| day |
notes |
hours |
| 2 |
To align the CS14 bellcrank mounting brackets, decide to try inserting the correct bolts in the spar holes, fitting full-thread 1/4" - 28 UNF bolts in the brackets held by nuts, and using a short length of 1/4" bore tube to confirm alignment between the two. The tube must be as long as possible, but short enough to slide clear of the gap between the ends of the bolts to ensure there is no side pressure being exerted on the bracket. Haven't got any 1/4" bore tube in stock, but there is some 6mm bore aluminium tube that can be drilled out. Will grease the bellcrank bolts and insert them before doing the bush and spar cup bonding so that they are ready for the bellcrank work after the first lot of Redux has cured. Remove 1/2" bolts and tilt wings to allow cockpit module to slide clear. Move port wing outboard slightly in the sling to ensure it is tip-heavy while doing the preparation. Scuff-sand the spar and cockpit module bonding areas with fine Perma-Grit flexible sheet. Cover the spar tips with parcel tape and cut holes at the bushes. Clean up the spar cups with coarse ScotchBrite. Degrease all bonding areas with acetone. Carefully apply grease to insides of bushes in spars with cotton bud. Grease bellcrank pivot bolts and insert in spar holes. Grease 1/2" UNC bolts, nuts, washers and spacers. Mix 10.5g + 4.2g Redux. Paint onto seatback bushes on bonding area only with a mixing stick split to give a narrow end, leaving entry end clean. Insert into seatback holes and wipe off excess Redux while holding down from other side. Add 1 dose flox to Redux and butter onto forward faces of spar cups, leaving a tiny amount for a sample. Slide the cups onto the spar tips. Grease the insides of the seatback bushes with a cotton bud. Slide the cockpit module under the tilted spars and carefully bring the port wing back towards the centre to re-align the holes. Lower the spars and insert the 1/2" UNC bolts, trying not to let the Redux get spread around where it's not wanted before everything is correctly positioned. Fit the spacer tubes, washers and nuts on the underside and snug up with a spanner. Touch up fillets of Redux around the edges of the spar cups with the narrow mixing stick and wipe off a few excess bits with tissue. Check angles of top spar and seatback - both 4.2 degrees so can't complain about that! Try not to touch anything again. 16C, 55% RH; turn on both fan heaters to thermostat 4. After a couple of hours, Redux still quite tacky and only 21C, 46% RH (because the wings prevent the plastic curtains from closing normally) and still the same at bedtime. Redux firming up well by then. |
1122.5 |
| 3 |
22C, 42% RH. Set up CS14s to measure how long the alignment tubes should be. 26mm seems about right, so cut 2 off 26mm lengths from the 6mm bore aluminium tube and drill them out to 1/4" in the lathe. Rust-remover order arrives from Arc Euro Trade. My stock of 1/4"-28 UNF bolts has only a couple of full-thread ones near the length needed for the CS14 alignment and one is pretty rusty, so try out the rust treatment on that. After a couple of hours soaking, although not yet rust-free, it has cleaned up enough to get a nut on without undue force. Assemble the full-thread bolts onto the CS14s - one needs a washer under the head to avoid contacting the bolt in the spar. Try out setting up the CS14s and clamping them in position. Even the lightest clamping pressure distorts the bracket and pulls it out of alignment. Decide to ignore completely the method in the manual with wooden shims as it seems both fiddly and unlikely to give good results. Instead, will set the brackets on flox pads first, with no additional clamping pressure, so that the brackets do not distort and the bolts will stay in line with the tube. Cut a couple of lengths of 8mm bore tube to support the 1/4" bore tubes on the spar bolts so they will span both bolts equally. (Could actually have re-made the 1/4" bore tubes much longer, but this is quicker.) File the bottom outboard corners of both CS14s slightly to keep them within the profile of the cockpit module when set vertical with respect to the cockpit floor. Check that they are still 162mm wide. Abrade the bonding areas on the seatback with the fine flexible Perma-Grit sheet, and take down a few big knobbles with a tungsten-carbide grit file. Wax thoroughly and buff all the flanges of both CS14s. Find that the resin pump spout caps have both fallen off into the drip cup and need cleaning. Leave them out for later attention. Clear the spouts with one stroke to the drip cup, then mix a 2-stroke batch. Add 2 doses flox and butter onto bonding areas, first adding strips of parcel tape along the edges of the port spar to avoid bonding to it. Lower each CS14 into position in turn, pressing down lightly and adjusting positions of mounting flanges until the alignment tubes slide freely. Scrape off excess flox, forming fillets around all accessible sides of CS14 flanges to provide positive location, but trying to keep it from spreading onto the tops of the flanges and trapping them. Check that alignment tubes are still sliding freely and leave to cure. 24C, 35% RH. After it has started to cure, carefully scrape out with a scalpel the flox that has squeezed up into the mounting holes; that should make drilling them out easier. Check that the alignment tubes are still free to slide. |
