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2015 F1 chassis design & development

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#1 JimF


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Posted 09 April 2015 - 02:21 PM

As most know, I've been off the track and off the jig since last November. Moving forward, I had to think about what I wanted to do with the various classes of cars that I build. I'm starting with the F-1 class b/c I had a pretty good idea of new direction and also, I had plenty of stuff that was really good anyway. Thus.....if my newest and brilliant-est idea was a bust.....no biggie.


Testing starts this weekend. Can Ams are being tested too but my direction is less clear there.



Starting from here.........I did articles on both these designs although the bottom is a variation.


Top car:


  • 5X .047, R-Geo bracket, pans, nosepiece. 107 gr all up.
  • This design has won on every flat track we run on except one.
  • Good basis design, reliable, not exceptionally fast in cornering speed.


Bottom Car:


  • 2 1/2 rail (all bronze) .062 tuning fork free in tubes. This is a spinoff of an an R-Geo kit design that I wrote an article on..
  • This is a bridesmaid car....has podiumed in two races with as loaner. (1 flat track, 1 speedway)
  • This car is always really good yet there was always something that I thought was a little better.
  • Probably best as a flat track car.






Then I went to this..........the "Toronto"


  • R-Geo kit with .050 nose and bracket. This one uses scratch built pans of .062. I have built several of these with slight variations. All have been very good.
  • Weight of 108 all up with body and weight on the center pans. This is flat track setup. With center pans off, ~~ 96 gr.
  • Finished cars in October, raced them once (loaning one out) to a 1,2 finish on a speedway. Excellent Speedway car. Not much time yet on flatsters.
  • I have some ideas that I've implemented in the frame shown below mostly for flat track use.




So........what do I want?...........high cornering speed of the Toronto but adapted to flat tracks.


Prototype #1 is below..........this is cobbled up from available stuff. I already know a few changes.


  • Hand made .032 nosepiece set up to left coast configuration.
  • Tuning forks are .047 each fork built in two parts. Soldered at front, flex limiter just forward of the crux.
  • .062 brass tail weights and .047 single frame rail outboard of that.
  • Pans are minimal, 2X .047. Weight 108.5 as shown with added lead.
  1. The goal was to get the weight out of the pans and get it inboard.
  2. Keep the weight rear biased and as close to the centerline as possible.
  3. Try to hit approx flat track weight of 110 gr, w/out adding lead on top. (missed on that idea)










  • Tim Neja, Bob Chaney, George Kimber and 1 other like this
Jim Fowler

#2 SlotStox#53


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Posted 09 April 2015 - 02:48 PM

Welcome back behind the jig & soldering iron Jim! Looks like a pretty sweet comeback F1 chassis :good:

#3 Pablo



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Posted 09 April 2015 - 10:01 PM

Looks like somebody is feeling a lot better :clapping: :good:

Paul Wolcott

#4 JimF


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Posted 10 April 2015 - 12:46 AM

Thanks guys and, yup.............feeling better. For four months, with all the crud that I had going on, I didn't even sit down at my bench and wasn't even the least bit interested. Then a week or so ago, I started piddling around and by now.............I have a full agenda of various chassis developments. This one was pretty clear but my Can Am plans are much less so. Hopefully, this weekend will give me some direction in that regard. I also built a new stock car and anglewinder this past week as well.


I'm getting warmed up........ :wacko2:

Jim Fowler

#5 JimF


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Posted 13 April 2015 - 11:13 AM

OK.....first track test. Tested on the twisty little 90' Korkscrew @ Motown raceway in Modesto. The track was nice and clean but a little loose. The best times that we run on this track are normally about 4.50-4.55. That was not in the cards on this day.


5 rail @ 108 gr (multiple winner here) = 4.58

Toronto @ 108, never yet raced on a flat track = 4.64

New car @ 108, = 4.67


Despite the similarities in basic concept to the Toronto, and also the similar times, the new car was noticeably different in feel. In the above configuration, the new car was notably quicker out of the corner than the Toronto. I suspected that the forks being soldered solid in front rather than in tubes would negate some of the "damping" that tuning forks seem to have on acceleration. That is what I think I felt. The new car had more "snap" off the corner. OTH, because it wasn't so snappy, the Toronto was easier to drive. I also thought that maybe some the wheel hop or chatter that some tuning forks exhibit was due to the looseness in the tubes and solid forks would mitigate this. This turned out not to be the case. With the frame as shown, it did not exhibit wheel hop. When I took the little flex limiter off, the wheel hop showed up, then when I soldered it back, it went away. It is too soon to tell whether the light pan-heavy center is good, bad or indifferent although I suspect the latter.


For first time out, the new car showed promise especially without motor and tire tuning for this specific track (the 5 rail is tuned for this track) I'm not sure that for this short track, the solid forks are any advantage although I built a new Can Am with this same basic idea and it was quite good on a speedway. The more direct power might be an advantage for an F-1 on a bigger track but for this twisty little track, the softer acceleration of the Toronto felt better.

Jim Fowler

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