Wing skeleton

Tuesday 12th August 2008. 7hr 15 min

Dimpled access plates. Removed 5th rib from leading edge and drilled out aft flange to clear main spar rivet heads befor replacing ribs in their respective leading edge assemblies. Assembled the left wing skeleton. Match-drilled ribs to spars. Marked ribs for position. Dissasembled and deburred. Assembled right wing skeleton and match drilled.

Even though it could be done much later, the instructions mention dimpling the inspection plates, so I decided to oblige. I am colouring each instruction with day-glow highlight marker when it is done and it has become something of an obsession to get as much as possible high-lighted - especially if it means covering the last patches of un-highlighted text on any particular page.

I assembled the left wing skeleton with clecos and match drilled it before taking it apart again and deburring all holes. I then went on to assemble the right wing.

While building the emp, I had difficulty getting ribs and stiffners back to their match-drilled positions because the sharpie markings came off at the etching (or even cleaning) stage. So, I came up with a system that uses a punch mark in conjunction with the pre-punched rivet holes in the flanges of each rib as a code to indicate position. To designate the outboard right wing rib as No.1, I put a punch mark to the right of the first hole on the bottom flange next to the aft spar. The next inboard rib is No.2 so it gets a punch mark to the right of the second hole from the aft spar, and so on for the remaining 13. On the left wing, the same will apply except that the punch marks will be to the left of the rivet hole. Leading edge ribs will be identified in the same way in a separate numbering sequence of their own - foolproof!

Plate nuts and Brackets

Monday 11th August 2008, 6hr 55min

Installed platenuts on right spar. Installed mid-section attach nutplates on both spars. Installed tie-down brackets and bell-crank brackets on both spars. Added hardwood bearing plates to wing stand brackets.

Great wedding -over 200 present! Always nice to meet Dorothy's extended family again. Since this project began, I am not visiting Athlone (or Kilkenny, where my own family are based) as often as I would like.

Having installed the tie-down brackets, I found that I had drilled and installed the W-933R tie-down bracket upside down (with the tapped end facing upwards). As the nutplates for the bell-crank brackets are not symetrically placed on the tie-down bracket, it was not possible to just reverse it. Solution? - Just tap the other end of the bracket of course.

It turned out that Vans have sent the wrong platenuts with the new spars. The ones marked K1000-06 (for the inspection plates) were huge and definitely not 'as advertised'. The others were marked K1100-06 but it was -08 I needed to attach the tanks. There were plenty more K1100-08s elsewhere in the kit so I was not stuck for those - just for the moment, but there are no other K1000-06s so I will have to wait for Vans to send the right ones. Fortunately, these are to join the inspection hatches to the bottom spar flange so they can be installed at any time up to first flight. I installed the 62 K1100-08s and finished up.

Catching up

Friday 8th August 2008. 4hr, 45min


Drilled and countersunk right spar. Primed all countersinks. Installed platenuts on left spar.


I finished the countersinking, using the same method as before (clamping a piece of waste with the right size hole for the countersink cutter underneath the pre-punched and reamed-out hole). This is slow but gives very nice results.


I really wish I had a third countersink cage. Without it, I had to swap between the #30 and #21 cutters a few times but at least I was able to leave the #40 cutter properly set in its cage. That cage will not be re-set for the rest of the project. Whatever tools I have to order next (and it is certain that there will be another order at some stage - probably soon) I will certainly get another cage for permanent use with the #30 cutter.

I primed all the countersinks at the same time, using an artists brush and a stanley blade to scrape off the set-but-not-cured primer off the top surfaces of the flanges afterwards.



I have now reached the point where I was when I discovered the spar under-bend problem. That was on the 21st July. Not bad to have the problem fully worked out (almost) within less than three weeks. I put the original spars back in the new Vans crate today before I began work and I am now waiting on the shippers to pick them up.

Dorothy and I are off to a family wedding (her 1st cousin) in Athlone for the weekend. Just as well:-5 full days on the trot is plenty and I need a break.

Leading with the Left

Thursday 7th August 2008. 6hr, 20min

Built wing stand. Assembled left leading edge. Received new spars. Drilled out and countersunk platenut holes on left spar.

The posts for the wing stand went up today. I left a 133" gap between them as recommended by Smitty. The advice he got was to put the brackets at 'chest height'. I interpreted this as being about arm-pit height which, for me, is 50". I am pretty certain now that this is too high for comfort by about 5"-6".


The replacement spars arrived. There had been some confusion caused by the shippers about who was paying for freight so I had to shell out €285 to take delivery, which I will get back. There is not much else for me to do at this stage so I need the spars in order to maintain progress, otherwise, I would have delayed and let them sort themselves out.

I went straight to work on them and had finished countersinking the 74 holes on the left spar by the time I finished this evening.

Sorry, no photos tonight. In fact, I don't know where I have put my camera. I suppose it will turn up.

Course Correction

Wednesday 6th August 2008, 1hr 40min

Completed reversal of leading edge ribs. Rearranged the workshop for wing construction. Glued posts for wing stand.

I wrestled the remaining ribs out of the leading edge and wrestled the correct ones in. None of them were easy - I definitely should have just disassembled the whole thing and started again. I bought more duct tape this morning so I was able to pad the saddles for the leading edge, which are now a perfect fit.

I had decided to erect the wing stand over to one side of the shop, leaving enough room to move around the back. This required me to move all three worktables across the shop to line up under the windows. With the castor arrangement, this was not a problem.

