178 replies to this topic

[Bigdogbro1]

Hey Rob:

I''m not a track builder but I have raced on a track similar to the first picture in post #74 above, and I thought it was really a great design.  It had everything, plenty of high speed given the straights connected by the banking, then some nice tight turns for driving, all connected by some short straights perfect for passing.  I'm not sure why you said you may not be able "pull it off to match the others" but I'm sure Steve or Mike could help you there.  The only downside to a track with no true cross-overs is that the lane length is very asymmetric but everyone has to run every lane so it all evens out in the end.

 

I don't know if you have the room but I would make the lanes on 4" centers so you could run 1/24 scale cars too.  Obviously you will need to have enough room to get a turn marshal in the "slot" but if you can put a little bit of banking on the turn under the bank you might get away with only 1 or 2 turn marshals (for the flat turns) which is always a bonus.  Hope this helps a bit!

Hi Jay,

 

I appreciate your feedback on the two track layouts.  I am warming up to the large turn layout for several of your reasons and a few on fabrication work.  I want a track that has more speed than road course turns.  Although the first track above has a slightly shorter front and back straight-aways at 12.3ft than the second track at 14.5ft it likely has a higher overall speed due to the large end turn.  I can live with that due to basement space and walkout slider door placement.  I may make the layout a foot or so wider towards the top (back basement wall) to allow for more marshall space on the inner turn and maybe make that inner turn a bit larger radius as well from a 6" to a 8" or 10".   Currently I think I'll go with a braided track opposed to copper tape due to current capacity.  But final decision I'm on the fence yet.

 

Regarding the unequal lane lengths....I am aware of all that and good with it. 

The top layout large curve track is outer lane is 78.3ft

The inner lane 72.8ft

 

The lower layout small curves track is outer lane is 75.4ft

The inner lane 69.9ft

Both layouts have a 5.5ft outer/inner lane difference.

 

I will be using Race Coordinator software with embedded lane sensors and lane power relays, four 30v/10A adjustable bench power supplies for the race control and heat races.  I am sticking with only 1/32 scale cars due to the space available.  They are large enough for the grandkids to handle and have a large enough quality selection of speed parts, chassis types, motors, gearing, tires etc. for my taste and friends to compete if they desire.  

 

If I get brave and bank (15 degree max) any turns it would most likely be the first track and the two nested turns on the left.  The large radius turn would be a two piece with a joint block mid turn and I'll need feedback from Steve or Mike if that is okay to do that without smoothness issues.

 

If anyone has any comments or thoughts, please feel free to kick me or pat me on the back.  That's why I'm here posting my plans.

 

Thank you all for your support.

[Bigdogbro1]

I tweeked the large corner layout.  I opened up the center walk space to 18" width from 12" for better marshall access and the inner nested turn inside slot radius is now 14.5".  I think it's about done unless anyone has comments they would like to add on it.

 

961.5" outer lane slot length (80.125ft)

895.5" inner lane slot length (74.625ft)

66" difference (5.5ft)

10.5ft wide

19.75ft long

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[Paul Menkens]

Why not put a donut on the end of the back leg for variety?

[Rob Voska]

If running foam tires 3 LH turns and 1 RH turns will wear tires uneven.  

[MSwiss]

My King track bank is 3 pieces with 2 tongue & groove connectors.

 

The top pic is the view looking down on the joint where the banking maxes out, which is 33 degrees.

 

You can see that there isn't any smoothness issues, nor should there be, because the tongue & groove is installed while the track is still flat, before it is pulled.

 

The fact that you asked makes me wonder if you fully understand how you are going to bank the track.

 

If you are planning on the track being 122" wide, you have to cut your outer circle wider than a 61" radius.

 

Depending on how much wider you make it, you'll be pulling it in X amount, to create the dishing, and then trimming off pie shaped pieces to get you back down to 180 degrees, to squarely meet up with the straightaways.

 

Make sure you have made your pie slice marks on the track while you have your compass pivot point still in place.

 

IOW, before you cut off the inner piece.

 

 

[Bigdogbro1]

Why not put a donut on the end of the back leg for variety?

Hi Paul,

Can you offer a picture to explain.

[Bigdogbro1]

My King track bank is 3 pieces with 2 tongue & groove connectors.

 

The top pic is the view looking down on the joint where the banking maxes out, which is 33 degrees.

 

You can see that there isn't any smoothness issues, nor should there be, because the tongue & groove is installed while the track is still flat, before it is pulled.

 

The fact that you asked makes me wonder if you fully understand how you are going to bank the track.

