Europa #435 G-RODO Build Journal - 2002 05

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1 Turn off heater about 10:15. Remove peel-ply from trim tabs with some effort. A couple of small pieces get left in the roots of the vees at LE & TE. The flange on the starboard one is lumpy in the hinge area. Call Martin Carolan and he says it probably needs ground out, so take it down to him. He grinds it fairly flat with a wheel on a die-grinder and suggests I flatten it more with abrasive on a wedge-shaped bit of wood, then add a couple of layers BID like the hinge reinforcements to stiffen it again. As it's the outboard hinge, it will have less torsion loads anyway than the inboard one which is next to the drive pin. While I am away, the Light Aero order arrives. The rest is OK, but the AN4H-16A bolts are too long for the brake caliper. I should have checked with a ruler before ordering replacements! The Europa-supplied bolts do not appear to correspond with any AN4 length, and have longer thread and shorter grip than the nearest AN4 lengths. It looks like AN4H-15A would be OK. Will have to phone Emma at Light Aero in the morning to see if I can get them changed. 243.5
2 Phone Emma at Light Aero. She says I can return the bolts for credit, but they don't have any AN4H-15A or equivalent available. Think about getting an air-powered die-grinder as the Dremel is not up to the heavy stuff that martin was doing yesterday, and the ordinary angle-grinder is a bit unwieldy for getting into corners. Both Machine Mart and Axminster Power Tool Centre do a kit with a selection of stones, and 1/4" & 1/8" collets. The Perma-Grit wheels come with either 3mm or 6mm shafts; more research needed to find out if the collets will take those smaller sizes, or if imperial shafts can be got with correct (3mm & 6mm) bores for the Perma-Grit wheels. Could always make my own I suppose!
3 On way home from flight medical, buy another pair of Wilkinson decorating scissors for £2.49 to replace the ones that are getting tired and resin-covered. Write covering letter for bolts and put in Jiffy-bag.
4 Post bolts back to Light Aero for credit.
6 Trim all tab edges with diamond wheel in angle-grinder and sand down flush. File down one corner of flange where closeout layup had separated slightly from UNI. File and sand down tab hinge flange where Martin had ground down the lump. No need to make special sanding block; the Perma-Grit file recently acquired is fine. Repair area now looks quite similar in thickness to main part of flange, so there should be about 2 plies left intact. Cut out foam at tips for flox corners, and sand inside of glass clean. Cut a couple of pieces of BID rather longer than the original hinge reinforcements, and some small pieces to reinforce the filed-down corner. Mix 2 strokes epoxy with 3 doses flox and apply. Holding each tab vertical, apply and wet out 2 plies of BID to each tip, then peel-ply with tape. Set tabs back into v-slotted foam blocks and apply and wet out BID repair patches over ground-down area. Apply peel-ply and remove one block to tilt tab and encourage surplus epoxy to run away from repair area and towards dry end of peel-ply. Apply and wet out small BID triangles to filed-down flange corner. Erect curing tent and leave with fan heater thermostat set on 3. 246.5
7 Turn off heat in curing tent & dismantle. Repair on root corner of starboard tab has wilted away again slightly from the UNI. Maybe it got brushed out of place when erecting the tent; although I checked the tip ribs after the tent was up, I forgot to look at that area. Decide to file flat and fill remaining small gap with flox. Peel off peel-ply, trim edges and file & sand flush. Mark out hinge rivet positions and hinge knuckle relief trim line (have to check back to rudder section of manual to find this is 3mm back from edge). Get out hinges and check hinge wire cutting plan. Decide to prepare rudder hinges at the same time, so get rudder and the hinge wires taped to it out of the trailer. Cut 7" tab hinges to 3" + 4", but somehow manage to cut one to 2.5" + 4.5"! Only notice it when I come to cut hinge wires. Shorten longer one to 4". Get out 3" hinge from stage 3 (for access panels) and use it instead, making a note to order a replacement later. Get out rudder hinges and mark and cut them more carefully. File and sand hinge knuckle recesses on both tab flanges, checking fit and marking which goes where. Slight chamfer needed for curve of knuckle. Chamfer ends of recess for hinge wire safety bend. Set up area at end of table for spraying zinc chromate primer, with polyethylene sheet and foam block. Clean