Europa #435 G-RODO Build Journal - 2020 07

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day	notes	hours
1	Review all the info and pictures I have on the location of the NACA inlet for cabin air. Fit F14 Instrument Module to firewall with a few screws. Temporarily fit the sticks to check clearances. Climb in and check possible locations for NACA inlets port and starboard. On starboard side cannot go down as far as the factory-suggested position because of the conduit and the fuel return line, but can just about go as far forward as suggested without fouling the edge of the IM shelf. It would be possible to slide the lower corner of the duct flange down under the fuel return line and the conduit, which would keep the opening more clear of the windscreen rebate. Try the blue eyeball vent for size against the duct and it would fit OK, but would have to be at the upper edge because the stick comes quite close to it. It should be in easy reach from the P2 position without having to loosen shoulder straps. I see that I'd already made a vertical mark both inside and outside the starboard fuselage for the aft edge of the hole, based on the factory recommendation of 160mm forward of the door edge. Now it looks as though that line could be the edge of the flange instead. On port side there is a bit more leeway forward but can't go too far forward as that would tend to obstruct view of, and access to, the master switches. Also, don't want to put it out of easy reach. Mark a vertical line as a possible location for the aft edge of the flange. The NACA vents will need some fettling. The holes from the useless and broken adjustable flap need to be filled, and the profile at the leading edge could be improved. Notice while sitting in the cockpit that the port footwell vertical conduit could be much taller, to pass the aft baffle fixing bolt. Not sure if I have any more conduit in stock to make a replacement. The starboard one needs to be shortened slightly as it is hard up against the grommet. Discover that the starboard stick is just touching the side of the IM with full port travel. Had not noticed that before - maybe never had the sticks and the IM both installed. In practice, it's very hard to get full stick travel to either port or starboard with legs present - I only discovered the issue by taking my legs out of the way. The starboard stick is fitted at a very slight angle inboard, so that is the cause. It would solve the problem if the stick were shortened very slightly. In fact both sticks could be shortened to provide more clearance from vents. Remove sticks. Mark each 24mm from top end and hacksaw off. File smooth, deburr and smooth with steel wool. The hole in the side of the P1 stick-top switch assembly is 4.2mm - correct size for tapping M5. Tap it with care, ensuring no swarf gets onto the switch terminals. Blow clean with air line. Check how far a 12mm M5 stainless steel button-head screw will go in and shorten it by about 5mm with the Dremel wheel. Chamfer end on the grinding wheel. The hole is 21mm down from the flange of the fitting. Mark a spot 21mm down from the top on the aft side of the port stick, centre-pop, pilot drill and drill to 5mm. Deburr hole. Fit switch assembly, insert screw and tighten with 3mm hex key. Wonder in retrospect if the ducts and vents would obstruct the fitting or removal of the IM - will have to check that!	3312.8
2	Print out the Ayton template for the NACA duct and cut out the hole. Looking at the NACA duct positions I proposed yesterday, it does not seem as though the F14 Instrument Module would have room to get past them (or even more so the associated vents) for installation (or removal - although the possibility of that is looking increasingly unlikely as time goes on!). If the ducts were as far aft as possible that might allow enough room for the IM to pass above them. Start to sculpt the leading end of one duct to smooth the airflow. Filing is not very satisfactory as it's hard to get a decent stroke without scratching the floor of the duct. Try the Dremel cut-off wheel but although that works after a fashion it tends to melt rather then cut even at the lowest speed. I had assumed the duct was a glass-fibre moulding but I see now it is some sort of thermoplastic, without any evidence of reinforcing matrix. Best results are by cutting with a hooked blade on a Stanley knife. Complete the re-profiling of that duct and repeat the process on the other. Climb into cockpit and position ducts to assess clearance for IM fitting, and for stick travel. With the aft edge of each duct flange about 60mm forward of the inside of the door recess it looks as though the IM could clear them. That is with the lower edge of each duct flange behind the conduit, and the top corner just clear of the windscreen rebate, and there is room for the recommended 25mm BID tape without encroaching on the windscreen. Leaving the ducts jammed behind the conduits, climb out again. Remove the screws and lift out the IM. There is room to lift it above the ducts and the intended positions of the eyeball vents. Check stock of small oval conduit and there is plenty to make a longer piece for the port footwell vertical section. Loosen both of the vertical sections of conduit in the footwells with a few taps of a light hammer and slide them up out of the clips. Clean up the hammer marks from the top end of the shorter one that was on the port side and insert it into the starboard clips. Align the paper printout of the duct cutout on one of the ducts and with a soft pencil do a "brass-rubbing" of the edge of the flange. Scan the pencil outline of the NACA duct flange and print it out on 160gsm card.	3314.1
3	Cut out the card outline of the NACA duct flange and take it down to the garage. Cut off a suitable length of the small oval conduit for the vertical section in the port footwell. Trim one end at about 45 degrees and smooth off both ends, first with round file then with wire wool. Slide it down into place but one tab of the top clip pops off as I try to spring it in. Even after sliding fully home the clip is distorted out of shape and needs a lot of pressure to get the tab back into contact. Conduit still slightly too long; cut off excess and re-smooth. Insert again into clips. Abrade bonding areas for top clip tab. Mix a batch of Rapid Araldite and spread it on bonding areas. Hold clip in place for curing with a length of wood jammed against the port cockpit side, interposing polyethylene sheet as a release film.	3314.7
4	Remove wooden brace from conduit clip. Clip is bonded really well, but the conduit has slipped down and the chamfered end is too close to the corresponding end of the horizontal piece. Will have to see if I can free the conduit and slide it up a bit.
