100 & 4 off 770x200), mark out BID for port tailplane TE and root closeout; some of the offcuts can be used up. File radius on foam at root/TE corner. Plug TP5 with foam. Humidity 58% and falling. Mix 2 strokes epoxy with 2 doses flox for TP5 flox corner and apply. Use some of the fluorescent green peel-ply with a star cutout to clear the foam plug in TP5. Leave to cure propped against table (no curing tent) with fan heater thermostats on about 3.5. 210.5
16 Remove peel-ply from flox around TP5. Mask off inside faces of glass flanges all around closeout. Temperature around 19C and humidity about 58%. About 14:00 mix 2 strokes epoxy with 7.5 doses q-cell for dry micro. Put fillet around foam/glass corners and fill all dents and remaining cracks. Realise I forgot to cut the glass, so clean off gloves carefully and do that. Put BID pieces on table so I can close glass cupboard again. Mix 3 strokes epoxy with 2 doses q-cell for micro slurry and paint onto foam. Mix 5 strokes epoxy for outboard rib brackets and 1st layer BID. Brackets go in quite easily, althugh not exactly square. Place root piece dry and cut cross for TP5 and foam plug. Wet out and it fits well. Trimming of TE end tricky as expected but feasible. Apply TE piece and wet out, and tab end piece. They all go around the various corners quite well, but wetting out TE flanges is hampered by the edges protruding from the opposite flange, which tend to get delaminated by stippling action. Scissor trim some large overhangs. 2 more batches each of 5 strokes used to wet out 2 layers of hinge reinforcements and 3 pieces of 2nd layer of closeout. For bedding and coating ply piece TP8, mix 2 strokes epoxy and 2 large doses flox. Enough left for sample after filling edges. 4 more strokes epoxy sufficient to wet out last 2 layers of root rib. Cut peel-ply and apply in sections. Needs a lot of fiddling to get it fitting at LE corner. Tends to lift off glass layer at edges of ply so can't squeegee near there, just stipple it in place to avoid bubbles. TE end of lower root flange was tending to bend outwards slightly, so put light cramp on there to encourage it to set straight. Turn on both fan heaters to thermostat setting 4 and leave to cure about 20:30 (no tent). At bedtime, check progress. A couple of large bubbles (one seems to be between the peel-ply and glass) have appeared on the root face, so pierce them and persuade them flat again. Leave heat on overnight. 217.0
17 Turn off heat about 10:30. Pools of resin in lower corners, but everything seems to have cured OK & bubbles have not come up again.
18 Trim layup around port TP5 with Perma-Grit wheel on Dremel. Foam plug breaks off flush rather than pulling out, so hack it out. Some epoxy has run down inside TP5, but quite easy to remove from the stainless steel. File down layup almost flush and chamfer entry. Check torque tube goes in OK. Trim port tailplane closeout edges with diamond wheel on angle-grinder then file and sand flush to skins. Put port tailplane and tab back into storage and get out starboard one. Dig out TP3 foam root rib and remove peel-ply. Find I can get a reasonable surface just with the knife used as a scraper, so probably don't need the Dremel router approach this time. 219.8
22 Mark out and cut off starboard trim tab. Use Dremel with Perma-Grit wheel on both surfaces this time instead of hacksaw blade. It leaves a slightly wider kerf, but, with care over depth of cut, avoids any damage to LE of tab. Dig out starboard tab tip recess. Round TE/root foam corner. File and sand all inside faces of starboard tailplane closeout glass that weren't peel-plied, and mask off. Dig out wedge at outboard rib and clean rib face with file. Make foam wedge to fit. 222.4
23 About 15C, 74% RH. Turn on both heaters and dehumidifier. Spend some time getting putty soft enough to use as seal around foam plug in TP5. Mix 2 strokes epoxy, 3 doses flox and 1 dose Cabosil for TP5 starboard flox corner. Peel-ply and leave to cure with whole area heated. Finishes about 25C and 35% RH local to workpiece. Mark out and cut all BID for starboard tailplane closeout, and leave on layup table ready for use. 226.4
24 About 14:00 19C, 57% RH, turn on fan heater to bring humidity down. Remove peel-ply from starboard TP5 flox corner. Mark hinge positions on starboard tailplane upper TE. Mix 3 strokes epoxy with 9 doses q-cell for dry micro, which is far too much for the fillets and the gaps in the root face. Mix 3 strokes epoxy with 3 doses of q-cell for micro slurry which seems slightly thick. Barely covers with brush but squeegees out with plenty to spare. Mix 6 strokes epoxy and paint onto glass flanges after peeling off masking tape. Fit rib brackets and foam wedge and wet out. Drape first layer on root and wet out. Start to drape first layer on TE and find that a small pool of resin collected in the corner has started to exotherm. Dig it out - it has left slight depression where it has started to melt the foam. Decide to ignore it and carry on. Fit and wet out TE tip rib. Mix 6 strokes epoxy. Fit hinge reinforcements. Epoxy in cup starts to exotherm as last hinge piece fitted, so put it in a water-bath outside. Mixed too much, before it could be used, and temperature inside is getting up over 25C, even with extractor going. Add all 3 pieces of second layer of BID. Temperature peaks at about 28C with RH down to 35%. Mix 4 strokes epoxy and wet out. Need a little more, so mix 5 strokes epoxy and finish wetting out, then add 3 doses flox to remainder and plaster it onto underside of ply TP8. Press down well, apply flox to upper side and add extra flox at ends to ease slope as recommended by Martin Carolan. Apply 3rd BID layer to root and wet out with 3 strokes epoxy. Apply 4th layer BID and wet out with another 3 strokes epoxy, leaving enough to paint around outside to retain peel-ply and some for a sample. Use peel-ply tape on all areas and find that easier to apply than larger sheet. Finish about 19:30, with 24C and 39% RH. Leave fan heaters on setting 3.5. 231.8