raw end of each hinge with emery paper and immediately spray with zinc chromate primer. Cover rest of hinge with light coat. Repeat for second ends, turning hinges over to allow spraying other face as well. For bending hinge wires, get a 175mm length of 0.25" mild steel rod from scrap box and drill end 2.4mm to fit hinge wire. Chamfer ends at 45 degrees so it looks like a pencil with the lead broken out. Test on scrap length of wire and it works fine. Find a piece of aluminium extrusion to clamp hinges onto. Position first pair against port tab flange and line up bores by eye. Check position again before fitting other hinge leaves and wires, and bending ends of wires to secure. Get out rivets and screw clecos. Note that rivets are specified as 3.2mm and holes are called out as 3.3mm, so drill 3.2mm and 3.3mm holes in scrap piece of BID layup to check rivet fit. They just about go into 3.2mm with effort, so 3.3mm is easier to work with. Hold clamped-up hinges in position and start to drill first hole in root hinge. Difficult to hold hinge in position and can't find any way of clamping it to flange. Drill not keen to go through hinge material, so swap to 3.2mm bit which should be sharper (as much less used) and it goes through OK. Forgot, though, to put something on adjacent LE face to prevent minor damage on breakthrough. Get a scrap piece of thin aluminium for remaining holes. Open up to 3.3mm, hold with cleco and drill first tip hinge hole at 3.2mm. With holes in flange and hinge aligned, it doesn't give same line-up of hinge to edge of flange as at root, where flange edge bisects hinge wire. Tip hinge is slightly further out. Reposition hinge slightly better and drill another of the holes. Open it up and cleco it, then return to root and drill more holes there, cleco-ing as I go. Can't do that in every hole as some are too close to get the drill in with a cleco in an adjacent hole. Drill and open out rest of tip hinge holes, then adjust centre hole slightly for correct alignment. Somewhat surprised how close to edges of hinges the outer rivet holes are, but all the measurements are correct. 252.9
8 Phone factory and speak to Neville about flox pads under hinges (rudder instructions called for Ampreg epoxy, tabs for 5-minute epoxy). He says it doesn't matter, but Ampreg give more time for working, and also recommends oiling the hinge wire before fitting to prevent epoxy jamming it (too late for my port tab hinges!). Also he suggest just snugging up the rivets before cure, then snapping them after cure, to avoid distortion of the hinges. Start to countersink rivet holes on port tab flange and find they can be cut quite cleanly and accurately with a hand-held twist drill bit. At the tip end, the rivets closest to the bottom of the vee foul the opposite face before going fully home. It has the 2 extra layers of the repair on it, so that problem was only to be expected. Drill relief holes for rivet ends in opposite face - they will get filled with flox later. Decide it would be good to have the straight-edge supported at its ends, so bandsaw off a couple of pieces of foam to appropriate thickness. To help stop epoxy getting into the hinge knuckle, apply parcel tape along it, holding it in correct postion. Mix 1 stroke epoxy with 1 and a bit doses of flox. Butter onto flange at hinge positions, keeping outer edge clean to minimise chance of epoxy getting into hinge joint. Clean flox out of rivet holes. Offer up hinges. Dip first rivet in Duralac and fit in root hinge centre hole. Taking care not to squeeze too hard, several tries needed before rivet is set enough to hold firm. Repeat with first tip hinge rivet - easier now I've got the feel of how hard I can squeeze. Repeat for remaining rivets, leaving centre one on tip hinge till last. Riveter nose is just small enough to allow placing all rivets without fouling adjacent stems. As humidity is about 63% and max strength is not required in these flox pads, don't bother putting up curing tent. Drill holes for mounting small storage bin racks beside resin cupboard, so I can keep rivets, etc handy. Move thermo/hygrometer hanging screw holes to opposite wall. 255.1
