Rudder Rolling

Sunday 13th July (3 hr)

Rolled and riveted leading edge of rudder. Put in rivets at narrow end of elevator end ribs. Pop-riveted ribs at narrow end of rudder tip rib.

With a clean shop, I set about finishing off all the left-over jobs from the empennage before settling down to the wing construction phase of the project.

I decided to roll each section of the leading edge separately. These sections are defined by the hinge cut-outs that divide them. Before rolling, I put slight bend in the leading edge of the overlapping skin so that it would lie flat after riveting. Not everybody does this, especially because it is such an inconspicuous spot, but I wanted to get a feel for the process before I get to areas where it may be far more necessary. I used the Isham-supplied tool for the job and I was reasonably happy with the results. There is certainly little or no gap between the skins but the bend that I put in was a little too aggressive and is still visible. It is possible to adjust the gap between the rollers so I may try to have them a little less tight in future. Also, I will probably borrow the Avery's tool from my friend and fellow-builder Bryan Sheane and see how that compares.

For the roll itself, I used a metal tube of just under an inch in diameter. In fact, it is the bottom telecopic section of a lawn umbrella with the plastic fittings removed. This was taped on to the skin using 3M duct tape. I don't think the diameter is critical but a bigger tube will not allow you to over-bend the skin enough so that it springs back to the position you want.

I clamped a vice-grip onto the tube in the hinge openings and rolled the skin making sure that I was also exerting pressure downwards into the bend. This was to prevent any bending of the skin at the point where it crosses the forward edge of the rudder spar. The duct tape adhesive was so strong that removing it threatened to alter the bend just created but, with a little care, it eventually came off. Getting clecos in to the holes was easy at the top but a little harder near the bottom where some hand pressure was needed to get the holes to match up. From there it was a simple matter of drilling out the holes to size and putting in the correct pop-rivets.

Riveting on the skins to the narrow ends of the elevator and rudder ribs was something I had not been looking forward to and had not had any success with until now. My new masonry chisel (with the sharp edge ground off and polished) was a definite improvement. The flats on the handle made it easy to keep everything in position while the rivets were being set. I still had not located rubber grommets of the right size to put over the rivet tail so as to squeeze the skin and rivet flange together but I was able to get the corner of an edge clamp cleco onto the corner of the rib flange close to the rivet without interfering with the job.

Ultimately, however, there just is not enough space in there to set both rivets in the last position, so I had to content myself with pop-rivets on the underside of the elevators and on both sides of the rudder.

First day of 'real' building since the break - and very enjoyable it was too.

Thin-end rivets

Wednesday 30th April 2008 (1hr)

Set last rivets at narrow end of elevator root and tip ribs except for the very last ones. Experimented with techniques for these last rivets.

The long-nose no-hole yoke is the obvious tool for this job and does well up to a point (yes that was a pun) where there is just not enough room for the unsqueezed shop end of the rivet as well as the pointy end of the yoke within the flanges of the rib down near the trailing edge.


On most of them, I was able to get the yoke nose in as long as the rivet was not fully inserted. You are then depending on getting the moving rivet set to push the rivet home as it closes before finally setting the rivet at the end of its travel. To do this, you have to have pretty good trigger control skills to get the squeezer to close slowly. Even then, I found that the skin and rib were not tight to each other at the point where the rivet set enough to grab the inside of the holes. These all had to be drilled out, leaving me with only one of the eight where the results were okay. To make matters worse, if you do happen to get one of these set, the rivet head now restricts the space further for setting the rivet on the surface opposite.


I decided to try the 'lever' method so I put some tape around the end of a piece of flat steel bar that I had. However, this wasn't really stiff enough to set the rivet properly, leading to some more drilled out rivets. I will have to look at using a wide 'bolster' masonry chisel, which should be really hard while still being thin enough to get into the space available. Also, I need a rubber grommet with a thickness closely matching the projecting shop tail of the rivet. Placed over the rivet tail, this will push down on the rib flange making sure that the two materials are in close contact as the rivet 'bites'.

That's it with the project for the moment. I really need to help Dorothy out with the remodelling job so I will have to stop work until that is done and the wings arrive. I still have these rivets to finish plus I haven't rolled the forward edge of the rudder skins. Still, building a plane doesn't mean you are no longer a member of the family and duty calls.

