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CMF3 1237-series design and build progression

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#51 Rick Moore

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Posted 20 July 2017 - 11:40 AM



A lot has happened over the course of the 1237-series progression to get to this point. The quick overview of the CanAm class chassis would be:


- The 1237-series are characteristically superior to previous 1219-series designs; some component structures of the 1219-series are not advantageous/necessary in the 1237-series.

- Framing in 0.032” wire has become the norm (for all classes).

- The 1237’s and 1245’s are the elemental core designs within the series.

- Design and structural modifications on the 1241 (ex 1244 design mods) negated subsequent designs/builds (1246 - 1249).


The next step would be to structurally combine the 1237 and 1245 designs with the same dynamic functionality as the 1241, and hopefully incorporating all the positive attributes of those designs. Yeah.


And that design is the 1250. This one was doodled out some time ago, shortly after the 1241-Cc3, with constant revisions right up into the build itself…


On the 1250 the basic center main rail and buttress rails of the 1237 are retained; the front axle rails of the 1241 are redesigned appearing as the buttress rails were on the 1245, but with the required structural modifications.


Nothing to it…


Of course, I’d be sticking to the all-familiar “c” dimensions for first-build baseline comparisons.


And the 1250-Cc3 looks like:















Initial calculations and guesses indicated the completed car without any pans would wind up about 96.5 grams; so two 0.025” semi-static brass pans were added adjacent to the central main rail. And, of course, a sissy bar was added after mounting the first body. When it all was done the RTR car came out to 100.0 grams… not bad for a WAG… better to be lucky than good… works for me…


Considering how well the 1241’s run, especially after the results of the 1241-Cc3’s last race outing, this design had its work cut out for it before it ever got on the track…


Test run:


Wednesday evening test & tune, Fast Eddie’s Raceway on the Hillclimb…


Still sorting through the “test” motors… After a second motor change on the 1241-Cc3 (the first being put in the “for later use” pile, the second dumped among the “ugh-slow” motors), I got two motors that were pretty much equal, so the comparison was better than usual with less guess-timation (and found a third equal pony in the 1245-Cc2…).


(Also still playing around with controllers, but that’s another story…)


The “feel” driving the 1250-Cc3 was every bit as good as the 1241-Cc3; smooth, predictable, consistent, and fast. The 1250-Cc3 was quicker on Orange, quite an accomplishment as the 1241-Cc3 has been the quickest since it got built. On Black, the 1241-Cc3 has been fastest (along with the 1245’s), and was at best about 0.02 s faster than the 1250-Cc3. On Red, where the 1237’s have tended to be best, the 1250-Cc3 ran an all-time best lap (with a test motor), but still only about 0.02 s faster than the 1241-Cc3.


Not sure how the 1250-Cc3 is more characteristically similar to the 1237’s than the 1245’s, or the 1241-Cc3 more like the 1245’s than the 1237’s, which is intuitively backwards, but there it is nonetheless… Have to think about that some more…


Anyway, on the gutter lanes they balance out, but averaged across all lanes the 1250-Cc3 was “faster” than the 1241-Cc3. “Better” is more subjective, but the 1250-Cc3 is every bit “as good” as the 1241-Cc3. From this initial run I’d say any further decisions as to car of choice between these two cars would have to be made in race trim. But, of course, more testing to come…


Not bad… A bit confusing, but not bad…


I think I’m starting to have fun with this slot car thing…


Rick / CMF3

#52 Rick Moore

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Posted 09 August 2017 - 10:57 PM



I wanted to have another CanAm-Plus class car to go along with the 1237-Cb3+, just because I wanted to have another one... or something like that… It was coming down to either a 1241 or 1250 version, but since with the CanAm class cars the 1250-Cc3 was more like the 1237’s characteristically, and similarly the 1241’s were more like the 1245’s, I decided a CanAm-Plus version of the 1241 might give a different option over the previous CA+ class 1237… or something like that…


So, with smaller fronts and without the dynamic pans on its CA sister, this is the CA+ class 1241-Cc3+:













The RTR 1241-Cc3+ weighs 94.9 grams; that’s 6.1 grams less than the CanAm sister 1241-Cc3, but 4.7 grams more than the previous other CanAm-Plus class build, the more structurally minimalistic and 0.125” shorter 1237-Cb3+. I have no problem with the greater mass for this class car, since the 1241-Cc3+ was less of a test of relative mass the 1237-Cb3 had been in concept, and more a test of the applicability of certain chassis dynamics between classes (which had been successfully explored between the 1241-Cc3 and its other sister build, the Stock Car class 1241-D3o, but for slightly different reasons than what might have been expected…). That, and I also wanted to see the fit of the “c”-dimensioned chassis under the Gulf-Mirage body.


Test Run:


Forced to do another evening of testing at Fast Eddie’s… Just terrible, right?