9 The port tab hinges have become suspiciously stiff after cure. Some of the epoxy must have found its way into the knuckles after all. I will oil the wires next time. Also I guess if I was to put a tiny drop of oil (eg from a syringe) onto the hinge knuckle joints it wouldn't be enough to contaminate the bonding surface. Pull all the rivets home (which takes a good strong pull - not actually much chance of snapping them accidentally as I was afraid of yesterday). Peel off the parcel tape and unclamp the straight-edge. The inboard hinge is reasonably free, although its hinge wire is a bit stiff. The outboard hinge is stiff but moveable, and frees up a bit after some flox/resin is cleaned out from between flange and moving parts of knuckle. A few drops of oil improves things more, and exercising the hinge pins using the bending tool as a lever eases them up a bit too. Extract and lightly oil the hinge pins of all remaining hinges including the rudder ones. To make holding the hinges while drilling easier, bandsaw a 15" length of mahogany window bead to 45 degrees and cut to 4", 5" and 6" lengths for the 3", 4" & 5" hinges. Dress the starboard flange a bit for the inboard hinge - it's rocking slightly because there is a small increase in thickness where I added a small BID triangle for the repair of the nearby corner. Set up the first halves of the hinges on the tab using the mahogany strips to wedge them in at the correct place. Clamp the other halves of the hinges lightly to the straight-edge so they line up with the first halves, then check truth by sighting along bores. Clamp up and check all alignments again. Release other hinge halves from wedges and insert hinge wires after again oiling very lightly. Make safety bends in hinge wires and check for free movement. Apply parcel tape to hinge knuckles, although it may not be needed now with the oiling precautions. Offer up to flange and hold loose hinge flaps in with wedges. Drill first rivet hole with 3.2mm bit and cleco. The mahogany is fine as a drill stop and the aluminium sheet is not needed yet. Drill first hole in other hinge and cleco. Alignment of hinge wires with edge slightly better than port one, but maybe not quite perfect yet! Continue drilling all holes and cleco-ing. Need to use the aluminium sheet once outer clecos are in place as the wood won't fit any more. Once all holes drilled, remove hinge jig and open up hinge holes to 3.3mm to fit rivets. Interestingly, the flange holes appear to fit the rivets fine without opening up - perhaps they were roughed out a bit by the swarf from the hinges. Countersink flange holes. Clear all swarf and lightly sand bonding areas of flange. Mix 1 stroke epoxy with 1 and a bit doses flox in a smaller (sponge pudding) mixing cup for easier mixing. Plaster it onto flange with less at front edge than back. Clean out rivet holes. Offer up hinge jig. Dip rivet ends in Duralac and pull closed just enough to hold without slop. Clean up Duralac from around rivet heads. Leave to cure about 20:00 with floor fan heater set on 3.5, giving about 18C and 63% RH. 258.4
10 Turn off heat about 10:00. Starboard tab hinges seem quite free. Snap all rivets, remove parcel tape and unclamp straightedge. File resin samples from last few layups and clear stuff off table to make room for tailplanes. 259.0
11 2 off AN4H-15A bolts arrive from Light Aero. Get out starboard tailplane. Find AN525-10R8 screws, MS21042-3 stiffnuts and 10-32 (3/16") pre-assembly plain nuts. Could do with some more plain nuts. Offer up starboard tab. Would need quite a bit off the tab cutout tip closeout on the tailplane to get it back into line at the root. Butt it up at an angle and it seems better. Mark out hinge and screw-hole positions. File and sand out edge cutouts for hinge knuckles. Drill 3.2mm pilot holes. Drop cordless drill off table and break 3.2mm bit. Swap in a #30 bit. Bandsaw a piece of wood to act as hinge support at the root end while drilling - not entirely satisfactory. After first couple of holes drilled and clecos set, not happy with position so move holes sideways slightly with round swiss file to get tab further outboard, and file tip end of tailplane cutout a bit to accomodate. Make restraining rail for back edge of table, from aluminium threshold strip with 15mm copper pipe legs. Re-fit clecos and drill first holes for screws. Fit screws with plain nuts then work along replacing clecos with screws in larger holes. Check for fit and file and sand tailplane closeout edge to allow tab to move to neutral and beyond. Root end of tab is still slightly proud of tailplane root line, but will try to get port one lined up better by trimming tip end of cutout closeout earlier in the process. 263.1
13 Check AN4H-15A bolts in brake caliper. They just about bottom, but taking a tiny chamfer off the entry edge of the threaded part with a countersink makes sure of it. Check A/F sizes of the various nuts and bolts in the hardware, and look at tool catalogues for A/F spanner sets - I didn't have a correct size combination spanner for the nuts on the tab hinge screws.
