1. Drilling the wing mount holes - Roger Partington

By:           Partington Roger
Date:         2nd July 2006

By the way, I notice that you have marked out the bolt holes in the ash fuselage members for the wing bolts. You aren't going to drill them yet are you ?? Bear in mind that due to the shape of the fuselage, it is not possible to drill through these holes from the front when the sides are glued on. I drilled the holes for my wing through the spar first, when I could still get it on a drill press and then when the wings and fuselage were mounted, I drilled through from the back. In order to do this, I left the holes at 8mm first and then opened them out afterwards. I also left the bottom centre panel off the wing until this was done, for access. To open out the holes from 8mm to 12.5mm (or 13mm if using 1/2 inch bolts) I ended up making a drill with a nose brazed on the front to guide it through (after I had allowed the drill to wander the first time and had to start again). I spent a lot of time thinking about this job as the consequences of getting it wrong are horrible !

2. Joining the wing to the fuselage - Roger Partington

By:           Partington Roger
Date:         24th July 2006

The fitting of the wing to the fuselage was something which I thought about quite a lot as the penalty for mistakes was at the very least some tricky rework.
The problems as I see them are :

1. to position the fuselage on the wing in the correct place
2. to drill the main bolt holes cleanly and in the correct position
3. to drill the trailing edge bolt holes cleanly and in line with the holes in the fuselage.

When I made the wing, I drilled the main bolt holes before I had applied the second web to the spar. This meant that I could check that the holes where right in the centre of the ash blocks. It also meant that I could use a drill press to get the holes square. After this, the second web was glued on and the holes completed by drilling back through. These holes were only drilled out to 8mm at this time to give me a bit more material to play with later.

To support the fuselage, I made a steel trolley which fits under the nose and has flat pads which locate at the strong points at the corners of the cockpit floor (where the reinforcement for the engine attachments and wing bolts are). This meant that when I came to join the wing and fuselage, what I did was to position the wing on its own wheels and a support under the trailing edge to keep it level and then wheeled the fuselage over the top (with the tail high in the air to clear it).
Once in position, I found that considerable tail weight was required to pull the fuselage down to the wing, as the engine is pulling the other way. I found that a small petrol generator and a half full gerry can hanging from the tail wheel spring was just about right !

Once positioned as described above, it was easy to see that the fuselage was central on the wing because it is a neat fit. Actually, some of the balsa shaping that is glued to the side of the fuselage had to be cut away to let the fuselage all the way back. I had left the central plywood panel off the wing to give me more access and this enabled me to drill through the main bolt holes in the fuselage from the back using a flexible drive and the main spar holes as guides. Again, they were only drilled to 8mm diameter due to the restriction on access. (The seat gets in the way).

The holes for the trailing edge bolts were drilled in the fuselage at a fairly early stage of construction and the captive nuts fitted. When the wing has been fitted it is very hard to gain access to these holes from the inside for lining up and drilling through so I came up with my own solution which is probably far too long winded but seems to have worked well. First I made brass bushes with a thread on the end which screw into the fuselage holes from the outside. These have a 1/8" hole through the centre which works as a guide to drill up and through the little stringer in the fuselage above the captive nut using a long series drill. Then, once the fuselage is positioned on the wing as above and with 8mm bolts through the main spar holes to pull the wing up tight, I used the same song series drill to drill down through the hole in the stringer, the bush and the wing. All that then remains is to disassemble the wing from fuselage, open up the trailing edge bolt holes to 6mm remove the bushes and fill the hole in the stringer with a plug and a little plywood doubler. I should say that I had jumped the gun a bit and covered the fuselage before all this so I had to do all this work through the small access hatch under the wing.

I hope you can follow all this and that some of it is helpful to somebody.