left-arrow

Europa #435 G-RODO Build Journal - 2019 10

 right-arrow
index sitemap advanced
search engine by freefind
tickgo to list of milestonestick Navigation & Acknowledgements
day notes hours
7 Check tightness of backnut and fuel hose nut on firewall elbow. Mark both with inspectors lacquer - difficult to do neatly as hard to reach.

Fit hose to firewall elbow and check run of fuel hose across engine to fuel pump with aft baffle in place. Photos of other installations show that it passes below the balance tube (and the ignition harness, in one case - but that seems a bit perverse). Factory manual calls for it to pass between the starboard carburettor and the ignition module, but there is no room for that on my engine. Will stick to passing between ignition module and coolant expansion tank. Once satisfied with routing and length, mark hose for cutting at pump end.

Remember that the heavy-duty cutting disc did not fit well on the Dremel arbour, so need to make a bush to keep it true. True up the end of an offcut of 10mm aluminium bar. Centre-drill and drill 1.7mm. Turn down about 0.5mm to 3.2mm diameter. Part off at about 1.5mm. Parting tool leaves a stub on the workpiece. Make a split collet from an offcut of aluminium, boring it out 1mm deep to 10mm ID to fit the workpiece. Chuck the bush in it and clean off the parting stub.

Mount heavy-duty cutting wheel on Dremel arbour with the newly made bush. Rotate hose in vise jaws at intervals so as to keep cutting inwards on the braiding. Clean off the very few whiskers of wire braid with the side of the wheel. Try the hose clamp on it and it goes on without bother. Fit hose to firewall elbow and check routing with it pushed onto fuel pump nipple - all looks good. Remove hose, fit caps at firewall end and tape over pump end.

Tidy up lathe and tools. 		3131.2
8 Check journal for fuel return line fitting sequence. Check Rotax and Europa factory manuals for guidance on routing of hoses to carburettors.

Not entirely happy with where the AN822-4D elbow finishes up when tightened into the fuel return firewall fitting (FRFF). Give it another quarter-turn with the 1/8" NPT tap and blow it out again. Elbow now tightens up nicely at the required angle. Consider location of FRFF, checking the extent of the baffle flanges on top of the footwell. Mark what seems to be a good spot. Drill 3mm and then 4.8mm. Get out the longest piece of 1/4" OD aluminium pipe from stock and flare one end. Fit sleeve and nut. Bend pipe about 15 degrees about 50mm from the end, to bring it roughly parallel to the side of the fuselage. Assemble loosely to the AN816-4D adaptor on the underside of the FRFF. Mark where the mid-point of the bend should be to bring the aft end of the pipe down to the AN822-4D elbow on the tank C fitting. Also mark roughly where to cut it, leaving a generous length for final adjustment. Make the bend to about 45 degrees. Cut off the surplus and offer up to the elbow on the tank fitting. Mark the final cutting point. Remove pipe from FRFF, cut to length, clean up, fit nut and sleeve and flare the end. Fit again to FRFF and then to tank fitting. A little bit of fettling needed to the routing, but otherwise looks very satisfactory.

Fit the AN822-4D elbow to the top of the FRFF, using Loctite 577 thread sealer, but ensuring that none goes inside the fitting. Fit AN826-4D tee to fuel pressure sender (which was already assembled to its mounting bracket with the AN316-10 nut).

With some effort and liberal lubrication, fit the two stock lengths of 100-04 braided hose to the nipples on the carburettors. Notice that the older piece is much less flexible than the newer one. Check how the hoses might be persuaded to bend around to reach the AN827-4D 4-way cross union. It's just possible to bend the older hose on the starboard carb out and up through almost 270 degrees to pass under the adjuster for the throttle cable and thence towards the centre, but I will have to re-check the oil hose routing before making any firm decisions. The newer hose on the port carb can be more easily persuaded to take a similar course. Taking the hose down and under the carb does not seem a good idea on either side as that would put it rather close to the exhaust pipe on port and probably interfere with the oil hoses on starboard.

