So…. It’s been a while… Sorry…. It turns out I’m not so good at keeping a blog up-to-date but that doesn’t mean progress hasn’t been made!
Apart from the general tidying up of some of the frames, there was a magical moment when a temporary floor was fitted. I say magical because up until that point it was quite easy to misinterpret what was in front of you. Yes, I know it’s a plane but, while its upside down in the jig with frames and other structural elements missing, it’s easy to forget that. The addition of the temporary floor, along with the missing frames 5 and 5a in place, really started to give the structure some shape – a moment for feeling smug!
Why a temporary floor? Because it’s not known exactly what shape the plywood skin will take when fitted round the frame. A close estimation has been made which, if accurate when in place after the skin fitting, can be used as a template for the actual flooring.
Another big change that’s been made is the location of the undercarriage at the front of the plane. Originally placed between frames 3 and 4, it now lies between frames 4 and 5. Both new plates and blocks were made to fit frame 4 as the angle between 4 and 5 differed from the angle between 3 and 4. The new plates for frame 4 were originally made from Perspex to allow the fitting to be gauge. Once satisfied with the fitting they were then cut from metal.
We also had a visit from an inspector who reviewed the work that had been done so far to check it was of the required standard. He seemed satisfied with what had been completed so far and listened as Alex outlined further plans whilst making suggestions himself. He also mentioned we were to keep a log of the work that had been completed.
The original outer of the Bowden cable used to control the trim has been replaced, although fixing it to the side of the aircraft proved somewhat of a challenge. The original cable was loosely held into place with pins and wooden blocks. Removing the cable damaged some of the old fittings however, it had already been decided to replace these with a new design. The new design involved using a laser cutter to produce a U shaped fitting (shown below) that would slide over the cable and be glued in place of the airframe.
In theory, this worked very well, allowing the cable to slide through the fittings without flapping inside the aircraft. In practice, this also would have worked very well had it not been for difficultly in accessing further down the tail of the aircraft. Access at the front end came via where the skin had been removed aft of frame 7, allowing enough space to squeeze your upper body in and reach down the aircraft. Access at the tail end came via two access holes either side of the plane. Despite allowing someone with slim arms to reach inside, due to the size of the hole viewing, access was limited. Between myself and Alex we could reach a fair bit inside the aircraft except towards the centre between the access points. This proved a problem when trying to attach the fittings as we could not reach to clamp or staple them after gluing. This led to a rethink and an alternative solution whereby a carbon fibre tube was attached to the side of the aircraft with the help of the original structure. The Bowden cable could then be fed through, guided by the tube, allowing for easier access and future maintenance of the system.
The replacing of the Bowden cable emphasised the importance of adapting your approach when design issues occur and accepting that although an idea works in theory it may not always work in practice.
One of the next tasks will be to fit plywood skin to the underneath of the fuselage where it had previously been removed before turning the fuselage over. The aircraft can then be moved to its new home in the Stephenson building of the University before further work is carried out.
(Once again anything posted on this blog is my own view, not that of Teesside University or anyone else associated with the project.)