Tuesday 19th August 2008. 1hr 30min
Match-drilled bottom left skins. Dissassembled wing. Began deburring and dimpling main ribs.
I was tired this evening but I still wanted to keep progress going so out to the workshop I went to see what I could get done.
Match-drilling the skins is relatively undemanding. I mark the cleco locations on the blue vinyl after the first phase of drilling as it can be confusing to remember in which direction the cleco was moved and which, therefore, is the yet-to-be-drilled hole in the second phase.
I took the wing apart and began the job of deburring and dimpling the main ribs. I only got three done before I just got too tired to continue.
I have a new project by the way. I intend to fit the full Classic Aero Designs interior kit, which of course weighs more than the typical Vans bare-bones interior ( I don't actually know how much because they don't publish that information. I have asked recently but no answer just yet). On the other hand, I intend to fit a very lightweight fully digital panel. However, I already weigh quite a bit myself (like 260lbs!!) and, as I don't want to be limited to flying on my own, I need to loose a lot of that weight. The project is to loose at least as much weight as the total weight of the interior and panel instruments (everything that sticks through the face of the panel) . Any shortfall will have to be met by leaving out bits of the interior kit or panel. That should be plenty of incentive!
I have been at this now for over six weeks and so far I have lost 13lbs, so I was 247 lbs at the last weekly weigh-in. I intend to publish my latest weight in the top line of each blog immediately following the latest weigh-in. Those of you who want to place bets on this should know that the form book records a previous successful attempt which began at an even higher 263 lbs in July'05 and bottomed out 47lbs lower at 216lbs in Feb'06 (shortly before the photo in my profile was taken). Regrettably, I put almost the whole lot back on in the space of only 30 months.
Showing posts with label wing skins. Show all posts
Showing posts with label wing skins. Show all posts
More Stringers
Monday 18th August 2008. 2hr 40min
Match-drilled J stringers to to skins. Removed top skins and fitted bottom skins.
I had the top skins off when I realised that I had forgotten the J stringers, so back on they had to go. I lost about 30 minutes to this mistake.
By the way, I find my (very masculine) workshop apron excellent for this work as it has a large belly pouch. I take a full storage box containing about 150 clecos and just tip them into the pouch before starting to cleco on something big like a wing skin. The pouch also takes the cleco pliers and keeps them to hand. There is another pliers in the toolbox for when I absent-mindedly hide the first one from myself. The pouch also works in reverse to collect clecos when dissassembling.
Match-drilling the J stringers and fitting the bottom skins went exactly like the righthand side but quicker.
Back to the Left Wing
Saturday 16th August 2008. 5hr 5min
Dimpled right wing ribs. Assembled left wing skeleton. Fitted leading edge and match-drilled ribs to spar. Fitted splice strip and match drilled to leading edge. Fitted tank and match drilled attach brackets. Match-drilled join strip to tank. Fitted top skins.
All of this was a repeat of the left wing so it happened without drama and much faster. The only difference was that I cut the join strip short to clear the wing flanges and stiffner bars, top and bottom. This still leaves way more edge distance than is needed and does not interfere with the fit of the leading edge or tank skins against the spar flanges. As I see it the join function of the join strip is to join the tank and leading edge smoothly. It has no function in joining both to the spar and it would spoil the fit if the skins if it was left long.
Stringing it together
Friday 15th August 2008. 6hr 35min
Completed match-drilling of top right wing skins. Cut and edge-prepped J channel stringers for both wings. Match-drilled J-channels to right wing skins. Installed bottom skins and match-drilled. Dissassembled right wing. Deburred right wing ribs.
You get 4 lengths of J channel stock in the kit, each long enough to produce the longer outboard stringer. If they made them just a little longer, you could get two of the shorter inboard stingers out of the same length and then they would only have to supply three; unusual for Vans not to have spotted that possible economy.
Fitting is quite simple, though in my small workshop, I had to lift one end of the wing off the stand and move it so that it was pointing towards the open door and then, with the other hand, slide the longer stringer into its place, beginning with one end out through the door. Even with lots of clecos on board, the wing is light enough that this did not count towards my quota of exercise for the day.
The outboard end of the outboard stringer is clamped flush with the edge of the outboard W-903 skin but it is not clear from the instructions wheter the inboard end of the inboard stringer is similarly set flush with the edge of the W-902 inboard skin or with the inboard W-910 rib. The manual says "Clamp the W-926A inboard stringer in place at the W-910 inboard rib, locate it and drill to the skin" which seems ambiguous to me. I went with flush to the edge of the skin on the basis that I can cut it back. However, this leaves me with less overlap. If I am wrong, I could put some extra rivets through both stringers (but not the skin) along the overlap to strengthen the join or I could use some scrap to make a third layer to extend the overlap. Most likely, I will just leave it, even if I have to cut the stringer back to the inboard rib.