So the real question was would the CA-Plus 1241 and 1237 versions show the same relative differences in characteristics as the CanAm versions, the 1237 being better on the upper-gutter/Red lanes and the 1241 better on the lower-gutter/Black…


No. These lighter stripped-down CA+ versions seem to be better all-around cars across all lanes. If anything the relative gutter-lane characteristics of these two CA+ chassis may be reversed with their respective CA counterparts, but, at least after these first comparative test runs, that would be marginally. I will give a first-outing nod to the 1241-Cc3+ being a bit more consistent, and, though it had what should have been the slower motor, could turn fast laps one right after another; but more tests are in order as track condition (slightly loose) may have been a contributing factor.




Got to try the new Parma ’69 Charger stock car body on the 1241-D3o. Not sure if it’s any faster than the Cyclone, but I love the way it looks… looks fast just sitting there... sweet.


Still playing around with the old moly-graphite RF guides versus the new nylon RF guides; still, no noticeable improvement in lap times or drivability on any chassis thus far. Your results may vary…


And, just to put this out there, despite a much steeper learning curve, and just getting my finger used to it, my “go-to” controller has become the ProModel PMCR, over the S&K which had bettered my Difalco HD30. That’s a tough one to call, as all of these are great controllers, and it really comes down to that subjective what feels “right” in your hand running your car. While the availability and overall price of the ProModel will be a deal breaker for some, which I fully understand (I just got one to try because I couldn’t find anyone who had one… curiosity killed the tax return…), my $0.02 is the ProModel is one killer tuning tool to have in your slot box (or boxes… who are we trying to kid…).


That’s all folks!


Rick / CMF3

#53 Rick Moore

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Posted 25 September 2017 - 01:18 PM

Racing Update:


For all you competition freaks, the latest fix...




(Honestly, I’d love to be able to get to other races at other raceways, not just in GRRR but other regions, to try these 1237-series cars out “under fire”, and for the fun of it, but at this point, especially after the beating my personal finances took for the better part of a dozen years or so back-when, I’m just not willing to give up my weekend work schedule at the hospital, where I also get the weekend and graveyard shift differentials; besides that, the occasional weekday shift openings that do come along are more important to some of my coworkers who are younger and need a little more normalcy, raising families… Anyway…)


A little R&R was needed from work, and what better way than to take the weekend off so I could participate in the GRRR races at Fast Eddie’s Raceway on Sunday September 24.


Let me preface this post, talking about motors. I have found that bench testing of the HR motors is all well and good, but at this point I am largely convinced you don’t know squat until you start trying them in different cars. Sure, bench testing helps to get them in some sort of order to start track testing, but after that it really doesn’t mean much… Some of my fastest “track” motors are ones that were in the mediocre “bench” motors, and vice versa… And just because one motor works “great” in one chassis/car does not necessarily mean it will be equally “great” in another chassis/car… While it is nice to know there are more options available than initially thought, it is a lot more work in the long run… I don’t know, maybe it’s just me… Your results may vary…


Anyway, this is what I got pre-race testing:


For the Stock Car class, to be run on the Oval, I had been testing my two left-turn-only retro stocker chassis, the 1237-D2o and 1241-D3o. The 1237-D2o had won its maiden race in this class, the previous GRRR stock car race at Fast Eddie’s back in January, and with subsequent set-ups was running faster and better; the 1241-D3o was easily as fast, and with a few set-ups a little faster. I was leaning toward the 1241-D3o right up until Saturday evening, after the FSCS races, when I ran some practice laps with both cars again, and changed my mind when I made the gut-call that I could turn more race laps with the 1237-D2o…


For the CanAm class race car I had been concentrating on testing six cars, the 1237-Cc3, 1237-Cb3, 1245-Cc2, 1241-Cc3, 1241-Cb3, and 1250-Cc3. The benchmark had been set by the 1241-Cc3 at the last GRRR CanAm race in June at Fast Eddie’s, setting new qualifying (4.538) and total race laps (291) records for the class on the Hillclimb (including the GRRR races when the track was in Jacksonville); it was my first car in the 4.5’s, so the idea was to get other cars with set-ups in that range. In test trim (virtually always slower than race trim) I was able to get the 1237-Cc3, and 1237-Cb3 into the 4.63 - 4.60 range, which was pretty good (would have been “great” back in January, but after June…); the 1245-Cc2 and 1241-Cb3 got in the 4.59 - 4.56 range; and the 1241-Cc3 and 1250-Cc3 could run 4.54 - 4.50, which also confirmed the qualifying run in June wasn’t some fluke “hare lap”. It really came down to the 1241-Cc3 and 1250-Cc3; both are easy to drive, and drive fast, and both are capable of running the gutters in the low 4.6’s. The Wednesday before the race I got them into semi-race trim, and it was still a close call between the two, whether on Orange, Red, or Black; but the 1241-Cc3 was just a hundredth or two faster on all, and a little more consistent. Finally the 1241-Cc3 ran a 4.492 on Orange (my first 4.4-anything), so it got the nod as my CanAm class race car again, while keeping the 1250-Cc3 ready as my back-up car.


