A weighty decision

Today I have made a very important, and significant, decision on the project. I am, basically, going to throw out everything I’ve built so far and start again from scratch.

Lest you think I am mad, there is method to my madness. It all stems from the change in focus of the project to add an enclosure. Having planned it out, it became obvious that the existing console I have built is not ideally constructed to fit into the enclosure I am planning. So I got to thinking about replacing it or at least heavily modifying it. This started me off on a course of thinking, but what really got me was when I worked out how much the enclosure (plus equipment plus people) would weigh. Which is to say, a lot.

The problem is that I’m building in a first-floor room in a house (more specifically, an Edwardian house conversion) and not in a garage with a concrete floor directly set into the ground. So, rather like those who want to put large fishtanks in their upper rooms, I must figure out the loading that is permissible for my room. Current UK standards require homes to be built with floors capable of supporting an imposed load of 1.5 kiloNewton per square meter, which is equivalent to 153kg over a 1m square area. For purposes of comparison, a washing machine, say, is usually about 75kg and occupies about 0.75sqm. This, and your bath and bed, are usually the heaviest things in any given house (except, perhaps for the occupants, if you’re as big as I am). I have some anecodotal evidence that older houses were built to rather higher tolerances – up to 5.6kN / sqm – but equally, old floor joists will probably have sagged a bit from age. The floor in my build room, for example, is slightly uneven – not so much you’d notice, but put a straight wooden beam across the floor and you’ll see a 5mm gap under it at the mid-point. So sagging has happened to some degree already.

Based on spec weights for the MDF and wood that I’m using as my primary materials, with a further allowance for the other gear going into the sim, plus 60kg each for three passengers and an amount I’m not willing to confess to for myself, and I came up with a magic figure (albeit probably slightly over-estimated) of 650kg, across an area of floor of 4.3sqm. That’s almost exactly 1.5kN; which is to say, if I carried on the way I was going, I would push the floor of my room to its design limit and given that it’s already a little saggy, I might end up causing the floor joists to sag further, possibly even cracking or damaging the neigbours’ ceiling below. While the whole thing breaking the ceiling and falling through would be highly unlikely – you’d have definite visible signs well before that happened – it preyed on my mind and I decided I had to do something to trim the weight.

So, my elegant solution is to abandon MDF for this build, which means saying goodbye to the existing console, pedestal and glareshield, and to go with plywood instead. This weighs between 30% and 50% lighter than MDF for the same volume. This, together with a mainly frame-based construction method, will save me around 150kg and bring things well within the floor’s design limit, even with 3 passengers in the enclosure.

My plywood arrives on Saturday courtesy of Wickes. The MDF, meanwhile, will be sorted into stuff I can use and stuff that needs to get junked. The new MDF I bought recently is usable for a variety of other projects around the house where the weight will be distributed – a new electronics bench, a book-case, a keyboard stand, and various other things. It won’t be wasted.

It’s a diversion I wish I didn’t have to take, because it’s a costly one, and I’d already put together three-quarters of the new sim base decking last weekend, which I will now have to take up, but I think it’s worth it to make sure I don’t damage the house or kill my neighbours in a freak ‘home cockpit actually flies – for 2 seconds’ accident. The work I have done so far will inform the new work to the point where I should be able to get back to where I was – with a console, pedestal and glareshield assembly – fairly quickly.

Expect more this weekend, when I try out my new video camera and – perhaps – publish a first video blog entry…