I used a small clamp on the stringers at the overlap to make sure they were lying tight together before I began to drill. I pulled out a new drill bit for this operation as I wanted to cut the holes with the minimum of feed pressure on the drill. The line was visible in the centre of all holes as soon as the two end holes were lined up. This required the stringer to be placed tight against the aft edge of the slots in the ribs, but the 'curl' of the J section seems to be perfectly centred in the cut-outs at that position. I would have preferred to work from the centre out but, this being impossible, I worked from both sides inward,, using a line of 6-8 clecos in the holes immediately preceding the one I was drilling and moving them along as I worked. I left a cleco in place at each rib as I passed.
The bottom skins went on without drama. I had to take off the top skins so that I had enough clecos Both leading edges are still clecoed at this point. These two, together with one set of skins, use my full stock of 300 3/32 clecos. In fact, I could do with another dozen so that the bottom skins could be clecoed in every 4th hole all over.
After match-drilling, I took the wing apart and deburred the ribs. If I had followed the Vans sequence, the wing skeleton would be primed and riveted at this point and I would have had to debur and dimple the ribs while assembled. My way is definitely easier and I believe (hope) that the assembly with clecos is firm enough to properly match-drill the skins.
Completed match-drilling of top right wing skins. Cut and edge-prepped J channel stringers for both wings. Match-drilled J-channels to right wing skins. Installed bottom skins and match-drilled. Dissassembled right wing. Deburred right wing ribs.
You get 4 lengths of J channel stock in the kit, each long enough to produce the longer outboard stringer. If they made them just a little longer, you could get two of the shorter inboard stingers out of the same length and then they would only have to supply three; unusual for Vans not to have spotted that possible economy.
Fitting is quite simple, though in my small workshop, I had to lift one end of the wing off the stand and move it so that it was pointing towards the open door and then, with the other hand, slide the longer stringer into its place, beginning with one end out through the door. Even with lots of clecos on board, the wing is light enough that this did not count towards my quota of exercise for the day.
The outboard end of the outboard stringer is clamped flush with the edge of the outboard W-903 skin but it is not clear from the instructions wheter the inboard end of the inboard stringer is similarly set flush with the edge of the W-902 inboard skin or with the inboard W-910 rib. The manual says "Clamp the W-926A inboard stringer in place at the W-910 inboard rib, locate it and drill to the skin" which seems ambiguous to me. I went with flush to the edge of the skin on the basis that I can cut it back. However, this leaves me with less overlap. If I am wrong, I could put some extra rivets through both stringers (but not the skin) along the overlap to strengthen the join or I could use some scrap to make a third layer to extend the overlap. Most likely, I will just leave it, even if I have to cut the stringer back to the inboard rib.
I used a small clamp on the stringers at the overlap to make sure they were lying tight together before I began to drill. I pulled out a new drill bit for this operation as I wanted to cut the holes with the minimum of feed pressure on the drill. The line was visible in the centre of all holes as soon as the two end holes were lined up. This required the stringer to be placed tight against the aft edge of the slots in the ribs, but the 'curl' of the J section seems to be perfectly centred in the cut-outs at that position. I would have preferred to work from the centre out but, this being impossible, I worked from both sides inward,, using a line of 6-8 clecos in the holes immediately preceding the one I was drilling and moving them along as I worked. I left a cleco in place at each rib as I passed.
The bottom skins went on without drama. I had to take off the top skins so that I had enough clecos Both leading edges are still clecoed at this point. These two, together with one set of skins, use my full stock of 300 3/32 clecos. In fact, I could do with another dozen so that the bottom skins could be clecoed in every 4th hole all over.After match-drilling, I took the wing apart and deburred the ribs. If I had followed the Vans sequence, the wing skeleton would be primed and riveted at this point and I would have had to debur and dimple the ribs while assembled. My way is definitely easier and I believe (hope) that the assembly with clecos is firm enough to properly match-drill the skins.
Winging it
Thursday 14th August 2008. 6hr 40min
Marked right wing main ribs for position. Installed W-919 joint strip and W908R leading edge rib, match-drilled to leading edge and removed for deburring and edge preparation. Fitted W-902/903 top skins and match-drilled.
With the tank still off the spar, I began the fitting of the W-908R leading edge rib and the W-919 joint strip that joins the leading edge and tank skins. This strip is sandwiched between the inside of the skin and the W-908 rib underneath. I had been dreading this job, knowing how tight the other ribs had been in the skin. However, it went quite easily. With the rib clecoed to the spar through its aft flange, I pulled the tip end well out of position, leaving about a 2" gap between it and the leading edge. Then I put the join strip in place under the skin. Because the joint strip was still not fixed in position, it was quiet easy to angle it's edge slightly upwards to allow the tip of the rib to pass underneath. As it passed under the edge of the joint strip, I paused to fix the strip in positon on the spar with edge-clamp clecoes over the flanges - the strip had not been trimmed for length and was overhanging.