1125.1 |
| 4 |
22C, 36% RH. Flox pads under CS14s well cured. As holes are quite near the sides, use tight-fit drill kit with 3/16" bit to drill through the seatbacks, using the flange hole as guides. Undo the temporary alignment bolts and remove the alignment tubes. Tap each CS14 sideways lightly to release from the flox. They come off easily and perfectly clean, leaving well-formed areas for re-fitting. Check assembly of CS15 bellcranks; the supplied AN4-12A bolts will need considerable shortening to leave only 2 threads clear of the nut. Try AN4-11A instead and that would be just about right without any shortening, so decide to use those instead. A check of the inventory shows that there were 4 surplus of that size supplied anyway! Cut 2 more short lengths of 8mm bore tube to act as spacers to retain the bolts while curing. Get the remains of 3mm ply sheet 1 out of the fuselage in the trailer and bandsaw 2 pieces 50mm x 150mm from it. (I know the manual says they should come out of sheet 2, but there is plenty of room to take them from this sheet because the tri-gear flap actuator hard point is not needed, and I cut the thigh support ribs much closer to the size required than that shown on the cutting plan.) Clamp them to CS14s and drill through each bellcrank mounting hole with a 1/4" drill. Unclamp and enlarge the holes with the taper reamer until the bolt head can just be forced in. Cut a couple of scraps of BID to cover the bolt heads (because the ply is slightly thinner than the bolt heads and I want to ensure a smooth surface is presented to the fuel tank), and a couple of pieces of peel-ply to match. Grease the spacer tubes. Abrade the outer faces of CS14s with coarse ScotchBrite and the ply with fine Perma-Grit flexible sheet. Degrease bonding surfaces and rinse bolts with acetone. Mix 20g + 8g of the older Redux (this not a structural bond) and butter it onto CS14, leaving a small clear area around the bolt hole to avoid getting any Redux on the thread or shank of the bolt when it passes through. Butter ply with Redux, including edge of hole. Dip bolt head in Redux just enough to cover underside of head and jam into hole in ply. Place into position on CS14 and fit greased spacer & nut. Clamp ply to CS14 at each end, aligning with edges. Wipe off excess Redux that squeezes out and apply it to the top of the ply around the bolt head. Tighten nut with spanner to ensure bolt head is firmly against CS14. Place BID over bolt head, wet out thoroughly with Redux and apply peel-ply. Repeat for 2nd CS14 and leave them both to cure on the floor a couple of feet away from one of the fan heaters. 22C, 46% RH. |
1127.6 |
| 6 |
Order fuel gauge mod from Europa factory. 22C, 43% RH. Turn off fan heaters. Remove the peel-ply from the CS14 assemblies and remove the nuts and spacer tubes. Clean off a small amount of Redux that has crept along one bolt. Re-mount the W16 bellcranks. Mount CS15 bellcranks on CS14 brackets and check position against W16s. Port mounting bolt protrudes too far and will need more washers under its head. Loosen and remove the nuts, washers and spacers from the 1/2" UNC bolts in the spar bushes. Withdraw the bolts. Slide both wings slightly outboard to clear spar cups and tilt them tip-down. Slide the cockpit module clear, then tilt the wings more to re-fit the rigging dollies for better stability. Check number of washers needed under head of port W16 bolt - settle on 8 of the spurious thin (0.032") EURO01 washers in addition to the one normal (0.056") EURO01 specified. With the spars out of the way, file down and clean up the flox pads for the CS14s where it was difficult to smooth them before curing because of the spar. Fit the CS14 brackets but, because of the adjacent curve of the seatback flange, need to file a bit off the edge of the AN470-3 washers at the lower outboard positions to allow them to sit flat. Fit the CS13 short pushrods to each CS08 & CS15 and adjust for length. The starboard CS15 bellcrank bolt (AN4-10A) is too long and rubbing on CS14; use an AN4-7A for now. Clear the low table of tools etc to make room for the cockpit module. |