Trim tab hinged.

Saturday 26th April 2008 (2hr 10min)

Bent and cut trim tab hinge pin. Trimmed and fitted elevator counterbalance weights.

Bending the hinge pin is not as easy as you would imagine. I marked where I wanted the centre of the first bend to be and heated the spot with a plumbers buthane blow torch until it was bright orange. By now the mark had dissapeared of course but I guessed that the centre of the heated area was the intended centre of the bend. Using my long -nose pliers, I grabbed the pin to the outside of what I thought was the centre point and twisted it over to create the tightest right-angle bend I could manage. it was surprising how much force it still needed and how quickly it regained its strength as it cooled.

Now, with the pin back in the hinge and the right-angled part hanging down ofer the inboard edge of the elevator, I marked where I wanted the centre of the next bend - about an 1/8th from the trim tab spar. Once again, the mark served only as an aiming point for the blow torch but the bend worked out just fine. It only remained to mark and cut off the unwanted tail and clean up the end on the Scotchbrite wheel. The finished item sits beautifully against the elevator trim spar.

I would like to have done as builders of other models have done and use one 'ear' from the hinge scrap screwed into a nutplate to hold the hinge wire in place. However, there does not seem to be enough space for the nutplate at the end of the trim spar on the forward side so I will probably have to just safety wire it as per the plans. I will leave this until later in case I think of some way around the problem.

The trim tab bottom skin's forward edge was interfering with the aft edge of the bottom skin and spar of the elevator, so I needed to bend this upward so that it just cleared this obstruction when the trim tab is deflected downward. I found the best way of doing this was to take the trim tab off and bend the entire length of the skin edge at the same time by pressing it against my bench.

I have heard of builders having problems in sawing the counterbalance weights because the band saw blade starts melting the lead. I saw no sign of this problem, maybe because my blade travels slower or because of the 16 tpi pitch. I did need to file some material from the top and bottom edges of the weights to get them to fit inside the flanges and rivets of the counterbalance arm webs. I hope this will not be a problem when it comes to balancing the elevators at final assembly. The weights are supposed to be too heavy so that material is removed rather than added in order to achieve balance.
I torqued up the nuts to 25 in-lbs and used Loctite to secure them.

Rudder Trailing Edge Riveting

Sunday 20th April (4hr 45min)

Riveted rudder and left & right elevator trailing edges. Pop-riveted trim tab end tabs and trim tab horn. Match-drilled hinge to trim tab upper skin & spar and cut to length.

It is a week now since 'tank sealant day' so I went back to work and began by removing the clecos and cleaning the little stray bits of solidified tank sealant out of the dimples and holes. The edges are still laser-straight at this stage but it is the riveted end-product that counts. I did notice one place where the tank sealant was lifting the skin off the trailing edge wedge very slightly. Obviously, this was close to the end of the sealing job when the sealant was getting very stiff and lumpy and difficult to spread.

The idea here is to half set each rivet with a back-riveting set, flip it over and then finish by riveting on the manufactured head with a mushroom set. In the event, I was not very comfortable with the back-rivet set and decided to try the air squeezer with the gap set to squeeze each rivet just enough to fix it in place. I found this easier although I had to be careful to exert enough pressure on the manufactured head with the non-moving side of the squeezer to ensure it was fully seated in its dimple before it was fixed in place. I worked on every fifth rivet from the centre out and then went back to do the rest randomly.

I was very pleased with the results. I would call it perfect if it were not for that little bump caused by tank sealant and I think the edge material is microscopically dented by the action of the rivet set at each rivet site. It certainly no longer looks like pristine new aluminium sheet but I think paint will hide that completely.

Another anxiety-causing job off the list!

With time on my hands, I went on to pop rivet the control horn to the trim tab. If I had not forgotten this step before 'tank sealant day', I could have easily done these with solid rivets using the longeron yoke. In fact, I should also have solid riveted the bottom skin-spar join at that stage so that will also have to be pop-riveted. The manual quotes MK-319-BS pop rivets as an alternative here. However, I don't have enough of these rivets to cover all locations where they are called out or are an option. I will have to get 30 more from Vans.

