left-arrow

Europa #435 G-RODO Build Journal - 2022 01

 right-arrow
index sitemap advanced
search engine by freefind
tickgo to list of milestonestick Navigation & Acknowledgements
day notes hours
3 Re-enlarge tubing for pressure side of fuel weight sensor with a warmed nail as before. Fit tube to sensor port and get it onto the larger diameter at the base of the port without too much difficulty. Try clamping it in place with 20G safety wire but it is quite difficult to get it into a good shape and when I try to apply the spiral lock the tube slips off the end of the port as it did once before. Try cleaning the inside of the tube with the end of a paper towel, to remove as much wax residue as possible. Try fitting the tube again, this time with an Eliza Tinsley 3mm clip. Manage to get the clip crimped with the end of the tube still on the larger diameter of the port, and the clip centred on the smaller part. Re-fit PCB to box, in a different slot this time because of the shortened legs on the sensor. Apply panel power and check MGL FF-1 indication. Now shows 0 litres alternating with a LOW warning. Sucking gently on the vent tube gives a rise in indication to about 20 litres, so that seems OK. Fit cable ties to both tubes, inside & outside box, to minimise possible movement. File the box lid lip to fit the new PCB position, and enlarge the hole for trimpot access to line up with the screwdriver slot again. 3582.6
4 Dress the wires in the port seatpan to the fuel weight sensor into a circle in the plastic lid to keep them tidy and protected. Fit the lid to the sensor box with the supplied screws.

For better conformity of glass-cloth covering, rub down with a scrap of emery paper the corners and edges of the recesses on the blue foam blocks for the port inboard and starboard outboard seatpan hollows.		 3583.1
7 Check the run of the sight-gauge tubing. Under the seatpan, it appears quite close to the rudder-cable pulley. Push against tubing but it is not possible to deflect it enough to bring it into contact with the pulley.

Check the route of the fuel weight sensor vent tubing and decide that it would be better lying alongside the sensor box than looping over it. Trim and sand the blue foam block to suit the new routing.

Slide a length of heavy, stiff, insulated electrical wire into the hole for the sight-gauge tubing in the top of the seatback. Push it in and across until it appears at the gap above the starboard aft corner of the fuel tank, above the C adaptor. Fit a Vital Parts SFB019 bush (12.7mm OD, 6.4mm panel) onto the end of the sight gauge tubing and slide along to near its required location for the hole at the top of the seatback. Push the end of the electrical wire a good way into the tubing and lead the assembly gently into the seatback and across the top of the tank. Pull the tubing all the way in, then dress it along the aluminium pipes for best run up and over the top of the fuel filler cobra. Once satisfied with the routing, cut the tubing to approximate length to get rid of the considerable excess.

Fit a SFB003 bush (7.1mm OD, 1.6mm panel) to the fuel weight sensor vent tubing and slide long to approximate required position. Drill the seatback 2mm adjacent to and inboard of the sight tube hole. Enlarge to 7mm and check that a 7.1mm bush will fit. The thick electrical wire won't go into this smaller vent tube so instead try a length of 18SWG (1.2mm) piano wire. Quite easy to get it in and across the top of the tank, going underneath the sight-gauge tubing. Attach the vent tubing to the piano wire using several layers of heatshrink sleeve. Draw the vent tubing through, remove the piano wire leader and re-position the end outboard of the sight gauge tubing, trying to remove a possible crossing of the tubes in the space above the fuel tank. Dress the tubing up and over the fuel filler cobra as for the sight gauge tubing. Cut off excess.		 3585.4
8 Not really happy with the freedom of movement of each of the tubes across the top of the fuel tank; suspect that despite yesterday's attempt to sort them out, that the tubes are still crossing over each other somewhere above the fuel tank. Draw back the sight-gauge tubing. Insert the stiff electrical wire across the top of the tank and into the end of the sight-gauge tubing as before. Try to pull the sight-gauge tubing through again, keeping it aft of the other vent tubing. However, although the wire comes through quite easily, I can't get the tubing to emerge above the C tank fitting. Try taping the tubing to the wire with duct-tape and that gets it through, but the duct tape is a bit of a bother to remove.

Now the 2 tubes are sitting nicely beside each other above the tank C adaptor and each can easily be moved independently, whereas before there seemed to be some interference.

Consider again the routing of the vent tubing from the fuel weight sensor. It really needs to be restrained at the inboard aft corner of the seatpan. Cut one tag off a 4mm glass-fibre cable clip. Abrade and degrease it, and the bonding area on the seatpan. Mix a small batch of Evo-Stik 2-hour control epoxy and apply to seatpan and clip. With a bit of fiddling, position clip on tubing and weigh down with lead weights to cure.

