More parts, more racing with the ARC R10

So, after a nearly two months without turning a wheel, I finally got the ARC out of the garage this month for two rounds of the CWIC. But I put a few new bits on it first.

Tamiya parts re-anodised silver

First job was to get the nasty Tamiya blue off the car. These parts were re-anodised for me by Metal Treatments in Portsmouth. I can’t fault their professionalism, speed of service or price (just a tenner plus return postage for this little lot), but the parts didn’t come out as shiny as I had hoped, ranging from satin to matt. I had been warned that the final finish would depend on how the various alloys responded to having the anodising removed but nonetheless it was a disappointment. Apparently there is a process called “chemical brightening” that can be tried before anodising, but all the businesses I contacted for a quote wanted an insane price, more than it would cost to buy the parts new. To be fair, I hardly notice the dullness now that they are on the car.

ARC Double Cardan Joint (DCJ) driveshafts


ARC DCJ's fitted

Next treat was the DCJ (Double Cardan Joint) driveshafts. These reduce the chatter from running a spool up front. The science is pleasingly simple – the cardan joint used in most RC driveshafts is not a true constant velocity joint, but by adding a second Cardan joint, the inequalities in velocity are corrected. In the car, the chatter is reduced (to be fair, the standard driveshafts were very smooth already) – and as ever with ARC, the quality is superb. Upon fitting them, I realised that a lot of the chatter is caused by vibrations in the long front belt, so…

ARC R10 belt tensioner

…in went the belt tensioner. Just gentle pressure. An inexpensive part that is easy to fit (there is an access hole in the bottom deck so I didn’t even need to remove the top deck). Belt vibrations are reduced but not eliminated, there shouldn’t be any real impact on efficiency.

Onto the racing, with Rounds 7&8 taking place on January 6th. It was a very twisty layout, and a familiar one, being more or less that same as one of the tracks from last season. A track I had really struggled on with my M-05. And it proved to be a track I struggled with all day in Blinky touring. Qualifying was a struggle, I never really felt on top of the car, and understeer was a persistent menace. I made a few changes to spring rates, damping, shock position and droop as the day went on but couldn’t find a happy balance. Part of me wondered whether the free-running DCJs were taking away turn-in, but I left them in. I was messing around with the motor timing and gearing too, with little success. In the end, I was very lucky to line up 2nd on the grid by just fractions of a second – a couple of my rivals cooked their motors in the last round of qualifying, and another was qualifying from the bottom heat which no doubt cost him a little time. Dean Jennings took pole by about half a lap, a scary margin.

I got away cleanly at the start of the first final, and Dean ran a smidge wide which gave me the chance to slip inside and take the lead through the first chicane. A lap later Dean rolled after clipping a marker, and I had a bit of a cushion. But as the race went on, Alex Everett was closing me down by the tiniest of margins each lap, and by 3 minutes he was on my tail. I was trying to keep it neat, but at times I wasn’t neat enough, and with four minutes gone he had the chance to take a look up the inside. Fortunately he held back – had he gone for it, I think we would have both spun – and I just about kept a safe distance ahead until the end, winning by 0.55 of a second.

I had a decent start to the second final too, but this time Dean didn’t go wide – instead, we ended up with about 4 cars trying to fit through the space for 2 at the second corner. Someone was bound to lose out, and it was me, clipping the flapper and ending up on my roof. By the time I was back on all four wheels I was ninth. Fortunately, most of the pack seemed more intent on knocking each other off the track than racing, so within a few laps I was back up to third, but a long way off the leading pair. After three minutes I saw a flash of orange caught up in a barrier, and as luck would have it, it was the second placed car. 1st place was a lost cause, and Alex Everett ended up winning by the best part of a lap.  A 1st and 2nd place was a great result considering my concern about the direction the car’s handling seemed to have taken.

Something seemed different about rounds 9&10 on January 20th. Scrutineering had been moved out into the pit area, and the rostrum was much closer to the wall. It took someone telling me what had happened for me to work it out – an extra width of carpet had been laid, making the track an impressive 30m x20m – and it was astonishing how much difference it made to the layout. It was both flowing and technical – whereas previous layouts could only be one or the other. Blinky laptimes were around 16s so there was less lapped traffic to deal with.

I’d made a change on the car before the meeting, fitting the 2.5 degree rear toe-in block. It seemed to have generated the steering I had been looking for, to the extent that most of the early runs ended with me wishing I had more rear-end grip. It all started to come together in the last round of qualifying though, where I managed to set the fastest time of the round – but not the fastest of the day, still 2 seconds short of Dean Jennings’ Round 2 marker. Another quick car had joined the class, and any of the top 6 would have had the pace to win.

The first final started cleanly, and once again I managed to pull a move on Dean, this time on the way into a chicane half way around the first lap. But I rubbed the barrier at the fast first corner and Dean got past me again. I decided to put him under maximum pressure before he had the chance to drive away, and forced him into a mistake and roll on the way into the same chicane a lap later. This left me with a fairly comfortable lead, and I brought it home in 1st place despite a scare a couple of laps from the end when a backmarker decided to spin me around as I lapped him.

The second final started cleanly as well, but I couldn’t do anything about Dean who drove away. Before long, I was under pressure from behind, and I made a mistake into the first chicane which let Alex Everett through. A couple of corners later I tagged him, so I waited and resumed the battle – but that had put us down to 3rd and 4th. I had a little more pace than Alex and was trying hard to find a gap, but a few laps later I tagged him again and waited again. A mistake from Alex then gave me an opportunity that I wasn’t going to refuse, and I started to chase down Les Baldry who was running in 2nd. I got past him quite quickly (I think he may have mistakenly thought I was a lap up), and tried to close the gap to Dean. But it just wasn’t happening. For lap after lap, I would see Dean running through the apex of the last corner just as I ran through the apex of the corner on the opposite side of the barrier. I knew I was counting on a mistake or a backmarker to bring the gap down, but it just didn’t come and I finished the race 4 seconds behind him. Another second place to add to the championship total – a championship I’m now leading, having dropped only four points from 8 rounds, although one that could still be won by any of three drivers. I’m not sure I can make the next round – it will be interesting to see who picks up the big points if I’m away.

I was quite happy with the ARC setup by the end of the day. Track conditions were quite slippery because of the very low ambient temperatures (10-11C in the morning, down to 8C at the end of the day), the tyres never really got working but the balance was good, setting the fastest single laps in some races. It seems that less rear toe and softer settings all-round are the direction to go in from the kit settings, getting rid of the slight understeer tendency, and reducing the sensation that the car is “floating” on the track rather than gripping it. cwic_setup_20_1_2013



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