I also put pop rivets into the ends of the trim tabs and match-drilled the hinge to the underside of the top flange of the spar. I got this dead wrong first time but fortunately caught my mistake before I had cut the hinge so I was able to re-position the hinge and match-drill again. The first set of holes won't do any harm and can be regarded as 'lightening' holes - if they are ever noticed in such a well-hidden location.

Trailing edges sealed

Saturday 12th April 2008 (5hr 40min)

Attached 2nd aluminium angle to edge of bench. Positioned HS and elevator assembly with counterbalance arms in line. drilled trailing edges to angle and clecoed. Cleared bench for rudder and rearranged shop. Cleaned AEX wedge of elevators. Cleaned skins inside trailing edge. Mixed tank sealant. Sealed in trailing edge in left and right elevators, sealed foam ribs into trim tab.
With the entire HS/elevator assembly in place on the worktables, I attached the remaining part of the aluminum angle I had bought (the first part was used on the rudder) under the trailing edge of the left elevator (now located on the right, as the assembly is upside down to allow the elevator control horns to stick up rather than down) One of the counterbalance arms had initially been about 1cm out of alignment but by the time everything was weighed down and the trailing edge clamped to the angles, it was all perfectly aligned again. I match-drilled through the trailing edge into the aluminium angle, putting a cleco in every hole. I worked from the centre outwards as I feel this is more likely to avoid any waves or curves in the trailing edges.

My drill press, bench grinder and band saw had to be cleared off the third worktable to create space for the rudder. These machines are attached to a second work surface which is cut into three sections, one for each machine. These usually just lie side by side on the worktable relying on the weight of the machines to keep them steady. I can clamp them to the work surface if I need to. Other than lifting the heavy drill press and band saw carefully for the sake of my back, it was easy to get them down off the worktable. I was pretty happy with the arrangement and pleased that I had gone to the trouble of installing them this way. BTW, the space under the table is taken up with my compressor. It is lined with two layers of scrap carpet and the front panel is removable. The compressor is an oiled belt-driven model and is fairly quiet anyway, but with this extra insulation, it makes only a little more noise than our kitchen fridge.

Before starting this morning, I went out to buy a length of wooden dowel. I used this to spread the skins slightly at the trailing edge (this is why the last three rivets at the narrow ends of the root and tip ribs are left open until now). I cleaned everything as well as I possibly could with methylated spirit, including the site of the foam ribs on the inside of the trim tab skin. Once the wedge with the sealant spread on them is in place, the dowel rod is drawn out sideways allowing the skins to close on the wedge.

Mixing the tank sealant in the cartridge took some figuring out but I got it done. I recorded the process on video with a view to posting it on Youtube after I edit it down to about 3-5 minutes. It takes quite a lot of strength to move the plunger up and down through the material in the cartridge. I wonder whether it was A) too cold (I stored it in a fridge) or B) too old. Also, once mixed, it was nowhere near as smooth as I had hoped and really quite difficult to spread on the AEX wedge surfaces. The trouble with this stuff is that once you start there is no turning back so I pressed on. I spread it as thinly as I could on the foam ribs and wedges, put them in place and clecoed and clamped them shut. By the time I got to the last trailing edge (the left elevator) the material was already clearly going off so I got the job finished just in time. I reckon it was useable for not much more than an hour after mixing. How you are supposed to carefully apply 3.5 oz of really thick muck within an hour, I really don't know. I suppose you could say that I am no longer a Proseal 'virgin' and the experience has left me feeling dirty (in fact, I am actually dirty). I will not be using the cartridge format again.

Anyway, that's it for a week until I am certain that the tank sealant has fully cured.

Elevators attached

Monday 7th April 2008 (2hr 20min)

levelled 2 benches, attached left and right elevators to HS. Checked for true.

There seem to be two risks in finishing the elevator trailing edges. the first is that you produce a hooked or wavy edge and the second is that you build in a twist so that one elevator counterbalance horn is out of trail with the HS (either high or low) when the other horn is perfectly aligned with its HS and the trailing edges are also perfectly aligned. This twist is locked in by riveting the tip ribs and trailing edges and the solution seems to be to drill out these rivets and allow the elevators to 'relax' into alignment. I planned to avoid this by having the HS and both elevators assembled and aligned while I riveted the trailing edge.

