To crossover or not to crossover

[slothead]

When I started thinking about updating my oval, Shepherd Speedway, the initial plan was for a one lane track since I've been a solo racer for years. I was planning on routing a single lane that spiraled inward to loop around twice and use both high and low grooves before a single crossover connected the lanes to start over. Then Harry suggest I build a 3 lane track just in case others showed up. "No need for that" I thought, but the idea grew on me.

Now the plan is to build a 3 lane oval that can be either a typical multilane track or a single lane that loops around 3 times to return to where it started.

How to do that? Just past the start/finish line on the front straight there will be a short section of the track that can be removed and replaced. They'll be 2 versions of this section that are identical in length, width, and lane spacing. One version will have 3 independent straight lanes and the other version will have a series of crossovers allowing lane 2 to crossover to lane 1, then next time around lane 1 will crossover out to lane 3, and next time around lane 3 will crossover to lane 2 so the cycle completes itself. Below is a sketch of what I have in mind for the crossover section.



The rectangle on lane 2 at the left is the deadstrip that will be used for lap counting and timing when 1 car is on the track. The power connections and deadstrip(s) will be on the longer section of the front straight that remains in place no matter if the crossover section is being used or not. I'm hoping to design contacts so power will be fed to the removable section from the sections before and after it and no new wiring will be needed. I want it to be 'plug & play', with the removable sections held in place by a few countersunk screws or perhaps even by strong magnets.

All of the sections will be done by a CNC machine so everything matches up nicely.

Comments and feedback requested.

[War Eagle River]

Not to crossover. Will no longer be an oval.

[chappyman66]

Easy. Several folks have done this or similar. I strongly recommend multi-prong connectors. Did that on my 3 lane, super easy and no connection problems across the joints ever. Literally plug and play.

[WB2]

I’d recommend doing the crossover on a long section, not short.
You’re running pretty much full throttle on the straights. Quick short lane changes aren’t conducive to that. A short section would be more like an autocross.
Or...make one turn removable and and swap in a lane-change-in-a-curve. That would depend on how large your turns are.

[Fathead59]

Ok , I have one question . Will this be for only one car ? It seams to me that all 3 tracks will be connected

[slothead]

The purpose of this section is to be able to have 1 car use all 3 lanes during solo racing. A car starting in lane 2 at the start/finish line before the crossover section would go to lane 1 for its first loop around the track, then crossover lane 2 to do a loop in lane 3, then go to lane 2 for a final loop before returning to the start/finish line in lane 2 to have it's lap counted and timed.

If the crossover section is replaced with a straight track section each lane will be independent so 3 cars can be raced normally. I'm considering this because on my 2 lane oval now I do all my solo racing on the outside lane and the inside lane is always cluttered with parked cars. With the crossovers all lanes will get used and a 'good' car will have to handle well on all 3 lanes and to be a 'good' driver I'll have to master all 3 lanes too.

[Fathead59]

With looking at it again , wouldn't you need three other cross overs to stay with one continual connection ?

[Wobble]

Like WB2 suggested, if you had the crossover piece the full length of the straight then you'd be running full throttle straights but just heading towards a different diameter each time you went around when running alone and you'd soon get used to that. Might even add to the flavour for you and a 3 straight piece could be added at a later date.

[slothead]

Thanks for the drawing to provide a visual to consider. You did a very good job creating the graphic. I'll address more about short vs long crossover sections in my next post (coming soon).

[Fathead59]

But Wobble , even with that layout you are still on one continuous track . Wouldn't you need three crossovers ?

[Wobble]

But Wobble , even with that layout you are still on one continuous track . Wouldn't you need three crossovers ?

The idea slothead mentioned in his 1st post is to have the option of 1 continuous track or 3 separate lanes. In actual fact if you had 3 crossovers you'd have to have 4 lanes to do have the same outcome.

[slothead]

I've 'driven' my cursor around an imaginary oval many times and am confident the crossover section will allow 1 cars to use all 3 lanes before starting a new cycle or lap as I'm calling it. My main purpose is if I'm going to route and tape 3 lanes I want to use all of them even when solo racing. On my 2 lane oval it takes a different driving style to be fast on each lane, but now I only use the outside lane. Also, some cars are faster on the inside lane while others are faster on the outside lane. With the crossovers a lap time will combine times on all the lanes.

As mentioned in the post above by WB2, yes putting the crossovers in a corner would be ideal and closely resemble the way cars change groves in a corner to make a pass. BUT, since I want to be able to swap the crossover section out and replace it with a section without crossovers swapping out a 6 foot wide corner section would be a major undertaking. I don't want any joints in the corners and intend to have corner sections be as big as I can get out of a 4' x 8' sheet of mdf. My current design has the outside radius of the corners being 34 inches for a 68 inch diameter. This will fit on a 70" wide table allowing 1" on each side for fencing and billboards. Each corner can be cut out of a 6' x 4' section of a sheet and include 14" straights leading into and out of the corner. These straights will be needed if I'm going to pull the corners in to obtain slight banking.

Basically, I think it will be much easier to swap out a 16" or 18" straight section than a 6' x 4' banked corner section.

As for location of the crossover straight section it seemed best to put it right before the straight part leading into the first corner (turns 1 & 2). This location would be right in front of the driver's station(s) where I have to 'blip' the throttle to set up for the turn. On my 2 lane oval to be really fast and stay on the track I have to totally let off the throttle (controller) just past the mid point of the straights and then quickly get back on the throttle before entering the turn. A very short interval of no power followed by adding power work together to help cars slow down enough to make it through turns 1 and 3. If I let off the power going into these turns the cars coast into the turns and crash or deslot more. That's why I think putting the crossovers about 2/3rds of the way down the front straight may work best.

Also, from the unused part of a 4' x 8' sheet after a corner is cut out I can still get a 4' long by 15" wide straight section, a 22" long by 15" wide straight section, and 2 short straights for the crossover and no-crossover sections. A full straightaway would be composed of the 14" straight coming out of a turn, a 48" section, a 16" crossover/no_crossover section, and the 14" straight leading into the next turn, making a 92" straightaway. Total dimensions of the track would be 13' 4" long by 68" wide.

Hoping to post some screen images of how I have things laid out in my next post.

[slothead]

I was able to take some photos of the screen to show how I've been planning materials usage for the new oval. I didn't think this would work but since I'm using a 32" flat screen TV as my computer monitor I was able to get some good images. (FYI - I got the Sanyo 32" flat screen TV for $110 at Walmart, which was cheaper than a 24" monitor and has great resolution.)

Here's how I envision the track layout for constant radius turns. The pink rectangles are the crossover/non-crossover sections. The pink section on the bottom (front) straight is where the crossovers would go. The pink section on the top (back) straight would be a non-crossover section.

The dark blue bar across the layout was used to ensure the track was the correct length, and the small green bars were used to ensure the track width was correct in the corners.



The corners are in light purple and the connected straights are in darker purple. The 4 foot long straight section is in blue. The shapes were made to scale using 3 inches to represent 4 feet. All track sections are 15 inches wide. The corner on the left shows that entire piece of mdf the corner would be cut out of, while the corner on the right shows just the corner after being cut out.

Here's how the track sections would be cut out of a sheet of mdf.



The green straight sections would be spare sections that could be used to extend the layout if more space was available.