Lots of it, in fact. I’ve been lathing away following Dan‘s suggestion on my post yesterday about how to resolve the issue about welding the super-thin sleeve into the bearing housing on the wishbone. His suggestion, which is pretty obvious in retrospect, like all the best ideas, is to leave a flange on the end of the sleeve that’s sturdy enough to be able to weld it to the housing. The only issue with this that I can think of is that machining the sleeve to exactly the right length is going to need lots of assembling and disassembling, but that’s no great deal really.
Author: Tim Hoverd
Balls, sphericals in fact…
I’ve finally managed to finish all the Delrin bearings which is a great relief. Mind you, as I went around the car I rather refined the process. So much so that the last few were much better than the earlier.
“Like pancakes”, Anthea said. Indeed, something to do with the frying pan, methinks.
Acetal swarf…
…I seem to have been filling the garage with it as I’ve been making the suspension bushes that I talked about. It took me a while to work out the best way of making them but I’ve mostly done it now although it’s taken an alarming amount of time for a few grams of car. Along the way I’ve reduced about 1500mm of 28mm diameter Delrin rod to, largely, swarf that’s in the bin. The big issue, actually, has been getting the tolerances right so that the bush grips properly in the wishbone but rotates around the bearing shaft properly.
Turntastic
Oh, I do like having a lathe.
I took time out this evening from the suspension bushes because I’m waiting for a particular tool to arrive in the post from those nice people at Chronos. Instead I made these things, which are bushes for mounting the engine. They’re just bits of CDS tube, cut to length and faced in the lathe (which means that ends are actually square), welded to some bits of 3mm steel, turned so that they’re mostly round and then a hole drilled in the end and the end faced off properly. Even if I never used it for anything else, the lathe is fantastically useful for drilling holes in the centre of round components, something that’s really difficult otherwise.
Suspending a spectre
I’ve still been thinking about suspension bearings. At one point I’d convinced myself that the thing to do was just to cut up the existing wishbones and weld some bushes in into which I could put some rod-ends. I still might do that, to be honest. In fact, I suspect Jeremy would be happy to provide a complete set of new ones.
However, in the meantime I was talking to one of the Baldwin chaps at Silverstone. Ian is one of the main designers of the BDN car that won the championship last year. What’s more, his new car is running well this year although hampered by a late start. I was talking to him about bushes and he said that the new car, as a bit of an experiment really, was using bushes made with Acetal. This is an engineering polymer that is commonly used for similar things. I did some calculations and it does look as though it’s up to the job. (And, to be honest, it’s clearly tougher than bungy rubber or nasty polyurethane anyway.)
So, I bought a stick of it to see how it goes.
Silverstone again
Well, it was time to be back at Silverstone again for the club’s annual festival meeting, which essentially means that all the club formulae are represented which means loads and loads of cars and only one race each. Unless, of course, you’re an RGBer and you’ve been let into Bikesports for a cheap(er) race than usual. I didn’t have time to do any testing, so that would have to do for me.
Controls
I think I might have resolved the pedal box conundrum. On the Fury I’ve got a pedal box that came from OBP which works pretty well. I had spoken to them about their top-hung pedal box but given up because it was too tall. Adrian mentioned in passing that they did a bottom hinged one with the master cylinders pointing back to the driver. After looking at their website they do indeed do so, so I’ve ordered one! This is the photo pinched from their website here.
Differential suspension
I’ve been pressing on with the Spectre, albeit not making real progress although perhaps laying the basis for real progress. As I said last time I’ve been measuring up where to put the engine. Oddly, the big issue here seems to be access to the spark plugs and coils; everything else doesn’t seem to be much of a problem.
I think I’ve come to the conclusion that getting the engine as far forward as possible is actually more important than being able to easily access the spark plugs. I used to drive a Subaru Impreza. These have a fantastic flat four engine, I never was able to work out how they got access to the plugs in that, it must have been through the wheel arches because you certainly couldn’t reach from inside the engine compartment! I think for the Spectre I might have to make some access panels so as to get access from inside the passenger compartment. Even then it’s going to be difficult though and it might be necessary to slacken the engine mounts to shift the engine slightly.
A Spectre of progress
I’ve kept you all in the dark a bit about how the Spectre is going. Sorry about that, I just don’t seem to have found the time to update this site.
However, lots of things have been happening. And, starting at the end first, the most significant is probably that I went up to Jeremy’s place yesterday to pick up the chassis and the bodywork. As you can see from the photo we managed to pile it all up on the trailer but, to be honest, we should really have rented a van. Still, it worked OK.
(Possibly) working again
Well, I think I fixed the clutch, and also changed the oil and so on so if I’m lucky I’m ready for the next race at Silverstone.
It turned out that the problem with the clutch at Mallory was due to something really rather dim. When we’d put the replacement plates in we couldn’t make things fit properly in that the plates seemed to thick. When I took it all apart, in the calm and lack of heat of my garage I realised that we’d left one of the plates behind; it was just that it had worn so smooth and shiny that it looked like the clutch backplate! Once I realised that I took it out and everything fitted properly.