Today, I began to implement this plan. I reversed the heavy aluminium angle that I have set into the top and edge of one worktable so that the vertical flange was screwed to the side of the table and the horizontal flange was flush with the top and extending out from it. Then I attached both elevators to the HS (BTW, there seems to be plenty of space to get the bolts in if your fingers are in any way nimble). I propped up the front of the HS with some timber under its forward spar until everything was 'in trail'. With one counterbalance clamped to the HS, the other was initially just 1cm or so out of true

This was the first time I had seen these three parts assembled- the horizontal surface area of the thing is vast!

Movng towards the (trailing) edge

Sunday 6th April 2008 (7hr 15min)

Riveted rudder except skin-tip & root ribs - last 3 rivets top and bottom. Prepared alu angle and match drilled to rudder trailing edge. Riveted left and right elevator tip and root ribs top and bottom to skins. Cleaned trailing edge parts of rudder in preparation for tank sealant. Installed rudder counterweight.

I spent the day finishing all the remaining jobs on the rudder and both elevators to get them ready for prosealing the trailing edge. ,

Earlier, Vans had sent me the 3.5oz size in the cartridge instead of the 1 oz size that I had ordered. From all I had heard, this job is very messy so the cartridge format of the 3.5 oz seemed like a good idea and I decided to order the dispenser gun that goes with it. By the way, the only difference between the gun that Vans sells and the cheapest gun you can get at your local hardware store is in the diameter of the disk at the head of the plunger. If I had it to do again, I would find a way of reducing the diamater of this disk on a cheap gun until it fitted into the end of the proseal cartridge.

The downside of the cartridge is that it is all mixed at the same time and goes off at the same time so you have to have everything that you want to use it for set up and ready at the same time. I have a heavy aluminium angle set into the edge of one of my worktables but this was not going to be enough to do both elevator trailing edges and the rudder trailing at the same time so I had bought an extra 8' length of 35mm x 35mm x4mm aluminium angle. I cut a piece off this to suit the length of the trailing edge of the rudder and match-drilled it to the existing holes in the skins and trailing edge web.

Elevation

Saturday 29th March 2008 (5hr 5min)

Riveted VS skin to forward spar and mid-span rib. Riveted in VS-706 tip rib VS-704 root rib and VS-705 nose rib. Replaced bad rivets in rear spar assembly and riveted it in place. Levelled table, drilled out and replaced bad rivets on left elevator top and bottom skin stiffners. Riveted top skin to the spar. Weighted left elevator and pop-riveted main spar to bottom skin. Riveted E-905 root rib and E-907 trim spar to bottom skin. Replaced faulty rivets in right elevator stiffners.

Dorothy and I continued our riveting partnership by completing the internal skin to spar and mid span rib rivets. I then inserted the two root ribs and completed the riveting of these plus the rear spar and the tip rib after fixing some bad rivets in the rear spar assembly that had been identified in the inspection. Being mostly around the edge of the skin, these rivets were easy. Only the three rivets through the two root rib flanges and the forward spar were a little tricky but the air squeezer easily got these done as the access is much easier that the similar joint at the root of each elevator.

Mick Bevin (my inspector) had suggested replacement of a number of rivets in the elevator stiffners. These had been put in before I realised the importance of adjusting pressure on the rivet gun and I had mashed some rivets by using too much pressure. Drilling out rivets is something you get a lot of practice at and I can generally get them out without touching the hole. Still, the process of setting the original rivet stretches the hole so you need a fatter replacement rivet. One way of making a fat rivet is to pre-squeeze a rivet of the next length up so that the shank expands and shortens. This will fill up the slightly enlarged hole. Doing this with an air squeezer is not easy but it is one way of developing a sensitive trigger finger.

I put on the elevator horn without any problem and then went on to rivet the elevator top skin to the spar. About 3-4 rivets either side of the hinge openings could be reached with the 4in thin-nose yoke.

Next, I weighted the elevator in the closed position with building sand divided among several of Dorothy's freezer food bags. Some people go to great lengths to get solid rivets through the bottom skin into the spar. I just went with the Vans suggestion and pop-riveted the join. Maybe I should have tried harder as the results were not wonderful, with a depression around each rivet. Good thing they are on the bottom. While the elevator was weighed down, I also riveted the root rib to the top and bottom skin and the trim spar to the bottom skin.

