Europa #435 G-RODO Build Journal - 2018 09

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day	notes	hours
3	Decide that an electric DA sander will be best for sanding down the filler on the tailplanes - the compressor can't really keep up with the air-powered one, and the belt sander tends to leave rather deep scratches that are hard to blend out. Get a 150mm Erbauer ERB382SDR from Screwfix. Check how it goes with a 1000 grade Abralon disc on one of the trim tabs. Seems easy to control and quickly gives a very good finish.
4	Find a plastic cap from a nasal inhaler is about the right size to plug the top pip-pin hole. Push it firmly into the pip-pin hole on the upper surface of the port tailplane and knife-trim it off flush. The port tailplane upper surface has virtually no nibs and ridges. Scuff-sand it with a 50-grit disc on the new electric DA sander, which is much easier than doing the majority of it by hand as before. Go over the low and glossy patches with a coarse Perma-Grit flexible sheet. Vacuum off the dust, take the foam block out of the way and degrease the tailplane with an acetone-soaked rag. Replace the tailplane on the foam support block. At 14:10, 20C, 39% RH. Turn on fan heater. Mix a peg-10 (128g) batch of Ampreg 21 and paint the tailplane with it. To the remaining epoxy, add 9 doses of Expancel and 3 doses of Cabosil. Lay down 2 nylon lines, one at root and one parallel to outboard rib, as before. Fill that section and trowel flat. Clean up mixing tub. At 14:55, 22C, 37% RH. Move 1st nylon line outboard beyond rib and touch up the slot left behind with the corner of the filling knife. Mix a peg-10 (128g) batch of Ampreg 21 and add 16 doses of Expancel and 3 doses of Cabosil. Fill the next section and trowel flat. Move nylon line outboard, tidy up the slot, fill next section and trowel flat. Clean up mixing tub. At 15:40, 22.5C, 36% RH. Top up the Ampreg 21 resin dispenser bottle from the can. Mix a peg-10 (128g) batch of Ampreg 21 and add 17 doses of Expancel and 4 doses of Cabosil. Move nylon line outboard and tidy the slot. Spread and trowel that section. Move nylon line outboard to tip and tidy the slot. Spread and trowel that section, and find that there is enough filler to go around the tip as well. At 16:26, 22.9C, 36% RH. Clean up tools and mixing tub. Put away epoxy dispensers. Refill Expancel tub from the big bag. Leave fan heater running to cure filler. Stop at 16:40, 22.9C, 36% RH.	2950.7
5	Flatten off some ridges and high spots on yesterday's tailplane filling with the RB10 plane. Open out the pip-pin hole by drilling through from the underside, then carefully enlarge the hole with the taper reamer until the plastic plug pops out. Bore needs no further cleaning up. Swap the blue foam support blocks over to do the other side. Lay port tailplane underside-up. Clean up the rough bits of filler on the LE with the block plane. Clean out the tab hinge mounting holes using a piercer and temporary screw as for the starboard one.	2951.8
6	About 12:55, wrap insulating tape around a 6mm wooden jointing dowel until it is a firm fit in the tailplane underside pip-pin hole. Push it in flush. Scuff-sand underside of port tailplane with 50 grit disc on DA sander, then coarse Perma-Grit flexible sheet. More glossy hollows and depressions than on starboard one so it takes longer than expected. Vacuum off the dust. At 14:00, 20.2C, 37% RH; start fan heater. Take the foam support out of the way and degrease the tailplane with an acetone-soaked rag. Top up the acetone dispenser bottle. Mix a peg-10 (128g) batch of Ampreg 21 and paint the tailplane surface. Lay nylon lines at root and a trowel-length outboard as before. To the remaining epoxy, add 9 generous doses of Expancel and 3 doses of Cabosil. That turns out a bit dry, but spreads without too much bother. Several passes of trowel needed to remove air pockets. Move the nylon line across. At 14:55, 21.8C, 35% RH mix a peg-10 (128g) batch of Ampreg 21 and add 13 generous doses of Expancel and 5 doses of Cabosil. Spread between lines, trowel flat, move line, repeat. At 15:30, 22.2C, 34% RH mix a peg-10 (128g) batch of Ampreg 21 and add 15 doses of Expancel and 5 doses of Cabosil. Spread between lines, trowel flat, move line, repeat. Just enough filler to cover tip rather meanly. At 16:05, 22.3C, 34% RH finish and leave fan heater running. At 23:05, 21.4C, 34% RH; filler cured; turn off fan heater. Realise, looking back through the journal, that I forgot to weigh the port tailplane before filling.	2955.1
