Friday, November 7, 2014

Halloween Meltdown

Didn't have a good time with the SP-1 at the Halloween Classic at The Gate in Cleveland OH.  Qualified 9th finished 10th.

    Other than Bill Jeric's VBC, everything at the front was CRC.  I think a lot of that has to do with the CRC cars ability to steer without wanting to traction roll, at least most of the cars I saw.  The VBC car was pretty stable as well.  

I went into the race with the same setup as I had the last time I was out there.  Traction was up as you may imagine.  Initially, the car had a lot of off power steering, but needed more on power.  Not a big problem.  One thing I was noticing, contact with boards was changing my trim.  If I touched a board it was making the steering go 7-8 clicks one way or the other. (note I replaced the ball cups on the steering links at this point)   I had the front suspension plate mounted direct to the chassis with 5mm spacers under the suspension arms.  I noticed the cams that set the width of the lower arms looked cock eyed.  Figuring that being raised off of the suspension plate, the arms could move, I instead raised the plate on the spacers and mounted the arms directly on the plate.  Everything should be fine, but when I went out for the first qualifier, the car felt broken.   It felt like when the foam on the steering wheel of your radio jams against the radio body and the wheel won't return (I DID check this LOL).  The car was actually good, but it was hard to determine exactly where it was going or how much to turn the wheel. 

I did add a set screw in the unused hole on the cam to try to stabilize the arm by putting another point of contact there.  I'm not sure how much it helped.

Anyway, I rebuilt the front end, checked the football and links, etc. etc. Same thing next round!  Now I was really confused.  I went through everything again.  The only thing I could figure was maybe I needed more preload on the side springs?  I added preload, but I'm not sure if that cured it.  This time I had also flattened out the upper arms to try to make sure it would not tip, but it was just pushy.  Bleh.

Looking back, maybe something on the steering was touching during suspension travel, as was suggested by one of my friends.  

In the final qualifier, I dropped that arm back down and added front droop. This helped but it was touchy.  Driving very easy, it was actually decent, but wanted to roll if pushed.  It was all for naught anyway as I had a crash and I popped off an upper arm.

In the main I set up the car with an Exotek upper am and Tamiya knuckle combo, mostly to ensure the front end would not break.  I didn't have enough new plastic with me to replace the front end parts.  6* caster and 1.5 camber.  Car drove ok, and I was fighting with the back end of the field until I crashed again...yay

One mistake I think I made was being wide on the suspension links.  Looking at the CRC car, the links are extremely narrow, which upon reflection of the last few weeks, may be the way to go.  I think it brings more steering to the car by allowing the rear end to work with the front end.  Being wide on the links I think that may contribute to the lifting/traction roll by limiting travel. 

Also, talking with a buddy he did bring up one interesting point among a lot of other things: a bunch of the 1/12 cars are moving the spring as far inboard as they can.  I have to look into this as far as how true it is but the theory is that it is working the spring more for the amount of pod movement.  Intriguing.

I am also looking at cutting a new front suspension plate with a hole to bolt the lower arm down with the unused hole near the  suspension ball.  Maybe this would keep the arm from moving in a crash and help with high traction stability.

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