1130.3 |
| 7 |
Get the plank of chipboard out of the trailer for supporting the cockpit module between the headrests upside down on the table, and set the cockpit module on it. Wrap and tape some paper tissues around the bearings near each CS07/CS08 and file down the corners where they were touching the fuselage floor, down to the edge of the screw and washer. That takes off barely a millimetre, but any extra clearance is welcome. Vacuum up all the swarf and remove the tissues. Turn the cockpit module right side up again and position for reasonable access to seatbacks for layups around spar pin bushes. Get the remaining offcut of 3mm ply out of the trailer and from it bandsaw 3 off 70mm squares. Take the 4th 70mm square off the end of the main part of ply sheet 1. Decide it would be easier to do these layups if the seatback was horizontal. Can't just set it on the baggage-bay end as it's not strong enough. Re-arrange the chipboard plank projecting 350mm past the table edge with 4 off 125mm wooden spacers under it and a couple of 5-litre bottles of water at the other end, and rest the rear face of the seatback on it. It needs a small amount more height, so slide a piece of melamine-faced chipboard under the seatback and that raises it just enough to keep the back of the baggage bay off the floor. The whole arrangement is reasonably stable but obviously won't stand heavy leaning on it off-centre. Order 1/8" & 1/4" NPT taps from Tracy Tools. Mark the centre of one 70mm ply square. Align and clamp them all together and drill through for bush 20mm with a Forstner bit into a narrow but thick piece of scrap to keep the clamps clear of the drill table and give clean breakthrough. Connect them together in pairs with M16 x 25mm full-thread bolts. Hold each in turn by the nut in the vise and chamfer the edges with a rasp, smoothing with Sandvik abrader. Remove, with acetone-soaked tissue, the last traces of grease around bushes from 1/2" bolts. Abrade bonding areas and all ply pieces. Degrease again with acetone. Apply wax carefully to inside only of bushes using a cotton bud. Cut 4 pieces of BID 120mm x 120mm and 2 pieces of peel-ply a bit larger. Refill resin & hardener dispenser bottles. Mix a peg-2 (45g) batch and paint the bonding area of the seatback with it. Decant off about a third of it and add a small dose of flox to that, making a less stiff mix than usual, but not actually runny. Butter ply mating faces with flox and position both stacks. Paint top surfaces of ply with epoxy and lay on 2 squares of BID, wetting out each layer in turn with neat epoxy. Apply peel-ply, slitting diagonally at corners to let it drape over the chamfers. 17C, 68% RH; turn on both fan heaters at thermostat setting 3.5 and leave to cure. |
1135.1 |
| 8 |
20C, 49% RH; layup and samples well cured; turn off heaters. Europa Club 16.5mm reamer for Mod 72 arrives from Frank Mycroft. Get landing gear mount out of trailer and remove bubble wrap. Rather disappointed to find 2 areas at the bottom quite corroded. They match port and starboard which is a bit strange. Hold off doing any reaming until I can speak to the factory. Remove peel-ply from yesterday's layups and with a combination of countersink bit to take out most of it, and scalpel to clean the edges, remove BID across hole in bush. Turn cockpit module upside down again ready for work on pitch torque tube. |
1135.6 |
| 9 |
 NPT taps arrive from Tracy Tools. Phone factory about corrosion on landing gear mount. Roger says it is quite common because it's difficult to clean off all the acid from the zinc plating process, and if I can't get it off satisfactorily with a wire brush, they will change the part for a new one. After clean-up he suggests etch-primer or ACF-50. Try the wire brushes I have but they are a bit big. The straight Dremel one looks as though it might reach, but mine is badly worn. Get a few more, plus stainless cup brushes and right-angle drive. That gets in a bit better, but still not right to the bottom of the problem areas. Try some of the rust remover neat and agitate it with an old toothbrush; that cleans it up a bit, but not completely. Seems to be about as good as I can get it, so rinse off and apply ACF-50. Clamp lightly in vise soft jaws and ream out holes, using cutting fluid to make it easier, going deep enough for parallel cut to about full depth of insert. Clean bores with tissue pull-throughs. The inserts drop in almost all the way. Clean both inserts with acetone and pull tissue through centre. Once dry, spray inside with etch-primer from both ends to ensure coverage, then spray outsides. Leave to dry thoroughly. Spray inside of frame tubes with ACF-50. Place inserts and tap home with plastic mallet. One goes easier than the other - maybe a thinner coat of primer. |