10	With the LE nearest to the working side of the table, start work on cutting back the filler on the port tailplane underside, using the RB10 plane. It's easy to remove ridges and bumps but not much comes off on the flatter areas. Adjust the blade to take a slightly deeper cut and that goes better. Work over the area I can easily reach, between the high point of the airfoil and near the LE, until greyish patches start to show, indicating that the filler is getting thin in places. Although a big pile of shavings accumulates, it is not nearly so messy as sanding (either dry or wet) and the rate of material removal is quite pleasing while feeling suitably controllable.	2955.4
11	Work some more on forward half of port tailplane underside with RB10 plane, then turn it around and work on the aft half, until greyish patches start to appear. The flatter area near the TE does not respond so well to planing; can't seem to get a bite there, but don't want to extend the plane blade any more as it would be likely to snatch and dig into the glass. Set the tailplane upright with its root on the floor and smooth off the tip with the block plane, then the coarse side of the small Perma-Grit block, and finally a sheet of 180 grit paper wrapped around and held between my hands (in the same fashion as for shaping the tip of the foam core, way back on 29 June 2001). Looks and feels quite good, although a few pinholes have appeared. Lay tailplane back on foam support and start sanding undersurface from TE side. By hand with a Perma-Grit block does the job, but it is quite hard work because the tailplane is not sufficiently restrained and I have to use one hand to hold it in place. Also doing it wet seems to clog the grit more than I expected. Dry it off and switch to electric DA sander with 50 grit disc. Can't use it wet anyway because of the extraction system through the holes in the disc. The rate of material removal with it is moderate but quite acceptable. It doesn't take too long to get down to the glass in spanwise stripes between the valleys where the hot-wire entries were. Check the dust bag after a while and find it is almost packed - the extraction system seems to be very efficient! Empty the bag and continue sanding, turning the tailplane around for access to the LE side, until blueish stripes showing over most of the surface.	2957.7
12	Rub down port tailplane LE with coarse side of short Perma-Grit block. Change to 120 grit disc on DA sander and go over all of the port tailplane underside with it. Quite a lot of pinholes visible. No point in going to anything finer until those holes are refilled. Swap foam supports to deal with upper surface of port tailplane. Work on it with RB10 plane, cutting spanwise with end of tailplane against the wall, until greyish areas start to appear. The aft part of the chord seems too flat to let the RB10 plane bite, so use the small block plane on that area. Vacuum up the shavings. Put the 50 grit disc back on the DA sander and start work with it on the LE to mid-chord area, removing all the planing marks and getting down to patches of blue-green. Empty the dust bag - interestingly, the dust is quite hot, although the disc and the tailplane surface are both cool to the touch.	2959.3
17	Continue work on upper surface of port tailplane with DA sander & 50 grit disc, moving on to area between mid-chord and TE, until greenish-blue patches appear quite widely. Go over it all again with 120 grit disc. Work on LE and tip with fine side of short Perma-Grit block, finishing off with 180 & 320 wet & dry paper freehand. There are still many pinholes and some low patches that will need to be refilled, which is a bit boring! From the top side, drill through the dowel plugging the underside pip-pin hole, then from the top enlarge the hole with 5.5mm, 6mm & 6.5mm until the remains of the dowel and the insulating tape pull out. Put aside port tailplane and get out starboard one. Work on the underside of it with the RB10 plane and the block plane for about 45 minutes, until greyish areas start to show.	2961.5
18	Vacuum up the shavings from yesterday's work with the plane. Start to sand starboard tailplane undersurface with 50 grit disc on DA Sander. Does not feel as though it is cutting very well, although the disc feels about as sharp to the touch as a fresh one. Change to a new disc anyway, and it does seem to bite a bit more keenly, with a better rate of material removal. Work on the aft section then forward section, until blue-green patches appear widely. Go over the whole surface with the 120 grit disc on the DA sander. Stand the tailplane on its root end and work on the tip with both RB10 & block plane, then coarse side of short Perma-Grit block and 180 grit wet-&-dry paper freehand. Vacuum up shavings. Swap the blue foam support blocks and set the starboard tailplane topside up. Start on it with the RB10 plane, working spanwise from tip until greyish patches start to show.	2964.0
