Wednesday, November 23, 2011

The poor man's F1R

One thing i did not mention in my last post was that I tried my home brew F1R style top deck.  I made it from some fake graphite- basically 3mm fiberglass with a graphite veneer on each side.  I have a big sheet of it laying around, so it was fine for this. There are 2 extra holes in the original Exotek chassis, so I also incorporated these into my upper deck so there could be the choice of 2 or 4 posts on the car. 

Running the car last night, it was traction rolling, so I wound up putting the full long upper deck back on to make sure that the cause of the traction rolling was not the chassis stiffness.  I do think that this sort of thing will be great for lower traction racing like asphalt.

Talking turkey with the link front end

I finally got out to my local track on a Tuesday, as the F1 class is becoming very strong every week.  This week there were I think 7 cars, which is good since there were basically zero about a month ago.  It's pretty loose, since there are F103s, 104s, F109s, a TRG car all different widths, most on foams (except me)...

I decided to run my F104/Exotek with the adjustable link front end and Pit rubber tires.  The traction really came up since the track has been operating at full steam for a few weeks.  My car was really flipping off the track everywhere.  Mostly, it was too soft on the side springs, and the front end had too much bite.  I could see the rear tires wanting to lift, but I also saw the car soft of diving onto the outside front as well.  Not good.

First I glued the side walls of the tires, which was helpful, but not enough.  I took a bunch of caster out of the car, to the point to where it only had a couple degrees, and went to about .5* camber as well.  Still flipped.  Raised the camber link to level it off.  A little better, but would flip when pushed hard.  Upped the side damper oil to 60..this helped, but the car was on the edge of rolling and had to be babied. 

The 2 things that got the car driveable: Gold Associated side springs, and going to 3.5mm ride in the front end.  The front end was way higher than it should have been.  The gold springs kept the car from twisting itself over, especially in the sweepers.  Now this did take away a bit of steering/rotation, but the car remained pretty flat.  I was able to race all over the track, albeit with a bit of an entry push. Some of this may also be due to the fact that I went to a shorter upper link setting as well (explained later) I knew I could drive with confidence as far as the flipping issue, so even a bit of a push was ok.  After the races were over, I added some caster back in and this brought steering back  I think I could have increased front dope as well, from the 1/2 tire I was doing. The gold spring may have been too stiff as well, since the car didn't get into the corner too well.  Unfortunately, I was pressed for time, so not all the adjustments were tried.

So in a nutshell:
To reduce traction roll-

Glue side walls of tires
Lower car to minimum
Stiffen side spring
Shorten upper arm
Reduce caster
Stiffer front spring

Finer tuning-
increase side dampening
flatten upper arm
Shorten shock

Also remember that the camber adjustment plate is the way to shorten and lengthen the upper link on the front end.  2.5 is the longest link, 1.0 the shortest on the aluminum piece.  2 is longer than 1 on the plastic, but both are shorter than 1.0 on the aluminum part.  A longer link increases roll on the front end (and traction, hence the traction roll).  Going to a shorter upper link when traction comes up is a good idea. The shorter upper link should make the car react faster as well.

Thursday, November 17, 2011

Wednesday, November 16, 2011

It's been a while...

I gotta get back on the ball over here...

Meanwhile, check out the beautiful end of season book UF1 has put out detailing this year's racing in their series.