Saturday, June 15, 2019

Access Hobbies 2019 TCS Race

Finals video

So the thing about Access Hobbies this year was the tight, 1/12 style layout they presented the Tamiya TCS racers with.  Before the closing of my local track, I was running my TRF103 with a peg diff tightened into a spool, and the battery lengthwise in the chassis.  This worked really well at home.

Despite the number of cars on the track, traction was not overwhelming.  The spool was hard to drive, especially off the corner.  Reverting to a slowed down ball diff was the way back to stability.  I am beginning to find that the spool must have a massive amount of traction to really be effective.  When the condition is correct, it is unbelievable, but I would say that most track conditions favor a combination peg/ball diff, or even a slightly loose peg only diff (non-TCS races you could use a gear diff as well).

The lengthwise battery did not work as well as a transverse battery, period. I have always favored the transverse battery in almost all situations, but the TRF103 really seems to like the battery lengthwise most of the time.  Not here, the car seemed a bit more planted and rotated better with a transverse set up.  I have to say it was just the tight nature of the layout.

The other factor was the track surface itself.  The traction peaked off on Saturday evening.  Leading up to this, I had shortened the wheelbase on the car, and steering was plentiful.  The last qualifier on Saturday was the fastest for me, and my car did the  fast lap of the weekend as far as I know.  Unfortunately, I had an accident that zipped off most of the spur gear, so the best time to qualify was wasted.  Sunday morning, the track had reverted to a state where the short wheelbase hurt more than it helped, and I returned to the long wheelbase.  I lost some steering, and to be honest, I think that the link setup might have been better at this point, as the link 103 cars looked to have a bit more steering in the lower traction.  Odd, in that most times T bar setups have more traction, and would be better when traction is down.  It may just be that the T bar in high traction allows the short wheelbase to work, and the improvement in corner speed is only available with the T bar's superior traction.  In any case, the car worked well enough on Sunday.  I feel like the other cars might have been a little better in the main, but I had a very good start and built up enough of a lead that I didn't have to push too much.

Other than those big changes, I was able to raise the upper arms at the kingpin, which tells me traction was not too great.  Normally, I run the upper arm pretty flat to avoid traction roll, but I was able to get away with maxing out the spacers under the arm.  I also ran 0.5 or 1 mm under the rear ballstud of the upper arm, just to take away any chance of lifting a tire.  Sometimes in the tight turns, if I had to get on the brakes, it could be hairy without the spacer.






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