Europa #435 G-RODO Build Journal - 2012 04

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4 As it's raining today, don't bother with rigging the tailplanes to check the reshaping needed for the trim link rod. Instead drill through the corners of the centre firewall area with a 16mm grit-edged holesaw. Join up the holes with the padsaw and remove the centre part. Try a plasterboard saw on the edges to see if that's easier but not significant improvement on the padsaw. File notches in towards the edges to get the saw started on cuts closer to the inside faces of the tunnel. Cutting the firewall flush to the flat section of the tunnel leaves quite a hollow in most places where the tunnel rounds the corner. Think I will need to finish off the edges with a flap-wheel on the angle-grinder to get a better corner for layups. 1408.8
5 Take LG01/3 and LG02/1 out of box 9 in trailer. Pull fuselage out of garage, rig tailplanes. File trim link rod slots, starting with servo at full down and gradually working towards full up. Trim servo rod fork fouls TS05 at full up trim & full up elevator. Post query on Matronics list. 1411.2
13 Pull rear of fuselage out of garage and rig tailplanes. Check again the angles of the tailplane. With the butt end of the fork about 11mm from the end fitting and full up trim (ie servo at bottom of travel) the digital level shows -14.9 degrees at full TE down, -9.7 degrees at neutral and link rod contacts servo link fork at +1.7 degrees. Working on the advice received from Ian, try shortening the link rod by disconnecting the fork and screwing it as far onto the end fitting as possible. That leaves the butt of the fork about 4.5mm from the end fitting. Cannot re-connect the fork to the bellcrank now as the fuselage slots do not permit enough movement. Not going to enlarge them just for this experiment, so make some measurements without connecting it. With TE at full up the fork hole is well below the bellcrank hole. Hold the link rod against the end of the servo link fork and lower TE until the fork and bellcrank holes line up in the horizontal plane. That is achieved at about +0.5 degrees, which is worse than before. I felt intuitively that Ian's suggestion was not going to provide the easement I need, and this proves it. Just for completeness, dismantle and wind the fork out until it's only got 10 threads engaged, which leaves the butt end about 15mm from the end fitting. TE full down about -15.2 degrees, neutral about -9.7 degrees and link rod contacts servo link fork at about +1.1 degrees. Thus, changing the length of the link rod either way does not appear to confer any advantage. Other suggestions were to trim the end of the servo link fork, move the servo up or shorten the link rod, but the latter can only be a small change as the damper shaft must not hit the end of its operating slot before the servo reaches its internal end-stop. Take out the servo mounting screws and loosen the damper a few turns to allow freer movement. Push the damper shaft to the top of its slot. Run the servo to the top of its travel. Clamp servo to bulkhead in this new position, about 3mm higher than before. Restore the link rod fork to original state with 9mm thread showing between check nut and end fitting (which gives about 12mm from end fitting to butt of fork). Run servo to bottom of travel. Check angles again. TE full down -14.9 degrees, neutral -9.4 degrees, link rod contact servo link fork at +3.5 degrees, so some improvement but not enough yet. Accept that I'm going to have to fettle the end of the servo fork so that it doesn't protrude beyond the profile of the bellcrank, so dismantle the bellcrank assembly to get at the servo link rod. Round the end of the plastic fork with a knife so that it matches the bellcrank profile in all operating positions. To save having to re-position the servo, shorten the butt end of fork by 1.5mm and likewise cut 1.5mm off the other fork. Re-assemble and check for fouling. Servo end stop operates almost at the end of the damper travel, just perfect. However, the crotch of the link-rod fork is now hitting the bellcrank at about +2.7 degrees. Dismantle it all again and relieve the edge of the bellcrank with a smooth half-round file by about 0.5mm opposite the fork crotch. Polish off the file marks on the ScotchBrite wheel. That allows the fork to move closer to the bellcrank until now it's the butt end that first contacts the bellcrank. Re-assemble loosely and check angles again. Full TE down -14.9 degrees, neutral -9.2 degrees, link rod touches bellcrank at +5.2 degrees which seems acceptable. The corresponding tab angles are -27.1, -14.1 and +19.2. Tighten everything up again and check the angles. With full up trim (servo rod at bottom of travel): full TE down -14.7, neutral -9.2, link rod touching bellcrank +5.1. The corresponding tab angles are -27.8, -14.0, +18.7. With full down trim (servo rod at top of travel) some enlarging of the fuselage slot is needed near the top, and after that: full TE down -15.2, neutral -9.5, full TE up +4.6. The corresponding tab angles are -14.8, -1.0, +34.5. De-rig and put everything away. 1414.6
16 Pull rear of fuselage out of garage and rig tailplanes. Set trim to neutral (2 centre LEDs both lit). To get tabs in line with tailplane TE at the neutral (port TP in line with fuselage fairing) position, have to screw the fork further in by 2.5 turns, leaving about 6.5mm thread exposed and about 10mm between the end fitting and the butt of the fork. Measure the angles now as: TE full down -15.3 degrees, neutral -9.7 degrees, TE full up +5.5 degrees. Corresponding tab angles are: -22.7, -10.3, +25.7. De-rig and pull into garage. Drill holes for lower tubes of landing gear frame from inside cockpit with 16mm holesaw. Offer up frame to check position and start to file out the holes to suit.

