Crossroads

[daufderh]

Huh... that's was weird, tried to make the same post 3 times and it didn't work. Seems okay now.

Here's another quick update:

I have two of the three lanes working pretty well in both directions, but its car dependent. My SG+ F1s run great as do the Wizards I've put on the track.

I have a couple of the original MegaG Audi's and they run but REALLY slow. That is, with the throttle at full speed they basically crawl around the track. They don't stop/get stuck, but its not racing. This is at 21v and all 4 behave the same way.

I also have a BSRT G3 that stops about every foot or two around the entire track. The G3 has power when it stops. It just seems to get stuck. The downforce on the G3 is easily the highest of all the cars by far. I did notice the guide pin had some MDF dust on it, but the guide slot itself seemed basically clean (at least there's no build up in the slot). The pin on the G3 seems about the same length as the other cars I ran and I'd be shocked if I somehow routed the guide slot too shallow. If anything it's probably a lot deeper than need be. The G3 is also the car that pretty much ran on every track I've built. So this one is a big surprise.

Last I have some Tyco 4x4's (I think). They're two pickup trucks that I love. These didn't drive well either and they also had MDF dust on the guide. These guys have those stupid guides that are long (not pins) and rotate around with the slot.

I'm not sure what any of this means, just reporting what I see in the hopes somebody has an ah ha moment. I'm probably going to finish off laying the rail on the third lane then resume working on getting all the cars running.

[daufderh]

<deleted>

[RichD]

It sounds like you have removed the tin plating in a few places, that would not be the end of the world, however copper reacts with carbon dioxide in the air to form a waxy substance that does not conduct electricity. If you do not use your track often the coating will be a problem. Running your cars a lot will keep the coating from building up and having a little Inox on the braid will help to keep it from forming.

[HO RacePro]

The tin plating on braid is very thin. You really don't want to sand it off. That said, braid on very old tracks does lose its tin plating through wear, but that does not cause issues, because the underlying copper is still pretty corrosion-resistant. Regular running will keep it in good condition.

I might suggest, instead of sandpaper, you use lightly dampened Scotch-Brite in locations where you're having trouble with glue. It is mildly abrasive, but not as much as sandpaper.

DO NOT use steel wool! Steel wool will leave an infinite number of small steel fines behind, which your cars will be collecting forever on their magnets!

Ed Bianchi

[daufderh]

Progress report:

I went through the working direction slowly and sure enough the SG+ stopped dead. So I went through the same cleaning routine, lightly wet the track with a sponge and used a putty knife and my finger nail to try and clean it up. I then drove over it inox on the shoes. Although it seemed like more "glue" came up, I actually made the track worse in that I once again couldn't get through the full turn in either direction.

So the next thing I did is take a very find sand paper (220 grade maybe) and very lightly went over the track section. Poof... Now I'm having trouble staying on the track around the hair pin in both directions.

I am thinking of putting this sand paper on a car (cleaner car) and driving it around the track. I recall doing this on my plastic track and it worked great. Is this a "safe" thing to do on the braid? Walking the track there's a small section that isn't shiny, instead its more a gold color. I suspect when I laid the braid I was too rough/aggressive trying to clean it up and scraped the coating off the braid. I certainly don't want to do that around the entire track...

Thoughts?

[HO RacePro]

Deane, apparently you don't know that braid on hard pickups was a 'speed secret' in the early days. And it might still be today if it hadn't been outlawed.

You also apparently missed that the original Aurora Super II had braid on its hard pickups. (Poorly executed however, as noted in my Car Model review article on the Super II.)

Less understandable is you forgot my prototype magnet car had wire pickups, which worked just fine, thank you, on the rails of Gerry Cullan's Buck Track.

And didn't you notice that the Scalextric HO cars used braid instead of hard pickups?

The problem with braid and wire on hard pickups is it can get scrambled in a spinout. But if you use a Slide Guide (or one of the many 3D printed copies) that problem goes away. In a spinout the braid/wire doesn't get dragged sideways.

HO remains alone in its use of hard pickups for a very good reason. It is inferior to braid and wire. We're stuck with it for the same reason we're stuck with the QWERTY keyboard. It is so ingrained that better solutions can't get a foothold.

Ed Bianchi

[NicoRosberg.]

Since pickups will produce a more reliable race on an HO track with conventional rail, they are not inferior technology in that application.

