The plane is now sitting on a holding surface while we finalise the mounting positions on the test floor. We’ve been working on two complicated brackets that are needed to bolt into the **wing spar. We’ve had to modify structural parts of the plane by trimming some parts out of seat pan so that the loading bracket will fit in. The wings attach with a big pin and that’s what the loading bracket attaches to. It’s not been as straightforward as we expected to get it all together. Sam, our welder came down from Nuclear AMRC to finish tack welding it in situ so it actually fits the plane. When we finished welding it yesterday we checked the drawings and were within 2mm. On checking this with the manufacturer they asked us if we could narrow down that amount so we ground off some of the tacks that Sam had welded, manipulated it over and got it down to just 1mm of the drawings. Customer is happy!
It’s important for us to get it near to the customer’s drawing as possible as they have calculated the load into the structure so if we are a few millimetres out it makes a big difference on how the load is introduced into the plane – they have designed where they want the load to go. That’s why we have quite a complicated load fixture. At the moment the brackets are in one of our other centres so we can do some TIG welding, one in particular at the front is really prominent.
The next step is strain gauges, which we will talk about next time.
** In a fixed-wing aircraft, the spar is often the main structural member of the wing, running spanwise at right angles (or thereabouts depending on wing sweep) to the fuselage. The spar carries flight loads and the weight of the wings while on the ground.
Top right: Rob (from the plane manufacturer) and Steve P fitting and checking alignment of the engine mounting frame.
Bottom right: Samantha putting the finishing tack welds in position as we fit the engine mounting frame. This has to be mm perfect before it is removed for final welding.