For the “IMSA” race on the Hillclimb (a combo-class race running CanAm Plus and GT Coupe at the same time), since I’d run the weighted-up 1237-Cc2 in GTC back in January (2nd place), I wanted to run one of the two CA+ cars I’d built since then for this race. If I had not built the 1241-Cc3+ for this class I would have had no problem running the 1237-Cb3+ for this race, but it may never get that chance now; I found a set-up (again, with a “mediocre test motor”…) on the 1241-Cc3+ that was running consistent low 4.5’s with ease, and after it ran a set of 4.50X’s I took it off the track (instead of pushing it to see if I could squeak out a 4.4-something), made my notes, and put it back in the box for this race.


(Here’s a FYI side-bar for all us slot car geeks who like to stash away little tidbits of info in our little noggins: For the GRRR races in August and September of 2016 I used my Difalco Genesis HD30 controller, and this year in January and June I used my S&K controller; for these races I would be using my ProModel PMCR ICE Compressor 2 controller (or as I like to call it, my “curiosity killed the tax return controller”). I’d spent about a month after the June race trying to “come to grips” with the ProModel, and doing comparison testing with the S&K; after that I was using the ProModel exclusively…)


Being only two weeks post-hurricane Irma, we were wondering how turn-out would be for the GRRR races. H-Irma had also postponed the last FSCS races, also to be held at Fast Eddie’s, and were rescheduled for Saturday, the day before the GRRR races on Sunday…


Oh yeah, I was holding the drawing for the CMF3 1237-Cc3 United Mitochondrial Disease Foundation (UMDF) Fundraiser Slot Car too.


Race Day:


The UMDF 1237-Cc3 drawing was held before the races started. Congratulations to the winner, Bryan Warmack!


Turnout, as was thought it might be, was a good bit lower than previous GRRR events at Fast Eddie’s…


As for the races:


First was Stock Cars on the Oval; six entries, no qualifying. Jeff Bonanno and I were literally running side-by-side and trading the lead all the way into the sixth heat! In the end I got a lead over Jeff, and the 1237-D2o finished 1st, setting a new lap record (2 min heats) of 254 laps. (In fact, the first five cars all beat the previous lap total record, set by the same 1237-D2o at the last race of 242, and all five also ran higher lap averages than the prior 3-minute heat race in 2016!)


Next up was CanAm on the Hillclimb; nine entries. The 1241-Cc3 qualified first, running the only sub-4.60 lap at 4.568 despite the driver doing a pretty lousy job. Another good race, this time fighting for the lead with Roger Whobrey, who drove a great race finishing second with a lap total of 291 (tying the record I set at the last race), but again I was able to get the 1241-Cc3 to pull ahead, winning the race with a new CanAm class total lap record for the track of 295.


The final race of the day, on the Hillclimb, was the “IMSA” race for GT Coupe and CanAm-Plus; six entries (four GTC and 2 CA+), no qualifying. The 1241-Cc3+ was able to show exactly what a good CA+ car should do racing against the much heavier GTC’s, finishing first in class and overall, while setting an outright retro lap total record for the Hillclimb of 298 laps, ten laps ahead of the second place overall / first place GTC of Roger Whobrey (another good drive, his 288 tying the lap record for GTC).


So, for these three chassis:

1237-D2o - 2 races; 2 wins (2 lap total records)

1241-Cc3 - 2 races; 2 top qualifiers (class qualifying record), 2 wins (2 lap total records)

1241-Cc3+ - 1 race; 1 win (1 lap total record)


Not bad…




All-in-all a fun day. Never enough thanks: to Grant Goerner for all his effort and time keeping the GRRR series humming along: to Ed Hoffman (and Elaine) for giving me and the other FL Left-Coast slot car geeks a great place to play with our cars; and to the volunteer turn-marshals! And it’s always great to see all the other slot car geek “kids” at the races (even the “grumpy ones”, LOL).


As for how “good” these weird wire contraptions of mine are compared to other scratchbuilds… well… I’ll let y’all be the judge of that… My subjective view is I’m happy with ‘em, and having ton o’ fun at that.


Happy and fun is what it’s all about…


Later, kids!


Rick / CMF3




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#54 Bill from NH

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Posted 25 September 2017 - 05:52 PM

Not many others can say they run & win with something they built. :)  It's a third dimension of the hobby.