6	Trim away the epoxy around the upper clip on the vertical section of the starboard footwell conduit, until the conduit frees and can be slid up a bit to increase the gap at the bottom. Stick the printed outline of the NACA duct flange onto a thicker piece of card for stiffness and cut out. Place a duct inside cockpit against the starboard side with the aft end aligned to the previously-marked line. When satisfied with position, trace around the flange with a felt-tip pen. Remove duct and place card template within the marked outline. Trace around the inside of the template for the area to be cut out. Drill 10mm at each corner of the marked area. Start cuts with a small piercing saw and then continue along inside the edges with a hacksaw blade in a padsaw handle. File the edges to the marked line with TC files. Offer up duct - hole still a bit small. File edges, re-check, file again until duct fits in the hole.	3315.9
7	Abrade bonding area on inside of fuselage for starboard NACA duct flange with various files and emery paper. Consider that it might be easiest to fill the redundant adjuster holes in the ducts before fitting them to the fuselage. It's difficult to abrade the hollows in the floors of the ducts in the usual way but making deep scratches with a #3 X-Acto knife seems work OK. Abrade the outside of the bosses with a coarse Perma-Grit file. Find an offcut of aluminium plate that can be used to back up the filler in the hollow to get a flat finish. Hacksaw another piece of aluminium plate to serve the same purpose on the other duct. Tape polyethylene sheet around both pieces of aluminium. Check clamping arrangements. Second plate does not lie as flat as the first and needs extra clamps to keep it in good contact with the duct. Cut off a couple of small pieces of BID and similar size pieces of peel-ply. Pick out a couple of offcuts of mahogany about 22mm thick that could be used for mounting the eyeball vents. SRBF would be another possibility, but that would be heavier. Eyeball vent fixing holes take M4 or 8-32 UNC screws. Don't seem to have any M4 wood inserts so will need to order some; not sure if wood inserts are available in UNC. Would prefer not to use woodscrews as they could split the wood, being so near the corners. The rear boss of the vent measures about 48.5mm diameter. The nearest holesaw I have to that size is 51mm, which, as the body of the vent is only 54mm square, would leave very little meat around the hole, as well as being a sloppy fit on the boss. Search online for a 49mm holesaw. The nearest I can find is 48mm at Screwfix so order that.	3317.7
8	Collect 48mm holesaw from Screwfix . Try out the holesaw on an offcut of softwood. The hole just admits the rear boss of the eyeball vent as a press fit, so that is perfect. Offer up a vent to the fuselage side and check how far away its edge will be when tilted to the required angle. The vent does not need to swivel further outboard than directly aft, so the body of the vent can be angled somewhat inboard. At an appropriate angle, the outboard side of the vent body is about 10mm clear of the fuselage side. Bandsaw the offcuts of 22mm mahogany to rectangles 54mm x 65mm. With the 45 degree engineers square, scribe centres on each for the holesaw. With a backing piece of softwood underneath, take the holesaw through the first piece of mahogany. Some roughness on breakout, but easy to smooth with emery paper. Check fit and both faces accept an eyeball vent with a firm push. Decide which face is optimum and mark a corner for chamfering with a felt-tip pen. Check again the angle for the vent body and transfer that to an adjustable square. Transfer that in turn to the bandsaw table. Cut off the outboard end of the mahogany at that angle. Fit eyeball vent and check how it looks in-situ - seems fine. After double-checking the orientation, chamfer the outboard edge of the second piece of mahogany, then take the holesaw through it. Strangely, only one face takes the eyeball vent easily. A very light rub around with a sanding drum eases it and the fit is now good. The outer corners of the wood will need to be rounded off but I think I'll leave that until I finalise the fixings. Order some M4 stainless CSK screws and some M4 wood inserts from ModelFixings .	3319.2