Later calculations predict the tab angles relative to the tailplane, for the tailplane deflections quoted in the manual pages 19-7 & 19-8, of 4 degrees TE down and 12 degrees TE up, to be 4.9 degrees [4.8 - 6.0 allowed] and 16.4 degrees [14.4 - 18.0 allowed] respectively. Still need to check the trim tab range of movement with tailplanes neutral - can't use Friday's measurements as they were before adjusting the trim link rod length.
18 Pull aft end of fuselage out of garage and rig tailplanes. Prop port tailplane at neutral (in line with fuselage fairing). Measure tab angles: servo centred -10.8 degrees; servo at bottom of travel -18.1 degrees; servo at top of travel -4.7 degrees; servo returned to neutral 10.7 degrees. So, minimum trim range of 6 degrees each way is achieved. Starting to rain so de-rig and pull fuselage into garage. Drill end of TP18/6 with TP18B insert in place. Deburr, coat with Duralac and assemble with bolt, washer & stiffnut. Mark with inspectors lacquer. Screw on checknut and TP18C adjuster until TP18C is about one thread diameter on from end of TP18B. Assemble to tailplane torque tube bellcrank TP9 with AN3-10A bolts and check clearance between end of TP18/6 and pitch pushrod with stick full aft, which is about 50mm. Remove TP18 assembly from TP9 and unscrew TP18C half-a-turn, leaving about 16mm of thread exposed beyond the checknut. Re-assemble and clearance is now almost exactly 65mm. However, that is required with tailplane TE 12 degrees up and full aft stick gives between 14 & 15 degrees up, so that clearance is certainly adequate. Could check again with TP rigged to see if the initial setting of TP18C would be OK at 12 degree up, but it seems unlikely. Unpack the TP19 weights (1 off 88mm, 1 off 53mm and 3 off 13mm) and try them for size on TP18/6. With TP18F "butterfly" fitted there isn't room for all weights inside the roll-pin hole. To accommodate all weights with the roll pin inserted, TP18F would need to be shortened from the supplied 28mm to about 11mm. The supplied plain sleeve TP18D is even more generous at 34mm. Store TP19 weights in box 3 for now. Return to holes in firewall for landing gear frame LG01/3. The manual calls for 3 tubes to be all between 1mm & 3mm clear of the vertical face of the firewall, but the relevant tubes are not co-planar. Top & bottom tubes are about 1 degree different from each other and the side tubes are about 0.5 degree different from each other. Post query on Matronics e-mail list about LG frame tube alignment. 1419.1
20 Draw up Ian Rickard's template for the TS05 link rod restraint in CADintosh and print out on 160gsm card. Cut out and offer it up to the intended position. Needs to be a bit wider. Adjust drawing, print, cut out, check fit. Repeat several times until satisfied with fit against fuselage sides. Check slot length and adjust it to centralize travel.
26 Can't find the first print I did of the final shape for the TP05 restraint, so print it again and cut to shape. Check position of slot. Trace onto 3mm ply sheet 1 (plenty of room as I cut the other parts very economically). Drill 20mm holes at end of slot. Cut out with power fretsaw, smooth edges and clean faces with coarse sandpaper. Cut 2 pieces of BID and peel-ply to size, and find a couple of pieces of polyethylene sheet to isolate layup from work surface. The epoxy resin pump has siezed again, but a couple of taps on the handle with the hide mallet frees it. Mix 3 strokes epoxy and wet out 1 sheet of BID on top of peel-ply & plastic. Paint both sides of ply with epoxy and lay onto wetted BID. Lay 2nd sheet of BID on top and wet out. Add peel-ply & plastic sheet, push bubbles out to edges, then weigh down with a piece of melamine chipboard. Erect tent and start fan. Return to landing gear frame attachment. Check level of big central tube against fuselage thwartwise. File the holes and inside radii to let the frame rotate a bit clockwise as viewed from the front. Eventually seems to be within about 0.2 of a degree which seems good enough. Fiddle about with tongue depressors as feeler gauges for the spacing from the firewall. Can get port side vertical tube pretty square to the firewall, but the starboard one is then a bit close at its top end. The top tube is also close at the starboard side. Leave it for now and will see how it looks with the swinging arm attached. Fettle the inside of the big tube on LG01/3 u/c frame with a swiss file so the LG01A/1 bushes can slide in unhindered by welding artefacts. Degrease the parts and assemble loosely with the bushes just entering the tube on the mounting frame and the LG09 shaft holding them in alignment. Apply a smear of Loctite 638 all around the first bush and push it in. Needs a tap with a soft mallet to get it all the way home, but then find the axle tube has seized! Assuming the Loctite has got somewhere it shouldn't, quickly whack it all out again with the soft mallet. Strangely, the Loctite on the bush is not yet cured. Clean everything up again and try once more with greater care and a very thin coating of Loctite. Same thing happens again - once the bush is fully home, the axle tube is almost immovable. Leave it for a while with the 2nd bush partly inserted to keep things in line while the Loctite cures. Find I can just about move the axle by hand. Extract it using a wooden dowel as a drift and try to find out what's going on. After a few insertions and removals find that diametrically opposite sides of the inside of the bush are getting polished. Apparently although the inside of the frame tube looked as though it had been cleaned up a bit after welding, it hasn't actually been re-bored. So, the bush is finishing up slightly oval when fully home. The shaft has very slight annular machining marks (tiny grooves) and further in-out cycles make it slightly easier to move. There is the faintest evidence of material removed from the bush on the grooves of the shaft. However, it's going to take a long time to get it running freely by this method. 1422.4
28 Decide what I need to treat the LG01A/1 bush problem is a bearing scraper so after some research on what's available order some Eclipse & Noga scrapers from Safe N Sound.

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