Bill Fernald

My wife says I don't pay enough attention to her, or something like that.  :unknw:

#55 Rick Moore

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Posted 26 October 2017 - 10:11 AM



Before setting off into the next set of new chassis designs (consider that a warning), I had one more iteration of the previous builds to consider…


Yep, another 1241 CanAm class chassis. Since I’ve got a pretty good understanding of the 1241s’ chassis characteristics, and with the original 1241-Cc3 posting up some TQ’s, wins, and lap records (and doing this despite the driver being “average” at best), I figured I’d be foolish not to use this design to explore one more dimensional variation that I’ve wanted to revisit for some time... So, since I already had the 1241-Cc3 and the 1241-Cb3, it was time to make a 1241-Cd3…


Some designs/builds and time ago, I had explored a single design, the 1229, with multiple builds using different dimensions: wheelbase (WB); rear axle to guide pivot center (RAX-GPC); and the resulting front axle to guide pivot center or guide lead (GL). This yielded the 1229-Ca2, 1229-Cb2, 1229-Cc2, and 1229-Cd2.


Those 1229’s, as their designations (“2”) indicate, were all built using 0.039” wire. The 1241’s are all 0.032” wire framed chassis.


Though not to say there were not tracks and conditions when the 1229-Ca2 or 1229-Cb2 could be the best choice, the 1229-Cc2 and the 1229-Cd2 were my “go to” chassis at that time. Also, the 1229-Cd2 had been one of the quicker and more consistent test platforms of all the 1229’s on the Hillclimb at Fast Eddie’s back when I started this thread and was first testing the 1237-series chassis…


So, the question is: Would the 1241-Cd3 have the same relative handling/driving characteristics in the 1241’s as the 1229-Cd2 had among the 1229’s…


For reference, here’s the ID and dimensional differences (no, not all of them), listed longer to shorter, in inches, as WB / RAX-GPC / GL:


a =   4.000 / 5.000 / 1.000

e =   3.875 / 5.000 / 1.125

c =   3.875 / 4.875 / 1.000

d =   3.750 / 4.875 / 1.125

b =   3.750 / 4.750 / 1.000 …


I haven’t built any “long” chassis (WB > 3.875”) since the 1229’s, when I was making the switch from 0.047” to 0.039” wire framing, and further exploring 0.032” wire framing; I had learned on the 1225-Ca3 it was prudent to limit the relative lengths of structures within the chassis when building frames using smaller wire…


Anyway, this 1241 “d-dimensioned” car I’ve been wanting to build would have the same RAX-GPC as the 1241-Cc3, the same WB as the 1241-Cb3, and yielding an atypically longer GL than both…


…making the 1241-Cd3, not surprisingly, look like this:















The sharp-eyed (which rules out most of us overgrown slot car kids) will notice the previously noted not-so-usual longer guide lead on this one. Also visible, the 1241-Cd3 has shorter side pans and longer front wings than the 1241-Cc3 (however the main rail and buttress rails are the same lengths). Other than that, the 1241-Cd3 looks just like the 1241-Cc3. (and 1241-Cb3)... Side-by-side-by-side:


1241-Cc3 (left); 1241-Cd3 (center); 1241-Cb3 (right)





And, like the 1241-Cc3, I figured the 1241-Cd3 would not need any added lead for the you-know-what rule. The RTR car came out to 100.4 grams.


Test Run:


First motor I put in the 1241-Cd3 was lacking brakes, but I noticed it was handling this rather well. The next motor was a mediocre one with good brakes from another car that 1241-Cd3 was able to crank out laps about 0.05 s faster. This was getting interesting… so I made one more motor change…


On Orange and Blue lanes the 1241-Cd3 was every bit as fast as the 1241-Cc3 and 1250-Cc3, running 4.5’s; and though 0.03 and 0.01 seconds slower than their best laps respectively, the 1241-Cd3 was turning fast laps more consistently. On the gutter lanes, Black and Red, the 1241-Cd3 was outright faster than either the 1250-Cc3 or 1241-Cc3 (both of which can run low 4.6’s on the gutters), turning sub-4.60 laps… the first any of my cars have run on the gutters… and only a couple of hundredths slower than the 1241-Cd3 ran on Orange and Blue… this is definitely getting interesting…


So, the answer is: Yes.


Okay, that ties up that loose end… at least for the time being… with the time being it’s time for more testing… and it is time to move on to the next design and build…


Hey, I warned you a long, long time ago this post could go on interminably to the point you’d be bored into a coma, and/or additional chassis posts may warrant additional medication… might be time for a real big dose… if you have any extra, please share…


Rick / CMF3

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#56 Rick Moore

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Posted 16 November 2017 - 11:42 AM



Moving on…


In the case of this design, the 1251, testing relative to the 1250-Cc3 and the 1241-Cc3 had prompted curiosity into further exploration of the design and incorporation of the front axle rails (FAR’s) within the basic 1237-series chassis design… which on the 1251 are quadrangular structures with no direct attachment to the buttress rails or main rail…


That’s the abridged version… let’s keep it like that, before I get to typically typing too much…


The 1251-Cc3 is still 0.032” wire framed (“3”), and keeps the generally favored 3.875/4.875/1.00” dimensions (“c”) for comparison purposes.