14 Put starboard tailplane away and get out port one. Offer up tab and file and sand tab tip cutout closeout to allow it to get far enough outboard to align root edges. Mark hinge & hole positions and file cutaways. Drill holes #30. Offer up tab and drill first hole through in root end hinge, with wooden wedge behind. Fit cleco. Drill first hole in outboard hinge and cleco it. Drill rest of holes through to 4.8mm, fitting screws and plain nuts as I go. Remove clecos and drill out in turn. File and sand edges to allow travel. Remove tab and clean out swarf. 265.4
15 Buy 3.2 & 3.3mm drill bits from Buck & Hickman. Buy 200 10-32 UNF plain nuts and 50 1/4-28 UNF plain nuts from Moorhouse Fasteners for £3.76. Buy 20-piece combination spanner set (both inch & mm) from Brown Brothers for £15.72.
16 Get out modified TP16 parts. Remove port tab from tailplane. Check both original manual and mod 58 instructions. Mod version gives slightly more detail about placing of lightening/bonding holes. Centre-pop positions on both parts and drill through 1/8". Quite hard going and plenty of lubrication needed; workpiece gets uncomfortably hot by the time 7 holes are drilled, so put on leather gloves. Drill out to 1/4" which is also hard work; place workpiece with drive pin down side of wood drilling pad to prevent snatch on breakthrough. Deburr both sides with 12.5mm drill bit. Offer up to tab to see how much of the flange needs to be removed. Check David Corbett's drive pin setting jig; seems fine at first then I notice the pin doesn't seem to be at right angles to the plate. Check both TP16 with square and they are both similarly in error, actually requiring that the plate is angled even further away from the root face to get the pin parallel with the hinge line. Decide I need to make my own setting template out of thicker material so that the pin is held true over its entire length. Find a suitable piece of 18mm ply. 266.6
17 After starting to think about how the ply would be used, decide to use a piece of birch ply instead of the rather softer stuff I'd originally picked. Mark out and make trial holes with various drill bits to get size just right for pin. Surprisingly, the Freud wood bit makes too loose a hole. Best is a standard 1/4" HSS bit. Drill hole in template and bandsaw to shape. Try with TP16 against port tab and saw off part of lower flange and file down to let it sit correctly. File the corners of TP16 slightly to get it to correct position. When pin is correctly at 90 degrees to hinge line, front end of TP16 plate is over 10mm away from root face of tab. 268.3
18 Phone factory to check the position of TP16 is OK. Andy says no problem, but is surprised to hear how far off square the TP16 pins are. Mark template position on port tab at right angles to hinge line. Mix 2 strokes epoxy with 3 doses flox and make flox pad for TP16 port. Clamp template to root flange to ensure everything stays in position and leave to cure with floor heater on setting 4. 269.4