Thumb pressure was all that was required to move the rib towards its proper position but the join strip wanted to move as well. Initially, I used a pliers to hold on to it while I pushed the rib but this was awkward and the pliers was marking the aluminium. Instead, I drilled through one of the forward-most pre-punched holes and the join strip. This held the strip in positon until close to the end. Eventually the rib flange hit that cleco and it had to come out to allow the rib to be moved into its final position. By this stage the surfaces are all more or less parallel so the forces involved were smaller and the strip did not move out of position.
After a bit more pushing and pulling to get everyting exactly right, I was satisfied enough to put the tank back in place and then match drill the join strip to the leading edge skin and end rib, clecoing every hole as I went. I didn't match-drill the holes for the tank attach screws just yet as I would prefer to see a perfect join with the top skins fitted before I do that.
I marked the ends of the join strip to be cut off flush with the aft edge of the tank and leading edge skins but I am not sure about this. I can't make out from the plans or the manual where the strip should be cut off. It seems to me that they should not be allowed to run aft between the tank and leading edge skins and the spar flange as that would raise these skins above the top of the upper wing skins immediately behind. However on the basis that you can always cut more but you can never put material back, I decided to cut them off flush with the aft ends of the skin for now. The strip and end rib had to come out to allow this to happen but putting them back after the cuts was easy once I knew how.
I got both sets of W-902 inboard top skins out and prepared both wing-walk doublers while I was at it. To save the worktable surface, I did this on my sacrificial sheet of chipboard, setting the forward edge of the wing-walk doublers back by the required amount from the forward edge of the W-902. Fitting the skins was a non-event as they overlap each other and simply but up against the tank and leading edge skins. Again, the join was spot on.
Though I started the match-drilling, I didn't finish out. That's a whole lot of holes! I better get Dorothy mentally prepared before we start to rivet them
Marked right wing main ribs for position. Installed W-919 joint strip and W908R leading edge rib, match-drilled to leading edge and removed for deburring and edge preparation. Fitted W-902/903 top skins and match-drilled.
With the tank still off the spar, I began the fitting of the W-908R leading edge rib and the W-919 joint strip that joins the leading edge and tank skins. This strip is sandwiched between the inside of the skin and the W-908 rib underneath. I had been dreading this job, knowing how tight the other ribs had been in the skin. However, it went quite easily. With the rib clecoed to the spar through its aft flange, I pulled the tip end well out of position, leaving about a 2" gap between it and the leading edge. Then I put the join strip in place under the skin. Because the joint strip was still not fixed in position, it was quiet easy to angle it's edge slightly upwards to allow the tip of the rib to pass underneath. As it passed under the edge of the joint strip, I paused to fix the strip in positon on the spar with edge-clamp clecoes over the flanges - the strip had not been trimmed for length and was overhanging. Thumb pressure was all that was required to move the rib towards its proper position but the join strip wanted to move as well. Initially, I used a pliers to hold on to it while I pushed the rib but this was awkward and the pliers was marking the aluminium. Instead, I drilled through one of the forward-most pre-punched holes and the join strip. This held the strip in positon until close to the end. Eventually the rib flange hit that cleco and it had to come out to allow the rib to be moved into its final position. By this stage the surfaces are all more or less parallel so the forces involved were smaller and the strip did not move out of position.
After a bit more pushing and pulling to get everyting exactly right, I was satisfied enough to put the tank back in place and then match drill the join strip to the leading edge skin and end rib, clecoing every hole as I went. I didn't match-drill the holes for the tank attach screws just yet as I would prefer to see a perfect join with the top skins fitted before I do that.I marked the ends of the join strip to be cut off flush with the aft edge of the tank and leading edge skins but I am not sure about this. I can't make out from the plans or the manual where the strip should be cut off. It seems to me that they should not be allowed to run aft between the tank and leading edge skins and the spar flange as that would raise these skins above the top of the upper wing skins immediately behind. However on the basis that you can always cut more but you can never put material back, I decided to cut them off flush with the aft ends of the skin for now. The strip and end rib had to come out to allow this to happen but putting them back after the cuts was easy once I knew how.
I got both sets of W-902 inboard top skins out and prepared both wing-walk doublers while I was at it. To save the worktable surface, I did this on my sacrificial sheet of chipboard, setting the forward edge of the wing-walk doublers back by the required amount from the forward edge of the W-902. Fitting the skins was a non-event as they overlap each other and simply but up against the tank and leading edge skins. Again, the join was spot on.
Though I started the match-drilling, I didn't finish out. That's a whole lot of holes! I better get Dorothy mentally prepared before we start to rivet them
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