1137.6 |
| 10 |
Fit pitch pushrods to bottom of CS01 with temporary nuts. Start to assemble aft ends of pushrods to CS10 flanges but find the holes need to be relieved with a 5/16" drill to let the bolts pass without binding. Using the combination of washers in the manual (AN960-516L each side of rod-end bearing) means that there is slight gap between the bearing and the flanges and so the flanges would be pulled together slightly when the nut is tightened. On the starboard flange, either changing to AN960-516 each side, or using 2 off AN960-516L each side would remove the gap. The centre and port flanges need one AN960-516 (or 2 off AN960-516L) plus one AN960-516L to fill the gap. Adding that extra thickness in the washer stack means that the AN960-516 under the bolt head has to be removed in order to get shank rather than thread in the other flange hole. Post a query about this on the Matronics e-mail list. |
1138.5 |
| 11 |
Bud Yerly responds to my e-mail query saying that my common-sense approach to the CS10 flange spacing is correct - add washers to fill the gap, and change the one under the head as needed to ensure the thread does not enter the far hole. Ian Rickard also says that the flanges seldom are quite the right distance apart. Bandsaw pieces of ply for the 4mm spacers between CS11 and CS05; then decide they are too wide, and instead cut 4mm wide strips off pieces of 3mm ply. Check that CS11s are adjusted to shortest length and tape the ply shims to the CS11s with parcel tape. Bandsaw a thicker piece of ply to support the CS10 flange in approximately central position. Abrade the bonding areas on the seatback. Wax the bottoms of the CS09s. Mix a 2-stroke batch of the older epoxy and add flox to make it fairly thick. Apply to the seatback and lower the CS09s into position, ensuring the shims on the CS11s are in contact with the insides of the CS05s. Add lead weights to keep CS09s in place. 18C, 59% RH; turn on both fan heaters to thermostat 3.5. By bedtime 22C, 44% RH and flox well cured so turn off heaters. |
1140.8 |
| 12 |
Order 1 foot of 1.5" diameter 2011T6 aluminium bar and a 7/16" x 20 TPI UNF die from GLR Distributors Ltd. |
|
| 13 |
Re-draw the fuel tank connector adaptors from Paul Stewart's mod application in CADintosh, modifying to suit what I think is the optimum installation for 912. Remove the lead weights from the CS09 brackets and drill through the mounting holes 3/16" using the tight fit drill kit. Remove the wooden packing and shims. Tap the CS09 brackets lightly to free them from the flox then file down the rough edges of the flox. Re-position the CS09s and fit the bolts. All stick movement now free to end stops with no interference anywhere. |
1141.2 |
| 18 |
Seeing Graham Singleton's latest picture of his fuel tank adaptor, which has no flats on the sides, consider that they could be made from slightly smaller diameter bar stock, say 1.25". That would avoid the need to mill the sides, but would still leave over 1/4" wall thickness for the side tappings. In Graham's picture the amount of thread visible on the AN822-6D suggests it has barely even 1/4" of thread engaged. Re-draw the tank adaptors in CADintosh as made from 1.25" bar to Graham's pictures; now 3 types. To try out the NPT tap, find an offcut of 1/4" aluminium plate and drill it 7/16". Need to find a much bigger tap wrench than usual for the 1/4" NPT tap. Hard to get the tap started square, but it goes in quite easily. Stop when tap thread emerges other side. Trial insertion of an AN840-6D shows a good fit and it tightens before emerging on the other side. It can be turned quite a bit further with a spanner before feeling really tight, so adjustment of elbow orientation should not be too difficult. After removing starboard CS14, try inserting the fuel tank into its place; it's a squeeze to get it past the bolts on the lateral link rod, but OK near final position. Mark with felt-tip pen for filler & vent cutouts on baggage bay bulkhead. Order Minitool jigsaw (as recommended by Ian Rickard for fine cuts in fibreglass parts) and spare blades from Hobbies. Mark out centreline and edges of strap layup on starboard spar. Draw up in CADintosh the shape of the support needed for the spar strap card spacer and print out 4 copies. Stick to pieces of 3mm ply and bandsaw to shape. Cut 4 pieces of 3mm ply to fit between the side profiles just made. Stick them to the starboard spar with parcel tape and apply a piece of card over them. Once done, realise that this shaping stuff will have to be dismantled from inside the layup before the spars can be separated afterwards. Decide it would probably be best to start again and cover the spar with polyethylene sheet before attaching the strap supports. That would allow the spar to be slid out from the layup without difficulty. |
