41 replies to this topic

[Brian Czeiner]

BTW, I'm assuming you meant that the highest RPM motor ISN'T always the best choice??

 
Fixed it. Thanks for check.

[rmjlmartin]

Ok, I have the Goblin together and mostly ready to run. I just need to set the guide height and get the correct spacers for the axles, which I'll hopefully do Thursday evening when I go to the track.

 

I'm noticing something odd, though. On the Goblin SS (and I assume the brass Goblin, too), the motor is designed to sit down in the cutout and be flush with the bottom of the chassis, presumably for a lower center of gravity. However, that puts the motor shaft center line 3/32" lower than the rear axle center line, which I would assume is at least not ideal for a good, smooth gear mesh. It definitely doesn't mesh as smooth as my Mid America Hammer or my old Parma Womps.) It's also going to be a bit borderline for rear clearance with the .825" rear tires I was given at the track as the standard Womp rear tires.

 

I know the Goblin is a popular chassis, so I assume that there's a workaround for it, or it's just ok for something that low powered. Does anyone know anything about this or have any thoughts? I haven't been to the track yet since it's assembled, so I haven't had a chance to ask the track owner about it, but my impression was that he didn't have anyone currently running a Goblin, especially with the Womp program here suffering a bit. (which I'm hoping to help change)

 

I also decided to build a third Womp for my daughter to run, so I went ahead and ordered one of the AA chassis. I'll build it, too, and then decide whether to build the third one out of another one of those or another Goblin.

[John Streisguth]

To make the gear mesh better on hypoid motor mounts, I use a very small butane torch and apply heat to the gears for about a second while running the car on a power supply. Usually smooths it right out, although I did find some red fox gears sounded horrible no matter what I did.

 

After re-reading your post, I was surprised that clearance could be an issue with 825 tires.  But that's about how retro cars run unless they have a motor bracket that puts the motor at an angle.

[rmjlmartin]

Thanks John. I actually often do basically the same thing with a cigarette lighter, spinning the rear axle by hand. I already did it some on this, and it did help, but I was a little hesitant to really go that far, unless I was sure that it was ok and the way it's supposed to be.

 

Mainly, I've never seen an axle/motor shaft this far off center before and wanted to make sure that I wasn't going to ruin a gear or something before I went any further.

 

On the clearance, I don't have a nice gauge made up out of .047 piano wire yet, so I'm using a .050 allen wrench, and it just touches. So it should pass as it is now, though it could be a problem after a little tire wear. I'll ask the guy at the track Thursday if I get a chance, but I'm wondering if it might be ideal to lower the rear axle height slightly, which would raise the back of the chassis slightly.

[John Streisguth]

Won't be a problem, I've been running retro cars for 13 years like that

[rmjlmartin]

Well, I feel a little dumb here, but I spoke a little too soon.

Just before I saw your last comment, John, I pulled out the only inline car that I've looked closely at recently aside from the Womps, a Tony P Retro Can Am Plus...And it appears to be the same offset as the Womp. It just meshed so smoothly when I put it together that I never looked that closely at it. I don't know why there's a difference in the mesh, since they're both Cox crowns. Unless the different size gears (11/27 on the Tony P, 9/26 on the Womp) make enough difference?

 

Also, my AA chassis arrived today, so I'll probably get at least some of the parts to put it together tomorrow evening. It's definitely very sturdy. I tried fairly hard to bend it by hand, and I couldn't which is a good sign. It's very rigid, while the Goblin is a bit more flexible, so I guess I'll see how they compare.

[Bill from NH]

Not all Cox gears or their generic clones run true. It could be more than a tooth difference. Do you have spares of the same tooth size you could try swapping out to see if it makes any difference?.

[Steve Adkins]

Hi, I'm curious what people who race Womps regularly would recommend for a sturdy Womp chassis.

 

I'm getting back into slot cars with my two sons after a 20+ year absence, and we've been mostly racing Flexis, but I have nostalgic memories of racing Womps as a teenager, and the local track is running Womp races that don't get a lot of people, so I'd like to branch into that some as well.

 

I still have my old Parma and Champion Womps that I had as a teenager, and I've played with them a little, but when I have, it seems that they need to be straightened about every other time they hit anything, which people tell me is somewhat just the nature of Womps. I built myself a Womp out of the Mid America spring steel Hammer chassis, and it runs very well, but we run mostly AWRA Womp rules here, and that chassis isn't legal for the Legends or Sportsman. That isn't a problem for just the local races here, but there will be an AWRA event here in a few months, which I'm considering running in.

 

I'd also like to set up a couple more Womps for my boys to run, so I'm thinking about what chassis to use. Is there one in particular that seems to be pretty tough, if not quite as tough as the Hammer? Having the motor screw holes at 9:00 and 3:00 for the modern minican motors would be great, too, since the AWRA rules don't allow drilling them in a chassis that doesn't already have them for the Legends and Sportsman classes.

 

Thanks in advance for your advice!

[rmjlmartin]

Well, I guess I should update this again, finally.

 

After a bit of working and tinkering in spare time between races, and missing a few track days due to our family having Covid, I have both the Goblin and AA chassis built to the correct specs for Legends Womps and running pretty well.

