63 replies to this topic

[gascarnut]

My home track is now open for a series of "Open Days" that will be held on the first Saturday of the odd-numbered months.

We will be running both plastic and scratchbuilt cars, in a casual atmosphere with the minimum of rules to make things fun but fair. I will start a few new threads for discsuuions of proposed classes.

For those who have not been here, this is a nice fast track, easy to learn, difficult to drive fast:



Lap length is 60 feet, 3 inches. Slot depth is 5/16" and the braid recess is .005-.010"

Power is from a Pyramid PS26KX, set at 12Volts, lap timing by Trackmate.

More photos are here: PMCC

[HarV Wallbanger III]

Can't wait till we get the cars back on "Da Rock" Pebblestone... lets see... oh! This is right up Bronco Barney Alley as I drive the...

[68Caddy]

Dennis
I think you are absolutely right about, this is the right place for the Pebblestone race track for questions and other issues and I will ask couple of questions as you know it will happen sooner then later.
After putting the Merc together i noticed that the Fly truck chassis was warped, I try to straighten it out but no luck, the problem
is it got ridges under the chassis, I can't use it on a flat test block to see where the issue is?
I guess I could shave it of, not that hard but I found it a bit drastic?
Some of this plastic chassis seems to me to be warped due to the manufacturing process. I know you stated that you will tweak in your
Merc if so? What have you done so far?



Nesta

[HarV Wallbanger III]

Nesta, also talk to Tony as he said something about putting chassis in the oven (very low temp) maybe it would relax them.???? I 1/10 scale RC in the very first days of racing off-road Tamiya cars we boiled the nylon to relax the plastic parts and make it less brittle.

[68Caddy]

Thanks Barney but I will hammer it down flat with the biggest hammer I can find.


Nesta

[gascarnut]

Nesta,

If you can find a flat surface to clamp the frame down, then do that, and heat the chassis with a hairdryer or a heat gun, just enough to allow it to relax.

[gascarnut]

Here are the details for the next Open Day:

Date: Saturday, May 1, 2010
Times: Track opens at noon, closes at 7:00pm sharp (not like last time!)

Please let me know by PM or email whether you can make it or not, to facilitate catering.

Sodas and snacks will be provided, and we will take up a collection for pizza so Bryan does not have to buy it all. If you want something stronger to drink, please bring it yourself.

It would help to bring a folding table and chair too, as pit space is limited.

We will run whatever you bring, but will make sure to run some heat races for the following:

* GT and Group C cars - the Slot.it McLarens and Ferrari F40s, all the Slot.it Group C cars and whatever other NSR or other make stuff you have that fits this description.
* Open sports cars - the Slot.it Ferrari 312, Alfa T33/3, Fly Porsches and Chevrons, stuff like that.
* The Team BURT (Butt-Ugly Racing Team) race trucks will hopefully be available so we can run an IROC-style truck race.
* Tony Kuljis from Fantasy World has sent 3 Racer Ferrari 250LM cars to Barney for us to run, so we can run some IROC heats with them too.
* Whatever scratchbuilt cars are available on the day.

Basic rules for all these cars:

Tires: Silicones or urethanes (like Ortmanns) work best.
Weight: As you feel necessary.
Motors: for the plastic cars, please stick with the motors issued in the cars.

For the scratchbuilt cars, I think sensible tire sizes will be 5/8" minimum at the front and 3/4" minimum at the rear. No width limits on the individual tires, but the whole car may not be wider than 2.5" Clearances should be .015" minimum at the front and .045" minimum at the rear, including under the gear. When it comes to motors, too much power is just an embarrassment with silicone or urethane tires, so here is what I would suggest, after testing in my Shadow with both Ortmanns and with Super Tires silicones:

