Europa #435 G-RODO Build Journal - 2019 09
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Roll fuselage out onto drive.
Still not entirely happy with the angle of the fuel elbow in the firewall. Find that I can after all get the 13/16" open-end spanner onto the nut at the back and slacken it just enough to turn the elbow slightly. With the elbow re-aligned, start to tighten the nut and then flip the spanner with a bit of fiddling to tighten fully.
Swing rudder fully to starboard. Fit cable and spring to starboard rudder crank, with stiffnut. Apply inspectors lacquer to that nut and to the one on the spring anchor.
Offer up lower SS firewall panel. Not quite fitting right, still needs a bit of relief, mostly at port side. Take it out again and trim port edge with nibbler & Tuff-Kut scissors. Relieve around the engine mount bolts slightly with half-round file. Offer up again, threading the line attached to the port rudder cable through the seal. Now fits much better. Fit the AN3-3A bolts on the upper edge and at starboard lower corner. For the extra hole that ties it to the patch piece, fit a 3/8" button head SS socket screw. Also use two more of those screws for the fixings into the bottom of the footwells - the AN3-3A bolts are not full-threaded and I think they may get threadbound before going in flush.
Swing rudder fully to port. Pull port rudder cable through seal and fit it and spring to rudder crank with stiffnut. Apply inspectors lacquer to that and to spring anchor nut. Centre rudder.
Roll the engine out of the garage on its transit pallet. Remove the front dolly wheels for crane access. Get out the engine crane and support engine with it using a rope looped between the propshaft and the top centre of the mount. Remove transit bolts. Lift engine up to line up with mount and fine-adjust height until one of the socket screws goes in. Keep tweaking the height and manhandling the engine until the 3 screws with heads aft are inserted far enough to get the Binx nuts onto them. Manhandle the engine a bit to get the 4th (head-forward) screw inserted and nut started. Wind in each screw (8mm hex key in screw socket, 17mm spanner on nut) until just snug, then tighten all fully. Slacken crane and remove rope. Put away crane again in carport. Store engine pallet in trailer. Replace dolly wheels.
Roll fuselage back into garage and put away tools etc.
Roll fuselage out onto drive. Prepare to insert split-pins into the castellated nuts on the engine mount, but decide that the bolt holes on the upper ones are too near the open ends of the castellations. For each of the upper bolts in turn, slacken off & remove the castellated nut, add another AN960-516L washer for a total of 5, refit nut, tighten up & re-align castellations with bolt hole. Insert MS24665-153 split pin into each upper bolt and bend the ends over. Insert and end the split-pins on the bottom 2 bolts.
Loop the throttle cable from the port side of the tunnel across to the starboard carburettor and fit it (8mm AF on sleeve, 10mm AF locknuts; 4mm hex key & 8mm AF nut on clamp). Likewise fit cable from starboard side of tunnel to port carb. Inner is not fully extended but seems OK after some fiddling. Peering into the throttle box I can see a slight kink in the cable inner on the starboard side of the throttle lever. Undo the fixing screws and drop the throttle box for access. Easy enough to straighten the kink, but note that there is no nut on the pivot screw and that the bolt through the cable ends has a plain nut. Seems a good idea to fit stiffnuts now.
Fit and tighten a MS21042-4 stiffnut on the pivot screw, but with the lever now firmly positioned, the end of the AN3-10A bolt holding the cable inners is scraping on the starboard side of the throttle box. The lever is positioned slightly asymmetrically in the box; this can be dealt with by reversing the AN3-10A bolt. Loosen the checknut on the pivot setscrew and slide the starboard washers and the lever off the setscrew. Lift out the lever, dismantle the cable inner retention system, reverse the bolt and re-assemble with MS21042-3 stiffnut. While lever is out, check diameter of stiffnut access hole for a blind grommet - it is 14mm. Replace lever on pivot screw, place washers with tweezers and re-tighten checknut. Fit and moderately tighten stiffnut. Clearance now OK but lever movement stiffens as it goes forward towards full throttle. The stiffnut is moving with the lever and the washers! Pause to think about what to do about that.
