A tardy Caddington Park

As seems usual these days, I start with an apology. Since the last post I’ve been racing at both Cadwell and Doningon. It’s the usual excuse, I’ve just been too busy, although I did spend a welcome weekend tramping around the Peak District. All the same, despite the tardiness, I did go to Cadwell and Donington and completed four races without major mishap.

Wasn’t quick enough though…

I’d decided to do the test day before the Cadwell race weekend to try and re-familiarise myself with the circuit. So, I drove up (without Anthea, she was following on by train on the Friday evening) on the Thursday evening. The weather was a bit gloomy on the way but the forecast was good. Even so, I started to worry when I saw the thick mist that descended that evening (a “sea haar”, said Tony). I tucked myself up in bed and woke the next morning to brilliant sunshine and cloudless blue skies, something that continued all weekend. Pity it’s since forgotten how to do this, especially as there’s another race coming up soon.

The plan, such as it was, was to try and get a bit quicker during the test day and, along the way, to experiment rather more with ARB settings. But, this was Cadwell and I’m the first to admit that I don’t think I’ve ever really got Cadwell. the circuit flows in a way that I never seem to get on top of. One problem is that the circuit makes me travel sick, I’m not alone in this, which I think is a consequence of the Mountain/Hall Bends section which is a really brutal series of corners with a jump in the middle of it.

Before this weekend, my fastest lap was a 1:36.22, hereinafter referred to as 36.22, which dates from 2009, just before I started thinking about the J15 in fact. I have to be honest and admit that goodly bit of me still wishes I was in class F and racing the Fury, or something like it. Ho hum…

All the same, the test day was good and things got slowly quicker. Along the way I chiselled away at the time, although still not beating that Fury lap. Along the way I actually removed the rear ARB and tweaked the dampers quite a bit. The problem is, of course, that the next circuit (Donington Park) is totally different… Along the way the FLs in the test sessions were 37.6, 39.3 (hmm…), 38.9, 37.2, 36.8, 37.7, 36.4. So, nearly down to that Fury time. Most of the people that I ought to be racing, though, are a bit faster than this.

The issues with all this are really that I’m sure I’m not getting everything out of the car and although it’s getting better it still isn’t as stable as the Fury was. Fundamentally, the balance is all wrong and I’m at a bit of a loss as to what to do about it, although see later for some musings. When I get it right, though, it’s quick. Far too often though, it’s nothing like as speedy as the Fury was.

You can see the effect in this capture from the analysis software. The graph on the left is the speed through the Charlies 2/Park straight section. As you can see, at the point marked where the speed is lower the J15 trace (the black one) is fully 4mph slower than the Fury one. That’s an age in race car terms. You can see the the J15 gets back on terms because the rear engine essentially gives it better traction and, furthermore, the chain drive means that I can get the gearing more suitable to the circuit. However, if I could get that acceleration out of a corner starting 4mph faster then I’d have a much better platform.

Problem is, I suspect that the biggest problem is me. There is bound to be a car setup issue and I must admit that I’ve lost my way a bit of this at the moment. Problem is, I could really do with some more testing time but it’s really hard  to do that; see earlier for comments about time.

Still, at least I didn’t break it and race day dawned bright, clear and hot. I suspect along with the rest of the paddock I went home rather sunburnt. It’s hard to do things like slathering yourself with sunblock when you’re forever getting in and out of race gear. The big problem at Cadwell is getting two decent laps in (for the times for two races) in a session where you get 7 competitive laps. As it was the Fl as a mere 36.4 with the second fastest a lametable 37.2. I think that made me about 12th in both races; really rather poor.

I got a decent start in the first race but just got slowly dropped. After a few laps Tony came past me and just slowly crept away from me and that was pretty much how it finished. Cadwell’s a great circuit but, as I think I’ve said before, it doesn’t really promote good racing. At the end I was 10th, 9th in class which is a reflection of the way that RGB is going. In summary quicker than me… FL was a 36.5, that was over a second slower than Tony who I used to trade places with. Hmmm…

The next day the weather was still good, too hot if anything. I was in much the same place for the race start and again got a decent start (at least I’m getting better at this). The race was quite fun, swapping positions with Colin and David. I’ve actually managed to get my act together for this race and done the video. Here you are:

Annoyingly, I just didn’t manage to get past Colin at the last corner. To be honest I don’t think he saw me there. All the same it was fun. At the end I was 11th, 10th in class. FL was 36.0 which was at least an improvement.

And so it was on to Donington Park. The big problem with this otherwise excellent circuit is that proper testing is essentially impossible due to the problems they have with noise. And completely barking problems they are  considering that the circuit is next door to East Midlands airport and the noise of the aircraft completely drowns out the circuit noise, and goes on for much of  the night too… Still, such are the UK’s legal constraints.

So, we arrived there late on the friday night and got set for an early start. The weather looked absolutely awful with a lot of wind and torrential rain. Bizarrely, though, all our track outings were clear, the dry tyres stayed on the car all weekend. Qualifying, though, was a real test as I had idea what gear to be in. Not surprisingly my lap times reduced all through the session but didn’t get to where they should have been. The biggest problem,  though, was that Bob spun off into the gravel at Coppice early on and we had yellows at that corner for just about the entire session. That completely ruined the lap times and, of course, it depended on how much you wanted to risk the ire of the Clerk of the Course how fast you went through that particular sector. I wasn’t impressed that they didn’t red-flag the session, to be honest. At least I didn’t have a car full of gravel to clean up though.

