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  • gmcullan
    started a topic Fabrication ADHD Continues

    Fabrication ADHD Continues

    The Micro-Cuc III (inline iso-fulcrum chassis with Slide Guide (tm)) and the Micro-Cuc IV (inline iso-fulcrum chassis with a conventional guide pin and wiper pickups) have proven to be reliable, fast, good handling chassis. But looking forward, I had plans (thoughts?) for a Micro-Cuc V that would feature an inline iso-fulcrum chassis with a center hinged central section that would feature a conventional guide pin and wiper pickups.

    Before I get too deep into this discussion and present photos, I'd like to give a shout-out for Al Thurman and his Landshark series of components. These components present all sorts of opportunities to experiment with different configurations and construction methods.

    My design/construction method can best be described as Ready, Fire, Aim; repeat as needed. One of the great things about soldered brass construction is that if you don't like your results, you can easily disassemble and reconfigure/refrabricate your components. This scenario was what I went through with the Micro-Cuc V. However, what I ended up with yesterday after all the brass cooled down definitely was not a Micro-Cuc V! I think I will call it the GCLS I, as I have a feeling I will me making additional variations of this chassis.

    Somehow, everything assembled itself on my jig as a center hinged inline chassis that not only features controlled movement in the roll axis, but also controlled flex in the pitch axis. Following are some photos of this resulting chassis. There is one interesting detail in its construction that I will not call out. I'm interested if anyone can catch it and identify it. Besides the center hinge feature which is new to me, I have my built in pocket at the base of the motor box. This makes a handy-dandy location for the weight that I like to add under the rear axle.

    The following photos were taken just after I finished construction. Since the photos where taken, I've cleaned up some of the solder joints and have run the chassis through my vibratory tumbler with crushed walnut shell media. Last evening I was able to appropriate insulate the front of the chassis and install the pickup wiper holders. By the way, I use Zap Goo for that and it works very well in retaining the holders. Later today I will make my lead ballast weights as well as install the running gear. I hope to be able run some test laps if not by this afternoon, certainly by tomorrow afternoon.

    Without further ado, here are the photos:

    IMG_8320 by gcullan, on Flickr
    IMG_8319 by gcullan, on Flickr
    IMG_8318 by gcullan, on Flickr
    IMG_8317 by gcullan, on Flickr
    IMG_8314 by gcullan, on Flickr
    Last edited by gmcullan; 01-24-2018, 09:45 AM.

  • HO RacePro
    replied
    It is not brass, it is steel. But I don't know if it is piano wire. The issue may be with the copper ring-tongue terminal rather than the hinge pin.

    Regardless, the handling issue is the big problem here. I have another idea how to achieve the pivot, and one that may be able to stand up to hard hits.

    One other concern is I may be running out of motor. I'm not sure if I solve the handling issues I will still have enough speed. Which is surprising, because my direct drive cars have always seemed to have insane speed on tap.

    I'm going to try again. Right? I mean, was that ever in doubt?

    Ed Bianchi

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  • gmcullan
    replied
    Ed, is the hinge post brass or piano wire? If piano wire, it shouldn't be bending that easily on you.

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  • HO RacePro
    replied
    I made a big effort last week, fabricating a new version of a Rattler chassis with the idea of shipping it to my friends at HOCOC in Massachusetts and having it run by proxy in the unlimited gravity car race on Sunday December 2nd.

    Short version, it came up short.

    Not to say it wasn't an improvement on the Rattler Mark 2, at least in terms of lap times. It was a tenth to two-tenths of a second faster, but that wasn't fast enough to be competitive with Gerry Cullan's new cars. Worse, the chassis had an unpredictable habit of desloting. I could not seem to find a driving style that would keep it out of trouble.

    Still worse, the front of the car, designed to pivot on banked curves, proved to be too easy to bend in a crash. So I just decided to put it in my collection of experimental cars that didn't make the grade.

    Not entirely a waste, mind you. Now I know something else that doesn't quite work.

    So yes, back to the drawing board. I have a few ideas how to make improvements. There is another race on Sunday the 9th. If I get lucky I could have a car ready for that run.

    Ed Bianchi


    The front sub-chassis, designed to pivot on the banking. Includes ball-bearing front wheels, which will mount O-ring tires. Note that a ring-tongue terminal has been used to mount the rod that will be part of the hinge that will allow the front sub-chassis to pivot in the 'roll' direction.



    The rest of the chassis, wider than a Rattler Mark 2, with a central hinge tube for the front sub-chassis, and a lead rattle-plate on each side of the chassis.



    The assembled chassis seen from above.



    The assembled chassis seen from underneath.

    Last edited by HO RacePro; 12-03-2018, 01:05 PM.

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  • HO RacePro
    replied
    Actually I was thinking, assuming there might be more than one driver willing to run the car, that the ride be awarded based on a qualifying run. Say, a three-minute run on one lane. Whoever scores the most laps and segments gets to race the car.

    Or, if there are enough folks in attendance, allow different drivers run the car in different heats.

    I would nominate you to be my pit crew -- making sure the car receives whatever attention it needs to remain on performance.

    And of course I will remain the shadowy figure in the background, confidently awaiting the news of my triumph while stroking a white kitty-cat.

    Ed Bianchi

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  • gmcullan
    replied
    Ed, I'll have to admit that I had quite the chuckle reading your response. While your unavailability to attend races sucks, could I be so bold as to suggest Al or possibly Eric as proxy drivers for your forthcoming creation? We are running Open Class this coming Sunday (12/2) here at Juniper Raceway and then we have the bigger show coming up at LenJet on 12/9.


    The Juniper Raceway Open Class will run on the Slider (tm) Oval. The LenJet race will run on the world famous Parma road course. Certainly different requirements between the two tracks.

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  • HO RacePro
    replied
    Yes Gerry, you hold the lap record by proxy.

    Which means your fabulous car plus MY legendary driving skills nailed it.

    And it means I'm back conjuring up slotcar magic in my dungeon workshop.

    I may need to offer a ride to another HOCOC driver for the open class competition next month. I'm not sure I'll be able to attend either event.

    And that sucks.

    But it may give a member who is a better driver than a fabricator a chance to show their stuff.

    Ed Bianchi

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  • gmcullan
    replied
    Ed, I forgot to ask. Does this mean that by proxy I now hold the lap record on your oval?

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  • gmcullan
    replied
    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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  • HO RacePro
    replied
    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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  • gmcullan
    replied
    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.

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  • gmcullan
    replied
    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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  • HO RacePro
    replied
    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

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

    Many thanks to Ed for the kind words.

    Leave a comment:


  • HO RacePro
    replied
    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.

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