A Second Round in Crailsheim - Unleashing Potential
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| My TT-02 S is ready for the upcoming event |
Introduction
The last Race with my TT-02 S went rather mediocre. Already seven weeks have passed since I could manage the third place in GT-Sport class in Crailsheim, with plenty of luck but relatively slow lap times.It was only by chance that I realized the MCC Crailsheim e.V. would host a second round of the RCK KleinSeries. A look at my calendar revealed that the race in Bad Berneck had been canceled but the guys from Crailsheim jumped in.
This time entries dropped to 26, with some guys racing two classes. Maybe not all potential drivers had taken note of the replacement date.
Rules, Dates, Results and Race Reports of the RCK KleinKram Series can be found here:
A report of the previous RCK KleinKram Series race in Crailsheim can be found @ Mikanews:
I have also written down my impressions of the last race:
More photos of the previous race in Crailsheim on 10-13-2019
are publicly available on their webpage and on their facebook page:
Space for Improvements
For quite some time I had the idea to make my TT-02 a lot lighter, since there is no minimum weight in this class. A quick calculation revealed that a LowShorty on the left side, with the ESC place behind it and a smaller servo on the right side should lead to a perfect balance left-right. I took some measurements and made a drawing, so my friend Jan could mill new battery fixings. Also the 1/12 scale servo is mounted on an adapter plate because the rules forbid drilling additional holes in the chassis. |
| The idea for a lightweight package |
The tub chassis had a couple of worn out threads that I had already repaired with instant cement. Therefore, I decided to start my rebuild with a new chassis. Unfortunately the rules of the RCK GT-Sport class only permit to use the soft kit tub (51532).
My ESC, an old Speed Passion Cirtix Stock Spec, was a pain to drive. Frankly speaking it operates anything but smooth neither when on accelerating nor braking. So it was replaced by a LRP Flow Competition.
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| Freshly wired combo |
I decided on getting a second 3 Racing rear differential and fill it with 7000cst Hudy oil. So I could swap between the 4000cst diff I had been using outdoors.
The lower A-arms from the kit had already developed extensive play on the outer hinge pins. Tamiya’s carbon reinforced “Y” Arms (51104) are an excellent option. They offer a more precise handling and more traction on high bite carpet and will develop less play.
The final car weights about 1230g ready to run. I pushed the motor 3mm further forward, with an old motor spacer I found shallows of a spare part box. This way the weight distribution is 48 to 52 front to rear, like it was before.
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| The lightweight TT-02 S is about 1230g ready-to-run |
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| The finished chassis without a bodyshell |
Before the rebuild the car weighed about 1370g. The HPI 28 C indoor tires are
about 50g heavier than the setup wheels and the shell adds another 90g.
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| Chassis from the last race |
Training in Saturday
I began the training on Saturday with nearly the same Setup as I had ended the last race in this venue. I had switched the 3 Racing Big Bore Dampers back to Xray’s and was testing 4 x 1,2mm pistons instead of 4 x 1,1mm.I was still using the first set of HPI tires, which had already endured two days of racing and it appeared as if the carpet was stickier then the last time. The car felt difficult to drive. Having a tendency to grip roll, an aggressive turn-in but a slightly lose rear end and.
I played around with the usual setup parameters like tire treatment, springs, damper positions, camber, roll-center and down-stops but never felt entirely confident. Nonetheless I had achieved several 9.4sec and even some 9.3sec laps.
Sascha gave me the advice to compare the hardness of used HPI tires against new ones. So I opened my second set and realized that the airgap between rubber and insert had increased noticeably, while the surface still looked fine. Perhaps the inserts settle over time, I don’t know.
The next couple of laps were a blast. No aggressive steering behavior, no tendencies to grip-roll, no loose rear end and a mild understeer. With great relief I switched back to my initial setup.
With new tires and harder springs the performance of the TT02 was amazing. It was planted to the track, with an amazing acceleration, sufficient steering and carrying high speeds through corners. The timing monitor revealed a fastest lap time of 9,037sec. What an improvement.
I did another couple of laps on old tires to cross check and the old problems were back. Again the tendency to grip-roll, an aggressive steering and a loose rear end. However the good lap times on new tires made me feel very confident for the upcoming race day.