1143.0 |
| 19 |
Order 1.25" aluminium bar from GLR Distributors Ltd and aluminium pipe (2m of 1/4", 4m of 3/8") from Speedflow. |
|
| 20 |
Phone Andair to check if small gascolator is still available; it is not. They also say the banjo outlets do not occupy significantly less space than an elbow. |
|
| 21 |
Aluminium pipe arrives from Speedflow. Start to compile full list of items for fuel system, showing each pipe run and what it connects to. |
|
| 23 |
1.25" aluminium bar arrives from GLR Distributors Ltd; Minitool jigsaw arrives from Hobbies, but without the spare blades which are out of stock. Connect it via temporary wires wrapped round the plug pins to the 12V supply for the MiniCraft tool. Tightening the blade clamp forces the blade out of square sideways, but it can be bent slightly to bring it more-or-less true. Try it out on a layup offcut and it cuts quite easily, with a very fine kerf. Get the filler pipe part XFS07 from box 9 in the trailer and use it as template to enlarge the marked-out area of the filler connexion on the baggage bay bulkhead. Leave the pipe in box 2 for the moment. Similarly, enlarge the marking for the vent using the 1" hose. Remove the fuel tank. Drill a starter hole, remove the safety tip from the jigsaw blade and cut around the marked outline, working from both sides where the flange obstructs topside access. Can't quite get into one corner, so finish the last part of the cut with a hacksaw blade. Remove the cut-out piece and slide the fuel tank in again. It fits without too much trouble and the cutout looks about right when the tank is positioned equidistant from each side. Note that the forward face of the tank is rubbing on the aileron cross-link, even with the tank lifted against the baggage bay bulkhead. It may be better with the cockpit module upright, instead of firewall-down as now, but will need to keep an eye on that. Cut away the masking tape and remove the card and ply support shape for the spar strap layup. Wrap a piece of polyethylene sheet around the spar, making sure that the parcel tape securing it to the spar is all accessible well outside the layup area. Re-fit the 3mm blocks to the upper side of the spar as before, using temporary spacers to position them. Re-fit the ply & card assembly and tape it in position. |
1144.0 |
| 24 |
Fit the second card and ply curved former to the underside of the port spar. After doing that, re-read the manual and realise that the curved former is only called for on the top edge of the spar! Remove the bottom one. Get out the port pip-pin and the starboard spar pin and insert them separately just as a check. Find that the pip-pin won't go in from the top (aft) side because the hole in the spar cup seems to be slightly misaligned. That must have happened because the 1/2" UNF alignment bolts are slightly smaller diameter than the pip-pin and so didn't align the spar cup perfectly. It works OK if the pin is inserted from the bottom (forward) side of the spar, so that will do for now, and I will have to relieve the spar cup hole later. Abrade the port spar in the bonding area with fine Perma-Grit flexible sheet, and wipe down with acetone. Renew the centreline and guidance marks outside the bonding area. Cut a couple of pieces of polyethylene sheet to put the layups on, and mark them out with 90mm x 180mm and 90mm x 250mm rectangles plus centrelines. Turn them over so the ink doesn't bleed into the epoxy. Cut 2 off 90mm x 180mm BID, 4 off 90mm x 250mm BID and 2 off 90mm x 250mm UNI. Lay them in correct order on the polyethylene. Take the port wing dolly off and get it balanced in the sling. 16C, 60% RH. Mix a peg-3 (60g) batch of fresh epoxy and pour onto the glass to wet out. The 6-layer one takes a good while to wet out. While waiting for it, cut the other piece in two for the brackets and apply each to the port spar, then peel off the polyethylene sheet. Take the starboard wing off its dolly and balance it on the sling, then slide it into the spar cup on the port spar and insert the pins. Finish wetting out the spar layup and add a small amount of flox to the remaining epoxy. Butter it into the corners between the spars with a mixing stick. Lay the strap on and fold it around both spars. Surprised to find it barely goes beyond the edges of the bottom (port) spar, and the short flaps are unwilling to stay in position. Cut a piece of peel-ply and wrap it around the whole thing to keep the bottom flaps in place. Turn on the fan heaters to thermostat 3.5 & leave to cure. Still concerned about the strap length, check the later PDF copy of the manual on disc; it calls for the strap layup to be 350mm, not 250mm! Go back and peel off the peel-ply and the 6-layer strap layup, trying not to disturb the 2-layer bracket layup underneath. Tidy up the flox fillets with a little more from the sample cup. Cut BID & UNI pieces to 350mm x 90mm, mark out a new piece of polyethylene sheet and lay them on it. Cut a piece of peel-ply. Mix a peg-3 (60g) batch of fresh epoxy and wet out the layup. Paint the underside (forward side) of the port spar with epoxy while waiting for the layup to wet out. The bracket layup is still just tacky so it's OK to proceed. Drape the layup over the spars and fold into position. There is now a small overlap so trim the ends slightly. Stipple into good contact with the spar and the bracket layup. Apply peel-ply. Still a tendency for the flaps to droop, even with the peel-ply, so put a couple of pieces of 3mm ply between the spars to keep them at the correct distance apart, then lightly clamp a piece of polyethylene-covered board under the spar to keep the underside layup in good contact with the spar. 20C, 49% RH; leave to cure. |
1148.7 |
| 25 |
21C, 44% RH; Turn off heaters. Unclamp and remove board under port spar. Remove peel-ply. Take out spar pins. Remove tape holding polyethylene around starboard spar and slide wings apart, leaving strap support stuff inside layup. Wings need to go back quite a bit to get the starboard spar out of the strap, but plenty of room for that. Extract polyethylene sheet, parcel tape, card and ply supports from inside layup. Lower wing tips onto dollies and clamp them on again. |
1149.0 |
| 27 |
File down sharp edges of spar strap. Enlarge outer spar cup hole on port spar with taper reamer. Tidy edge with deburrer and clean up inside surface with fine Perma-Grit flexible sheet. Clean up swarf very carefully and try pip-pin - now goes in smoothly. Wheel wings out of garage and round to lawn. Open trailer and get out fuselage dolly and other stuff in front of fuselage. Roll out fuselage. Notice that the aluminium tube in one wing tip hole is in danger of disappearing inside. Although it could be tapped M14 x 1.5 like the other one, there are no more bolts of that size in stock, so instead find that a M8 nut can be driven into the end to hold a M8 bolt and penny washer. As I'm starting to put the wings into the trailer, it starts to rain. The port wing will not fit into the spar clamp as before now that it's got the strap fitted. For the moment, roll the wing further into the trailer and clamp the slimmer part of the spar. Roll the fuselage in again and put all the parts boxes etc back in. Once everything is in, the rain stops! Once it looks set clear for a while, open the ramp again and set the fan heaters up at the entrance to try drying out the interior a bit. Doesn't seem to have had much effect by the time I have to close up again because of more rain approaching. |
1149.5 |
| 28 |
Brian Fogg phones to relate some of his own experiences with the fuel system after reading my posting on the Matronics e-mail list and some of the responses. He has fitted 2 of the nice but no-longer-available Andair GAS125 gascolators to his 914 system. They are under the baggage bay, connected with Versatube soft aluminium tubing from Aircraft Spruce (probably similar to the Speedflow 817 stuff I have) run along the bottom of the tunnel and attached to the fuselage bottom moulding. His fuel pump is under the port seat, mounted at the recommended 45 degrees on the thigh support rib with an access panel cut in the seat. He tried Graham Singleton's seat-back sight tube modification but found that even with the breather connected at the top corner of the tank there would still be fuel getting into the top of the sight gauge and making airlocks and bubbles. He is planning to revert to the factory standard breather on top of the fuselage, but I pointed out the trouble Tim Houlihan had found with that; the sight gauge (and the associated pressure transducer) would go off-scale with small changes in aircraft speed or attitude. I have theorised that it may be because the small holes at the back of the breather tube are going in and out of the boundary layer and so experiencing large changes in pressure, enough to overcome the ram effect from the forward-facing end of the tube. In our work on his fuel system earlier this year, Tim & I never got around to making a test flight with the rear holes taped up to explore this theory before it was time to depart on the Europa Club trip to Ireland, but I'd still like to check it. Brian has finally got rid of the fuel smell in his cockpit by sealing the flange of the fuel gauge sender with Loctite 5922, available from Halfords at £4.50. |
