Just a short post this time, so you realise I’m still here.
Here’s the rear of the chassis with the ends of the tubes blocked up. To be honest, there’s still a bit of welding to be done on the bottom of these bits. But, I’ve learnt my lesson about welding on the bottom of things—I’ve got the scars to prove it—and I’ll leave it until I can turn the chassis upside down again.
Another small mod is at the front of the chassis. One thing that the Fury suffers from, and the design of the front of the J15 (for that is what it’s really called now) is much the same as the Fury, is cracking of the front of the chassis. In fact, one race at Brands Hatch the front of my Fury practically fell to bits. In an effort to forestall this, I’ve welded in some little stiffening gussets, made out of triangular pieces of box section tubing.
Hopefully, that’s about all the major modifications done to the chassis. The main thing left is to weld in the roll cage. Unfortunately, I haven’t yet got the tubing for this. Admittedly I ordered it 3 months ago but the suppliers have been rather frustrating. I’ll tell you all about it as soon as I can. In the meantime, I’m going to have to find some other things to do, there are lots, after all.
Nice to see you’re making progress Tim. I was wondering if you thought switching from front mid-engined (Fury) to rear mid-engined (J15) will make a significant difference to the lap times ? I watched Jon & Mark have the first outing of their J15 at Brands recently and it looked a stable car.
Also (!) I noticed that when Jon or Mark where driving the J15 it looked as if they sat quite high up. Of course it is actually the sides of the body are lower than the Fury (by 2-3 inches). It will be interesting to see a J15 done as a race car and not a ‘retro’ look which both Jeremy’s and Jon’s cars are.
Well, that was the original intention. The mid engined car should be able to be closer to the ideal weight distribution which (unlike what BMW adverts will tell you) is not 50/50. There are certainly RGBers who believe that that issue is significant. There are other advantages for a race car; ease of changing gear ratios for example and better access to a front mounted radiator to improve the cooling. Whether all those things are “significant” is anyone’s guess though. The other issue is my Fury is pretty well sorted which the J15 clearly isn’t. I’m pretty sure, for example, that the new car will need a lot of work on the aerodynamics (much to JP’s chagrin). What I really need is a wind tunnel… 🙂
It’s certainly my intention to get my bum as low as possible. How well I succeed is anyone’s guess. 🙂
In theory you should get better traction out of corners with the weight further back. I presume you will be running larger discs & calipers on the back of the J15 compared with the Fury to make the most of the different weight distribution ?
Unfortunately, I doubt I could fit larger discs in than I use at the moment without increasing the wheel size which I don’t want to do. However, the bias will almost certainly end up further rearwards; I certainly don’t think I get any problems at the moment with the rear brakes overheating.
Hi Tim
I’m very interested in your build. Can you tell me the centerline distance between the sprockets?
What do you estimate for completed weight of the car?
Thanks
Chet
According to the CAD model it’s about 300mm between the sprockets. This isn’t too long but hopefully it’ll be OK if I can arrange for enough cooling for the chain. The model seems to be borne out by the car, I’ve mocked up the transmission mountings to check, photos coming soon.
My race Fury weighs 448 kg with no fuel in it. If I could make the car for the same weight then i’d be ecstatic because I’d be pretty close to the weight limit which is 560kg for mid engined cars; especially if I continued to scrape a few kilos off the lard-arse driving it. However, the J15 bodywork is perhaps a bit too substantial, JP’s not interested in making lightweight bodywork although I might try and prevail upon him at some point. However, I’d hope that the J15 wasn’t too far adrift from the Fury as it’s about the same size, perhaps a bit smaller, and uses much the same materials. However, time will tell…
Tim
I believe that Jeremy’s Rover 1600 powered car weighed in at 515kg so I think your car may be lighter than you may think. I expect my Hayabusa powered car to weigh less than 450kgs.
Chet
Well, if it came out at 450kg then I’d be well chuffed. However, as a race car it’s going to have a full cage, and an extinguisher, and so on which all adds to the weight. I guess we’ll see in a while! 🙂
Tim