* TSR D3/Falcon 7: Way too much for these tires!
* Slick 7 Mini-brute/Falcon 2: A little too much power to be nicely driveable, but not completely overboard
* TSRF motor - more controllable than the S7/F2, quite nice in a heaver car, and they don't seem to worry too much about rotation direction for use in an anglewinder.
* Slot.it motors: I have run the Orange (23krpm) and Yellow (26krpm) endbell motors and they are both nice. There is also a Red endbell (29krpm) which I will try soon, it should also be good. I have not tried the Slot.it Flat-6 motors or the Boxer motor yet, but if you like lots of torque, then these might work, and they have mounting screw holes like the TSR/Falcon motors.
* NSR Shark (30krpm) this works nicely too, similar to the SLot.it motors.
* ProSlot motors: I tried the 4001, it is in the same class as the S7/F2, a little too much. I have run the 4000 version and it is nice for these cars. The chinese armatures seem to last in these cars too, probably because they are geared short and the cars are light.
* Professor Motor Fox 3: This works nicely, perhaps a little underpowered, but very controllable and smooth. Being a Mabuchi FK130 motor, it has the same mounting holes as the TSR/F7/S7 motors.
* Ninco motors: I have used mostly the NC5, which is OK in a plastic car but won't cut it in a brass car, I don't think.

For gearing, start around 3.5:1, a little less for the torquey motors, a little more for the high revvers.

As far as frames go, let's leave it completely open at this point, so if you want to run an inline, or an anglewinder, or a TSRF frame or even a JK Cheetah 11, if it will fit inside 2.5" width and have everything under the body, you can run it. I would like to see if anyone could get a Cheetah 11 to run on silicone tires though!

For bodies, let's use whatever 1/32 vacforms we can find for starters, but try to stay away from the "Eurosport"-style things with molded-in spoilers and side dams. If anyone needs bodies desperately, I have a small stash of suitable stuff, and Barney is going to bring in a selection from Betta in the UK too.

And since all this is really just for fun, please let me know if you have any other ideas or suggestions.

[HarV Wallbanger III]

Be careful Nesta.... you just want to warm it up a little not melt it like that grilled cheese ya just made! Or it will become a smoking pile of plastic! I would use a hair dryer and watch out!

[Keith Tanaka]

Dennis, I sure would like to take a few laps on your Pebblestone track but I always seem to have a Wing car race when you have one of your race days.
Hopefully, in May you'll have another day available other than our D3 race days in May (9th, 29-31st). I'll be trying to build a 1/32 car as soon as I get a body (from Barney?).

Keith

[68Caddy]

Dennis this sound great and the suggestions are very good for running some kinda class and thanks for the tip to use a heatgun but if you
look under your Merc truck you will see it has ridges so you cant make it flat?
Thanks Barney for your word of caution. Love to see Keith in this race also.


Nesta

[gascarnut]

Keith,

Thanks for the interest - I'm sure we will be able to find a time that you can come down for a trial run.

[68Caddy]

Dennis a small tutorial of truing silicon tires would be great? I did not know but Merc got lights to.


Nesta

[gascarnut]

Dennis a small tutorial of truing silicon tires would be great? I did not know but Merc got lights to.


Nesta

As a general rule, silicone tires are almost impossible to true, but they are generally quite round as they come out of their molds.

You can take off the edges by using some drywall sanding mesh or the foam-backed sanding pads, or if you are like me and you are impatient, then you can use a disposable razor to trim off the square edges, just be careful and do it slowly.

I have put Indygrips on my Hudy and run them just touching the drum for about 20 minutes or so, and they do true up a bit. With Super Tires, it takes even longer. I am going to replace the regular Hudy drum with a diamond drum at some point, it might be better.

[Bill from NH]

Dennis, what's your opinion of the solid silicone tires vs. silicone coated sponge ones? My first two years of commercial racing in the late 60s was done exclusively on solid silicones. Some worked better than others, Cox for instance, but they easily chunked. I don't recall seeing many silicone coated sponge tires in those days.

[gascarnut]

Bill,

The modern silicone tires, like the IndyGrips and Super Tires, are rather softer than the old silicones were, and do not chunk at all. They are mostly made to be put onto the 1/32 scale rims that have a central ridge to retain the tire, and as such need to stretch easily.