The adhesive tape around the edges of the polycarbonate fuse tray cover is still oozing adhesive and looking very messy, so peel it off and separate the layers. Can't find the bottle of meths stock to clean up the edges of the sheet - I think I may have finished it.

Order 5 litres of isopropyl alcohol online.

With the rotary trimmer, trim the clear margins of the fuel sight gauge backing strips down to the bare minimum.

Order online a couple of pieces of balsa wood 6mm x 25mm x 910mm for building-out the cowl towards the spinner.		 3586.9
9 Check diameter of spinner and front of cowl. Spinner is 260mm; edge of cowl front face is not so sharply defined and could be as much as 265mm.

Draw up in CADintosh the potential arrangement of balsa pieces for the spacer. 12 pieces at 30 degrees looks good, with an outer diameter of 265mm and inner of 215mm. That leaves the 25mm flange as called out on page 7-2 of the October 2004 Issue 6 Europa XS Rotax 912S Engine Manual. Print out on A3 to use as a plan on which to assemble the ring. There will be plenty of stock in the 2-off 910mm lengths of balsa I have ordered for the required 12 pieces 106.26mm long each, even if cut without minimising waste. The pieces can be cut in alternate directions, which will lead to very little waste. Draw up a cutting plan and there is actually room and to spare for 13 pieces arranged alternately on a single 910mm sheet.
10 Remove the lead weights on the clip in the seatpan. Bonding looks fine.

Prepare another 4mm clip for the step adjacent to where the sight gauge tubing emerges. The bush on the sight gauge tubing is not inclined to stay in place, so decide to epoxy it in position. To keep the bush in place, find a suitable length of tube for a prop and a wooden wedge. Mix a small batch of Evo-Stik 2-hour Control epoxy and apply it to the clip bonding areas and around the bush. Jam the prop in place between the bush and the roof with the wedge, and put lead weights on the clip to hold it while curing.		 3587.6
12 Remove lead weights from clip and prop from bush. Epoxy cured OK. The sight gauge needs a lot of pressure to get it close to the seatback at the bottom. Not sure if an epoxied-on glass-fibre clip would be able to hold it sufficiently. Consider instead using a metal clip fixed through the seatback. Check underneath - there is certainly room for an anchor nut, but access to the aft face of the seatback would be very difficult. 3587.7
13 Isopropyl alcohol delivered.

The manual (page B-30-4-1) calls for the sight-gauge to be secured with P-clips but the kit doesn't seem to include any of the right size. I did get some MS21919-WDG6 (3/8") rubber-lined P-clips from LAS Aerospace but trying one on the tubing shows it is quite bulky and will not hold the tubing closely against the backing stripes. I have in stock some 9.5mm nylon ones (Maplin SJ35) which look much more promising. They take a M5 or 10-32UNF screw. It may be necessary to site the bottom clip a little way further up than I originally intended, just to reduce the stress on the clip and allow a more generous bend radius in the tube. It would be really easy to fit a M5 rivet-nut, but I am not sure if it would stand the necessary tightening torque, and of course it would need Loctite or similar to prevent the screw loosening. A 10-32 anchor nut would be much more satisfactory, but installing it would be difficult. Try placing one with different types of long-nose pliers, but it is not really possible given the obstruction posed by the drain valve and the other fuel system parts. However, notice that the anchor nut fits quite firmly into the end of the remnant of sight-gauge tubing. I think that could be used to place the anchor nut for riveting in position.

Try the isopropyl alcohol on the adhesive tape residue on the edge of the polycarbonate fuse tray cover. Doesn't seem to dissolve or soften it at all.		 3588.6
14 Check location for sight-gauge backing stripes and trim length slightly to fit below the bend at the top of the seatback. Outline the bonding area on the seatback with masking tape.

Later consider that the upper securing clip for the sight-gauge should also be below the bend of the seatback and perhaps the backing stripes should be longer to go past that upper clip.		 3589.1
15 Re-arrange the cutting template for the balsa cowl extension ring. Print out.

Re-measure the height for the sight-gauge and decide that 315mm is the maximum height for the paper part, leaving a few mm for the clear lamination.

Cut out the balsa ring cutting template and stick it to an offcut of aluminium sheet with contact adhesive. Cut to approximate shape with hand nibbler, file down to the line and deburr. Store it in the bottom of the electrical terminals drawers.