25 Turn off heaters about 10:30. Table meter shows 20C, 44% RH; wall meter shows 18C. Phone factory about corrosion-treating metal parts and speak to Neville. He says anodizing or Alodyning is probably not worthwhile unless aircraft kept on a beach! Agrees no point in treating parts such as FL7 which is completely embedded & so abraded all over. For such as FL1, FL2, FL3 that are part embedded and part exposed: Mask off areas that will not be bonded with parcel tape. Abrade areas to be bonded with Scotchbrite immediately before bonding to minimise time exposed to air. (SP recommend using mixed resin as abrasion lubricant to prevent any air getting at sanded surface.) When ready to paint, abrade with fine emery linisher or Scotchbrite & immediately spray zinc chromate before top coat. Some ali parts (eg FL3, W20) appear natural aluminium (bright, brushed) - they have been linished. Others (eg FL1, FL2 W19) have a duller speckled grey look - they have been tumbled. CS08 appears anodised - no, it has been heat treated. Are MS20001 hinges anodised? No, they are Alclad. Use Zinc chromate on cut ends. Autoglym or Mer (boat shops) for main u/c leg after polishing. Many unplated steel parts rusting. Clean up and apply Duck oil for storage. When ready to use, wipe oil off with acetone, fine sand off any remaining rust, degrease, spray zinc oxide (Halfords). Use Waxoyl for inside of tubes - liquid when warm but sets waxy.
26 Order more sanding blocks etc from Perma-Grit. Order Duralac, zinc chromate aerosol etc from Light Aero. Remove peel-ply from starboard tailplane closeout. Trim edges with diamond wheel on angle-grinder and trim around TP5 with Perma-Grit wheel on Dremel. Leave sanding down until the new Perma-Grit stuff arrives. Remove the surplus foam from the LE flange of the starboard tab and file down the LE to blend in. Still a sliver of peel-ply trapped under glass at one end but on consideration there is no point in destroying the profile trying to get the last bit out as it's between the foam and the glass and is not preventing a good bond for the next layer going on top of the glass. File the epoxy samples from the flox corner and closeout. 233.3
27 Move flaps from trailer to garage. Notice that upper layup on port one is still not trimmed. Look out some 12mm ply to make the flap hinge templates.
29 Perma-Grit order arrives. File and sand starboard tailplane closeout edges. Put away starboard tailplane & get out port tab and port flap. Cut off port flap edges with diamond wheel on angle-grinder and file & sand flush. put away port flap. Notice that the hinge marks on the port tab are laid out from the wrong end - fortunately they are done on the peel-ply so put correct ones on glass. Add hinge marks to starboard tab. Clean up foam residue on tab flanges and sand down foam to blend with LE into flange recess. New Perma-Grit flat files work well for this. Check hinges against flanges; should be no problem here although on starboard tailplane flange (only one checked) it looks marginal. How could a too-shallow flange be corrected? Check BID sizes for tabs and decide they need to be a bit bigger. Change 65cm x 10cm to 670mm x 125mm and 15cm x 10cm to 180mm x 100mm. Mark out all pieces for both tabs; manage to get all but one out of offcuts. 237.5
30 Buy Mer, zinc oxide spray primer, aerosol Waxoyl and Halfords dewatering fluid aerosol (couldn't find Duck Oil) from Halfords. At 14:00, climate about 17C and 77% RH. Turn on both heaters. Dig out the foam blocks with v-notches used for holding the rudder during the LE layup. Make up a couple more to fit the tabs exactly, so I can work on both together. Cut out the BID except for the tip closeout pieces. Humidity down to about 68% RH. Mix 2 strokes epoxy with 6 doses q-cell for dry micro - far too much again as only a little needed for the joining slot. Mix 3 strokes epoxy with 2.5 doses q-cell for micro slurry. Mix 3 strokes epoxy. Drape & wet out first LE piece. Fits quite well and goes around corner reasonably easily. Mix 5 strokes epoxy. Drape and wet out 2nd LE piece and 6 of the hinge pieces. Epoxy gelling faster than I'd like, and feeling pretty warm, so turn off heaters as RH is about 62%. Mix 5 strokes epoxy. Drape and wet out last 2 hinge pieces, 2 root pieces and most of 2 LE pieces. Mix 4 strokes epoxy. Fit last 2 root pieces and wet out. Peel-ply with tape; 2 lengths on LE and several small lengths on root. Erect tent and set fan thermostat at 3. Gets up to 25C & 45% RH quite soon. 242.0

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