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  • #16
    Following are some photos of the completed chassis as well as preliminary test results on both my Slider (tm) oval that features 10 degrees of banking in the corners as well as my BuckTrax Banzai road course that exhibits a 48' nominal lap length. All testing was in 25 lap blocks with the track power set as 12.0 VDC. One of the new OS3 Pro controllers was used for all test runs.

    IMG_8321 by gcullan, on Flickr
    IMG_8322 by gcullan, on Flickr
    IMG_8323 by gcullan, on Flickr

    Oval testing was conducted one lane in from the outside lane. Data is presented as median lap time/best lap time pairs.

    Micro-Cuc III 1.96/1.814 (inline iso-fulcrum with a Slide Guide (tm))
    Micro-Cuc IV 1.71/1.635 (inline iso-fulcrum with guide pin and wiper pickups)
    Thurman 1.75/1.672 (center hinged anglewinder with guide pin and wiper pickups)
    GCLS 1.69/1.608 (center hinged inline with guide pin and wiper pickups)

    Discussion: All four chassis handled very well on the oval with excellent tracking and only very slight fishtailing observed on corner exit. The Thurman chassis was run with no choke and almost full throttle all the time. All other chassis were run with full available choke and a highly feathered throttle. As the motors in all the cars were essentially similar, I believe that the greatest differential in power delivery is due to the fact that the Thurman chassis has a 10 ohm resistor in series with the motor, while the other three chassis are receiving direct track power.

    Road course resting was conducted on one lane in from the outside lane. Data is presented as median lap time/best lap time pairs.

    Micro-Cuc IV 7.69/6.988
    Thurman 5.82/5.536
    GCLS 6.12/5.992

    Discussion: The Micro-Cuc III was not tested on the road course as the equipped Slide Guide (tm) flag is too wide to fit into a standard width routed slot. The road course really highlighted the differences in power deliver. The Thurman chassis was run with a slight choke setting and light brakes. Even with full choke and maximum brakes, both the Micro-Cuc IV and the GCLS were almost undriveable. High speed roll through the corners exhibited excellent handling but throttle control was way too touchy making it extremely easy to break the rear tires loose at the worst possible moment. I have 10 ohm resistors on order and will repeat this testing when the are delivered and installed in the test chassis.

    To date, the HOCOC Open Class has been run on high speed banked oval tracks. We do have one major Open Class road course event coming up this season. For that reason, the majority of my testing in the near future will be on the road course. I think I have the "oval thing" pretty much nailed down. Now I have to optimize for road course performance. And it may very well be that a chassis that is a rocket on the oval might be well off of the pace on a road course.

    I have two additional builds planned and they are in the early fabrication stage. The first will be an inline iso-fulcrum chassis that also features a center hinged central tongue. The second will be an iso-fulcrum chassis in an anglewinder/sidewinder configuration. The center tongue of this chassis may also be center hinged.

    Thanks for following along on these projects, and as always, your comments, thoughts, and suggestions are welcomed.

    Comment


    • #17
      And here are the pictures I promised . The blue car is a John Reimels built M10 powered full sidewinder . In the one race we have used it it showed excellent competitive handling but just didn't have the power to match the M20 anglewinders on the long straights of a big track . The red car is the Cuc knock off I built a couple of years ago . It is a M20 inline chassis with tapered rails and a perimeter unit based on a TJet weighted axle kit . The side weights and body mounts need some refinement but are made to be lightweight but easily removable . Drive traction was outstanding but the handling was iffy . Motor lead wires that are way too stiff and my lousy grasp of the methods for adjusting the wipers make the handling issues prominent . Still , for an untested car on it's first outing it showed some promise .

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      • #18
        Isn't there a "Standard Track" version of the Slide Guide?

        Comment


        • #19
          Yes, there is a standard track version of the Slide Guide (tm). Unfortunately, I have none.

          My resistors are supposed to be delivered today, so I will add them to the chassis and retest sometime next week.

          I am behind on guitar repairs, so I have to get cracking on them. And then there is that little matter of the 20 hours a week that I put in at Hog Heaven Hobbies. I really need at least 36, and preferably 48 hour days. Dang, supposedly retired and there is still so little time!

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          • #20
            Originally posted by gmcullan View Post
            I really need at least 36, and preferably 48 hour days. Dang, supposedly retired and there is still so little time!

            At least you can say you are doing the things you like to do, right?