Temporarily fit the P-clip to the sight-gauge tubing and mark a suitable location for it on the seatback, allowing a gentle bend and not too close to the bottom. Drill through 2.2mm and open to 4.9mm. Fit a stainless-steel button-head screw wrong-way round to the anchor nut and place in the seatback hole. Drill through the bottom rivet hole 2.5mm and insert a TAPK36BS rivet to maintain the location. Drill through the top rivet hole 2.5mm. Remove the anchor nut and countersink the rivet holes with a hand-held 5.9mm drill bit.		 3590.0
18 Balsa strips for building-out the cowl towards the spinner delivered.
19 Edit the fuel sight gauge backing stripes CADintosh file to extend the length of the black version to 315mm & print out for laminating.
20 Trim the stripes printout to size. Get laminated then trim clear edges down to a few mm. Offer up in position. Trim bottom inboard corner to better fit curvature there. Mark and cut out notches for bonding upper securing clip to seatback. Mark and punch a hole for the lower P-clip screw. 3590.3
21 Contrive means of holding a button-head screw in place in the P-clip securing hole with Mole grips and lead weights. From the aft side, a 3/8" screw looks just long enough to get started in the anchor nut thread. Check the TAPK36BS rivets - they barely reach the aft face, so enlarge the countersinking considerably until it looks as though there is enough length to clinch the anchor nut. With the screw in place, get underneath and offer up the anchor nut held in the end of the offcut of sight-gauge tubing. Need to form a bend in the tubing with the heat gun to get the anchor nut presenting at the right angle. Should now be able to get the screw started, with an assistant driving the screw from above. 3591.3
22 With Dorothy holding the IXO electric screwdriver on the 3/8" button-head screw, try offering up the anchor nut on the tubing from the aft side. Screw does not catch on anchor nut threads when rotated, so change the 3/8" screw to a 1/2" one, with a couple of washers. Try again and this time it catches OK. Slacken screw slightly and rotate anchor nut to align with rivet holes in seatback. One rivet goes in OK but 2nd one baulks. Open up each hole right through with 2.6mm drill, with a rivet holding the alignment on the opposite hole. Now rivets go in OK and are just protruding through the anchor nut. Tighten the screw to pull the anchor nut tight against the seatback. Set rivets in usual fashion with air riveter and nose extension. Remove temporary screw.

Vacuum up the swarf and debris. Coat the masked-off area of the seatback and the back of the prepared backing stripes with Evo-Stik Time Bond contact adhesive and leave to dry for a few minutes. Place the backing strips on the seatback and insert P-clip screw to ensure correct positioning at bottom. Once satisfied with alignment, remove masking tape and press stripes firmly onto seatback. Fit P-clip. Checking from aft side, screw could be longer as it does not quite protrude from the anchor nut. Also the sight gauge tubing seems to be even nearer the rudder-cable pulley. Maybe some sort of protection would be advisable; need to figure out how to do that in the small space and through the restricted access.		 3592.8
28 Have another look at the possibilities for a guard between the rudder cable pulley and the sight-gauge tubing. Decide that a strip of aluminium about 10mm wide could be attached to the underside of the tunnel beside the access hole and bent down to cover the aft side of the pulley. The access hole cover would need to be relieved to clear the screw-heads. Attach bench shear to a block of wood with M12 coach bolts. Mark a 10mm strip on the width (~190mm) of a sheet of 6061 T6 aluminium and shear it off. I had forgotten that the driving wheel of the shear leaves quite deep nicks on the workpiece. Spend some time filing smooth that edge. Cut off about 95mm and try inserting it through the access hole above the rudder cable pulley. Possible to get it into place, but also very easy to drop it! Bend down about 40mm at about 45 degrees. That seems to fit OK over the pulley. Hold in place with cleco clamp while checking underneath for appearance and fit. The bent end is longer than necessary and the angle is too great - about 30 degrees would be better. The other part, for the mounting anchor nuts, need to be longer - but not much, as it would then be impossible to insert through the access hole.

Cut another strip of 6061 about 17mm wide, this time using the Gilbow tinsnips (the el-cheapo "aviation" snips I bought some time back are really not much use). Deburr edges. Bend about 35mm down at about 30 degrees. Trim other end to about 75mm. Slide into place and hold with cleco clamp to allow marking the area to be trimmed off around the access hole. Trim to marked line with power nibbler and smooth with file. Offer up again & clamp. Now rubbing against pulley. Slide along until clearing pulley, mark and re-trim for access hole. Continue further small adjustments until satisfied with clearance from pulley and position against tubing; deburr all edges and smooth with ScotchBrite wheel.		 3595.4
left-arrowgo to previous page of journal listgo to list of narrative pages list go to next page of journalright-arrow
Return to Rowland's home page
This page last updated 2022-03-05 11:00. I try to make this page as accessible as possible, by adhering to HTML 4 standards. Valid HTML 4.01! Valid CSS!
I welcome comments on this website. However, because of the amount of spam it attracts, I no longer post a direct e-mail address on any page. Instead, please click here to contact me. You will have to confirm that you are human before the message will be sent on to me.