Europa #435 G-RODO Build Journal - 2017 11
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|4||Wonder if using the oscillating saw with a sanding pad would be any easier than hand sanding. Without clamping the aileron, try it with a 60 grit sheet but it doesn't seem to be noticeably easier than hand sanding, and the rate of material removal is not significantly different either. Go back to using the small 3M sanding block (2.25" x 4.5") and work using that for some time, pausing to vacuum up the dust and to clean off the face of the sander. Continue until the sandpaper starts to come loose from the block. Reverse the paper end-to-end to get a better grip and carry on until it starts to loosen off again. No grade is visible on the back of the paper but it looks and feels very similar to the paper on the larger 3M sanding block which is marked P120. Vacuum up and weigh aileron - 2955g; that is 20g removed since last weighing and another 70g to go.
Hand sanding is quite effective but very tiring. Wonder if a powered palm sander would be any use for this job. Do some online research, settle on one from Screwfix which is cheap but with good reviews and order it along with some packs of 120 & 180 grit sheets.
|6||Pick up the palm sander from Screwfix and briefly try it on the aileron with 120 grit paper. Does not seem very aggressive, but at least the paper stays attached to the backing pad (unlike the sanding pad for the oscillating saw). It also has a vacuum extract port so might try that to keep the mess down.|
|7||Connect palm sander to vacuum cleaner hose and try some sanding with that setup. It's a bit awkward with the long overhang of the hose but do-able. Rate of removal quite modest, so after a few minutes of that go back to the 3M detail sanding block. Cut a piece of 120 grit 3M production paper to fit it and that goes OK for a while; but (probably because the paper is thinner and lacks the plastic backing of the stuff supplied with the block) the paper won't stay in place for long. (Maybe some extra padding might help.) Next try cutting down the cork sanding block from 100mm to about 46mm and use a strip of sandpaper about 47mm x 172mm. That is OK but it is hard to keep the paper in place. Change to a strip about 46mm x 230mm and that is a bit better as it overlaps on the top of the block so only one finger is needed to keep it in place. While looking at sandpaper stock, notice the 130mm x 65mm soft drum sander. Put a 120 grit belt on that and try it on the cordless drill. Works quite well, with a good rate of removal and not too hard to control. Keeping speed low and tilting slightly to use one edge rather than the full width gives best control, with minimum skittering and a small contact area. Work with that until much of the whitish filler is gone and a large part of the underside is showing the greenish-blue glass colour. Smooth a few lumpy areas with the small cork block and weigh it - 2915g. That is 40g removed since last weighing and now only 30g need be removed to reach target of 2885g - although there is now not much area left that is not already down to the glass layup.||2909.4|
|14||Continue working on remaining white areas on underside of starboard aileron using soft drum sander. It's easier to control with the cordless drill set to low speed - should have thought of that before. Stop when it looks as though not much more can safely be taken off. Vacuum off and weigh it again - 2920g - 5g heavier than last time! (Reality check: 5g in 2920g is less than 0.2% difference.) Rub down a bit more with the soft pad fitted with a 120 grit DA sander disc, then with a 400 grit disc. That brings the surface finish up well in most areas, but highlights a few uneven places left from the drum sander. Vacuum off & weigh again - 2915g. I may need to take paint off the upper leading edge after I do a test fitting to the wing, which may alter the balance in the undesired direction, but will wait & see how that goes. Set starboard aileron aside for now and start on the underside of the port aileron with the belt sander and the 120 grit belt. Progress seems slow; switch to a new 120 grit belt and the waste production seems faster, although it still takes some time for patches of primer to appear. Get the belt cleaning block out of the belt sander box and clean the belt occasionally. Vacuum off and weigh - 3080g. That is 25g down from the starting weight of 3105g, leaving 220g more to remove for the target weight of 2860g.||2910.5|
|15||Clamp port aileron by the horns with carpet softening as before and continue sanding the underside with the belt sander using 120 grit belt, cleaning it from time to time. Seems to take a long time getting through the paint, primer and filler but eventually small dark patches start to show in several places. Unclamp, vacuum off and weigh it - 2980g. Not enough area left to work safely with the belt sander so continue working on the whitish areas with the coarse side of the small Perma-Grit block and the soft drum sander. When significant area is down to near the glass, rub all over with the soft circular pad fitted with a 120 grit disc. Vacuum off and weigh it - 2930g. That is a total of 150g removed today leaving another 70g to remove to reach the target weight of 2860g.||2912.0|
|16||[09:20] Open carport, pull trailer out and drop ramp. [09:30] Remove the flaps from the cockpit area and winch out the fuselage clear of the ramp. [09:50] Find a stand to support the wing spar. Fit the wingtip handling rod to the starboard wing and move it out from the side of the trailer for access. Take starboard aileron out from garage and fit it to wing with 2 short screws per hinge. Holding wing dolly tilted clear of aileron, move aileron throughout travel. Up-aileron seems fine, but in the down position there is rubbing between the aileron LE and the wing TE at several positions. Mark all the tight spots with a felt-tip pen, using a piece of paper between aileron and wing to check the limits of the tight areas. [10:40] Search without success for carbon paper for making witness marks. Consider that there is a layer of paint on the hinges which is not helping, but I can't think of a way to remove the paint safely without scratching the hinges.