            Jerry, I have a couple questions about brass chassis design.

            1. The mounting of the motor....is it screwed in from the back of the can with the screws passing through the rear bulkhead plate?
            2. Is there anything holding the front of the motor can down, or does the front of the can "float".
            3. When the wiper shoes wear out, is it just a matter of melting the solder and installing a new set back in place?
            4. What about the possibilities of the metal ever crossing over both rails at the same time. Does it cause any shorts or blow fuses? Is the metal you use all "non-conductive"? Just curious.
            5. What about the sourcing of the can motors? Are they easy to get as far as volume?


            This is really a cool build. Thanks for sharing.
            Gar


            .

            Comment


            • #21
              Gerry,

              I'll get some narrow Slide Guides in the mail to you soonest.

              What were you using for tires in your tests?

              Ed Bianchi

              Comment


              • #22
                Here goes with my first attempt at using "quotes".

                Originally posted by fastlap View Post
                At least you can say you are doing the things you like to do, right?

                Answers in Blue

                Jerry, I have a couple questions about brass chassis design.

                1. The mounting of the motor....is it screwed in from the back of the can with the screws passing through the rear bulkhead plate? Yes
                [/COLOR]
                2. Is there anything holding the front of the motor can down, or does the front of the can "float". The front of the motor floats.
                3. When the wiper shoes wear out, is it just a matter of melting the solder and installing a new set back in place? Some of my first builds have the wires soldered to the wipers. My most recent builds have the wires soldered to the wiper holders. In that case, wipers are very easy to change.

                4. What about the possibilities of the metal ever crossing over both rails at the same time. Does it cause any shorts or blow fuses? Is the metal you use all "non-conductive"? Just curious. I set up my builds so that the chassis clears the power rails by about 0.010". Pickup wipers are short enough so that if the car gets sideways that there is no shorting across the power rail/braids. To date, I've not had any issues with shorts or blown fuses/popped circuit breakers.


                5. What about the sourcing of the can motors? Are they easy to get as far as volume? I've bought a bunch of motors from China. Its been sort of hit or miss with some being dogs and others being great. The Host motors as sold by Lucky Bob's are reliable and of good quality. I've also bought motors from Al Thurman through his sales on that big bad auction site.


                This is really a cool build. Thanks for sharing.
                Gar
                Thanks for reading and commenting!


                .
                Last edited by gmcullan; 01-26-2018, 12:54 PM.

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                • #23
                  Ed, The Micro-Cucs III and IV have LandShark tires. The Thurman and GCLS chassis have Quicker Engineering tires.

                  I have a "goodie" box that I have to get down to you. Like yourself, I've been quite busy lately.

                  Comment


                  • #24
                    Gerry Cullan has, very kindly, given me a copy of his Micro-Cuc 3a car, complete with beautifully detailed body. So danged impressive, inside and out. Makes me envious it does.






                    A side view of the works, below, shows the iso-fulcrum aspect of the chassis. The motor and Slide Guide are all integrated, while the front wheels and side pans pivot from the motor mount. The iso-fulcrum concept dates back to 1966 (http://www.slotcarhistory.com/slot_car_history5.htm). The guide and side-pan assembly bounces up to absorb road shocks, allowing the guide to stay planted.



                    The construction of the side-pans, built up from brass wire, is shown below. Note that the front axle is soldered between elements of the side-pans. Also shown here are two lead sheets Gerry added to lower the center of gravity of the car. I don't know whether Gerry soldered* them or glued them in.



                    More detail of the front end is visible here. Also a third lead sheet between the front axle and the motor. The O-Ring front tires are also evident here. Body mounting tubes are soldered on top of the side-pans.



                    'Nother coupla shots of the chassis...





                    At present I don't have a track set up to actually run this car. Maybe in a week or so. In the meantime its a sweet, jewel-like example of Gerry's fabricating skill, to admire in detail.

                    Ed Bianchi

                    * Little known fact. It is possible to solder lead sheets into a chassis because the melting temperature of lead-tin solder is much lower than that of lead itself. It's surprising, but an alloy of lead and tin (solder) has a lower melting temperature than either pure lead or pure tin.

                    From fctsolder.com:

                    "The words eutectic solder describe a solder alloy that melts and freezes at one single temperature. A good example of this is Tin 63% / Lead 37% solder which melts and freezes at 183 C. This melting point is much lower than the melting points of either pure metal which are 232 C (tin) and 327 C (lead)."
                    Last edited by HO RacePro; 02-18-2018, 08:35 AM.

