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A somewhat different Can-Am - track test update


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#1 JimF

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Posted 04 September 2015 - 10:30 PM

Along with the 1/32 frames, I’ve also built this new Can-Am. This is probably not exactly revolutionary, but it is pretty different than anything I’ve done so far. While I sort of invented the 1/32s as I went along, this was visualized from the start to accomplish a few specific things.

 

The experimental Can-Am that I dubbed the X-1 has remained my fastest Can-Am since I built it. However, although it has positives regarding cornering speeds, it also had a few challenges that I’ve discovered as I’ve gone along. Primary among these is the fact that it can develop some frame twist over the length of a run. I can set it up with all four corners touching down properly and evenly, only to find at the end of a race, one front corner is lifted. This can mean that the car can sometimes develop odd handling habits at unpredictable times. I’ve re-jigged it and relaxed all four corners and that mitigates the problem to an extent, but it still shows up.

 

The positives of the X-1 are a lot of torsional flex that enables the cornering speed and I also think the corner weighting is, in general, a good idea. This frame was thought out to include some of the attributes of the X-1 and also utilize some features of a more conventional multi-rail frame.

 

What it is:

  • Five .047" rails with two parallel rails inboard and three triangulated rails outboard.
  • All brass in the nose areas and the rear corners = .032".
  • Pans are four .062" rods.
  • Forward of the intersection, this has similar twist flex as a four .047" straight rails.
  • However, this has more longitudinal and torsional stiffness right at the bracket face.
  • Can vary the stiffness by reducing the parallel rails or the triangulated rails as needed.

 

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  • Cheater, MSwiss, macman and 2 others like this
Jim Fowler




#2 macman

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Posted 05 September 2015 - 12:56 AM

Interesting, is that a 3/4 motor bracket, or 1"?


Ben Kernan
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#3 JimF

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Posted 05 September 2015 - 01:41 AM

Interesting, is that a 3/4 motor bracket, or 1"?

 

That is a 3/4" R-Geo bracket. In addition to a narrow bracket, the first inside rail is set as narrow as possible without interfering with the motor. The idea being that "X" number of rails on a narrower center will be more flexible in twist than the same number of rails on a wider center. The goal here was more twist flex (more bite) but a more solid rear portion for more stability and perhaps less danger of the dreaded wheel hop (chatter).


Jim Fowler

#4 Dominator

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Posted 05 September 2015 - 07:57 AM

LooKs like with having slightly more flex on the front of the car it should work good on a flat track.

A motor is only as fast as the chassis it's in.
 
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#5 Eddie Fleming

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Posted 05 September 2015 - 08:22 AM

I like that much. Let us know how it works.


Eddie Fleming

#6 JimF

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Posted 05 September 2015 - 09:17 AM

LooKs like with having slightly more flex on the front of the car it should work good on a flat track.

 

Very perceptive thinking. That's exactly why I did it.

 

I have built a couple of very simple and fairly light tripods lately and while both were very good on a King with a lot of banking, neither was especially great on a very flat King that has a lot of bite. The tripod stiffens the frame ahead of the intersection while this has the opposite effect of stiffening it behind the intersection.

 

Of course.......no idea how it'll work.


Jim Fowler

#7 JimF

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Posted 24 September 2015 - 01:53 AM

I've had this new Can Am on track on two different tracks so far and it is about what I hoped it would be. The pics below show the new one in between two others with a lot of time on them. The goal was to get a frame with high torsional flex for higher cornering speeds than the conventional 5 rail (right) but a little more forgiving than the X-1 (left).

 

In testing on the flattish King at Slot Car Raceway in Rohnert Park Ca., this new frame did about as intended. The testing was done right before our last race on 9-20-15 and the conditions were a mix of hooked up really well and spotty and weird depending upon lane. All three cars were set up as shown here and with a Parma Lola T163.

 

X-1:

  • Fastest of the three with a practice best of 5.01 sec, avg in the high 5.0s. but just a little touchy.
  • Lightest car @ 96 gr.
  • Best motor of the lot.
  • This car practiced well but traffic, going from hooked up lanes to not etc. made it a little unforgiving.
  • Ended up racing this one and it turned out well but in retrospect, probably should've run the new one.

 

New Car:

  • Second fastest with a practice best of 5.08 and avg practice times in the mid 5.1's
  • Medium light @103
  • Good motor.
  • Felt easier to drive at 5.10 than the X-1 did and similar cornering speed.
  • Probably with the top motor on board this would have been as good as X-1 and easier to race.
  • X-1 is still my fastest car (I think) but this one is close and (I think) going to cover more bases.
  • Next is to take a stab at a little more flex (maybe 4X .047 or a herd of .039)

 

5 Rail:

  • Third fastest at 5.21 best but could average mid 5.2s that easily.
  • Medium light @ 104
  • Good motor
  • With center weight in place, easy to drive.
  • With center weight out....great on some lanes but way tippy in the grippy spots.
  • This car was just in between this time out.
  • This car has been my all arounder but I think that will now go to the new one and this one will get rear weight tabs and become a flat track specialist.

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Edited by JimF, 24 September 2015 - 11:01 AM.
Added bottom view and deleted duplicate pic.

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Jim Fowler

#8 Dominator

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Posted 24 September 2015 - 07:07 AM

Sweet!

A motor is only as fast as the chassis it's in.
 
Dominic Luongo

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