The trailing edges did not initially lie exactly on top of each other and had to be pulled into alignment and clamped using side-jaw clecos. This makes we worry about twist. Some builders have reported that they have perfectly straight trailing edges but with the two trailing edges aligned with each other only one elevator horn lines up with its elevator while the other one is well off. The solution seems to be to undo the end rib rivets and/or the trailing edge rivets, get everything into alignment while weighted down and re-rivet. I hope to avoid this by riveting both elevator trailing edges while mounted to the HS assembly and held 'in trail'.

Nose out of joint

Saturday 22nd March 2008 (7hr 10min)

Finished riveting right mid nose rib. Riveted left HS nose ribs. Replaced faulty rivets on forward spar. Assembled both HS with clecos. Pop-riveted internal main ribs to forward spar. Riveted left skin to spars and ribs. checked rivets and replaced faulty ones.










Things went no better with the right mid-span nose rib - some scratches to the internal primer but looks okay from the outside. The scratches are not deep and really only amount to the removal of the primer. I don't see any need to obsess about them. I just applied a little primer with an artists brush and moved on.

Now that it is time for the forward spar, I made an extra set of cradles so that I can support both HS at the same time, with the forward spar (and eventually the aft spar) running between them. I felt this was much better than doing one HS with the spars hanging out in mid air and needing to be supported to avoid unnecessary stresses being into the structure.

Before the forward spar went in, I riveted the "intermediate" main ribs to the aft side of it. These are the ribs that have no nose rib sharing the same rivets. Mine were numbered 1 to 10 from left to right (looking forward) and the ribs involved were numbers 2, 4, 7 and 9. The air squeezer (I'm getting tired of typing "pneumatic") earns its keep here

Next step was to pop-rivet the main rib that goes behind the mid-span nose rib. This gets pop-riveted to the forward spar and the aforementioned nose rib. This required me to angle the main rib to one side (with clecos through two of the three holes) so that I could get the pop rivet puller into position.

My wife Dorothy helped me with shooting the skin rivets on the forward spar and main ribs. She smiled when I asked her for her help as she knew I was reluctant. "Did you think I would say no?" she replied. Dorothy is meticulous in everything she does and I couldn't hope for anyone better as a riveting partner. For someone that is not too thrilled about aviation in general and this project in particular, she did the job like a trooper and we got a very good result.

St Patricks day parade

Monday 17th March 2008 (8hr 15min)

Drilled out and re-riveted faulty rivets from R606pp reinforcement plate, R902 spar, R904 rib, R405PD. Set up for riveting right elevator skin and spar. Riveted right and left elev skins to top of E902 right and left spars. Attached right and left elevator counterbalance assembly to E902 right and left spars. Assembled HS front and rear spars.

Our national holiday and what am I doing? making a plane! Well, that is my kind of holiday. Contrary to the public stereotype, I don't drink much and I drink Guiness only rarely - usually when I feel called upon to prove that I AM Irish.

The long nose yoke was able to reach three to four rivets either side of the hinge openings in the elevators. That left only about a third of the holes along the bottom of the spar to be pop riveted.

Counterbalance & corrections

Saturday 15th March 2008 (2hr 40min)

Dimpled holes in the end tabs of the trim tab. Riveted the counterbalance assembly for both elevators. Riveted rudder counterbalance assembly. Drilled out mashed rivets on rudder skins and elevator skins and re-riveted them.

I borrowed a long-nose no-hole yoke and a longeron yoke from my pal Bryan (QB7). I really did not fancy bucking inside a restricted space such as the rudder counterbalance arm. These yokes made the job easy. The only difficulty was in getting the longeron yoke over both flanges of the elevator counterbalance arm. The trick here was to remove one of the rivet sets. There is plenty of space to put it back in once the yoke is in place inside the flanges.

Left Elevator completed and on to Trim Tab

Sat 8th Dec 7hr 10min

Dimpled the left elevator skin and stripped vinyl from the inside and from the rivet lines on the outside. Prepped and dimpled the E-902 and E-907. Countersunk the E-907 top flange. Made the E-921 gusset. Made trim tab clamps. Made trim tab ribs and marked their position.