I ended up with a lap of 1:18.7. That’s way quicker than my Fury times, but only because I never came here in the class B car, only when it had the 919 engine. But, it was only good enough for 17th place, 19th in the second race. That’s what doing no testing at all does, along with perhaps taking too much notice of that yellow flag than I should.

Later on in the day it was time for a bit of racing. Here’s the video of the first race. As you will be able to tell I still haven’t got the car working well, in fact it was worse here at Donington it’s been anywhere. I wasn’t helped by my guesses on gearing being hopelessly wrong, I was never in 6th gear, but the car was way too loose at parts of the circuit. Down the Craners in particular it was horrible and I never seemed to get Macleans right. Still, see what you think:

I ended the race in 12th place, 10th in class. FL was 17.4, rather quicker than qualifying. As you may notice, Colin made a last lap lunge at the chicane and came unstuck. You may also notice that neither Colin nor I saw the chequered flag. In fact, my time in the first sector of the lap was faster in the lap after the flag than any other!

So, I left the car alone in the evening although in retrospect I should have twiddled something, anything really to try and get a bit more information about how it was working, or not working. Problem is, it was really cold and we were huddled in various motorhomes keeping warm.

On the Sunday it still looked as though we might get a dry race and so it turned out. I was starting even further back in this one. As seemed to happen all weekend there was a bit of a fracas at the chicane on the first lap and Colin (there’s a pattern here) and Austen were involved this time. Unfortunately Austen came off much the worse this time and although Colin finished it turned out that he’d bent an upright and a wishbone. Not surprisingly really, because he must have hit Austen pretty hard given the damage done to the front of Austen’s car.

Although starting rather further back than is usually the case for me, I had a rather fun race. mixing it with Andy and Dave. The latter ran wide at Coppice on the last lap and just let me past. I pulled his leg about it alarmingly later on… Here’s the video:

FL this time was 17.3 so that was a little quicker again with me finishing the race in 13th (9th) position.

Still, in many ways that was a very unsatisfactory race weekend. I need to do something radical to make this car quicker. The fundamental problem is that the car is unbalanced with the rear end developing too little grip. My principal suspicion here is that the rear wishbones are just too short, something very clear in the photo here. I think the camber change is well controlled, but the rear wheel just moves about too much. The other problem with the rear suspension is that the upper wishbone is retained at the inner end by a long bolt that goes through both mountings. The problem with this is that it’s very difficult to arrange for everything to miss everything else. While at Donington Tony noticed a witness mark on the driveshaft showing that it’s been hitting the tube that contains the aforesaid long bolt.

I think the ultimate solution to this is to completely remodel the rear or the car. The reason the wishbones are so short is really to allow enough room to fit in a car engine which is really the intended power plant for the J15. Of course, this doesn’t apply to me.

The notion that’s hatching in my mind is to essentially completely rebuild the rear end of the car. This is really what Tony has done with his latest car and it’s working really well. The problem is, of course, is what basic components to use. For example, it’d be nice to start with a proper race car upright but it’s not clear which is the best one to use. Tony used the BDN ones but I’m a little unsure about what the supply of those will be like. Any suggestions gratefully received.

In the short term, I’m wondering if I ought to re-engineer the rear upper wishbone mountings to remove the need for that tube; it’s quite a lot of faffing about though, especially if it’s something if it’s something that I’m going to be throwing away anyway.

 

11 thoughts on “A tardy Caddington Park”

  1. Oi!! Bob didn’t spin off into the gravel at Coppice early on in qualy, that was Mark Conroy. I went off near the end of race 1. And I drove straight in without spinning 😉

  2. Interesting update Tim.

    Can I offer an observation? I don’t profess to being the world greatest driver (or any good at all) nor have I driven an RGB car so please take this in the spirit it is offered i.e. complete rubbish…but !

    You appear to be losing time on the braking phase and the part upto the Apex compared with the cars in front.

    I have a suspicion that the J15 is fundamentally flawed as a race car and, given your competition, you may need to swap chassis if you want to move up the grid. You are, as you well know, competing with full on race cars now which are only going to develop further.

    1. No problem at all.

      You’re right in that I’m having real trouble with the chassis, in particular with weight transfer under braking. The big problem at Donington, though, is that I’ve actually done very little time on the track there over the years and I had a HUGE accident there in 2005. You may notice that I’m very slow into Redgate on the opening lap of each race; that’s because I spun there and go hit head on at some considerable speed. There’s some horrific photos somewhere but, thankfully, I’ve lost my copies. At the time they got published all over the place.

      Hence all the discussion about rebuilding the entire rear end of the car…

  3. What I also found interesting in the Cadwell video is how you where able to drop your lap times by 1.5 secs or so (36.0) once the BDN got passed again. I’m sure you don’t need me to tell you how much further up the road you would have been if you where able to do that pace on your own. This is an issue I suffer from as well (at least in karts).

  4. Maybe a test day with a driving coach and the datalogging would be money well spent? If you could get an experienced race driver to help setup the car and point you in the right direction from a driving perspective it would be money well spent. Someone like Mike Wilds maybe (http://www.mikewilds.com/racing.html).

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