19 Turn off heating about 09:30. Workpiece and sample in cup seem well cured.
20 Unclamp template and lever it off drive pin. The template has got stuck to the flox a bit so some effort needed. Peel off peel-ply around flox and sand down to remove frayed edge strands. File down LE flox to blend better with existing profile. Cut 3 pieces of BID 75mm x 125mm (no size given in manual). Don't have any 1/4" bore tubing to align the second drive pin with, so find a damaged bolt from the steel scrap drawer, face it up and drill it out in the lathe to 1/4". Looks good until I start to consider how close the pins can actually get to each other. The tailplane root angle means a rather longer tube is going to be needed. The manual says use one of the TS06 bushes but clearly that is impossible unless the root of the tab is cut back to be parallel. Check manual for trimming instructions at rudder hinging, but from that and the 3-view, it looks as though only minor chamfering should be needed. 271.5
21 Phone factory to check about use of TS06 bushes for aligning TP16 pins. Roger says that probably what was meant was to use the TS06 bushes fitted in the TS05 link rod, and that otherwise my understanding of the procedure is correct. Order (among other things) 500mml wax polish from Axminster Power Tool Centre for layup table. At last remember to put into practice advice from David Cripps about capping the epoxy pump outlets to avoid crusting in between uses. Find a small piece of seasoned apple wood (from prunings at Trimley) and out of it turn caps for the epoxy pump outlet pipes. They are 1/4" and 3/8" OD, and holes drilled that size in the short wood cylinders make good tight fits on the pipes. Must also finish off the foam floats for the reservoirs.
22 Climate 17C and 71% RH, so turn on heaters and dehumidifier. Mix 3 strokes epoxy (far too much, as it turns out) for port tab drive pin plate. Mask off hinge with tape. Lay up 3 layers of BID. Some trimming necessary to clear hinge and pin. Peel-ply, but the BID is not holding close to the surface around the LE corner, so prop a piece of foam there to keep it in contact. Clean up the pin with acetone-damped tissue, making sure not to get any on thelayup! Leave 2 fan heaters on set about 3 & 4. Select piece of aluminium rod for pin alignment. Face it up to length (76mm) and drill it through 1/4". Temperature up to about 22C and RH down to about 55% by bedtime. 274.2
23 Turn off heaters about 10:00. Sample in cup is well cured. Foam is well stuck to the peel-ply where propped against it.
24 Axminster Power Tool Centre order arrives with wax polish.
27 Remove most of peel-ply around port TP16 plate. Where the resin has run down into the TE corner it's a solid lump and almost irremovable. Saw off edges of layup and file back to align with root flange. Re-fit tab to tailplane and saw off corner of root flange to allow pin plate to travel forwards. File resin samples. Remove all stuff from layup table and clean off accumulated resin spillages. Re-wax, & buff off, finishing off last of old 150ml tin and starting new 500ml tin. Get out tailplane torque tube and remove bushes. Fit to port tailplane. Get out starboard tailplane and slide it onto torque tube. Replace 3/16" BSW screws on its tab with correct ones and plain nuts. Check length of 1/4" bore tube and it seems OK, although starboard root flanges not yet relieved to let TP16S sit properly. Find a couple of pieces of aluminium angle to clamp on TEs to align tabs with tailplanes, and try out with soft-faced clamps. Some resin weeps need cleaning up to allow good contact with aluminium angle. 277.2
29 tickRemove starboard tab to allow easier trimming of root flanges for TP16. Saw off a corner of tab & tailplane root flange and file to fit. Use template to get correct position, and again TP16 needs small radius on corners facing tab root to fit properly. Re-fit tab and check for clearances. Clamp tabs in line with tailplane at TE. Pack up tailplane TE halves with foam strip to get TEs naturally in line at centre. File off TE centrelines slightly to get 1/4" bore aluminium tube going right home on pins. Grease it at each end to prevent any resin weeping onto pin and bonding. Abrade bonding area of TP16 and put in acetone to degrease. Mix 2 strokes epoxy with 3 doses flox and trowel onto tab root. Place TP16 and slide tailplanes together. Apply several pieces of peel-ply, including one through the bottom gap and around the LE, to stop bonding to bottom tailplane flange. 279.6

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