19	Vacuum up shavings from yesterday's planing. Work a bit more on the aft section near the tip of the tailplane with the block plane. Turn the tailplane around and work on the root area with both planes. Vacuum up the shavings. Work to remove the planing marks with a 50 grit disc on the DA sander, and get down nearer the glass all over, until blue-green patches appear widely.	2965.3
25	Set starboard tailplane vertically on floor, LE up and work on LE with block plane and then 180 & 320 grit paper freehand. Lay it on the blue foam support again and go over the whole upper surface with 120 grit disc on DA sander. Set tailplane aside and change to 400 grit disc. Go over all the aileron surfaces with that, which leaves them largely in a state that I hope will be OK for re-painting. However, there are a few small areas that need refilling. Go over both trim tabs with the 400 grit disc; they have some pinholes remaining. Briefly try the Abralon 100 grade disc on one trim-tab surface; it produces a slight sheen which I think is too smooth to key paint, so take it back again with 400 grit disc.	2966.5
27	Phone Toby at Targett Aviation to ask when he could fit my tailplanes and ailerons into the paint shop; he reckons there should be a window or opportunity in about 6 weeks. Check the journal for the size of balsa TE strip that I used to make the Flettner strips on the trim tabs, but cannot find any dimension other than the thickness (must have been about 6mm originally, planed down 1.5mm to 4.5mm to give a total TE thickness of about 9mm). The vestiges of the balsa on the trim tabs are about 0.5" or 13mm wide, but Cheltenham Model Centre only seems to list 1", 0.75" and 0.375" widths. However, if the thick edge of the 0.75" x 0.25" were removed to make it 0.5" wide, the thick edge would then be 4.23mm thick, which sounds pretty ideal! Checking in the PDF manual shows the max chord of the Flettner strips is to be 12mm and the overall thickness at the TE is to be 8mm - 10mm. A later re-check of the CMC stocklist shows that they DO have 0.5" x 0.1875" (12mm x 5mm) so that would be OK too. With short Perma-Grit block and TC file, clean up edges of starboard tailplane where filler has gone over. Remove starboard tailplane from blue foam support and wipe all over upper surface with acetone-soaked tissue to degrease it and remove residual dust. Likewise undersurface of port tailplane. Also wipe down trailing edges of both ailerons as they also have some pinholes that need filling. Put starboard tailplane back on the foam support and arrange a LED floodlight to shine across it, the better to see the pinholes. 21C, 31% RH. Mix a peg-1 (24g) batch of Ampreg 21 and add to it 4 doses of Expancel plus one dose of Cabosil. Apply it to the pinholes on the starboard tailplane, then set it carefully aside and put the port tailplane on the foam, bottom side up. Fill the pinholes etc on it and set it aside. Put each aileron in turn on the work table and fill the pinholes on both sides of the TEs. Prop them up carefully without letting the TEs touch anything. 208C, 30% RH. Turn on fan heater and set thermostat to 2.5. Order some short stainless steel pop rivets from About Town Bolts in anticipation of having to patch a gap in the stainless steel firewall sheet where it won't conform to the shape of the engine mount.	2968.2
28	Yesterday's filler all appears cured OK. 21C, 25% RH. Remove blue foam support and wipe upper surface of port tailplane and then lower surface of starboard tailplane with acetone-soaked rag to degrease and remove dust. Put the other foam support under the starboard tailplane. Mix a peg-1 (24g) batch of Ampreg 21 and to it add 3 good doses of Expancel plus 1 dose of Cabosil. With LED floodlight shining across the work area as before, fill first all visible pinholes on the starboard tailplane lower surface and then those on the port tailplane upper surface. Leave fan heater on for overnight cure. 20.9C, 25% RH.	2969.5
29	Stainless steel rivets delivered. Go over the whole of the upper surface of the port tailplane with 120 grit disc on DA sander. Set it aside and start on underside of starboard tailplane but is seems the filler there is not so well cured because it is picking up on the disc quite a bit. Switch foam supports and start on the top surface but still getting a bit of pick-up. Change to a fresh 120 grit disc and that goes better for a while but also starts to pick up a bit. Scrape off the blobs adhering to the disc and manage to finish off the top surface more or less OK. Go back to the undersurface and there is a lot of pick-up so decide to leave it for a while to cure more fully.	2970.5

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