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New "spec" class for flat track racing


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#1 gc4895

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Posted 24 July 2017 - 05:00 PM

We created a new (new for our track anyway) "spec" class that is very popular with experienced racers as well as new racers.  We grabbed all the JK C11 chassis that had been made obsolete by the new JK C43 chassis, stuck the new JK MB (mini brute) motors in them geared from 3 to 3.5 - 1 and covered them with the JK LMP body of your choice.  Let's go racing on the flat track!  (Actually, we know the JK C43 would be just fine for this racing as well.  Our original intention was to create a class to take advantage of equipment that most people already had but weren't currently using.  Sort of like the Champion turbo-flex class we race.)

 

This combination is EASY to drive with plenty of brakes, which means there was very little turn marshaling needed.  These are also very responsive to driver input so you can get from these cars what you put into them.  Want to just stay on and cruise?  No problem.  Want to work and set the best possible lap time each lap, go for it!  The cars are forgiving as well as responsive. 

 

After the race we all agreed that this was a very fun and exciting racing experience.  We hope this will be a way to get less experienced racers off the King track and on to gaining experience on the flat track.  We are thinking the high torque, low RPM mini-brute motors lend themselves to flat track racing by helping minimize driver input error.  These cars aren't "jumpy" and don't typically deslot due to the guide rising up out of the slot with to too much horsepower. 

 

While we highly recommend this combination, as always, YMMV!


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Mark Bauer




#2 Bill from NH

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Posted 24 July 2017 - 07:45 PM

Mark, it sounds like that's a cheap. fun class to race in. All the cars must run pretty much equal, depending upon setup. Have you been getting a good number of entrants? :)


Bill Fernald
 

How old should a highway be before you tell it, that it has been adopted?


#3 gc4895

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Posted 24 July 2017 - 10:15 PM

Yes, the cars are very, very competitive with each other. On the flat track, motors don't matter much - well, of course they matter a lot. It's just that the power has to be applied effectively and not in a way that deslots the car. That is the beauty of these MB motors. They work with you to keep the car in the slot, not against you looking for an over throttle mistake that may deslot the car. A nice balance. . It's really so interesting how these are the bottom of the food chain (almost, among JK motors ) yet the lap times of these cars are faster than anything else we are running on this track.

Among racers, the word of mouth has been so positive that a lot of racers are putting cars together. This race has become part of our monthly rotation. I'm really encouraged.
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Mark Bauer

#4 Ramcatlarry

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Posted 25 July 2017 - 04:12 PM

What is the lap length of you track and the longest straight?  Have you tested the different gear ratios enough to confirm a narrower range than 3/1 - 3/5/1?  Set a spec gear for the track and rear tire minimum>


Larry D. Kelley, MA
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#5 gc4895

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Posted 25 July 2017 - 05:09 PM

Larry,

 

Excellent questions for which I have few insightful answers.  In terms of main straight, it's exactly the length of 8 driver stations reasonably normally spaced.  Length of track, I actually knew this but I've forgotten!  I'm guessing about 120 feet, give or take a furlong or two.  Average lap times with retro F1 cars using the Mini Brute motor (from which we developed the idea to slam MB motors into a flexi chassis) is around 6.5 - 6.7 seconds/lap.  The F1's are geared 8/27 on average hence the 3+/1 ratio.  To appeal to the widest group possible we have tried to keep things as simple as possible.  The easiest gearing answer that jumped out at us was 12/36 in 64p.  This is important since the owner only carries 48 and 64p gears exclusively while shunning the very thought of 72p.  The C11 chassis is a bit constrained in terms of spur gear diameter since the bushing rides rather low in the chassis compared to other flexi chassis.  Consequently, we can't get larger than 37 without extending below the bottom of the chassis. 

 

It's quite interesting how impactful the LMP body is in taming the difficulty of the flat track.  With all that down force to tame the corners, the 3/1 gear ratio provides lots of braking and is found to be quite user friendly.  We did have a participant that tested 3.2 and 3.5 /1 gearing.  He determined there wasn't a clear favorite and optimizing gearing will, quite simply put, require someone to perform more testing.  In terms of tire sizes, etc. we don't go there at all.  Most participants try and have 1/32 rear clearance, if for no other reason, to not be dragging the chassis on the track at the end of the race.  We don't actually do or enforce any tech inspection of cars so each participant is responsible to manage their own toy cars.  Generally speaking, most participants operate within the broad guidelines of the class being raced. 


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Mark Bauer

#6 JimF

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Posted 26 July 2017 - 12:46 AM

Here is a pic of the track in question from a retro race last year. I think that I've been told that it is 135' or a bit more. These cars were fun to race and pretty close in speed. The cars were well conceived for this particular track or really for any smaller track. They would probably not have been quite as ideal on a super-speedway type layout. It was a very clean race and I think a very good start for a new class. Mark did a good job as the driving force for getting this established.

 

Motherlode F-1.jpg


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#7 Half Fast

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Posted 26 July 2017 - 11:09 AM

I am surprised that the high downforce/ high drag body doesn't cause that mild MB motor to blow.

 

 

Cheers


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The most dangerous form of ignorance is not knowing that you don't know anything!

 

 

 
 

#8 JimF

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Posted 26 July 2017 - 12:08 PM

I am surprised that the high downforce/ high drag body doesn't cause that mild MB motor to blow.

 

 

Cheers

 

I wouldn't disagree with that speculation at all. This time out, the track was pretty stuck, and a few of the cars were geared a little taller than I would have, yet........no problems, at least so far. I do think that these JK bodies are not real high downforce compared to some that are around. JK does have some that are pretty high downforce (at least higher than this one) and those should possibly be excluded from the menu. There are plenty that are like this one that are sort of.......uhhhhh......medium (tech term) in downforce.