 

I ran them a bit this evening after the regular Indy car race on the tri-oval that Womps run on here, and they both seem to run pretty close to the same lap times. The Goblin seems to be the "faster" one so far, by a whole .05 seconds using my fastest lap times. I haven't added any weight yet, so I guess I'll see how they do when I have a chance to run them some more.

 

I also haven't had a chance to run them on the King with the Sportsman bodies and motors, so there's more testing to do...

 

If anyone has any more thoughts or tips, that would be welcome. Thanks!

[smithspeedway]

LVJ chassis and component weights can be found at https://lvjchassis.w...ress.com/parts/

 

Steve

[rmjlmartin]

Just a quick update here.

 

I've had a chance to run both chassis on the King set up as Legends, and they both seem to do well. The AA is easier to keep on the track, but I can get the fastest lap times with the goblin, by a tenth or two of a second. I added a little weight behind the guide on the Goblin, and that helped with the handling a bit. I haven't had much chance to run either on the oval again.

 

I also discovered running on the King that both of them will bend, though it takes much more than with a typical Womp chassis to do it. I would say that the AA is a little tougher, but both seem to be pretty strong. of course, at almost double the weight, the AA chassis better be tough!

 

I also built the AA chassis into a Sportsman. It seems to do pretty well in the little time I've run it, though it definitely doesn't handle like my flexi! I initially put a Hawk 7 in it (actually got a decent one), and it would keep up with the 4" flexis that were also on the track down the straightaway geared 10/27. However, with that heavy of a chassis, I think it needs an Eagle with the stronger magnets, which would give it more brakes. I run my flexis (with a ProSlot 4002fk motor) with very little brakes, usually at 3-4 at the most, and my JK Indy car with them almost off, but I was cranking the brakes up to at least 6 or 7 and still not getting as much as I'd like.

 

Here are a few of my final thoughts/observations-

 

You definitely feel the weight of the AA chassis. All that weight down low make it a very stable chassis. It also slows it down a little, which you could probably compensate for with the right motor and gears.

 

The Goblin needs taller tires or adjustable oilites. The AA chassis will pass tech with .790 tires on it with a little room to spare, but the Goblin needs some a bit taller. I don't remember exactly, but I think it needed something like at least .825 to have enough ground clearance and potentially go through tires in a real hurry because there's not much margin for tire wear.

 

The Goblin also has the body pin holes further back that the AA, or any of the other Womp chassis I checked. And since the body pins pretty much have to be in the notch in the side of the body, that makes for some clearance issues for the wheels and guide on some Sportsman bodies. Maybe there's a workaround for that?

[Steve Adkins]

The Goblin SS is a great chassis. It is absolutely conventional, basically a refined Riggen 5003. It's not bulletproof, but it's pretty hard to bend. I run mine unweighted in AWRA Sportsman with an Atomic Products C200 Raptor body and a JK Hawk 7 or a H&R Crusher. I like taller tires, so there is no issue there. I am partial to ARP pinions and Koford crowns, although I would like to see Koford offer something other than a 28t crown.
 
I will be using the Goblin SS for Stock Car and Dirt Late Model as well at the AWRA WOMP Nats in Kannapolis, NC, in April 2022. 

Steve Adkins

[rmjlmartin]

Thanks Steve, I'll check out the Raptor body. I think the local track has some in stock. Is it proportioned differently than the Caveman or old Parma bodies? Those were what I was trying to mount before.

 

Also, I just looked at the AWRA rules page and noticed that only the Atomic Raptor and a couple of Outtasight bodies are listed as legal for the Sportsman class. Are the Caveman bodies that were listed earlier no longer legal?

[rmjlmartin]

I should probably clarify a couple of points from post #36.

 

I didn't mean that the Goblin handled poorly, though you could get that from the way I said it. But it did do better for me on the King with a little weight behind the guide. I did start building the Goblin into a Sportsman but switched to the AA after discovering the body mount issue. Maybe an Atomic body will fit better.

 

Also, my thoughts/observations shouldn't be taken as necessarily a criticism of either chassis, just things that stood out to me.

 

And finally, I didn't mean to say that they were my "final" thoughts. I missed that when I read back over it before posting. I'll continue to update as I continue to tinker, as long as it seems relevant to this thread.

[Brian Czeiner]

 

The Goblin also has the body pin holes further back that the AA, or any of the other Womp chassis I checked. And since the body pins pretty much have to be in the notch in the side of the body, that makes for some clearance issues for the wheels and guide on some Sportsman bodies. Maybe there's a workaround for that?

 

This same situation was brought to my attention shortly after the Goblin was approved by the AWRA. It has taken several prototypes to solve this issue. The math, the measurements and then the design required a bit of thinking. You can check the Caveman Bodeez FB page or this slotblog thread for some pics.

 

http://slotblog.net/...-something-new/

 

http://www.facebook..../?ref=bookmarks

[rmjlmartin]

Thanks Brian, I'll check them out.

[Slotracer17]

The RGeo stainless steel Goblin is hands down the best race chassis available. Weight can be added to tune handling and it is durable. It's the only chassis of it's kind and has revolutionized WOMP racing. The AWRA has a new class of WOMP racing called Legacy. It's a spec class for all the traditional WOMP chassis that all have similar handling.