Silicone-coated sponge tires make a car feel much more like a foam tire car, nice and smooth and quiet, but the grip level is not always as good as the full silicones, as the coated tires are dependent on having a spreadable silicone to achieve the coating and it is difficult to get the same super-smooth surface that the molded tires have.

[68Caddy]

Thanks Dennis for clearing that up with truing silicons tires, and I guess that's the nature of silicon tires.


Nesta

[Prof. Fate]

Hi

Dennis, the change in silicone is mostly a matter of adding non-silicone "fillers" to the base material. This also makes them more "sandable" with the right materials. Some of the newer plastics cause other problems, but can be "sanded" by using the edge of a #11 as the "sander". Another good idea is gluing down the tire. With repeated use, the slip ons streach more and more and start getting off. So, if you use permatex black silicone calk or "shoe goo" you can recover the tired tire and re-true.

As for silicone coating the sponge, it is easy, you would be GREAT at it. Simply using a bit of glass with a dab of permatex black on the glass and slowly rotating against the dab on the glass, you get smooth and round. This stuff does not, on some surfaces, have the same amount of grip as some of the other compounds. Testing is everything.

Similarly, some silicones can be improved by giving them a thin coat of Permatex clear caulk which is very soft.

Fate

[68Caddy]

Dennis, I need to ask you what brands have been good runners on your track?
Looking at all my junk I might have some thing that will work well.


Nesta

[AJK]

Dennis, I need to ask you what brands have been good runners on your track?
Looking at all my junk I might have some thing that will work well.


Nesta

NSR , Race tuned Slot.it Spirit LMP, Scaleauto Toyota GT1 Do you need me to send you down a car?

[68Caddy]

OK buddy, let's see what you got that is so hot, send it down, I and the others will race it.


Nesta

[gascarnut]

Dennis, I need to ask you what brands have been good runners on your track?
Looking at all my junk I might have some thing that will work well.


Nesta

Nesta,

I guess you are talking about brands of tires, not brands of cars?

Of the silicone tires, Super Tires work best, then Slot.it S2, then Indygrips and Slot.it S1.

Of the Urethane tires, Ortmanns are best, I have not tried Yellow Dogs yet. The other urethane tires (K&D, Ultrathane, Jel Claw, etc) are all OK, but not as good as Ortmanns.

Some kit rubber works quite well too, like the NSR rubber, the new compound that Slot.it has on the Chaparral, and some Ninco rubber.

As for car brands, the only valid comparison would be for box-stock cars, and even then the price would have to be part of the comparison, so to my mind it is a pretty pointless exercise. Especially since we tend to run races with the same brand cars.

[68Caddy]

Thanks Dennis, I will bring a set of Super Tires never ran it. Question did you get your Burt truck dialed in?


Nesta

[68Caddy]

Thanks Dennis had a great day today racing with you and the usual suspects, Craig had a great scratch build one that was a rocket. Dennis your Chappy was great, I wish I had bought one.
I guess there is a race report coming up soon?


Nesta

[68Caddy]

I'm not a patient person. I guess I got to do what I want to do, post pictures.


Nesta

[gascarnut]

OK, "pebble people":

Next Open Day will be Saturday June 19th.

Same times, track opens at Noon, closes at 7:00pm.

Similar classes to last time:

• Short wheelbase cars (Slot.it Ferraris, Alfas, Chaparrals, Sloter Ferraris, Lolas, etc)
• Slot.it Group C cars (Porsches, Saubers, Jaguars, Mazdas)
• Modern GT cars (McLarens, Ferrari F40, Nissan GT390, Mosler, etc)
• Fly Racing Trucks
• Scratchbuilds

And if you have anything else you want to try, bring it along, as long as there's 3 of anything we can make a race. I have a few IROC classes we can run - Scalex New Mini Coopers, and for the really brave:



Let me know about attendance so my wife can plan the lunch - it will be something different again.