I could not find 4X4 lumber for the posts of the wing stand so I had bought 2X4s planed. This stuff was refered to in the store as "CLS". I don't know what that means but it was beautifully straight, nicely planed with radiused corners and had tight core-wood rings, indicating that it was likely to stay straight. I can't understand why it was so cheap ((€4.40 for an 8' length). Construction timber grows very fast in Ireland but it is not of a high quality like this stuff.

Anyway, I glued four lengths together in pairs back to back, with the rings on the end of the posts looking like this: [))][((]. I glued and clamped them overnight.

Wrestling with the leading edge skin

Tuesday 5th August 2008 5hrs 20 min

Drilled conduit holes in main ribs and deburred. Countersunk outboard holes in W-907A aft spars. Made Leading edge cradles. Assembled right leading edge.

I am going with the conduit option, though I have not decided what lighting set-up to go with. Not to put it in would seem to limit my options. There is no guidance as to the optimum placing of the 3/4in hole for the conduit so I placed it by eye in the centre of the area suggested by the instructions downloadable from the Vans site. I initially drilled a #40 hole and then used that to back-drill a scrap of aluminium jammed up against the lower flange and placed with its edge against the the edge of the vertical stiffening indentation - basically any landmarks that were convenient and would be the same on every rib. Using this template, I put the same #40 hole in every rib and then opened them out to 1/4in - the minimum dimension on my unibit. Then, I opened the hole out to 3/4in with the unibit before finally deburring the edges of the hole on both sides - not that they needed it much as the unibit gives a very clean hole.

Countersinking the spars was a step I had left out so I decided to catch up on it now. I had to research how to approach the need for flush rivet heads on the outboard doubler holes that go under the outboard aileron attach brackets. The .040 material of both the doubler and spar are too thin to countersink for a #30 hole though that material can be successfully dimpled. I did not want to also dimple the aft flange of the nose rib that gets riveted with these two so I decided to countersink the spar which is the 'meat' in the sandwich comprised of the doubler and the rib. This will leave a flat surface on the forward face of the spar under the rib.

The countersinking operation is standard except that the top hole is too close to the flange of the spar for the countersink cage. It is possible to cut away the flange of the cage to get closer but I did not feel like doing that so I removed the cutter and used it in the hex adapter that is normally used for the hole deburring cutter. The slow electric screwdriver was not giving good results so I switched to the the high-speed air drill. This was still not nearly as good as the countersink cage but I think it is easily good enough for this situation.
I made the cradles from the HS cradles. There is plenty of timber in them for the size of the leading edge. I used a rib to mark out the shape and then cut outside this line with a jigsaw to allow clearance for some padding. As it happened, I was out of duct tape and decided to go ahead without the padding anyway. This didn't work out so well as the cradles were loose around the leading edge. However, the blue vinyl was (just about) enough protection for the time being.

I began by attaching each rib in position on the skin with the two forward-most holes on the bottom. This was done with the skin out of the cradle and was just to fix the ribs reasonably firmly in the right positon. Next I put the assembly into the cradle, which forced the skin to wrap around the top of the ribs. Getting the rest of the holes to match up was a real pain. The temptation to use the awl was huge and I did, in fact, use it to help line things up. However, I did not exert any leverage on the holes that would have come close to damaging their edges. In any case, the match-drilling stage should sort out any minor imperfections caused by the awl.

Having done the whole leading edge, I became suspicious and found that I had the right hand leading edge skin but the ribs were for the left leading edge. They were all facing the wrong way! Swapping them around one-by one turned out to be slow. I probably should have just started again with the left skin. It took the best part of an hour to do three of the six and at that stage it was long past time to quit.

Edgy

30th, 31st July, 1st, 2nd and 3rd August 2008 20hrs 45min

Prepared edges of main and leading edge nose ribs for both wings.

This was a complete head-wrecker! Pure monotony! The only way to get through it was to put the shop radio on and do it methodically. Normally, I find that talk radio or music lessens your concentration and can lead to mistakes. However, for this job, it was exactly what was required because brain-power is a distinct disadvantage for such a repetitive task.

There are 30 main wing ribs (in six different flavours) and 16 leading edge nose ribs (4 flavours) to be done. I am lucky, I didn't have to do the tank ribs as Evan Johnson has done them for me. That would have been another 12 or so.

The routine was to:

• Set the flanges to 90 degrees with the flanging tool.
• Straighten the rib using the fluting tool
• File the long edges of all flanges with my big file
• Use small half-round and 'rat's tail' files for the edges of all the notches and corner cut-outs.
• Deburr all long edges using a combination of my two deburring tools.
• Deburr the inside edges of the lightening holes
• Sand the edges in all notches with very fine wet&dry paper
• Polish the long edges (and some corner notches wherever possible) on the Scotchbrite wheel.
• Polish the lightening hole edges with a small Scotchbrite wheel on a die grinder.
• Repeat 46 times

There is no way either deburring tool was going into the small notches without making things much worse. I just had to rely on moving the sandpaper around to knock off any burrs in these areas.

On average, it was taking nearly half an hour for each rib, though I broke it down into a series of sub-operations and ran through the set several times. This was to get a rythm going by having a shorter cycle to repeat.

Luckily, there are not many half-hour operations in the project that you have to repeat 46 times. Anyway, it's done now and won't need to be repeated as all the ribs for both wings have been completed.