Loop the choke cable from the port side of the tunnel to the starboard carb and fit it. Not happy with the slot-head screw supplied with the nipple, so substitute a same-size (M4 x 6mm) socket-head screw from stock. Start to assemble the other choke cable to the port carb but one strand of the inner has unravelled slightly, making it difficult to push the inner around the bend of the guide, and practically impossible to get into the nipple. After some thought, straighten the wayward strand as well as possible. Slide a length of small heat-shrink sleeve onto the inner. Mix and apply some Araldite Rapid to the inner, then slide down the heatshrink sleeve and shrink it, while trying to dress the loose strand into place. Leave to cure.
Return to the throttle friction problem. Undo pivot stiffnut and apply grease to both faces of both plastic washers. Re-fit stiffnut and tighten - no improvement. There is just room to fit a checknut on the pivot screw as well as the stiffnut, so try fitting a AN316-4R checknut tightly against the washer, then tightening the stiffnut to lock against it. Alas, no better - movement of the lever loosens both nuts almost immediately, even though I tried to lock them together as tightly as I could. Post a query about it on the Matronics Europa e-mail list.
I note while crawling around underneath the fuselage that the AN970-3 washers on the AN525-10R16 bolts holding the flap hinge brackets to the fuselage floor are all quite rusty. The bolts themselves all seem OK. Wonder if I need to replace the washers - maybe with stainless?
Back to the port choke cable. The Araldite has cured. Strip off the heatshrink sleeve, but it hasn't held the loose strand in tightly enough. Snip off the sticking-out bit with micro flush-cutter pliers. Still leaves a bit proud. Snip again, trying not to lift it away from the rest beyond the cutting point. Try to get it through the nipple and after considerable gently fiddling it goes in without catching the stray end. Fit socket screw to retain.
Get out silencer and downpipes. Remove temporary nuts and exhaust port caps. Store them with silencer outlet pipe. Fit the silencer downpipes to the exhaust ports with the coppered stiffnuts, remembering that the nuts on the insides of the pipe bends need to be fitted before the pipes go snug against the ports. Discover that the stiffnuts are 12mm AF - the temporary nuts are 13mm AF and I had bought an offset spanner specially to tighten them. However, find that a long 12mm socket fits quite well and makes it possible to get the awkwardly-positioned ones fairly tight.
The Bowden cables to the carbs are now quite close to the engine mount upper nuts and split-pins. Offer up the aft baffle to check how the cables will sit. Can't see but by feel is seems they are pretty much in contact with the nuts, so I think some sort of soft protection there would be advisable.
With the baffle in place I recall some talk at the LAA Rally that the conical air filters I have at present are being superseded by a cylindrical type, which would foul the baffle and necessitate surgery on it. Must check if that is true.
Offer up the 100-06 braided hose to the elbow in the firewall to check how it will run. Goes through the slot in the aft baffle OK, but tends to touch the engine mount. That can be relieved by pushing it slightly aft. Remove aft baffle.
Put away a lot of tools and roll fuselage back into garage.
Order a couple of offset 12mm open-end spanners from Prime Tools . Nothing in the Rotax documentation indicates that the K&N air filters (SP-2704, Rotax p/n 825551) might be going obsolete or being replaced by a different type. Search online for suppliers and find that Skycraft have 71 in stock at £34.99 + VAT, so that seems pretty reassuring!
Kelvin Weston replies to my query on the e-mail list saying that in place of the washers, he made special plates which conformed to the shape of the bottom of the throttle box and thus were prevented from rotating.
Undo temporary screws and drop throttle box again. Undo stiffnut and checknut and dismantle pivot assembly completely. Return the AN316-4R nut to the storage drawer.