 

If you are planning on the track being 122" wide, you have to cut your outer circle wider than a 61" radius.

 

Depending on how much wider you make it, you'll be pulling it in X amount, to create the dishing, and then trimming off pie shaped pieces to get you back down to 180 degrees, to squarely meet up with the straightaways.

 

Make sure you have made your pie slice marks on the track while you have your compass pivot point still in place.

 

IOW, before you cut off the inner piece.

 

20240529_211624.jpg

 

20240531_123026.jpg

Hi Mike,

 

Thanks!   I do understand that the radii need to be larger by X amount to do a bank turn.  Thought both the inner and outer radii needed to be increased.  I planned to attach the two half length straights at the turn end joint blocks to bend in the bank with both straights attached.

 

I think I understand your "before you cut off the inner piece" means.  Leave the center raidus point there...match up the straights and trim the inner radius to the inner straights sides.  Then I can radius cut the inner apron on the turn.   Yes?

 

Does one route the slots before or after banking?  I felt routing before when all is flat.

 

I was going to place ONE joint block at the middle of the large turn radius to give me a two section turn with a joint block a each end.   Okay?

What is the radius of your King track banked turn that has three piece and two joint blocks used in it?

 

The track now has a 64" radius LH turn from the 61".  This was to get a wider marshall area in the inner nested turn.

 

I have been using this article for reference.

https://www.slotcarr...build/bking.htm

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[Bigdogbro1]

If running foam tires 3 LH turns and 1 RH turns will wear tires uneven.  

Hi Rob,

Thanks!  Not sure if foam tires will grip good enough on a wood track with epoxy top coat.  I planned on going with rubber tires.  Besides tires are inexpensive and available.  It's more of a concern for track speed and layout interest that fits into my available basement area.

Cheers

[MSwiss]

 

The Bank on my King is approximately 13 ft. at it's widest point. I'm not sure what the radius I used but the top pic shows my buried under other boards, compass extension, I had to make, to attach to my compass. The circled holes were where it was bolted on. I may of also  used some of the existing router attachment holes. It was 19 years ago but the Bank was probably approximately 14.5 feet in diameter, when flat.

 

If you are going to use your straightaways with the connectors attached, for leverage, to pull the Bank, you have to cut the turn to look something like this  (before you glue the other end of the connector on) to get those straightaways parallel. 

 

While some people have sometimes complained about the difficulty of getting the turns to bank and the straightaways to twist from right to left banking, I had very little problems because I had the idea to do the extra work and mess of mapping out where the slots are, and relieving the area between them, on the underside of the track, with a large diameter, bull nose router bit.

I had never heard of another track builder doing it, before or since.

Possibly because of the extra work involved, Possibly fear of it somehow comprising track strength/integrity, but I haven't had any issues in 19 years.

[Bigdogbro1]

Thanks Mike,

 

I have added 13 double tounge and groove joint blocks and 28 adjustable legs to the layout.  The straight-away legs are 3ft apart.

 

Steve Ogilvie....If possible could I talk about a few fabrication details. 

I would greatly appreciate it if you could send me a message to get in contact.

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[Steve Ogilvie]

A banked turn has the same circumference as a flat turn. The only thing that changes is the radius of the turn. You cut the turn with your calculated radius and measure the circumference and mark a start point and end point and draw lines from those points to the centre pivot point. Cut the inside of the corner and then trim the edges using the drawn lines. This is the only accurate way to do it and works every time.

[Steve Ogilvie]

Near the end of my track building thread I made a list of radiuses for various banked turns . The formulae to figure out radius is in there too.

[Steve Ogilvie]

Circumference =PI x diameter. Divide circumference by 360 to get inches per degree and multiply that by the degrees of the corner and you have the outer circumference of the corner you want to make. The inner circumference is irrelevant it just is what it is

[Bigdogbro1]

Well I went and did it, I added a loop.  I hope I can pull this off.  A few banked turns and a lot of work.  This layout has all four lanes at 944.87 inches ( 78.7ft).  I will attempt banked turns on the large RH 10ft sweeper and the nested inner turn and maybe one other.  I calculate 13 joint blocks and 32 legs, Oh my.  The joints and legs are not shown on the first drawing.

 

Feel free to add your comments, that's why I landed here.

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[Don Weaver]

Love that decreasing radius turn of the donut...

[MSwiss]

I have a decreasing radius turn on my jig routed flat track.

 

It played havoc when I got down to the inner turns.

 

The slot went totally schizoid, in the exit of the turn where it got tighter.

 

As I recall, it was something like the below pic.

 

Nothing that a slot car could possibly navigate.