 

DSC02916.JPG


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#9 Bill from NH

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Posted 26 July 2017 - 03:31 PM

We weekly ran JK's LMP bodies powered by Plafit Cheetahs (before Falcons were thought of) with flexi chassis 15 years ago. None of the JK bodies with the stepped rear spoiler have been high downforce. We once ran these bodies in a 4-hour endurance race using S16D motors. Those cars were quite a handfull to drive on the then 185' engleman.


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Bill Fernald
 

How old should a highway be before you tell it, that it has been adopted?


#10 JimF

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Posted 27 July 2017 - 01:18 AM

I agree, these are not really high downforce bodies. A decade or more ago myself and several very notable racers ran these bodies on a 120' Kingleman in Reno also with S-16s. That was a really fun and hard fought period in which any of 4-5 guys might win every week. We were so close that we tried everything to get an advantage. The bodies were a constant variable but not one ever really showed as the proven advantage. Races were won in successive weeks by the BMW (shown), the Audi, Toyota, Mercedes, and Porsche coupes as well as the BMW, Lola, and Audi open top cars. IMO, staying away from the latest and greatest is (IMFHO) a good way to build a program. Pick something that is good, workable, and available and stick with it.


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#11 gc4895

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Posted 27 July 2017 - 09:35 AM

Just wanted to step back and offer a little perspective in how we ended up with this combination of motor, chassis and body.  The purpose was an effort to make our under-utilized flat track more "accessible" to attract more competitors (photo of the track included by JimF, thank you!).  Our facility offers 2 tracks with the other being a swoopy King.  The King is basically the accepted "go to" track for most competitions.  The challenge was to offer a class that a) utilized equipment most racers already had; b) was easy and cheap to finish a genuinely competitive car; and c) The difficult part, make the flat track less difficult so that racers without years of experience could compete without crashing or de-slotting lap to lap.  It's this last part that has frustrated some competitors such that this wonderful flat track sits unused while we race darn near everything on the King. 
 
OK, so the chassis, C11's, was the easy choice since we are generally transitioning to C43's for races on the King.  For this class my testing found that all the race prep needed was a little body reinforcement under the bite bar and that was it - no lead, no nothing special needed. Just flatten the chassis and go.  The motor was a challenge since we generally choose from 16d, s16d and Hawk (not the sealed kind).  My observation racing on the flat track was that the motor caused most of the de-slotting issues, and the more powerful - the more problems.  [I had no interest in needing employ an army of turn marshals for each race.]  This application required a motor that offered balance between fast enough for fun (perception of speed) and slow enough that it could be controlled.  Thanks to JimF's retro program, I was introduced to the JK mini-brute.  Jim specifies these motors in his NorCal retro program for F1 cars and for excellent reason: they are plenty fast yet very balanced (user friendly), easy to control and CHEAP.  This cheap part speaks to goal "b" noted above. 
 
The bodies were a guess.  I knew I needed a balance of down-force to tame the track a bit, but not so much as to kill it.  Looking at all the options available I chose the stepped wing LMP as the best compromise.  I first tried the Red Fox (as used by Buena Park in their program) and yes, these really work!  But they seemed to crash the balance aspect of my goal with too much down-force. [Cars were "too easy" if that is possible.]  At this point JimF offered wise counsel that pointed me towards the JK LMP offerings.  These are numerous in style though seem very similar in performance for this application.  These bodies are also readily available which also helps. 
 
Bottom line here was to seek the balance of fast, fun, accessible to less experienced racers - yet not constraining more experienced racers into a dull, easy or boring race class.  So far, we seem to have accomplished much of this.  The cars have almost an IROC aspect to them in terms of one vs. the other.  But they stay slotted without the feel of a wing car.  The faster and harder you drive them, the faster they go and more slotted they stay.  They seem to offer challenge to a wide variety of experience levels.  That's pretty cool.  Thanks to all for the help in putting these pieces together! 
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#12 Gator Bob

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Posted 27 July 2017 - 10:11 AM

Using 'yesterday' chassis', low power motors and pretty bodies is a great concept.

 

Yeah I know this doesn't support the track owner as much by repurposing old stuff, just raise the entry fee a couple of bucks to help out with that part.

Everybody wins.

 

Good luck, hope it takes off big time for youz guyz.


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                            Bob Israelite

#13 JimF

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Posted 27 July 2017 - 01:21 PM

Mark:

 

Great job in putting this together. You deserve a ton of credit for getting it off the ground @ ESCW. I know that's not an easy thing to do. I just wish you ran them a little more often......... :laugh2:

 

It has occurred to me many times that the "go fast" thing is overdone. Many tracks have small or tight tracks that don't get used all that much b/c the cars are just too fast for the rank and file. Thus, they wreck all the time and the races are messy. I can think of a tiny Kingleman in Buena Park and a 90' Korkscrew in Modesto where these cars would be just great.

 

Naturally, every region and every track has a few guys that can race anything on any track. However, time and time again, I have seen slightly slower cars tighten up the field and improve the racing. It's a gross oversimplification to just say that racers "just want to go faster" Of course they do......but it's in relative terms. Racers for sure want to go faster relative to their fellow competitors. That's racing and finding that next 0.05 sec. while still staying on is the challenge. In general though, they don't necessarily want the whole field to instantly go a full second faster. Naturally, some will want that, but once even experienced racers try a slightly slower car that is still racy.....most really like it.


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