While shifting starboard wing to remove aileron, it slips out of the dolly and hits the trailer floor, taking a flake of paint off the LE - curses! Remove starboard aileron and return it to garage. Replace spar in clamp and stow wing against side of trailer.
Unclamp port wing spar and rest it on the stand. [11:25] Take out port aileron, fit it to wing and mark tight spots as for starboard. Not so many points of contact as on starboard, and feels as though it's touching less firmly. Here it definitely feels as though a light bit of filing along the wing TE is all that is needed, and probably the same would work for the starboard one. Remove aileron, replace spar in clamp and stow wing, pinning dolly in place. Return aileron to garage. As a heavy rain shower is advertised within the next hour, decide not to spend time re-positioning the tee-hinges that brace the dolly for the starboard wing. Take tools and screws etc for ailerons out of trailer.
Put flaps back into cockpit area, further in this time as I have better access with the fuselage out. Cut away small areas of fuselage dolly flange that were touching the wheels and causing the alarming wobble as the dolly crossed the change in slope between the trailer floor and the ramp. Winch fuselage back into trailer. Put back engine box full of blue foam, and engine pallet, and close up trailer. Reverse it back into place - in the process damaging the nearside bottom rear corner again slightly where it caught a pallet. [12:20] Return all tools to garage and tidy up a bit. [12:55]
Later, just for a change, start to make a new version of the protective cover for the fuel level sensor in the top of the tank. Screw down to a piece of chipboard the top of the tub which is to be used as a mould. Screw the tub firmly onto the lid so it is now held firmly upside-down. Cut a couple of pieces of BID from offcuts, each to enclose roughly a 170mm diameter circle. Mix a peg-1 (30g) batch of standard epoxy. Drape one piece of BID over the tub and wet it out, encouraging the sides to drape smoothly and trimming off excess points. Add second piece of BID and similarly wet it out and trim it. Squeegee it with a plastic card then bring in to the boiler cupboard to cure overnight.
|20||Take the fuel sensor cover layup down to the garage, abrade the skirt and remove some bulges. Mark out and cut a 50mm x 650mm strip of BID (to go more than twice around the skirt). Mark out the same size rectangle on polyethylene sheet and lay BID on it. Mix a peg-1 (30g) batch of standard epoxy and wet out the BID. trim excess polyethylene sheet from around it then wrap it around the skirt of the fuel sensor cover layup. Add several layers of peel-ply. Take it in to the boiler cupboard to cure.||2916.8|
|21||Take fuel sender cover layup out to garage. Remove peel-ply. Remove mould by cutting and cracking inwards. Clean up skirt edge with Perma-Grit block. Will need to offer it up to the hole in the headrest floor to check how much the skirt will need to be trimmed (and indeed if it fits!).
Hang each aileron in turn by its hinges on nylon line and photograph the resulting angles. The flat undersurface of the port aileron is now still slightly tail-down but the starboard one is slightly tail-up which is better.
|25||Copy the photos of the suspended ailerons as TIFFs and import into CADintosh. Draw lines over the photos to measure angles. The centreline of the port aileron is now 84.9 degrees from the vertical and the starboard one is 77.6 degrees.
Send e-mail to Ryan Woodward asking if he has facilities for spraying now.
|27||Ryan replies saying he can bring his compressor to me and spray at my premises. Respond with further queries about compressor power supply, overspray, personal protection, etc and asking if it would be better to wait until I've filled the tailplanes as well.|
|28||Can't find a source of sanding sheets the correct size for the 3M Sandblaster detail sander. Even the 3M website does not list such a thing, although there seems to be no problem getting the ones for the larger version. Cut a sheet of 120 grit paper in half then one half into 4 pieces each about 57mm x 139mm. Attach one to the detail sander behind the original 3M sheet. That seems to hold it pretty well as I sand the whitish areas of the port aileron underside to get back nearer to the glass more extensively. Vacuum off and weigh: 2925g; still 65g shy of the 2860g target. Mark the centreline of the root end with a felt-tip pen. Suspend by hinge pins with nylon line and photograph root end. Put lead weight on top and position to get centreline horizontal by eye. Photograph again. The 366g weight is about 34mm diameter and its forward edge is about 2mm forward of the suspension line. Thus the moment is 366g x 15mm. The mass of paint (spread over the entire surface) to get the equivalent moment would be about 62g, which is much less than the 160-200g that Ryan estimated. Looks as though I will have to sand down the upper surface too (sighs deeply).||2918.4|
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