13	M4 screws and wood inserts delivered from ModelFixings . Mix a peg-1 (24g) batch of Ampreg 21. Wet out the small BID patches on sheets of polyethylene. To the rest of the epoxy add 3 or 4 doses of Q-cell (micro) until it is almost dry and non-slump. Apply a lump of the mix to the hollow of one NACA duct and tamp it well in, but not quite flush. Position the polyethylene-covered piece of aluminium plate over the hollow and clamp it in place. Wipe off most of the tail squeezed out at the back. Trim down one of the wetted pieces of BID to fit better between the clamps and apply it over the hole. Apply several layers of peel-ply on top. Repeat the process on the second duct. Take both ducts into the boiler cupboard to cure overnight. Mark through the starboard eyeball vent mounting holes onto the mahogany mount with a centring punch. Drill through 4mm. Invert mount and counterbore each hole with 6mm drill bit about 10mm deep. For each hole in turn, insert M4 x 25mm screw and start a M4 plain wood insert on it to ensure squareness, then wind the wood insert in with a 4mm AF hex key and remove the 25mm screw. Fit the vent to the mount with M4 x 20mm CSK stainless steel screws (2.5mm AF hex key). Repeat the process on the port vent mount.	3321.4
14	Take NACA ducts down to garage from boiler cupboard. Sample cup well cured. Remove clamps and aluminium plates. Inner filled surfaces not as flat as I'd hoped. File them down with a coarse TC file until reasonably flush. File off excess BID around rear bosses and smooth off. Roughen the flanges on the side to be bonded to the inner surface of the cockpit with coarse Perma-Grit file. Chamfer edges on inner face of flange for better transition of BID reinforcement. Roughen the flange on the inside face to key for BID reinforcement. Offer up starboard duct to hole in fuselage and check clamping required for bonding with Redux - 2 positions will do. Drill a few 1/8" holes in both duct flanges as recommended in the Ayton documentation.	3322.9
15	Check NACA duct outline against starboard fuselage hole and abrade fuselage a bit further out for the BID reinforcement. Drill a few more 1/8" holes around the duct flanges. I wonder if it would be desirable or even possible to make some sort of scaffold for the layup to connect the duct to the vent; without something like that, the layup might sag undesirably. Degrease the inside of the fuselage around the hole with acetone. Degrease the plastic duct with methylated spirit. Mix a 15g + 6g batch of Redux (Araldite 420) and add a few small doses of flox to stiffen it. Spread the mix onto the bonding area inside the cockpit and onto the flange of the duct. Position the duct and press into place. Wipe off excess epoxy squeezed out. Drape a couple of pieces of polyethylene sheet over the bonding area and clamp the flange to the fuselage side in 4 places. Clean up the excess epoxy and smooth the edges. Leave to cure. Measure the fuel filler top area with a view to selecting a plastic box as a protective cover. About 200mm high, 180mm wide and 100mm deep would enclose it completely. Have a look at Really Useful Boxes and at Lock & Lock boxes. The latter seem to have more promising sizes in the range.	3324.6
16	After considerable online searching for a box of an appropriate size to cover the top of the fuel filler and the pipework, order a HPL858D 3.7l Lock & Lock box from Amazon. Redux in sample cup looks well cured. Remove clamps and polyethylene sheet. Despite my considerable attempts at cleanup before curing, there are quite a few areas of squeezed-out Redux that need further fettling. Still quite rubbery so can be cut away without too much effort, using an X-Acto knife or a 1/2" chisel. When reasonably tidied up, offer up vent in wooden mount and consider how the layup connecting the duct to the vent might be done. Probably need to do it in sections. Could I use several flat pieces of pre-preg offcuts with BID at the joins? Will need to make card templates to check feasibility. Note some discussion on the Matronics AeroElectric e-mail list recommending a device called NanoVNA as a good tool for setting up comms antennae. Do some online research and order a Hugen NanoVNA-H through AliBaba. [Much later I receive advice from one of the NanoVNA developers that the URL I show in the online journal is for a clone of their original design. I amend this journal web page to show links to the original and to the appropriate software and remove links to the clone on other pages.]	3325.1