I intend to make plates as Kelvin described, but I will retain the AN970-4 washers instead of replacing them with the plates, as there seems to be plenty of room for that. The plate adjacent to the checknut will be thin stainless steel and the one under the stiffnut will be slightly thicker aluminium. Try to use the multi-finger profile copier tool to capture the inside shape of the throttle box, but the tool is too big to get in there. Instead, capture the outside profile. Trace that onto card and cut out. Offer up the card to the inside of the box; rocking a bit so needs trimming back on the central curve. Trim it a bit and try again - now fits against the bottom faces of the box without rocking. Hold the card against the inside face and mark the hole position, although that will be a bit offset because of the curve of the box corner. Punch the hole with the leather punch.
Trace the outline of the card template onto an offcut of 0.50" aluminium. Cut it out with the nibblers and smooth edges. Offer up and note that the hole position seems to have come out slightly different from that on the card template. Centre-punch slightly high (to allow for adjustment) and drill 1/4". Try it on the bolt and it is definitely too high. Trim edges of aluminium with the millennicut file and that brings it nearer correct. Trim a bit more and now that is too far - the aluminium can rock slightly when the bolt is true to the face of the box. Re-check the hole position on the card template, mark again and re-punch.
Mark the template outline on a piece of 6061 aluminium alloy sheet, cut out with the small hand nibbler and smooth edges. Initial fit seems good. Cut a small piece of plywood to place between the side of the box and the aluminium sheet, to keep it square but away from the corner curve, while I mark the hole position with a felt-tip pen. Check the marked position against the template and it looks reasonable. This time I will adjust the hole rather than the edges, and the large washers each side will ensure that the nut has a good face to bear on. Centre-pop and drill the hole somewhat above where I think it should be - but when I check it on the bolt it is still too low and the aluminium sheet is rocking when the bolt is square.
Scribe the outline of try 2 onto the 6061 sheet again and cut out with a hacksaw. Didn't quite manage to keep to the line so re-scribe angle from try 2 outline again and file down to the line. That now sits nicely on the bottom of the box. Using the plywood spacer as before, mark the hole position on the aluminium. Centre-pop well above the centre of that mark and drill 1/4". Try it on the bolt - hole is too high and slightly forward. With a round file, drift the hole down and slightly aft, a little at a time, checking frequently until it looks OK. Bolt is now sitting square and the aluminium sheet is firmly against both fore and aft faces of box bottom.
Offset spanners delivered. Check fit on exhaust port nuts - both are OK, but the Stahlwille has slimmer jaws than the Facom and could get into even tighter spaces. Tighten the few nuts not yet fully done up.
Scribe the outline & hole of the final 6061 aluminium plate for the throttle box onto an offcut of stainless steel firewall sheet. Cut it out with Tuff-Kut scissors and smooth edges. Offer it up with the plywood spacer behind it and mark the hole position with a felt-tip pen. That mark is in line with but below the scribed one. Centre-pop just above the centre of the scribed mark and drill out in small increments to 1/4". Re-fit bolt, washers and spacer to check hole position - well-aligned fore and aft but a bit high. Drift the hole down a little with a round file and re-check. Now almost correct. Give it a few more strokes of the file and when re-fitted looks perfect.
Decide that the grease on the plastic washers might actually be counter-productive in terms of getting a consistent throttle friction setting, so wash the plastic and adjacent steel washers in unleaded petrol and dry them off. Assemble checknut, SS plate, steel and plastic washer onto setscrew. Fit lever and wind checknut on a bit further. Fit plastic washer, steel washer, 6061 plate and another steel washer. Fit stiffnut finger-tight. Tighten up checknut fully. Tighten stiffnut; throttle lever travel now quite smooth with light friction. Tighten stiffnut a bit more until the friction feels enough to avoid unwanted throttle movement from the carb springs. Check carb lever movement and adjust nipple on port carb to get it roughly synchronised with starboard one.
Assemble a 101-06 hose end to the stock length of 100-06 SS braided hose, using 10W-30 oil and the same technique as last time. A couple of stray strands on the braid, but they fit in OK with the hose offered up to the socket at a slight angle. It seems a bit harder than last time to push the hose fully home in the socket, but it gets there eventually. After tightening the nipple with 11/16" ring spanner, check the gap that I can only just get my thumbnail into - it's actually only 0.020" so well under the maximum 0.031".