                    Comment


                    • #25
                      The lead sheeting is self-adhesive and is available from Lucky Bob's.

                      Many thanks to Ed for the kind words.

                      Comment


                      • #26
                        You can buy lead sheeting from McMaster Carr -- without adhesive -- in thicknesses from 3/64" up to 1".

                        https://www.mcmaster.com/#lead/=1bqqvbj

                        If you want to go heavier yet, try tungsten. It is 1.7 times more dense than lead.

                        https://www.eaglealloys.com/tungsten...RoC-UUQAvD_BwE

                        I have no idea what it costs. I'm afraid to ask!

                        Ed Bianchi

                        Comment


                        • #27
                          GCLS/O and GCLS/R

                          I currently have two versions of my GCLS chassis running. The /O is optimized for banked oval racing while the /R is optimized for flat road course racing.

                          The differences between them is the weight distribution, gearing (8/15 for the /O and 7/22 for the /R), and the /R variation uses 0/005" thinner piano wire for the wire flex elements.

                          In the following photos, the /O is on the left and the /R is on the right.

                          IMG_8362 by gcullan, on Flickr
                          IMG_8363 by gcullan, on Flickr
                          IMG_8364 by gcullan, on Flickr
                          IMG_8365 by gcullan, on Flickr
                          IMG_8366 by gcullan, on Flickr

                          As anticipated, the /R version is quicker on my Banzai BuckTrax. Lap times will be reported in my Controllability thread.

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                          • #28
                            Oh, and as I'm sure that many an eye have picked this out, repurposed LandShark pans and motor/axle boxes were used for these builds. Many thanks to Al Thurman and LandShark for the availability of these components.

                            Comment


                            • #29
                              I want to get this down before I forget the exact number...

                              The official lap record on my 4 x 12 foot banked oval is now 1.532 seconds.

                              It was achieved by a car that Gerry Cullan sent to me back in February (see above), before I had my tracks set up in the basement of my new home, in York Pennsylvania. Said car has been sitting on my desk all this time, waiting for its moment of glory.

                              When I took it out on the track this afternoon it looked fast, which was expected. But when I did a quick check of my TrikTrax lap counter/timer, I was shocked to see I was turning laps in the 1.700 plus range. With a little bit of concentration I could see with quick glances that I was pushing it into the 1.600 second range. Then the 1.500 second range!

                              Between quick looks at the lap timer I had trouble cutting consistent laps. If I was too aggressive the car would deslot rather than spin out. With a little discipline I think I could turn 1.700 plus second laps all day. Maybe even 1.600 plus. One-and-a-half second laps as a race pace? Maybe, with a speck of magic.

                              The car could probably benefit from a bit more weight in front. I may experiment with that later.

                              Let's take a look at that machine...





                              Note that this is not a direct-drive car. It has an N20 can motor mounted inline through a conventional gearset. Unlike some of Gerry's inline cars this one did not have excessive torque that would cause wheelspin or pop-up deslots. The motor is superbly matched to the chassis. But like a direct-drive car it could be floored through the corners -- though you had to ease on the throttle, not punch it.

                              The primary feature of this car is its ultra-low center of gravity. Gerry supplemented the soldered-up brass frame with strategically placed lead weights. The chassis has a drop-arm mounting a Slide Guide -- also lead weighted. The front wheels are ball-bearings with O-ring tires. The rears are sponge-silicones.

                              Gerry claims all he has been doing is re-creating chassis design features that have proven successful in 1/32nd and 1/24th scales. And I suppose that is literally true. A lot of that has been made possible by the new generation of micro-motors. Still, Gerry is the man who pulled those design concepts together and made them perform spectacularly in HO scale.

                              Will this challenge go unanswered?

                              Oh, come on...

                              Ed Bianchi
                              Last edited by HO RacePro; 11-27-2018, 02:08 PM.

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                              • #30
                                Ed, it's good to hear that you achieved such low lap times. It will only get better once you completely break the glaze from the sili-foam tires.


                                You know, it's been so long that I'd forgotten that I sent that car down to you.. I can't wait to see what comes out of your workshop, as I know you will not leave the Micro-Cuc III unanswered.

                                OK, soldering irons at ten paces: one, two, three, four, …………...
                                Last edited by gmcullan; 11-27-2018, 02:45 PM.

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