18	Move car and roll fuselage out onto drive for access to port side. Check location for port NACA duct. I had thought it would be OK with the aft flange about 60mm forward of the door rebate, same as on the starboard side. However, that puts the bottom of the duct outlet hard against the conduit. On the starboard side, the conduit is lower because of the fuel return line and that is sprung out of the way at present. Some small space is needed for the layup connecting the duct to the vent. I don't feel like taking the conduit off again, and the duct can't go higher because of the proximity of the windscreen, so try a location further forward. Eventually settle on a spot that allows enough space above and below without getting too close to the F14 Instrument Module. In the fore-and-aft dimension it's about half way between my first choice and the factory suggested location. Clamp the duct lightly in place and mark the outline of the flange onto the inside of the fuselage with a felt-tip pen. Remove the duct and position the card template within the marked outline. Mark around the inside contour for the hole. Drill in the 4 corners with a 16mm holesaw. Saw along the edges with a padsaw and file out to the lines with TC files and powerfile. Offer up duct and file again where needed to get a fit. Abrade and chamfer the inner faces of the duct flange. Rather late in the day, put in the P1 stick and check clearance between stick top and duct+vent - about the same as in the originally-intended position, not a problem. Abrade inside of fuselage all around the hole for bonding the duct flange and for the reinforcing BID layup. Degrease duct with methylated spirit and degrease fuselage with acetone. Mix 10g + 4g Redux (Araldite 420) and add a few small doses of flox to stiffen. Spread onto fuselage bonding area and duct flange. Position duct and wipe off excess epoxy squeezed out. Drape small pieces of polyethylene sheet over and clamp in 4 places. Smooth out and wipe off more excess Redux. Roll fuselage back into garage and leave to cure. Notice that the masking tape I put around the propeller brushes to hold them retracted has softened and allowed the brushes to spring out. Remove the tape and put a clamp on instead to hold the rubber pad in place over the brushes.	3328.5
20	Roll out fuselage onto drive. Remove clamps and polyethylene sheet from port NACA duct bonding area. Clean up some excess Redux squeezed out of joint with knives and chisel. Smooth along inside of flange with emery for BID reinforcement. While the fuselage is out with plenty of room to work, decide to remove rudder for access to fin closeout for comms antenna and coax. Undo plain nut (7/16" AF) at forward end of rudder pushrod and remove bolt (with washers) holding rod-end bearing to bellcrank. Undo the temporary screws on the rudder hinges, starting at the bottom and supporting rudder as last one at top removed. Take rudder out to trailer and store it resting against a tailplane with a soft rug interposed and underneath. Collect up all the sockets that have been left lying around after various jobs and store them in their respective 1/2" and 1/4" drive trays. Roll fuselage back into garage.	3330.4
22	Lock & Lock box delivered from Amazon; collected by neighbours as we are out.
25	Offer up the Lock & Lock box to the top of the fuel filler. Looks as though it would be difficult to use the lid attached to the inside of the fuselage. Also the box is quite deep so would protrude into the baggage bay more than necessary. Perhaps the box could be cut back from its lid edge enough to fit more snugly, and then its sides could be screwed to a small flange attached on the fuselage wall. A card mockup might still be needed to get the cutting right.
27	nanoVNA delivered. After checking instructions and advice, order some SMA-BNC adaptors and SMA cables & adaptors from CPC .
28	Majority of CPC order delivered (in 3 separate packages!). Scribe "O" on open-circuit calibration plug and "S" on short-circuit calibration plug with diamond bit in Dremel . Fit female-to-female adaptors to all 3 calibration plugs and go through the calibration and setup procedures outlined in some of the nanoVNA help documents. Although display is not exactly as shown in the documentation, it looks quite promising. Take the ferrite toroids down from the office to the small drawer unit for wiring terminals in the garage. Check the existing coax cable for the comm radio. It goes all the way forward from the fin to the headrest, but the aft section of smaller conduit does not line up well with the larger one in the baggage bay - a bit of re-alignment will be needed. There is a piece of string going all the way through the conduit from the fin to the aft face of the baggage bay.
