10.5 Setup Carbone Chassis

10.5 Setup with Aluminium Chassis


The classic GP3F (Grand Prix of 3 frontiers) was held over the weekend of 21 and 22 January 2017 in Longwy (France) close to the Belgian and Luxembourg borders.

This immensely popular event was fully booked out in 5 minutes when the entries opened late December 2016. As Florian Joos, my 13yo son, raced in stock last year, he wanted to race in this class again where he had to compete against 106 other drivers.


The format of the 2 day event provides a lot of running, with 4 timed practices (followed by a reseeding based on the fastest consecutive laps), a practice qualification, 4 qualifications (of which the two best count, based on a points system) and 3 finals.

Florian was racing his Tamiya TRF419X with a Trinity Revvtech 24K motor and a Hobbywing XR10 Pro speedo. The tyres were handout Volantes and you got two sets of tyres.

Florian already did some high level races in the past. He was always quite fast in the beginning, but faded towards the last qualifiers and finals. We wanted to solve this and keep him competitive throughout the racing event. The reason for this drop off is that he mostly race on low to medium grip carpet.


A busy and friendly pits

After the 4 free practices, Florian was in 20th position. His best laptime was 12.467 and the front runner was at 12.0. During the last free practice he improved his best 3 consecutive laps, but wasn’t able to improve his single laptime. All the topdrivers improved by almost .2 seconds.


The aluminium chassis looks great!

During the free qualifier, we decided to let him run the alloy chassis car. This particular 2.0 mm thick aluminum chassis is made by the German Tamiya driver Christian Donath. Christian used it at the ETS race in Hrotovice to claim TQ.


15 grams heavier than the carbon chassis, but the TRF419X still needs weights to reach the minimum 1350g requirement

The chassis itself weighs 84,6 gramms, which is 15 gramms heavier than the carbon version. I decided to use titanium screws in the lower holes to compensate for the weight difference. With this, the car weighted in at 1351gramms, so almost spot on.

During the practice qualifier, one of the motor cables came loose. Despite that, he managed to record a fastest laptime of 12.4 with a non timed Muchmore motor. Florian said that the car had more speed and a better feeling, but was at times a bit twitchy to drive. I added .5 degrees of rear toe in (I went from XA C to XA D in the back). With this setup, Florian was very quick and his car had some tremendous pace. As he had one or two faster drivers in his group, he was a bit intimidated and went very wide to let them through and lost about 2 seconds in this heat. Despite that, he claimed a P13 in the first qualifier, which was very good. His fastest laptime was 12.324.


In the second qualifier, I let his car unchanged, but put the additive on for only 15 minutes instead of 30. He finished 20th overall, but again ran a bit wide to let the faster drivers pass. He felt the car was ok, but a bit twitchy overall. For Q3, I installed a cut open upper carbon chassis. Christian Donath also used this during the last ETS race. Florian recorded a fastest laptime of 12.277, but he said the car was a bit of a handful and didn’t give him the confidence to push.

For the last qualifier on Sunday morning, I kept the cut upper chassis, but moved the 4 dampers into the inner hole. As there was a free practice from 7 till 7.50am, we tried this and he felt that the car was safe and easy to drive. Unfortunately, it proved to be too safe, and he didn’t manage to lower his laptimes. The car was a bit too lazy and his fastest laptime was 12.316.

Because of this, he just missed out on the B main and claimed P21. I thought it was quite good, but he found it frustrating as he had a chance of participating at a B-main for a big event for the first time.

For A1 I put the car back to its Q2 configuration with the solid upper deck and the dampers in the 2nd hole. I also reduced the additive time to 10 minutes. His car looked ok and he held on to his first position, despite a tremendous pressure from the car who started on P2. On lap 10 this driver tempted a pass and put Florian a bit sideways. Florian straightened his car and kept his P1 position. This went on till lap 17 when the other driver tried an impossible pass and hit Florian hard. He crashed out off the track and as his car was completely tweaked, he wasn’t able to continue.


Body painted by my good friend Stefan Snauwaert, who painted the body I used to win the Tamiya 2002 F1 worlds

The aluminium chassis is quite prone to tweaking, so you should unloose the upper deck, realign it and adjust the spring tensioners on the dampers if necessary.

As he complained his car was still a bit loose, I added a .5mm washer on the inner rear bulkhead to lower his rear roll centre. This seemed to do the trick as despite a huge pressure from the P2 driver, Florian held on to his lead and took the victory. He also marginally improved his fastest laptime to 12.251, so we knew we had his car sorted. The fastest lap-time of the A main winner was 12.051 so this really motivated him to do even better in A3.

In A3 Florian did a warm-up lap, his car really looked great, but then disaster struck and the pinion fell off. The race director didn’t want to wait for the repair to be done, so Florian had to start from the pits. The fix took me 2 minutes, but his motivation was gone and he parked his car.


A honoured Florian placing Ronalds car down at the start of the A final.

In modified, Ronald Volker was in a class of his own. He was so much faster than the other drivers. Mark Reinhard driving very well as well whilst trying different cars. Christopher Krapp had only tested his Yokomo once before this event, but he was already very fast. It will be an exciting racing season I guess!

Overall it has been a good weekend. Some setup changes worked well, but I think with these two setups below, one for the carbon chassis and one for the aluminium chassis, we have a very good starting point.

Besides using the aluminium chassis, we also used SMJ springs. Progressive 2.5-2.8 in the front and the harder 3.0 for the rear. This makes the car turn in a bit better.

Hobbywing XR10-Pro Set-up


Florian would like to thank all the people who support his passion; T2M (French Tamiya importer), Tonisport, EP Fun (Belgian Hobbywing importer), The RC Racer, MCM Racing, Shepherd Racing, Carrozzeria De Buck and Ollie and Krist Buyltinck for their tips & tricks.

David Joos

Source:

D. Joos