In any case, the 1251-Cc3 comes out like this:



















With the 1251 there is no adjustable bite bar, just as there wasn’t on the 1250, or 1245’s (if at any time it is deemed warranted it can be reengineered into the design). Of note, the 1251’s dynamic pans are suspended within but not attached to the FAR’s; had to get them in there somehow for that ding-darn 100-gram minimum thing…


In actuality, after getting all the runny bits on and the body mounted along with the “sissy bar”, the RTR for the 1251-Cc3 is 101.7 grams…


I realized during the build that the 1251 is a prime candidate for building another “d-dimensioned” car, something I might have to consider in the future, depending on…


For all intents and purposes, the 1251 is a slightly redesigned 1241. But it was a redesign that had to be done before venturing any further. However that redesign was enough to make the build more, for lack of a better word, involved. So, to warrant its creation, and any further creations and variations, the 1251 cannot be “as good” as the 1241’s, it needs to be “better”… and that is quite a tall order. But with slot car chassis you just never know until you build it and get it out for a…


Test run:


Another evening at Fast Eddie’s Raceway, testing and tuning… Yeah, it’s a dirty job, but someone’s gotta do it…


I did a lot of motor swapping this time out, comparing the different chassis/cars with various but the same ponies. This made for a jumble of info. Even before I got it all sorted out it was apparent the 1251-Cc3 was every bit as good as the 1241-Cc3; fast, predictable, and easy to drive. But so are the 1241-Cd3 and 1250-Cc3, both of which rather unexpectedly showed faster times with some of the motor/gear/tire combinations. The 1250-Cc3 was just outrunning everything last night, and in one set-up even cranked out an easy sub-4.50 s lap that was faster than the 1241-Cc3’s best and only other sub-4.50 s lap (4.481 vs 4.492 respectively), which I would not have expected with the track conditions…




Anyway, as it currently sits the 1251-Cc3 would have to be considered a “failure”, due to it being more involved to build than the 1241’s, even though it is easily one of my four fastest chassis/cars. The 1251 needed to be “better” than the 1241’s…


But, until last night, I was pretty much thinking the 1250-Cc3 was also a “failure”, since it too had yet to prove “better” than the 1241-Cc3…


More testing to come, of course…


As I said, you just never know…


In the meantime, what to build next…


Rick / CMF3

#57 Rick Moore

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Posted 13 December 2017 - 10:06 PM



The F1’s in this progression sort of got stuck on the back burner… actually, more like they got put in deep-freeze… There were no F1 races scheduled at Fast Eddie’s Raceway in the 2017 GRRR series, and with my work schedule (some of you may recall I’m one of those freaks who works the weekends shooting x-rays at a big hospital…) it was highly unlikely I’d get to any other FL raceways to run the F1 races, or any other races at all, that were scheduled.


But this design had to be built regardless. There just wasn’t any rush to do so. Since I hadn’t built an F1 for a while, this seemed like as good of a time as any…


The A218-e3 is, for all consideration, the A216-e3 redesigned to incorporate what I’d learned on the 1241 CanAm design and builds. Basically, the A216 had the front axle rails lateral to the buttress rails, while the A218 has these components swapping positions with the front axle rails medial to the buttress rails. The A218 is again built to “e” dimensions so as to build it using the “3” designated 0.032” wire framing.


So the A218-e3 looks, not too surprisingly, like this:















Of note, the A218-e3 now has the Parma 1060B McLaren M7 body mounted, as opposed to the Parma 1038B Matra MS80 body used on the A214-c2, A215-c2, A216-e2, and A216-e3. One result in this change of body is the A218-e3 has a relatively longer reinforced front fork to fit the larger and more forward placed M7’s front wings. (I could’ve put a M7 on the A216-e3 for better testing comparison, but I already have a good idea how the chassis structural changes would manifest, and if this was the case there was little sense using up a body on the A216-e3; if things proved different, I could always put an M7 on it too.) While framing the chassis out, and aware of the M7 lexan lid for this car, I decided to build up and shape the front tines so they would fit snugly under the front wings of the McLaren body; like this:







The thought (term used loosely) was that it might take better advantage of any downforce afforded by the body front wings and apply it more directly to the chassis front and guide… with the afterthought that it probably won’t matter diddly, but it was fun making it, and I think it looks kind of cool anyway.


The RTR car came out to 99.6 grams; to make the (derogatory term omitted) F1 class minimum 100-gram weight, a small piece of the dreaded lead was added to bring it up to 100.0 grams.


Test Run:


Short test session. Pretty easy to call this one. The A218-e3 easily ran the flat-out fastest laps of any of my F1’s on the Hillclimb at Fast Eddie’s, on orange, black, and red. It wasn’t even close. I left the car in its “out of the box” set-up; didn’t play with tires, motor, gearing, nuttin’; I just got lazy; however, I did finally get to play around with the ProModel controller, something I hadn’t gotten ‘round-2-it with the F1’s since getting it this year, and things only got better… Sure, the body might have some to do with it, but not near all of it… More testing is in order on the A218-e3, most certainly, working on the set-ups… But, for a first run, not bad.