29	Final item of CPC order (SMA to BNC socket) delivered. Roll fuselage out onto drive for access. Clean up and abrade bonding area for BID around both NACA ducts with a combination of powerfile, detail sander, riffler and hand sanding. The fuel return line has slipped upward beside the conduit and I accidentally touch it with the powerfile, leaving a slight nick. Dress it out with needle file, fine emery paper and superfine ScotchBrite. Degrease bonding areas with acetone, taking care not to dwell on the ducts as the acetone will dissolve the plastic. Measure the lengths of BID needed; aft 120mm, top 170mm, forward 90mm and bottom 100mm. Mark and cut 4 off each of those lengths of BID, 25mm wide. Lay them stacked in pairs on strips of polyethylene sheet. Mix a peg-2 (36g) batch of Ampreg 21. Wet out all BID strips. Paint the bonding areas around the ducts with epoxy. Apply the BID strips in turn to the appropriate edges of the ducts, peeling back the polyethylene once the BID is bedded down. Bottom BID strips need to be trimmed with a taper to clear the conduit. Apply strips of peel-ply all round. 34/35C, 26/20% RH in cockpit. Pause for lunch and leave to cure in the sunshine. Later, roll fuselage back into garage and tidy up some tools. 21/22C, 43/25% RH in cockpit now. Layups curing nicely.	3334.1
30	Remove peel-ply from NACA duct layups. Cut off excess BID in windscreen aperture at starboard side and smooth with half-round TC file. Roll fuselage out onto drive. Cut off and smooth down excess BID at port windscreen edge. Round off the inboard corners of the wooden eyeball mounts on the belt sander, using the fence to keep things square. Now ready to bond eyeball vents in place; no need to abrade the bonding areas as they are fresh from the peel-ply. Degrease those areas and the mounting faces of the wooden eyeball mounts with acetone. Mix a 10g + 4g batch of Redux (Araldite 420) and add a few small doses of flox to stiffen it. Paint it onto the bonding area and the face of the mount. Position eyeball mount and clamp in place with speedclamp. Wipe off excess Redux all around. Repeat the process with the remaining Redux for the starboard vent. Will have to reverse the clamps to get the fuselage back in the garage, but for now leave the bonds to cook in the sunshine - thermometers are showing between 30C & 40C in the cockpit. Bring the new RG58 coax down from the office to the garage. Climb into aft fuselage, and by temporarily removing the transponder from its base and unplugging the antenna, rearrange the conduit to lie above the transponder loom. Pull the coax back from the baggage bay section of conduit ready for pulling in new coax. Abrade and degrease a new conduit clip and the fuselage area for bonding it. Mix a batch of 90-sec epoxy and spread it onto clip and bonding area. Hold it in place while curing with wooden bridge and polyethylene sheet interposed. The two conduit ends are now rather close together and I wonder if I need to shorten one to make more room to work. Re-consider how best to get the new coax drawn in. Push and pull through, from the firewall end of the conduit to the aft of the baggage bay, a length of 250lb nylon line. Tie the aft end of it to the string in the aft conduit. Pull string from the fin end and that seems to go OK. However, the string suddenly goes tight and breaks inside the fin - not a good result! Pause for a drink and consider options. Try putting a piece of heatshrink sleeving on the free end of the old coax. Once cooled, it has a very good grip on the cable and is pretty strong in tension. For better access to the cable, shorten the aft conduit about 25mm with snips, being careful not to cut off the coax inside. Feed the old coax forward from there through the baggage bay and cockpit conduit, which proves surprisingly easy. Making sure that the aft end does not disappear into the fin, pull a good length through forward to work on. Cut the somewhat scruffy end of the cable off square to get a good butt joint. Join it to the new coax with a generous length of heatshrink and let it cool. Pull the old cable out from the fin, drawing the new one in. The edge of the heatshrink catches on a couple of the conduit breaks but that is easily fixed. The join emerges at the fin, leaving plenty of length in the cockpit. Remove the heatshrink and leave a good length of coax dangling from the fin. The Redux sample in the mixing cup has cured pretty well, so it seems OK to just remove the clamps from the vents rather than reversing them. Roll fuselage back into garage and tidy up.	3339.1
31	Mark and cut out card templates for possible flat plates to join starboard NACA duct to eyeball vent mount. Bottom one will need to have a slight twist, but the other 2 are fine as flat sheets. The plates could be either offcuts of 3-ply pre-preg (of which there is plenty) or made up as 2-ply BID sheets. These plates can be epoxied or Reduxed in place along their edges, and then BID laid over the all the joins to strengthen them and make it airtight. Round off forward inboard edge of eyeball mount to ease BID bend there.	3339.3

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