Wednesday, August 31, 2011

TCS Finals

It was a pretty long week.  At the same time, it was a 100% different experience than last year.  By the time qualifying started, I was really confident in my car.  One thing that was different was having a better awareness of tire prep.  In the beginning runs, I was using Simple Green to clean the tires, which does work very well.  The only thing I did notice was that it was not as good on longer runs, the tire would tend to overheat a bit.  Oddly enough, Buggy Grip to clean and SXT 3.0 heated up with tire warmers was really good any time of the day.  It also ran as long as the battery lasted.  The only caveat to this was the fronts.  I ran new rears each round, which was great.  I found they actually ran the best for about 3-4 runs, then traction began to drop off, but for the nationals I just ran new skins each round.

  The fronts were actually broken in, and could be used for many runs.  However, as I found out the hard way, the insert has to be monitored to make sure it is still in good shape.  I basically threw away rounds 2 and 3 because the fronts I had been using became very soft as the inserts started to break down.  The car became very unstable, and was pretty hard to drive.  As soon as I went to a less used set of fronts, the correct feel came back and the car was very good.  Just keep an eye on the fronts, and especially watch for the death groove.

Another big issue was lead weight.  A little discussion has already occurred on RcTech about Austin Brumblay's lead setup.  I noticed his car looked like it was kind of hard to drive in Q1, which allowed me to Tq the round, despite his very fast initial pace.  From what I could tell, the lead showed up in Q2, and his car was VERY dialed from that point out.  In short, he cantilevered the lead out sideways from the radio trays, and stacked lead up (6+ oz.).  This was more like a 103 with the battery sideways in terms of weight distribution.  This added weight transfer really worked for him.  After seeing how good his car was, I added 4 oz. (as much as I had, LOL) to my car in a similar fashion.  What was interesting was not the fact that the car became much more stable- in fact I had to add 30 points of dual rate to get the steering back.  What was more interesting was the tire wear on my rears was much better.  Without the weight, the rears grained pretty bad, and I'm sure the car broke the rear end loose quite a bit.  After the weight, the tires came back in almost new shape.
For asphalt in general, I can't recommend this more.  I haven't run it enough to monitor improvement in the number of runs on a tire, but I would imagine there should be a couple more before the tire is slow.

Before any of the racing started, I did show my "lowered" front end setup to race director Fred Medel, who shut me down immediately, LOL.  I was sort of expecting it, and Craig "Cuda" Hammon warned me it would probably be thrown out, as they were pretty harsh on creative setups at  the last couple races.  It worked out fine though.  I did use a short Tamiya ballstud on the camber plate to get a bit of the angle back into the upper arm, but they seemed ok with that.  I was allowed to run the shorty servo with the output shaft facing up and forward as I have in the past.  This was ok since no parts were cut or altered.   I ran black front springs, which was fine until I put the lead on the car.  Looking back, I could have run gold or even softer, since I needed steering.  Austin B. mentioned on RcTech that he used gold springs with AW grease, which sounds just about right, and his car was great.

I'll probably have more in the next couple days, but for now congratulations go to Austin Brumblay TCS NAF winner!  I'm sure he'll be issuing beat downs in Japan...Also congrats to Anthony Fung in 2nd place, and thanks to my team pit buddy T Marshall.  The team managed to qualify 2nd and 4th, and I got to the podium in 3rd, which wasn't too bad.

Monday, August 22, 2011

Pre TCS Nationals

I arrived at the Tamiya facility early Saturday morning to get some testing in.  After last year, I waanted to get a handle on things early.  I had not planned to come out so early, but some friends urged me to do so.  Luckily I was able to change my flight (and actually get a better price!!) and come out early.

Just some quick thoughts:
*The track like last year doesn't have a ton of traction.  However, it seems a little stiffer chassis is working better as I thought.  There is a limit to this, but stiffer helps the car have a better feel out of the corner.

*Simple green!! LOL

*Maxing out the front ride height may not be the way to go.  I was trying this to help stability, but it may be making the car hard to drive.  Essentially, the roll center raises with the ride height due to the fixed arm, so
too high of a ride height may make the car too reactive...

*I am a big dummy dept: The plastic camber plate is 0 and .5 camber, I guess.  I did not realize this, but using a caliper, the 1 position has the holes ~21mm apart, 2 is ~20mm, and 1.0 on the aluminum piece is ~19mm.  Closer hole spacing = more camber...........