Besides, I’m already building the next chassis…


Rick / CMF3

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#58 Rick Moore

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Posted 20 December 2017 - 09:33 PM



Here we go again...


Holy cow! It’s the 1244!


This asymmetric retro Stock Car chassis design has been lurking around for some time, mostly as a lot of scribbles and doodles in the notebooks. The 1244 has probably gone through more adaptations, variations, and incarnations than any chassis design of mine to date, even more than the original 1237 design. However, while doodling around on the 1244 all that time there would be a lot of design and construction ideas that would contribute to and find their way into other designs and builds, like the 1245’s, 1241’s, 1250, and 1251… It also contributed heavily to the 1252, another asymmetric LTO stock car chassis design that is currently residing in the same scratchbuilding purgatory where the 1244 had been lurking for so long…


Okay, let’s do this… finally…


As I said before, the 1244-D3o is an asymmetric retro Stock Car chassis design, solely for oval track racing, a left-turn only (LTO), hence the “o” at the end of its alphanumeric moniker. By asymmetric I mean the left side and the right side framing aren’t the same; in the case of the 1244 the left side is basically a 1241 design, while the right side is a 1250 design. If I had built the 1244 way back when, prior to the 1241 and 1250, that would have been a lot harder to explain, so let’s just leave it at that.


As with the 1241-D3o, I framed the 1244-D3o out in 0.032” wire.


The 1244-D3o:





















On the 1244-D3o the pans, not surprisingly, appear just as they do on the 1241-D3o on the left-side; while the right-side looks like a stock car version of a 1250, it is devoid of pans (well, except the static rear pans, but they don’t count). Out-of-the-box the 1244-D3o RTR car came out to 115.4 grams… yeah, I know about the 120-g minimum weight thing...


Both previous 1237-series oval retro stock cars were under 120 grams out-of-the-box; the 1237-D2o at 119.3 grams, and 1241-D3o at 118.1 grams. Their current race configurations with added lead ballast are 129.5 grams and 124.5 grams respectively. By all observation these RTR weights would be considered “light” for this class…


The 1241-D3o, besides proving a 0.032” wire-framed retro stock car chassis was viable, showed me that overall mass is not as important as chassis dynamics, even with these relatively big honker stockers; I was genuinely surprised and pleased how much lead I could take back off… So I saw no reason not to continue in this direction.


Similarly the 1244-D3o will start out at its OOTB RTR weight, and with testing and tuning a more regulation acceptable final mass should be achieved… Granted, there is 4.6 grams to go before this thing hits the 120-min. I figure if I tacked on six to ten grams on the last two cars for that LTO bias, this one should be no sweat. As on the previous chassis, I precut a bunch of lead to fit the left side pans on the 1244-D3o, so this will be easily accomplished, using various mass distributions and totals, so we’ll see where the final weighted RTR comes out… subject to change, of course…


Test run:


Wednesday evening, Fast Eddie’s Raceway, on the Oval… life (with slot cars) is good…


Keeping in mind the 1237-D2o won both of the races it has been entered in, and the 1241-D3o is just as fast, I was real curious to see how the 1244-D3o would stack up.


Out of the box it was immediately obvious the 1244 was going to be fast; an added 0.010” change of guide depth, and it was already handling better (maybe “easier” would be the correct term) and faster than both the 1237-D2o and 1241-D3o. Trying to keep the total weight as low as possible I added a minimum of lead to the left side pan, front wing, and the forward portion of the semi-static pan, bringing the weight to 119.7 grams, just under the class 120-g minimum; the 1244-D3o ran laps faster than any previous fast laps turned either in practice or in a race…


I have no intention of adding any more lead until this car would go into race trim, and then only enough to make it 120.0 grams, no more. It doesn’t need it.


Honestly, I did not expect a Stock Car this light to work anywhere near this well. Shows you how much I know… and I keep asking myself…


So, exactly WHY did I put off building this thing for so long?


Rick / CMF3

#59 Rick Moore

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Posted 03 January 2018 - 10:34 AM



GT Coupes… yeah, well…


Here’s the thing about GTC’s: typically if I want to run in the GTC class I take a CanAm chassis and slap on enough lead, a lot of lead, to make the 110-gram minimum. A description of my general attitude in regard to adding lead to a chassis would involve derogatory declaratives with profuse profanity. My current inventory of GTC’s consists of the 1237-Cc2 and the 1121-Cc4, and, as noted, with a boat-load of ballast added to them.