The vast majority of HO tracks have rail, ergo.....

Braid does have some plus points. Much, much easier to spec when making your own cottage industry chassis is a big one.

I believe the ultimate would be a hung pickup shoe/braid hybrid. Something to experiment with?

[HO RacePro]

It should be noted that hard pickups are a really inferior technology. Stranded wire or braid works much better, simply because they offer more points of contact. Only HO uses hard pickups, and only because of a (bad!) design decision made over 50 years ago. Ask anyone who runs 1/32nd or 1/24th if they would trade in their braids for hard pickups.

Hard pickups can work very well on braid, once a track has been properly 'run in'. The adjustment can be touchy, but then it is ALWAYS touchy with hard pickups. The good news is that, once hard pickups are properly adjusted, running on braid, they will last pert' near forever. Braid does not cut grooves in hard pickups the way rails do. Hard pickups run on braid get polished, but hardly wear at all.

Ed Bianchi

PS - I used to race 1/32nd sprint cars on a commercial oval track. I discovered that unraveling the braid into separate strands gave me superior pickup, but the strands wore out faster. I ended up running braid on one side of the guide shoe and wire strands on the other. Have you noticed that braid wears out faster on one side of the guide shoe than the other? It is due to electrical effects similar to electroplating. I used braid on the high-wear side of the shoe, to get adequate life, while I used wire strands on the low-wear side for their better performance.

[JimDouglasJr]

Damp sponge might also be leaving a thin film of glue behind. Keep cleaning. Keep running.

[model murdering]

Generally, I dont see glue as a directionally dependent foible, but Lord knows I've been wrong before.

IMHO, the condition you describe is a very fractional "unparallelism" between the pick ups and the track contacts; an under-bite if you will. I see it all the time with braided scratchbuilds on my vintage L&J. Sorta the polar opposite of you're conditions. Please bear with me.

On a railed track, typically vintage sectional, if the rail height exceeds the available pick up travel; the shoe is pinned against the chassis. It'll make a skkkkkkkkkkkkk sound and the car will scrub off some speed. It's a fairly rare occurrence, who's frequency increases in combination with lowering ride heights, and pick up shoe window restriction.

Consider the antithesis of the aforementioned condition. The same can be said about the opposite direction of the pick up travel too. If the shoe bottoms out prematurely on travel, and the rail/braid is fractionally low; the current flow is interrupted. When flipped around in the opposite direction, the shoe with the compromised travel is on the high rail/braid, and the shoe with more travel is on the lower rail/braid.

Sight unseen, and the fact that the condition is directional; I'm leaning more towards a set-up issue. Try a less sporty platform, where the pick ups have sufficient bite beyond the front tire profile, and see what you get.


I love a good puzzle! Good Luck!


Bill




Edit: Let the car die in the area in question, in the problem direction. Hold the throttle and push gently on one side or the other until it wakes up. Then check the pick up geometry/travel of that side.

[daufderh]

Missed RichD's last post. I take it back about wondering why its only one direction. I'll also try going slower in the direction that works and see what happens.

[daufderh]

I only have a single 1/32 car, but its got no wheels. I use it as a prototype car for the SRMS. So that's a no go.

Sponge is definitely damp not wet. I started out very light and never really did much more as things got better pretty quick between everything I did.

Short of the braid shoes, I'll just do what I've already done again and see what happens. It still seems really strange to me that now its only one direction.

[HO RacePro]

One other thing you can try. If you have a 1/43rd or 1/32nd car that uses braids for pickups, you can run that on your track to help clean the braids. Don't expect it to clean off much glue, but if there is still a thin film in spots this should help.

If you routed 1/8 inch wide slots you'll have no trouble running large-scale cars on your track. If you routed 1/16 inch wide slots you'll need to cut down the width of your guide.

And please, if you are using a sponge to clean glue off your braids, just have it damp, not wet. If it is too wet you risk dissolving the glue underneath the braid.

Ed Bianchi

[RichD]

If your pickup shoes are making poor contact in a particular spot you can still get through it without stalling if you are going fast enough. You might have to slow more in one direction or possibly there is still a little glue on the braid in that spot. In one direction you may catch the glue but not in the other direction.

[daufderh]

I'm not doubting what you're saying here, but why would one direction work basically flawlessly (all be it at high speed) and the other direction has issues. Same car, same shoes, just a different direction and different speed.