The springiness of the elevator skins makes dimpling awkward. If it was not for the DRDT2, I could not have managed it alone but this dimpler leaves you with one hand for the work and it does the job without too much fuss.

Dimpling the spars was the first outing for my new small diameter dimple dies. Perhaps I could have made do without them but it's great not to have to worry about the die digging into the curve of the metal. I don't have a particular problem with the idea of grinding one side off the full-size dies but as we are only talking about $17 per die, I think it is better to have the correct tool for the job. Postage was effectively free as I had to get a replacement for the #40 countersink cutter anyway.

I have remarked before how tedious it is to set up a countersink cage for a particular rivet size. There is no calibration so it is a trial and error process that takes a lot of time and care to get it right. Even now, having done it three or four times, it still takes 15 minutes or more each time. Some builders recommend getting three countersink cages and leaving one permanently set up for #40, a second for #30. The third is then used for any other sizes that crops up. This would save a lot of time. I think it is worthwhile so I will order two more cages the next time I need something from Avery or Isham.

Making the E-921 gusset was not a problem. I don't have a deadblow hammer so I used a normal hammer with a piece of wood scrap against the metal. I did the bending in my vice, to which I have fitted wooden jaws. While I was fitting out the shop before the kit arrived, I had looked for soft jaws from a number of local tool shops but couldn't find them so eventually I made some from teak scraps and fitted them in place of the metal ones. The teak is hard enough to get a firm grip but I have never noticed any marks on metal pieces that come out of the vice.

I decided to postpone the drilling of the trailing edge for the moment. I may wait until the remainder of the elevator is riveted. If I do that I will have to prime the wedge extrusion on its own as all the other pieces will already have been primed but I feel I will get a better result if the structure is already stiffened up before I set the trailing edge.

The band saw was very useful for cutting out the V clamps for the trim tab as well as the foam ribs. I don't bother changing back to a timber saw blade for these small jobs. The metal blade does a good job if you give it plenty of time. The belt sander made quick work of tidying up the foam ribs but I had to use sandpaper for the clamps. I finished up the day by marking the location where the ribs will go inside the skin of the trim tab.

Left Elevator Edge Preparation

Tue 4th Dec 1hr 40min

Preped the edges of the Left elevator skin and skeleton parts and trim servo doubler and cover plate

The elevator skins are difficult to handle. My two bench-edge vices with the lengths of timber running between them were a help for the trailing edges. However the elevators are longer than the horizontal stabilisers, vertical stabilisers and rudder and I only had two lengths of timber long enough. Still, I managed by using a shorter piece between the two trailing edges and a clamp in the middle to counteract the bowing of the outer timbers.

The edges around the hinge openings in the leading edge also needed to be prepped. In this case, I held the skin between two lengths of timber lying loosly in my vice. The vices were set to about two thirds of the width of the leading edge so that the skin just rested there in a good position for access. No clamping force was used so it was not held securely and one hand had to be on the work all the time, but it went okay.

When it came to the ends, unlike the VS for example, the elevator was much longer than the height of my table so I had to secure the piece to the table top as best I could and work horizontally over the table's edge. The outboard end was okay as I could get a piece of timber clamped across the section of skin that overlaps the counterbalance assembly and still leave the edge of the skin just overlapping the edge of the table. For the angled outboard end, all I could do was put one clamp on the trailing edge and another on the edge I was working on, moving it as necessary. This provided some support but was not ideal.

I used wet and dry paper on most of these edges (other than the trailing edges) as I felt they were too delicate for the small scotchbrite wheel in the die grinder, especially as the work was not securely held in most cases.

Match-drilling Elevator Stiffeners

Mon 3rd Dec 2hr 30min

Match-drilled stiffeners to left Elevator skin

With the experience of the right elevator, this was no problem. There are two wrinkles: Firstly, all but one of the stiffeners are left-handed (the flange with the holes is to the left of the vertical web when looking forward). This means that when you install them in the top skin, the reverse is true and the flange extends across the skin to the right of the the vertical web. The end effect is that the webs of the top and bottom stiffeners do not interfere with each other because they are separated by the width of the flanges. Secondly, the only exception to this rule is E-908 - R which closes off the edge of the elevator in the recess where it abutts the trim tab. In this case the two webs will lie cheek by cheek with two pop-rivets through the two of them.

