[woodcote]

Leo - most of the drag proxies I've come across remove the driver from the equation. It's all about the car. Either both cars are launched with one controller, or each lane is triggered by a start button via a relay. The latter is probably better - especially in terms of powering each lane separately. The number of amps HO drag cars pull can be quite big - 10 amps per lane minimum - although nowhere near as much as the equivalent 1/24 cars. Top speeds for the quickest HO cars are over 40mph at the end of a 20 foot strip, running at 20 volts.

Andy - you definitely want some magnetic help in the shutdown. The problem with putting magnets in the track is that you have to get the polarity right - otherwise they will repel rather than attract the magnets in the cars. What you see in the shutdown of HO quarter-mile strips running the fastest cars are thick slabs of high-iron steel that offer up as much attraction as possible to the traction magnets. They will still need foam catch boxes and a towel for the cars to go under, even with six feet or more of shutdown.

On the strip I am building now, I have already extended the shutdown very slightly and have used an HO track that offers more metal for the traction magnets. I have also shorted out the shutdown after a dead section of 3-inches. It seems to be working okay, but needs a little more testing before I commit to drilling holes for sensors. I want to keep the 82-inch (1/87 scale eighth mile) timed section and be able to run a range of different cars with adequate shutdown. Having said that, I'm expecting to limit voltage to 13.8 volts (14-15 volts is not unusual on US scale 1/8 mile strips) and be looking at the slower end of the HO slot car spectrum - pancake cars with 14-16 ohm armatures and 6+ ohm ceramic magnet inline cars. Because of the track I'm using, all cars will need to be fitted with braids.

My plan is to rig up the strip with Drag Race Coordinator, which - I think - I can use to trigger a 2-channel relay direct from the Arduino board. That will mean the cars will be launched by the software and any difference in reaction time will be entirely down to each car's start characteristics.

More tomorrow!

[dvd3500]

I saw Scalextric have released a loop-the-loop for their new Micro series.

It would look silly, but you could put that at the end with the loop only going half way, pit a bit of foam on the end and then hang a basket it on. The cars then go up the loop, hit the foam and then fall in the basket. :-)

Another one of those crazy brain sparks I have while doing chores so maybe too silly...

[BAracer]

I had the same thought, although mine involved a quarter loop and a gentle arcing flight into a strategically placed laundry basket.

[woodcote]

It is definitely a thought that crossed my mind - the idea of gravity helping out was excellent in theory. When I tried it out using a 90-degree ramp, there were some issues. Apart from being an affront to my aesthetic tastes, the ramp used up about 6-inches of flat shutdown space. Most cars were stopping fine on the flat. Those that weren't tended to be the non-magnet (or low magnet) pancake cars that would then slide back down the ramp, messing up their braids, or falling on their roofs. The really quick cars continued up the wall and then fell off. And the Top Fuel dragsters were too long to go up the ramp safely (they de-slotted). It was an idea, but one I rejected. It is better to keep the cars on the ground. There were other compromises that worked just fine within the space and for the range of cars I was looking at running.

Anyhow, back to the story...

I couple of years ago, Gareth and me chatted about building an HO drag strip each. We'd look at routing our own from 10mm thick black Foamex (expanded PVC) and use 1.6mm wire as rails. It would take practice to get the routing right - three pockets for each lane, the rail pockets needing to be an exact 1.3mm deep all the way down - but routing six straight lines wouldn't be a bad learning process. Gareth has the stuff, I had the issues around wonky walls to overcome. But as drag strips go, it's a good plan. At that stage, the original DOS-based Trackmate Drag Basic would have been used as a timing system. I think that's still my long-term goal. The great thing is that the lane width can be widened to give more of an authentic drag strip look and have space for either Christmas Tree lights or a flag man between the cars at the start.

But I did want a medium-term solution using plastic sectional track. I was erring towards Tyco track as the lane spacing is slightly wider, but the electrical continuity isn't great. Or stick with the marginally more reliable Tomy AFX track I used with the Auto World strip and add sensors for Drag Basic. That I was struggling to get the DOS programme working was another issue. A few weeks ago, I set up a Tyco version to play with - and from the juddering of the cars, it was clear I'd need to solder the rails at each track join to get even a half decent track. Mildly peeved, I counted up all the new 2019 'second generation' Micro Scalextric straights that I had in sets and - including the powerbases - I had just enough for the length of the shelf. I tried a couple of cars and it was sensationally smooth, quiet and quick compared to the Tyco track I'd been playing around with.

The new Micro Scalextric track is really smooth and does have excellent connections - physical and electrical. It is a lot better than any other brand of traditional HO sectional track. There were two reasons I'd not thought about it for a drag strip... First, the straights are really short - only six or three inches long, compared with the standard 15-inch HO pieces. However, the smoothness and much better connectivity of the Micro track really didn't make that a problem in practice. The second issue is the flat rails - that means only cars fitted with braids (or the HO RacePro 'Slide Guides') will run on them. As fitting braids to HO drag cars is pretty much the done thing these days, it's not a deal-breaker - indeed I'd already decided that was fine when considering another option. At one point I looked at using 1/43 scale Carrera Go track for an HO strip. It was 50% wider and had better connectivity, but the rails were just a little too close for the HO pick-ups. The Micro Scalextric track had most of the positives (apart from the width), but with perfect rail spacing for the pick-ups. Life is all about compromise.

   

As you can see from under the track sections, the are tabs on the rails that keep them secure in the plastic. Bend those tabs straight up and the rails drop out. They are then easy to solder power cables to and then replaced into the plastic - no risk of melting anything. If you look closely on the underside, you see where the plastic connecting lugs clip into the next piece of track - it is important not to solder to the rails and bring the wires through at that end... the track won't go together (don't ask me how I know that). You can see how I've soldered wires to short out the shut down section here...

       

What we have is - from right to left - a final powered section with metal lugs removed at the end; a short dead section with rails removed and strips of plastic sheet glued in their place; a short section with rails shorted out underneath and metal lugs removed towards the dead section; and finally a normal, unmodified straight. Dragster shows direction of travel. The plastic sheet is important - removing the rails leaves quite deep recesses that cars' braids will drop into and catch the edge of rails on the next piece of track. I mashed up a few braids before I made the modification. The only issue now is the plastic being a little too high and cars that sit very low (eg the Auto World Funny Cars) lifting up and de-slotting. Some further tweaking is required.

   

The basic padding I have at the end of the strip (a proper catch box to follow) has foam sheet glued to the wall, a gap and then another sheet which deforms back into the gap. The track goes underneath the front sheet, but stops in front of the sheet on the wall. The idea is - ideally - for the car not to stop instantaneously or for it to bounce back too far - especially with close lane spacing where one car can bounce back into the other. So some 'give', but not too much springiness. The foam I've used is not bad.

   

I braided up and tested cars on both 12v and 13.8v to evaluate the shutdown and the foam...

• Various T-Jets (mag and non-mag) hit the end with a small bounce at 13.8v and merely ran into the foam and stopped at 12v.
  
• Aurora AFX Magnatractions (no traction magnet) and AW X-Tractions did pretty much the same.
  
• Auto World Top Fuelers (magnets, but tall tyres) 'banged & bounced' at 13.8v and hit with a slight bounce at 12v. They are 3-inches longer at the front.
  
• Auto World Funny Cars (magnets, but very low to the track) stopped 16-inches after the end of dead section at 13.8v and 14-inches at 12v.
  
• A rapid Tomy SRT (with strong magnets and tall tyres) didn't stop as quickly, hitting at 13.8v and tapping at 12v, rather like the T-Jets.
  
• Stock Micro Scalextric (1995 version) were stopped quickly by their magnets - 12-inches at 13.8v and about the same at 12v. Even at 15v, they were stopping well before the end.
  

I tried to use drag set-ups where I could, certainly in terms of tyre heights. The Funny Cars need some work to get them back to their prime - they are pretty tuckered-out. However, that seems a nice range of cars to race - focusing on the Auto World pancake cars, plus the old Micro Scalextric cars and possibly some 6-ohm Tomy and Tyco inline cars. I do think it's the T-Jets that will look the part on the strip...

   

So I didn't have to use my set powerbases and to have some extra track for experimenting on, I bought some new Micro straights from Jadlams (£6.30 for six 6-inch straights, £4.40 for six 3-inch straights). This is the same decorated track as in the sets. However, Scalextric have just released a track expansion pack (£12.99 - or £11.69 from Jadlams) which I believe has plain black track - 180-degrees of corners and six 6-inch straights. The James Bond 'No Time to Die' set due in July also has the undecorated track. I might replace some of the decorated track with the black stuff in due course - but at the moment I am happy to experiment with what I have.

[woodcote]

As I mentioned, the simple timing upgrade to the Auto World strip is the Slot Dragon Drag Race System. This is how it looks working in conjunction with the Auto World module...




And as a stand alone tree and timing system...



You can use it with any type of track and any scale. I ask myself, why don't I go with the easy option? And I have no sensible answer.

[woodcote]

Of course, the Slot Dragon system would be the simplest way to add timing to my Micro Scalextric drag strip. However, there are other options...

   

Top of the range is the Trackmate DP3000HO timing system (there is also a 1/24 scale version). This has six sensors per lane - Prestage, Stage, 60-foot, 1/8 mile, Speed Trap and Finish - plus a six-inch high tree. The software requires a Windows PC running XP or higher. Everything you need comes in the package, which costs US$795. Slightly cheaper is the DP2000 system, which has an older module that only handles four sensors per lane - Pre-stage, Stage, Speed Trap and Finish. Otherwise the features are the same. It costs US$549. Both systems will print proper time slips with an additional time slip printer (US$369).

   

I have the oldest version of the Trackmate drag race system, which was then sold as 'Drag Basic' until about 3-4 years ago. The software is DOS-based and no longer available. There are only two sensors per lane - Start and Finish - with speed estimated at the finish line if you enter the car length. The tree is on the screen, with no way to use an external tree. There is the option of Full or Pro tree, plus full bracket racing features - dial-in and split tree. Results for the session can be logged and sorted. It is recommended that the software is run in a true DOS environment (available in Windows up to 98SE). Sensors are wired to a 25-pin D-sub connector and plugged into the computer's parallel (printer) port.

   

The new kid on the block is Drag Race Coordinator. This has been gradually put together over the past 2-3 years as a stand-alone program. As you'd expect from a Race Coordinator app, it looks great and has some cool features. The software is the usual donation-ware and you'll need to set up an Arduino to communicate between the sensors. At the moment, there is very little documentation (it's all in Dave's head) for either software or hardware, so it a challenging journey to get set-up. However, the aim is to offer a DIY alternative to the features in the top-end Trackmate systems. With times shown only to thousandths of a second (rather than ten-thousandths) and the speed averaged over the entire strip, we're not there yet...

I do intend exploring Drag Race Coordinator for the future. However, with racing to be organised, I am going to stick with Drag Basic. It is a very solid piece of timing kit. Daniel knows his drag racing - he also produces timing systems for full-size drag racing.

There was work I needed to do - making a sensor set-up to fit my seven-foot strip (yes, I've stretched it to 84-inches) and two IR LED gantries for the start and finish lines. Here's my working-out sheet...

   

I needed to test combinations of emitters and receivers with my old 1996 Toshiba Satellite 110CS and Drag Basic. A neat pairing of emitters and photodiodes I was planning on using didn't work. Thankfully I had a choice of two options of photo transistors and I chose the one that worked at the furthest distance. It was then a case of soldering everything up. It's been a while since I soldered up a D-sub...

   

I then measured up and fashioned two gantries from PVC ducting and installed the 5mm IR emitters so they will sit directly over the receivers...

   

Everything seems to work and I'm not far off installing everything on the strip - then testing, tidying-up and making it a bit pretty. Might get 5 of those new plain black straights for the first part of the run. They will look better.

[Scuderia_Turini]

Hello Andy,
I have been trying to figure out Drag Race Coordinator and searching for info on the hardware. I'm glad to hear that its still in the pipe-line as it looked like it had gone cold.
Have worked out that for my immediate purposes I really only need sensors at the end of the strip (I have started to learn the jargon, LOL) as I will be using a "cold-start" to launch the cars and set normal Race Coordinator to one lap and "start after sensor".
Not wanting to divert your current project, hopefully we can converse on Drag Race Coordinator at a later date.

Leo

[woodcote]

Leo - it would be good to document progress with Drag RC in another thread - with lots of pics and detailed problem-solving. I think is it a bit of a sideshow to Dave's main focus - Race Coordinator proper - but it does offer a very accessible entry point to a PC-based drag timing system for any scale. The latest version of Drag RC was released just before Christmas 2019. One of the guys who hosts races with the NitroSlots group has used it for competition this year.

An Arduino Uno clone (£5-ish) will do the job, plus IR emitters and sensors and lots of cabling. Throw in a 2-Channel relay board plus various connectors, fuse holders and switches I think I spent less than £25 on components. With what I've built for Drag Basic, I will be able to use a female D-sub socket to swap it over to the Drag RC set-up. It's only right and proper to contribute to Dave's charity fund, so that's potentially a great little drag race timing system for around £50. It does need a fully updated version of Windows 7, 8 or 10 with .NET 4 installed. So it won't work on my Satellite 100CS...

[woodcote]

I have a messy, but fully-functioning drag strip

   

Lots of cabling to tidy up, sensor bridges to complete, relay box to build and a week's worth of finishing touches. It still looks like a construction site, but it works - which was the aim of today.

It was fun to get some timing done with Drag Basic. At 12 volts, Elapsed Times (ETs) are around the 0.700s mark for dug-out-of-the-box Micro Scalextric cars on road course standard Super Tires. I threw in a decent Tomy SRT on high-ish tyres, which did a 0.506s. A little bit too quick for the shutdown - a bang & bounce... A pretty good T-Jet went 0.875s. The top Fueler looked good and managed a 0.809. None of these cars (apart from the T-Jet) have been tuned - they are simply to test the strip. Some representative times will hopefully be set next weekend at the trial run. And then on to the first official event - the sign-up thread is here: https://slotracer.online/community/showt...p?tid=1267

[Mazda]

Looking good Andy.