 

My decreasing radius was achieved on a single board, using 4(?) different pivot points.

 

Every time I moved the pivot point, it would route off a banana shaped piece of MDF exiting  the turn.

 

Anyway, I had to abandon the router jig for the last 3-5 lanes.

 

I bondoed in that crazy jog and rerouted those inner lanes using MDF circles I cut, screwed down on the track, as my router guide.

 

Maybe with only 4 lanes and 2(?) radiuses, you'll be OK.

 

[Bigdogbro1]

Love that decreasing radius turn of the donut...

Thanks Mike, Don,

 

Don, Are you talking about the small sweeper turn at the loop.  Yep I thought it would give a good lead in to the inner straight.  All the turns are true radius slots from a center point meeting at the tangent faces.  No sure which direction to run this layout  CW or CCW.  Add a reversing polarity switch.

 

I spent some time doing a nesting layout to get an idea of material used for the track panels.

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[Bigdogbro1]

I enjoyed some Sunday fun racing at a local shop "Professor Motor" near me and had the opportunity to meet the group.  My brother met an old friend that has a nice wood track very near my home so we grabbed some lunch and spent some fun time at his house with laughs and making some new friends.

[MSwiss]

Are you routing the slots off of the compass pivot point or just the shape of the track?

 

Below is my decreasing radius turn.

 

 

[Bigdogbro1]

Was thinking on using the outer shape of the track which would be the inside side of those two radius turns butt ended together.  Your layout radii turn looks combined where as on mine the smaller radius turn stops near 180 degrees then the second larger sweep starts.  

[Jay Guard]

Hey Rob:

If you are not absolutely sure of how some of your routed turns are going to turn out you may want to try this before you actually cut the slot(s).  Install a pencil (or Sharpie) in place of the router and then run the jig around to see if you are getting want you want.  Seems like that would be a pretty simple non-destructive test in the same vein as measure twice and cut once.  Hope this helps a bit.

[MSwiss]

I have that fixture for my router jig.

 

It works great on the first lane when you are working off of the wall.

 

But lanes 2-4 or 2-8 are referenced off the routed slot previous to it.

 

And the issue is the later lanes, such as 4 or 8 .

 

I never tried it, but with two people, you might be able to get some idea by trying to trace the first subsequent lines with the pins.

 

IOW, one person would try to run the path by moving the jig slowing on the drawn line, with each hand steering a pin.

 

The 2nd person would be needed to keep a bit of pressure on the pencil or Sharpie.

 

The 2nd p

[Bigdogbro1]

Thank you Jay and Mike,  I will use the info and watch out for the pitfalls when I get underway.  I am currently finishing up the track layout design and nesting layout for materials cutting. I will update this thread as I progress in the build.

 

The picture below shows two layouts of the same track.  The lower version picture is where I'm headed for a few reasons.

 

1. The driver stations are to be located on the lower LH short straight and I will have inner track access from that side.

2. The track will be against the LH basement wall and 40 inches off the back wall to get better sliding door usage and bench access.

3. The proposed direction of travel will be CCW based on a few of the turns and back straight-away entry.

4. I think I will have the bridge short straight stay on top with the small sweep on bottom but not yet final on that.

5. The three turns on the LH side of the support pole I would like to bank 10 to 15 degrees.

 

The back straight is 12 feet (straight only).  The track footprint is 19' 9" long and 10' 6" deep and all four lanes at 78.7 feet lengths.

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[Steve Ogilvie]

If you make a slot cutter like mine(shown in my how to build slot car tracks thread) yo will not get any distortion of any of the slots. Distortion like what is shown in the pictures above using my jig can only be caused by a bad cut of the piece you are routing off of. A simple two pin jig is easy and cheap to make and nothing works any better. Cut your pieces accurately and you will have consistent perfect slots.

[Bigdogbro1]

Thanks Steve for your input and attention to my build thread.

 

I have settled on this 1/32 layout design with two banked turns.

1. Bank1  15 to 20 degrees

2. Bank3  10 to 15 degrees

 

No banking in Bank2 as it would cause a pretzel twist in the 70" straight with the opposite Bank3 turn also.  Bank2 will be flat for now.

The banked turns 1 and 3 are dimensioned currently as flat radius dimensions and not for the banked turn dimensions which will need to be calculated.

 

77' 6" lane length and 4" lane centers with 5" gutters.

 

 

I'm maxed out for space and really like this layout for the technical and speed aspects for a smaller track.

 

I am awaiting for a contact offering some assistance soon and can get some details on a few build questions.

 

Feel free to offer your comments...This still has time to refine the design and would love to hear from anyone.

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