Some years back I built the 1229-Ca, the last chassis I built using 0.047” wire for the framing, as the 1229’s were meant to be 0.039” wire framed chassis from the onset (and would lead to the first successful 0.032” wire framed chassis as well). I built the 0.047” wire 1229-Ca to be a purpose-built GTC car. It came out RTR at 110.5 grams (not needing any added lead), and it worked very well… but still not as well as its 0.039” wire CanAm sisters…


Well, I figured it was about time to try to make another purpose-built GTC again, now that I’m neck-deep in the 1237-series. My original thought was to do similarly as had been done on the 1229, and just build one of the 1237-series designs using a larger, in this case 0.039”, wire. But while looking at my left-turn-only 1237-series Stock Cars and the left-side pans on those cars I figured I could do that on both sides of a CanAm chassis design/build, still frame using 0.032" wire, and get a lot closer to the 110 grams…


I opted for the successful 1241 design for this GTC project, for obvious reasons… However, for this GTC version I decided to build it using “d” dimensions (instead of the usual “c”) for two reasons:

1) The “d” dimensions would make the addition of the extra pans relatively easier;

2) I had noticed previously that the heavier mass-added GTC’s tended to exhibit greater drop-off in performance, relative to their lighter CanAm versions and counterparts, moving towards the gutter (Red/Black) lanes; testing has shown the 1241-Cd3 to be the CanAm chassis that exhibits the least amount of drop-off in lap times from center to gutter lanes (and, on the Hillclimb here, on Red and Black lanes the outright fastest lap times for CanAm class); my hope was to get this better performance on the gutters with this GTC.


So, the panned-up 1241a-Cd3 came out like this:















Lots of pans. Anyway, besides the usual 0.010” brass sheet rear flanking static pans forward of the rear wheel-wells, a small wire was added between the lateral and medial (motor box) rear axle upright wires to frame this space completely at the rear to add another 0.010” brass sheet static pan to each side; 0.010” brass sheet static pans were also placed inside the side pan rails and front wings. The pans between the side pan rails and the buttress rails are semi-static 0.032” wire-framed 0.010” brass sheet. And, just like on the CanAm versions, the pans between the buttress rails and the center main rail are dynamic 0.024” wire-framed 0.010” brass sheet.


With all the requisite runny bits, sissy bar, and Parma Lola T-70 Coupe mounted up, the total mass came out to 109.9 grams…


Close enough. Not bad for a WAG of an idea. At this point I don’t see any need to make up for the 0.1 gram deficit. When this thing goes into race trim at some pre-race time in the future I’ll make up any difference to tech it at 110.0 grams.


Test run… or maybe not…


Nope. Not this week. The only thing crappier than the weather is the cold I have which seems to be stubbornly insistent that I cough up one or both of my lungs… an experience I see no reason to share with the general population (well, with some individual exclusions, of course…), instead deeming it more prudent to burrow deep within the domicile during this period of crappiness… perhaps I’ll do some slot car chassis building… ya think…


…cough… cough… cough, cough…


Rick / CMF3

#60 Pablo



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Posted 03 January 2018 - 11:40 AM

"A description of my general attitude in regard to adding lead to a chassis would involve derogatory declaratives with profuse profanity."


Concur. Only one thing stupider than having to meet a weight minimum in a wing car -

and that's having to meet a weight minimum in a class designed to promote scratchbuilding.


Bunky says "it's to keep complexity minimized and costs down"




That's why he still lives in a trailer with his mom and gets food stamps

Paul Wolcott

#61 Rick Moore

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Posted 03 January 2018 - 12:19 PM

Mr. Pablo! Kind of worries me someone who builds high quality beautiful chassis looking at my “yeah, that’ll work” builds… Hope I don’t embarrass you guys too much…


Maybe Bunky’s right… Sometimes, like now, I wish I lived with a mom* that could bring me some chicken soup… ( * any mom… for pete’s sake, any women I’d be dating would be in the grandma age range… gives me the willies just thinkin’ ‘bout it…)


With the possible exception of LTO chassis, I’ve always considered any addition of lead to a chassis, especially those to correct handling deficiencies, to be an outright failure of that chassis’ design and construction. The end result of a chassis design and build should yield the mass that is what that chassis is… if it is too light or too heavy you’re going to find out…


As for class racing minimum weight rules… well… yeah… can’t say I’m a proponent… But, just like I said before about the chassis, it is what it is… and it doesn’t make much sense peeing in the sandbox if you’re going to play there…


Hey, if you think these wire things have been weird so far, wait’ll you see the next ones! Scary thought, hunh?