The Race on Sunday
First Qualifier
I was set on fifth position to start the first qualifier and had some difficulties to overtake the slower guys. The car was lacking some steering and had a slightly loose rear end. Obviously the carped was missing some traction compared to last night. With two slower and inexperienced drivers in our group some hair-raising incidents where programmed. Leaving the ideal line to overtake them made the car slightly nervous for the next lap, which wasn't very helpful either. The HPI tires don't seem to be very tolerant when driving through the dirt.After a turbulent run I finished fourth, behind Chris, Sascha and Manny. The bulletin revealed 29 laps and a fasted lap time of 9.678sec which felt really disappointing. I had hoped to manage lap times around 9.4 seconds, but even with a medium time of 9.8sec 31 laps should be possible.
Second Qualifier
Since the rear end was a bit loose I installed the 4000cst diff for the second qualifier. This change worked better for me, but the heat went even more chaotic than the first one. With two slow chaps on the track who could barely control their cars or were able to let you pass it was a gamble not to crash.I had to leave the ideal line several times which led to unstable handling and made me hit some corner markers. One might consider it an invitation to overtake back and block me. It must have been about four times I rolled the car over, what a bummer.
Once again I finished in fourth place with disappointing 29 laps. The fact that cheered me up was a fastest lap time of 9.195 seconds and a medium time of 9.5 seconds. Counting down my bad laps on the timesheet revealed about 17 seconds that I had lost due to incidents during the run. It’s obvious that the car could reach 32 laps within 5 minutes even in my hands.
Third Qualifier
Things went a lot smoother in the third qualifier where everyone seemed more relaxed. This time I manage 30 laps and only missed the thirty-first be a fraction of 0.25 seconds. Skimming over the timesheet I could make out about 6 to 7 seconds of room for improvement. Finally a shimmer of light!One more interesting fact was my fastest lap time of 9.307sec driven in the last lap. I didn’t realize any crucial voltage drop from the lightweight 3500mAh battery.
First Final
The low overtime in the third qualifier lifted me up to third place on the grid for the finals. As the track was building up more and more traction my TT02 developed the tendency to roll over. Eight minutes can feel like an eternity and the track conditions lead to some hair-scattering maneuvers. With some caution I was able to defend position three at first but was facing some fierce attacks.Going circles around moving obstacles can get really annoying at some point. Getting blocked, being shot off the track and rammed into the wall is not what I build my cars from. At about 6 minutes into the race I was so fed up that I reminded myself “we should all do this for fun - take a breath and relax”. So I wrote off the run and reeled down the last two minutes with a slower pace. In the end finishing fifth felt like being beaten far below value.
Second Final
Some days everything just goes wrong. Having made some small setup adjustment to cope with the changing conditions I felt quite confident for the second final. After all I had still achieved several 9.4sec lap times in the last heat. But within 4 laps the race should be over for me.My car grip-rolled in the infield, flew over a barrier and landed on its roof on the long straight, leaving no chance to react for the following traffic. Someone crashed into it at full speed, what ripped the whole rear axle off the plastic-chassis.
Third Final
Unfortunately the rear holes in the chassis got stripped. Since the whole day had been fairly disastrous already I didn’t consider a repair. I packed up, had some coffee and cake, some nice chats, watched some race action and did my marshaling duties. |
| Part of the pit area |
Conclusion
Slightly disappointed I drove back home. Frankly, had I been able to unleash new potential off my TT-02S chassis?Surely. The training on Saturday and especially the third qualifier made me feel very confident. On new tires the car felt better than ever and lap times decreased. With the lightweight package the car has a blasting acceleration which is all too soon is terminated by the low FDR of 5.0. It is faster trough chicanes and the LRP Flow reacts far more harmonic to throttle- and brake inputs. Having a second differential at hand is a good option.
The HPI tires could be a disadvantage on this track as they seem to react critical when picking up dirt. Chris, who won the race, told me he prefers Sorex 28 with JB blue inserts.
When you race at these smaller, permanent indoor tracks it is mandatory to know how grip levels change over the course of a day and how you need to adjust the setup to accommodate. What combinations of tires, inserts and treatment work best at a particular track?
Tiny nuances in braking points and a smooth steering operation are the key in keeping the car stable, when fighting for the last tenths of a second. To sum it up, I should do more testing and training in these conditions.
Highgrip - Always getting high on 𝝁
All Results of this Race are public on myrcm:
More Photos are provided by the MCC Crailsheim with public access in these two Facebook posts: