[woodcote]

SlotNav technical requirements & track design basics

Because most of the challenge is wrapped up in the navigational gameplay, a SlotNav layout need only be functional. However, any constraints on the design of a SlotNav track are mostly down to the space you have available and the extent of your imagination… There are a few technical limitations – and that’s what I’ll look at here...

1. The Spine

I’ll start with the ‘spine’ of the layout – a straight section with a return loop at each end, a powerbase in the middle and two pit lane sets branching off either side. A SlotNav layout might not 100% absolutely need this spine, but it's  certainly very neat and concentrates all the potential digital power issues into an easy-to-test unit. I think it works perfectly for the navigational aspect too.

   

The two pit lane sets need to be the same to work with the return loops – ie both need to be left-handed or both right-handed. This just means the active ‘pit-entry’ junction turns off to the left or to the right of the track. I've gone for two 'lefts' in the plan and in my actual layout. The ‘pit exit’ is simply a passive ‘merge’ piece and is not classed as a junction in SlotNav, since there is no choice whether to merge or not. It’s the same with any curve piece, chicane, jump or return loop you include in a SlotNav layout – none of these involve a ‘turn / don’t turn’ decision and so don’t require navigational instructions.

This is a digital layout – the car changes lanes at a press of the lane-change button on the controller. I am using Scalextric Sport Digital (SSD) – and have successfully tested SSD and oXigen-chipped cars running on ARC Pro or the older 4-Car Digital Powerbase. Any digital system that has both a lane-changer and pit lane system should work, although may need careful testing and tweaking.

Standard digital controllers aren’t bad, but higher-quality alternatives are available: a Slot.it oXigen controller can be used with oXigen cars (or with ARC Pro) and Truspeed digital controllers can be used with older wired Scalextric, SCX, Ninco and the current Carrera powerbases. Timing is entirely manual, so any associated apps or PC software are mostly redundant… that means the much-maligned Scalextric 4-car digital powerbase is a perfectly good budget option, especially paired with a lovely Truspeed SSD III controller.

Because of the return loops connecting the two lanes, most powerbases will go into ‘safety mode’ when powered-up. To get the spine to function, you’ll need either an electrical break in the return loop or to modify the powerbase. It’s a simple mod – remove the track piece from the digital powerbase, disconnect the track power wires to one lane and either tie them off or re-solder them in the reverse direction. With my 4-Car Digital powerbase, it was a ten-minute job – mostly waiting for the soldering iron to warm up. For an out-of-the-box solution, the original ARC Pro base is perfect for this set-up – it has the two lanes already wired in opposite directions.

This is what I have used for my development track...

• Original (2017) ARC Pro Upgrade kit – unmodified – with standard ARC controller
  
• 2 x C7014 Pit Lane (left-hand) – two entry pieces with sensor, two passive exit pieces
  
• 2 x C7016 single lane half straights to connect to the pit entry pieces as they enter the ‘wings’
  
• 1 x half straight with power taps soldered to each lane – these are necessary to power the ‘wings’. I ran the taps to the single-lane sections nearest the spine.
  

You have plenty of choices in creating a spine – it can be as long as you want, not necessarily straight and using whatever return loop designs you fancy. Jason has two possible return loops in his original design – a ‘doughnut’ loop (which is great fun) and a tight Radius 1 loop. I’m using a pair of Ninco loops, connected via Ninco-to-SCX and Classic-to-Sport adapters. The same method can be used to fit specialist SCX and Ninco rally pieces into the wings...

2. The Wings

I put together the most basic layout possible – a Radius 2 oval – as one of the two ‘butterfly wings’…

   

However, this wing contains all the navigational elements we need: a lane changer junction and two Stop Boxes…

   

A Stop Box functions as a punctuation between strings of navigational instructions – to give the crew a breather (a ten-second timed pause works well) and also allow them to reset their navigation. It’s possible the car has ended up at the wrong Stop Box… in which case, the Rally Master will tell the crew the correct location to drive to, where they will then take their ten-second breather – it’ll take some extra time, but they will on the right track to start the next string of navigational instructions.

Because it’s quite easy to get lost – and the slot track goes round and round in circles – I thought a reset mechanism was important. The Stop Box / Time Control doesn’t look out of place on any navigational rally, but its function on the slot car track is slightly different. Essentially, it allows you to ‘turn back’ and recover the route.

   

I could have simply added another oval for a very compact SlotNav track, but I’ve gone to town a bit more with the second ‘wing’ of my development layout. I found the most difficult bit to get right is the single lane section on the inner lane. I cut up some Radius 2 curves and standard straights into single lanes – and with a lot of traditional hands-on trial-and-error came up with something I was happy with. A word of warning: when using sliced-up standard pieces, the connection tabs don’t always match up. The C7016 and C7017 single lane pieces are designed to create a single-lane track – and have tabs to match any eventuality – so keeping a few handy is certainly a good idea.

Although there are more driving challenges in this second wing, there’s the same number of navigational features – another lane changer junction and two more Stop Boxes. I’ve given all four Stop Boxes on the track a scenic theme… The OS map symbols are simply planning ahead for more advanced navigational gameplay, but the scenics will look good too – a church, a pub, a small river and lay-by with a phone box.

A Google search will give links to download cheap (or free) model railway card-stock models that can be scaled up to near 1:32 scale by printing an A4 design to an A3 sheet – or simply build them in OO gauge to give a quirky board-game feel. A 1:32 scale marshal should probably be stationed at each Stop Box too. One Stop Box will act as the start time control and one (unknown to the competitors) will be the finish…

Using just one lane changer in each wing is sufficient. In trial runs, the ‘junctions’ came along quickly enough. I wouldn’t be tempted to throw in more lane changers – unless I had a large space to work in and could spread out the lane changers with a comfortable time gap of between 2 to 3 seconds between each junction.

   

That's my development track laid out, ready for testing some basic navigation and driver-navigator communication. I'll post that later, but before that, expect a brief interlude to look more closely at the digital kit...