Now, if you’ll excuse me, I have to pick up my left lung off the floor and put it back…


And Joey says “…”


Rick / CMF3

#62 Pablo



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Posted 03 January 2018 - 03:59 PM

Joey farted? Yup, I knew he'd agree with us :laugh2:

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Paul Wolcott

#63 Rick Moore

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Posted Yesterday, 10:45 AM



Everybody run for cover…


For those of you who thought that so far the 1237-series was worse than having dental work without the benefit of an anesthetic, the next set of designs will probably make electric-shock therapy seem like a reasonable solution to your mental anguish…


With a skip over the 1252 and 1253 designs…


The 1254 is the first major deviation of the original 1237-series design; the 1254 has a redesigned rear assembly (which includes the motor box, rear axle tube and supports, adjunct motor bracket, and the flanking static side pans forward of the rear wheel wells). In a nut shell, or is that nut case, the forward aspects of the rear assembly have been angled to extend the point of convergence further forward, and additional structural rails have been added between that point and the medial and lateral rear axle tube support rails; this shortens the already relatively short length of the basic “c” and “d” -dimensioned 1237-type central main rail from the previous 2” to about 1.25” on the 1254, which is quite a bit relatively speaking. However the basic 1237-type front assembly (guide mount and front wings), and side pans remain the same, with the exception the buttress rails have been moved just a little more laterally, because…


In actuality the 1254 was back-designed from what would become the 1255/1256 designs… With the changes in the design and the construction, I decided it would be prudent to sort things out with the 1254 before diving in completely… which turned out to be a good decision…


And some of the more attentive out there (I feel your pain…) might have noticed another addition to the already convoluted alphanumeric identification system I use, in this case the “.2” after the “1254”… All apologies, but this was becoming necessary for my own benefit, as, beyond the hyphenated suffix already used for myriad variations (for class/drive type, dimensions, and size of wire framing), there are now additional varieties of design elements that can be incorporated into any base design (variants based on the 1237, 1241, 1250, 1251, on and on…) and the possibilities were becoming so numerous as to warrant an additional numeral, letter, or combination thereof, to designate the “version” of the design…


Which for this 1254 build, the “.2” designates it is a 1241-variant; for the usual inter-chassis comparison reason I’m starting with the “c” dimensions, and, as with all chassis now, it is a “3” or 0.032”-wire framed chassis…


See, I told you electric-shock would start to sound like a viable option…


The 1254.2-Cc3:















That wasn’t so bad… well… maybe not yet…


No bite bar on this one. My best WAG was this would still need the dynamic pans between the shorter main rail and more laterally located buttress rails to help get it close to that 100-gram thing… Joey farted again… or maybe that was me…


As it is the RTR car came out to 100.4 grams… you gotta love it when a WAG ain’t as bad as it could’ve been…


Test Runs:


Wednesday! Wednesday! Test & Tune Wednesday! Fast Eddie’s Raceway! Wednesday! Wednesday! Be there!


1241a-Cd3 (GT Coupe)


Leftover from the previous build’s post. While the 1241a-Cd3 GTC would of course be compared to the other two lead-added CanAm/GTC’s, more importantly it would be compared to the 1241-Cd3 CanAm sister car; that, and there are some target GTC performance numbers I’m looking for…


As a GTC, the panned-up 1241a-Cd3 is better than the leaded-up 1237-Cc2 or 1121-Cc4 CanAm’s-turned-GTC’s. This didn’t surprise me. I didn’t get the chance this time to run the gutters, but judging from the better handling characteristics I saw on this first test run, it should be even better on Red and Black.


But, when the 1241a-Cd3 GTC is compared versus the 1241-Cd3 CanAm, there is no comparison. It is still a 110-gram car, and that extra 10 grams does absolutely nothing beneficial.


1254.2-Cc3 (CanAm)


The primary comparison needed to be versus the 1241-Cc3, since the 1254.2-Cc3 is largely a 1241 with the redesigned rear assembly. As long as the 1254 with the new rear is as good as the 1241, then it is okay to proceed with the 1255 build; if it creates any adverse characteristics, that will need to be sorted out; if it is better, that would be more than acceptable…


As it was, it ran just as well as the 1241-Cc3 in this first test session. As it is, that means it’s a green light for the 1255.


Sidebar; Motor stuff


That would be “stuff” by the George Carlin definition.


Following the threads and posts “discussing” the variations in JK-HR motors has been interesting… kind of like watching some internet video of close-ups of people popping pimples or cutting cysts and squeezing all the gook out kind of interesting, but interesting nonetheless…


My current stable of active chassis designs/builds/cars include ten CanAm’s, two CanAm Plus, three GTC’s, three F1’s, and three Stock Cars; that’s twenty-one motors right there… and when you add in…


Do I have a “motor program”? Well, kind of…


Do I have a boat load of motors? Well, probably more than many… and less than some…


Do I care about any of the hyperbolic folderol going on about motors? Well, not really… sort of gave up caring… if I ever did…


Some folks take themselves way too seriously… Comments to be considered accordingly…


I mean, we’re talking toy cars here… silly little hobby… that a few of us happen to enjoy very much… fun, yeah, but still not all that important in the grand scheme of life, the universe, and everything…


Besides, I can always use more test motors… Might as well start building more chassis…


Have some fun yourselves…


Rick / CMF3

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