Offer up assembled hose end to the fuel elbow on the SS firewall and find I can't get the hose square enough to the elbow to fit it; the length of the hose-end prevents the hose bending enough the clear the engine mount cross-tube. I should have checked that before fitting the lower SS firewall panel and re-hanging the engine etc. Wonder if changing to the 90-degree elbow would improve matters, but a trial check of the hose assembled to it shows that the hose would not bend sharply enough to clear the aft baffle. The only solution seems to be to swing the existing 45-degree elbow further inboard and down so that the hose can pass under the engine mount tube. A trial offering-up of the hose in that position suggests it would work.
Not relishing the prospect of taking off the silencer, engine, and lower SS firewall panel again, I wonder if it might be possible to get at the backnut on the elbow from that aft side. Looking up from the tunnel, it certainly seems as though there would be room to work from the aft side, but I can't get my shoulders past the wheel to reach far enough forward. Taking off the wheel seems a lot less work that taking off the engine etc, so decide to give it a try. Undo the brake pipe (10mm AF) from the slave cylinder and tape off the exposed end and the fitting. Cut off the lock-wiring from the 3 bolts on the starboard side of the wheel. Loosen those 3 bolts (1/2" AF) and the similar one on the other side. Loosen the M6 socket screw (5mm hex key) and its stiffnut (10mm AF). Pull out the socket screw & remove the 4-off AN5 bolts. Pull out the stub axles and the wheel drops, but I can't get it out of the fork - the tyre is too large. Will need to deflate it before I can remove the wheel, but getting too late to continue tonight.
Thinking further about access to the backnut on the elbow, and the nut on the hose-end, order from Prime Tools 3/8" square drive crowfoot wrenches in 11/16" & 13/16" sizes, which will allow me to turn the relevant nuts from slightly further away with a suitable 3/8" drive extension.
|23||Get a 3/8" square drive extension set and a sliding tommy-bar from Halfords .||
|27||On our return from a short break, find crowfoot spanners have been delivered from Prime Tools . They are both the "flare" style (ie like a ring spanner with a section cut out), although one was shown as like a standard open-end spanner on the Prime Tools website.||
Check the fit of the crowfoot spanners on the made-up hose end. The 13/16" accepts the hose and slides over both the socket and the nut easily, but the 11/16" will not go over the socket to reach the nut. So, grind off the tips of it slightly with the angle-grinder until it will slip onto the nut sideways like a standard open-end spanner.
Deflate the tyre. Doesn't seem to be much air in it anyway, but it shrinks enough to get it out of the landing gear fork easily. The cross-bar at the aft end of the sub-dolly is going to get in the way too, so undo the bolts and remove that.
Put the magnetic LED torch on the landing gear frame to get some light on the aft face of the firewall where the fuel feed goes through. Offer up the 11/16" crowfoot spanner on 250mm 3/8" drive extension to the hose nut. Can't get enough leverage with one hand, so add 125mm extension to get both hands on it. Change to the ratchet handle which is much easier than the tommy-bar to turn. It is at least easy to see what I'm doing and with the 2nd extension not too difficult to reach. Loosen the hose nut. Change to the 13/16" crowfoot spanner and loosen the elbow backnut.
Crawl out and swivel the elbow downwards to about horizontal. Pass the hose end under the engine mount tube, offer up to the elbow and screw it on. To keep the elbow in place while tightening the backnut, secure the hose to the engine mount tube with a couple of releasable cable ties. Check how the hose will run forward to the fuel pump and all looks OK. Tighten the backnut, then after releasing the cable ties, consider that perhaps there should be more clearance between the hose and engine mount tube for the firesleeve. Slacken backnut again. Interpose a an offcut of wood between the hose and the engine mount before re-applying the cable ties. Tighten backnut, remove cable ties and now it all looks good with suitable clearance between hose and mount. However, when I try to tighten the hose nut, the elbow moves slightly. Reposition the wood spacer and cable ties. Fit an adjustable spanner to the flat on the elbow and jam its handle in place against the landing gear frame with another offcut of wood. Tighten backnut again, then tighten hose nut.
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