Tuesday, August 16, 2011

F104X1 Carbon lower deck?

Just a quick thought, I have been thinking about trying the carbon lower deck vs. the FRP that comes with the car.  As I alluded to in my previous post, the car was better with two chassis post installed all the way forward.  I'm wondering how a carbon chassis with no posts installed would be, maybe a medium between no posts and posts on an FRP chassis.  It's food for thought....

Monday, August 15, 2011

F104X1 panic at the racetrack

So Sunday I was trying to get some last minute testing in at the local track before setting out for California and the Tamiya Nationals.  There was a bit of rain during the day, and I had a lot to try out, so I was scrambling a bit.  Not to mention, there wasn't an F1 turnout, so I was trying the car between rounds once practice ended.

A couple quick things that stood out to me:
One thing that I had used in the past on the F103 was the shorter kingpin setup that traps the spring between the top of the steering knuckle and the upper arm on the standard front end.  Usually, the spring rides under the lower arm.  I can't remember the Tamiya part # or the name, but it's very close to how an Associated "old school" front end is set up.  The main point is, it seemed to produce a bit of preload on the spring, and I even added shims at times to increase  the preload.  The car has a more stable feel, especially entering the corner.  This was helpful with the 103 on foams.

I was trying some "sag" or droop on the front end of the 104 by removing a .5mm spacer.  That did add some on power steering, but it came with a less than predictable steering feel.  Going to a extra .5mm spacer over standard (.5mm preload) gave a very confident steering feel.  The relationship of the steering wheel to how the car turned was very proportional, very linear.

I also changed the steering links to the forward hole in the steering arm.  This does two things, changes the ackerman relationship, and also speeds up the steering.  Mostly I wanted to change ackerman, but I didn't want to move the servo.  It was easier to have an extra set of links.  I think that it helped the car get through the turn a little better because of less wheel scrub.  Now, what I'd really like to do is set the servo to have straighter steering links (mine are currently very angled) and also go back to the rear holes in the steering arm.

Another positive result was adding chassis posts in the forward most holes.  My car had a bit of a loose out of the corner/under power condition.  I remember I had tried the posts before at the Memphis race, and it tightened the car up a little after turn in.  So I added the posts, hoping it would help.  They actually did tighten the car up a bit where I needed it, coming off the corner.  Memphis was pretty high bite, so the posts were not needed there, but the local track facility's beautiful euro style road course is literally 20 feet from their off road track.  This does tend to throw some dust on the road course unless there is a ton of cars on the track and a lot of sugar water.

Overall, progress was good.  I would have also liked to have tried increasing the center shocks angle, as it usually stabilizes the car, but it wasn't super important since I have tried that adjustment several times before.
Side damper oil was also increased to 10000 wt diff oil to aid in stability as well, but that is a pretty well sorted adjustment.

One other thing was that straight Simple Green to clean the tires seemed to have the longest "run" on the track before the tires got dirtied. 

Sunday, August 7, 2011

F104X1 front end thoughts...

Due to a couple big events this weekend, there was no place to run my car.  The only on road race was at a hobby expo, and they didn't offer F1.  Luckily, the shopping center where one of the local hobby shops is located just had the lot repaved, so I was able to fool around with a few things.  I was trying out different ways of tire prep, but I did have a chance to play with the front end a bit.

My car did oversteer generally.  The first move I tried was to set the camber to minimum by going to the 1.0 setting on the camber plate, but keeping camber gain in the car by raising the arm up at the kingpin.  This was a pretty good compromise, but I was still not there.

My car was a little loose on corner exit.  One way to cure this is to raise the front end.  I raised the front end to the maximum, removing all washers from under the knuckle.  This definitely helps to settle the rear end down, but in effect you are raising the front roll center.  That, coupled with the rear end being as low as possible, creates a situation where the car turns in, but now is prone to pushing more mid corner and exit.  Obviously, I want to keep the positive aspect of a more stable corner exit, but I want to get some of the push out.  The problem was that it began to rain a bit so I had to cut my session short.  I would have liked to lower the shock to a more horizontal positon to get a little more on power steering.  One other possibility would have been going to the gold front spring from the black to let the car roll a little more, but I'm not sure if it would be too much.