The second issue is simpler still. It is that the 5 long E908-L stiffeners go in the full width section of the elevator and the shorter E-909 stiffeners go in the narrower section forward of the trim tab.

The E-616PP trim cover plate is itself a stiffener and is match-drilled in place at this stage also.

On to the Left Elevator

Sunday 2nd Dec 7hrs 40min

Prepared the edges of all remaining right elevator parts. Dimpled the skin. Assembled Left Elevator skeleton and skin and match-drilled all parts. Cut and prepped the edges of skin stiffeners.

The manual contains plenty of fair warnings about the left elevator. They say that it is responsible for a very large proportion of support calls for the RV-9 kit. Suitably chastened by all this, I got the parts together and began.

I initially cut all the stiffeners to the standard length and did the filing at blunt (forward) end. This was to establish a fixed point from which to measure the length at which the short ones should be cut. Once the first of these short stiffeners was measured off, I decided to cut the whole lot in one go on the band saw (which has been having a quiet time of late). I probably should have taken care to line up the forward holes of all the stiffeners in my stack but I did not think of it and just used the forward end to allign them together. Anyway, the band saw went through them as if through butter and there was none of the 'chatter' and fuss I found when sawing such thin material one piece at a time. Naturally, I stayed well back from the cut line to leave plenty of safety margin and I tidied them up using my belt sander to remove material back to the exact length required. They turned out just fine and not aligning the forward holes does not seem to have caused any problem.


Match drilling them to the skin was essentially a repeat of the process for the right elevator except that securing the trailing edge of the skin took a little extra ingenuity. The problem is that the 'indent' where the trim tab goes means that most of the trailing edge is not near the edge of the bench where it can be secured (or else the rest of the trailing edge is overhanging the bench and you have nothing to drill into). I came up with the solution pictured here, using scrap timber placed on the bench so that it slightly overlaps the trailing edge and screwing this timber to the bench just beyond this overlap with the edge of the skin.



The instructions refer to dimpling the E615PP for #6 screws. I don't really understand this as I thought the nut plates would rule that out. I will have to look into this further but for now I just match drilled the holes for riveting the E-615PP to the skin. Incidentally, it is the vinyl that is wrinkled in this photo, not the skin itself.

Elevation

Sunday 25th Nov 7 hrs 45 min

Cut and edge-prepped 16 E908 stiffeners for the right Elevator. Match drilled stiffeners to E901-R skin. Dimpled Stiffeners.

Building the elevators, particularly the right elevator, is like a lot like building the rudder. Much of the time today was spent marking out and cutting the stiffeners and then preparing the edges after match-drilling. This time I didn't have to worry about the length of the stiffeners as they are all the same.

The main difference is that the skin is pre-bent so that it wants to stay closed. This makes it quite awkward to gain access to the inside, particularly if you are working alone. I am quite sure that Dorothy (my wife) would be happy to help out if asked but she was away visiting her mother as she does on most Sundays and in any case, I don't want to call on help too often so that I have lots of 'credit' left for the times when I can't do without a second pair of hands.

So I rigged the set-up you see pictured here (actually this is the left elevator). I used the wooden cradle from the horizontal stabilisers, clamped one trailing edge to the bench and placed one of my lengths of teak seating rail running between the two cradle blocks. The spring tension in the skin kept the length of teak fairly securely in place. I was working on my sacrificial slab of chipboard again as I needed to drill into the surface. The piece of scrap timber you see under the drill is placed so that the far edge just overlaps the trailing edge where it is 'indented' to allow space for the trim tab. It is screwed down into the chipboard to hold that section of the trailing edge firmly.

The tension in the skin is such that it bends up between the clamped trailing edge and the leading edge so it was important to work systematically from the trailing edge forwards and from left to right ensuring that the stiffeners hold the skin perfectly flat.

I kept the blue vinyl in place for this operation as there is a lot of potential for scratches from the stiffners whose edges have still not been polished.

Dimling the stiffeners was done with the pneumatic squeezer.