|
| 29 |
Draft a machining schedule for the tank fittings. Get the F18 filler moulding out of box 9 in the trailer to check how much room is available for attaching tube fittings to the top end. Looks as though there is plenty of room, even if I want to add another fitting for the sight gauge breather. Hacksaw 3 off 2.5" lengths from the 1.25" aluminium round bar. Still no reply from Gloster Air Parts to my e-mail and phone messages, so phone Harry Hopkins and ask if he knows anything. He offers to post a message on the RV e-mail list to see if anyone has a second-hand flaring tool or one that they might loan. |
1149.7 |
| 30 |
Set up 1st piece of 1.25" aluminium bar in the 3-jaw chuck to run true by eye. Centre-drill the end. Find a toolbit with a reasonably curved corner and plenty of top rake that I can use for both facing and turning. Touch it up on the grindstone and sharpen the edges on a diamond whetstone. Face off end enough to remove hacksaw marks. Fit 1/4" drill, which needs the tailstock partly off the end of the bed to get it in. Drill through 1/4"; needs several re-positionings of tailstock as the stroke of the tailstock barrel is much shorter than the workpiece. Remove from chuck. Trim an offcut of thin aluminium plate to bridge machine vise sides and set workpiece on it, faced side down. Use a couple of 3mm plywood offcuts to prevent vise jaws marking workpiece and tighten up. Drill through on the bench drill 8.5mm (for 1/8" NPT tapping) and then drill 2" deep with a 1/2" drill to make room for the boring bar. None of my tiny boring bars that will enter a 1/4" hole are long enough to do a hole this deep. Repeat operations for 2nd and third items, making the through hole 7/16" (for 1/4" NPT tapping) on the last one. Set up a jig with vee-blocks for cross-drilling so that I can do all 3 without having to re-measure. Unfortunately, so pleased that I had organised things so well, I didn't notice that the first item I drilled was the one with the 7/16" through hole, which (now that I intend to take the sight gauge vent to the top of the filler moulding) needs only one side hole, and of course I took the drill right through. Oh well, that will need an extra 1/8" NPT plug to fill it - I'm not making another one! Repeat cross-drilling on other 2 pieces and manage to remember that one needs only 1 side hole. Set up first one in the 3-jaw again with the faced end against the chuck. Face to 2.375", then remove whole chuck with workpiece in it. Fit 2nd chuck and 2nd workpiece. Face to same length. Repeat with 3rd chuck and 3rd workpiece (tank adaptor B). Start to turn down the outside diameter for 1.375" (about 35mm) from end, but despite good finish and ease of taking up to 0.25mm cuts on facing, suffering from chatter on turning. Adjust the toolbit slightly (losing the settings, of course) to present a shorter face to the work. Re-find the start setting and re-adjust the auto-feed stop. The new angle has not eliminated the chatter completely but at least is some improvement. I guess I could really do with a big centre to support the end of such a long workpiece. Still doesn't explain why it was so smooth and apparently effortless when facing; the turning must be exciting some different vibrational mode. Harry forwards quote from Gloster Air Parts for a tube flaring tool; about the same as LAS Aerospace so may as well get everything from them and save one lot of postage. |
1155.5 |
| 31 |
After a few more turning passes on tank adaptor B with various depths of cut, stone up a sharp-pointed toolbit and replace the rounded toolbit with it. Set up again the start point; can't use the auto-stop because the different shape of the toolbit means it's just not long enough now so have to stop it manually. The new tool cuts much more smoothly and can take a 0.125mm cut comfortably. Use the diamond sharpener to round the tip slightly so as to avoid a stress riser at the inside corner. Proceed to take the diameter down to 25.4mm. Consider stopping at 27mm as the tank bosses are all actually over 27mm diameter. However, checking the ID of the nominal 1" fuel hose shows it will be hard to fit it onto that size, so stick to the same 1" size as the factory-supplied F09B & F09C tank adaptors. Note the settings for that diameter and then continue to turn down the outer 0.75" (about 19mm) to 0.75" (19mm) diameter. Find I can safely take a 0.25mm cut as the diameter reduces. Note the settings for the final dimension. Rub off the sharp edges with a fine emery board. |
1156.8 |
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