Day one, page one

29th October 2007 1hr 30min

Assembled the HS-902 forward spar halves and HS-907 forward spar doubler, match-drilled them. Fabricated the HS-908-L&R attach angles.

After 18 months of planning and over three months of hard work on the shop, I finally got started on building the plane today. What a let down! I had just come from a chastening experience on building the Vans Training Project, so I was aware how important it was to read the plans carefully. Despite this, I really messed up and find myself today ordering a replacement part from Vans.

Step one was to cleco and match-drill the doubler plate to the two forward spar channels. Right away, I couldn't reconcile the instruction to cleco the positioning hole in the attach angles to the ONE matching hole in the appropriate position on the spars. It seemed to me that there were two matching holes, not one. I scratched my head for fully 10 minutes before realising that, while the spar halves are identical left and right, they are not symetrical top and bottom and the one matching hole was on the edge facing away from me. If it takes a similar length of time to figure out other simple instructions like this, I better plan on an eight-year build instead of four-years.

Then I came to make the actual attach angles. Completely failing to read the plans properly, I marked out the first one to the finished width of 1 21/32 inches, and marked an angled line from this point on the edge of the section back to the narrower dimension of 1 1/2inches for the vertical back plate AND CUT IT! Then I realised that the flange is too long and needs to be shortened back to 1 5/32. When I did this, because the part narrows as it goes back along this angled line, the width at the new edge is now shorter by 1/8 inch. Clearly, this will not give me the designed edge distance for the fasteners that go into this horizontal flange. Whether or not it will give me enough edge distance, I was simply too sick to go and measure. Either way, I am not happy with it.

Not content with that, I noticed that the height for the vertical flange of the angle comes really close to the rounded lip of the angle stock. In fact, shortening it back to the designed height would not fully remove the rounded edge profile of the original section. Now it hits me that the original section has flanges of differing depths. It is 2in X 2 1/2 in and I attempted to cut the longer flange of the attach angle from the shorter flange of the angle stock! By now, I am thinking of putting a shot of my best Irish single malt whiskey in my coffee (a once-in-a-decade event) while I try to calm down. It was the nausea that prevented me from wasting good whiskey. I went ahead and finished the part anyway, just for the experience but I am certain it won't pass muster and will have to be redone.

Anyway, picking myself up, I moved on to the second angle. This time I marked it out correctly and cut it on my new band saw with plenty of allowance for smoothing. Maybe a little too much allowance because I am tempted to go back and take a little more metal with the saw. Working by hand with no guide fence this time, I get too close to the line at one point near the ? Disaster! In order to get a straight line, I have to remove all the metal down to the same closest point using a file but when I do, I am on the line and there is still a gouge mark to be removed so I have to take out the line itself, which I marked up in such a way that it needed to be left on the metal. When I remove this gouge, the part sits within the lines on the plan and is about 1/64th too small. Perhaps this is not critical on its own but, combined with the 1/8th error on the other attach angle, there is no getting away from the fact that I have to make a replacement set.

The most upsetting part of this is that my confidence in my workmanship is badly shaken and for the first time, I am beginning to doubt that I can produce the necessary standard. As a result, I have decided that I am going to firstly take a night off and get plenty of sleep (I think tiredness may have been a contributory factor). Secondly, I am going to constantly read and re-read the relevant section of the manual as I go on with the work. I keep a photocopy of the manual with the small preview plans in the office so I can look over them at lunchtime. I will underline each instruction in the manual immediately before I carry it out as well as every part number, material and fastner call-out, note, etc on the relevant plans pages. Finally, I am going to experiment with a clearance of about 3/64th outside the marked dimension when I am making cuts. The original clearance I used on the attach angle was closer to 3/32, which was a bit too much for finishing though, as it turned out, far too little to be removed with a band saw.

So today (30th Oct) I found myself on the Vans website ordering a replacement 5 inch length of angle. It only costs $5.90 and should be easy to ship. To maximise the use of the shipping cost, I also ordered some riveting tape that I wished I had bought at the beginning and I included the smallest quantity of tank sealant available, for use on the trailing edges of the HS and rudder