It looks as though the side port of the tee on the fuel pressure sensor can point straight up to connect with the 4-way cross; there is no advantage in angling it forwards. Temporarily position the aft and starboard aft baffles to check that the sender mounting bracket will not foul them. Connect the made-up hose end to the tee on the sender. Fit a nipple to the elbow on the FRFF and check where the hose should be cut to give a sensible position for the sender bracket. Mark the hose. Remove the hose from the tee and cut it with the heavy-duty cutoff wheel on the Dremel . Braid seems very inclined to splay out this time. Check the size of the orifice in the restrictor; it will take a #70 drill but not a #69 so must be 0.7mm ID. Chamfer the leading edge of the restrictor slightly to ease its entry into the hose - I intend to push against the end of the restrictor which has the larger bored hole, to avoid any possibility of damaging the actual orifice. Push restrictor into open end of hose - it gets very tight before long. Set up the hose vertically in a vee of the aluminium jaws, with a piece of wood on the vise bed under the hose-end fitting. Tap the restrictor into the hose using a ground-off nail as a punch. Pretty hard going to get it in far enough to clear the hose-end nipple. Apply masking tape around the open end of the hose and trim it very slightly again with the disc on the Dremel ; that gives a much less untidy result. Fit the 101-04 hose end with the usual technique.

Blow out the assembly with the air line. Seems to be some black rubber shards against the restrictor, but swilling the oil residue out with petrol and giving further blasts with the air line seems to clear them. Fit the hose between the elbow and tee and mark the outline of the sender mount on the top of the footwell. Dismantle tee from sender so I can remove the sender from the mount for access to the holes. Position the mount on the marked lines and mark through the holes. Drill 3mm and then open to 4.8mm. Fit anchor nuts underneath in the usual way, with TAPK36BS rivets. Fit the bracket to the footwell with 5/8" stainless steel button-head socket screws. Check fit of hose - need to keep sender securing nut fully loose to make enough room to fit the hose between the tee and the elbow.

Make a paper placard for the hose and secure it in place with clear heat-shrink. It will of course be covered by the firesleeve later. Assemble hose to tee and elbow and do up the nut securing the sender. 		3136.8
12 Tape up and cut off, using the disc on the Dremel , the frayed end of the newer, more flexible length of 100-04 hose. Leaving tape in place, try fitting a 150-04 cover clip to it. It goes on with some persuasion, but when removed the end is badly frayed again. The inside of the clip adjacent to the drive screw is not truly circular and is catching the braid at one side. Cut off the frayed end again. Given this experience, note that I will need to avoid fitting the cover clip until finally needed and am sure that I won't need to remove it again. I suppose that it might be possible to use some sort of shoehorn-like device to get the hose braid past the offending edge of the clip.

Temporarily assemble the fuel hose to the firewall elbow, the aft and starboard aft baffles to the footwell, and connect the oil hoses to the oil tank. With some difficulty position C04 water hose; I recall that previously there seemed to be very little clearance but this time the clearance appears to be non-existent to negative! Will need to investigate that routing further, but for now the main thing is to check if the top of that hose will interfere with the fuel hoses to the carbs.

Form the end of the more-flexible 100-04 hose into a loop from the starboard carburettor barb (without actually pushing it on) to the planned position of the AN827-4D 4-way cross union. With the nipple of a 101-04 hose end fitted to the cross, mark for cutting the hose. Tape the hose at that point and cut with the disc on the Dremel .

Similarly, form the remainder of that piece of hose to align with the port carburettor barb and mark it for cutting on the port side of the cross union. Tape it and cut off where marked.

Fit, in the usual way, a 101-04 hose end to the longer (starboard) carburettor hose. 		3138.3
22 Assemble hose end on shorter (port) carb hose. The hose goes into the socket with no difficulty and no loose strands of braid getting in the way, and fits closely against the back of the threads. After oiling liberally with SAE 30 oil the nipple starts quite smoothly but quite soon as I tighten the nut it becomes very hard to turn. The resistance gets worse until just before the required clearance between the nut and the socket is achieved, and then it suddenly becomes easier and I realise the threads have stripped. Undo the nut and the threads are obviously badly damaged. Pull the hose out of the socket, with considerable effort. The braid is splayed and will need to be cut off before any further attempt is made; I hope there will be enough length left. 3138.5
23 Phone Speedflow for advice. The technician says that the assembly has probably been cross-threaded and that it occasionally goes wrong like that for her even after 20 years of doing it. Order a couple of 101-04 hose ends and a half-metre length of 100-04 hose that they have in stock.
25 Speedflow order delivered. Looking again at the dismantled hose-end, the leading part of the threads do not look very damaged - I feel they would have shown evidence if it had been cross-threaded from the start. I wonder if the hose had been pushed in to the socket so far that some of the braid was getting into the thread.
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 2020-01-07 20:49. 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.