I want to be able to let a Cub do the tuning on the car himself.
The normal bent DFW axle and screwdriver adjustment is difficult for some adults, and super hard for a Cub.
The Plug & Play is perfect for Cubs, but I want to do the next step up without going all the way to a Pro bent axle setup. When you might run on a poor track and jump off at the stop, you want the most rugged design, and that is the straight axle with drift built in. The approach I use is to drill a 4 on the floor canted car. Back two wheels canted away from the rail, front two wheels canted toward the rails, and it runs straight- no drift. I can get this most of the time, but a Cub gets it off a tad from time to time. I have one Pack that has very strict 4 on the floor rules where they roll the car on a mirror, and all 4 must roll. I also have other Packs with different kids that have loose rules and of course we will run a 3 -wheeler rail runner. So we start with a try at a 4 on the floor, and then cut the car in half just behind the front wheels. We then use either a few thin rubber bands or one big band to hold the car back together { small wood blocks added to adjust tension so wood does not move without some effort} on a simple wood jig. The jig allows a slight twist of the front wheels to get 4 on the floor very simply. It also has a hex-nut height adjustment to lower or raise the slope of the bottom of the car, and last of all you can add a few strips of newspaper to get the drift you want by testing on your tuning table.
Too make a 3- wheeler, just add the wedge under the NDFW and that rotates the front of the car to increase the set angle of the DFW, and decreases the angle of the NDFW as it lifts that wheel. It was noticed that with a 4 on the floor, only two strips of paper were needed to make the correct drift because with both front wheels touching and steering, not much extra offset to straight was needed. When the car was twisted into a 3- wheeler with the wedge, it then took 6 strips of paper to get correct drift.
Now the last adjustment you can make is to push the entire front of the car to the side so that the DFW just hits the rail, and then carefully lift off and re-test drift on your tuning table and go back and forth if you need to until you get it all the way you want. The typical Cub gets all this and quickly understands how we are adjusting the car, but he will not normally see that putting drift and rail running is faster than 4 on the floor straight. You can quickly go back and forth and show on a track if you have one. If not, you just have to say- trust me, and show a few NPWDRL videos where the car with big wiggles is out of the running..
So you can now shave off how much wood is needed to get a perfect spacing on the NDFW [ on the right] to the rail, and cut it off of just the front of the car. Leave the DFW side alone. If you mess up, it will not be a big thing to adjust the NDFW spacing over and over.
Now the best way to glue the rough body back together is something like marine epoxy with a 30 minute working time, or PC-7 which gives you a full hour to re-position and test drift and test on the track where you can change all kinds of things in an hour, and let it sit of 24 hours and you have a pre-tuned block to shape back into the 7 in. limit if needed, and smooth the bottom and sides to remove any sharp edges without messing up the area near the axle holes.
The normal bent DFW axle and screwdriver adjustment is difficult for some adults, and super hard for a Cub.
The Plug & Play is perfect for Cubs, but I want to do the next step up without going all the way to a Pro bent axle setup. When you might run on a poor track and jump off at the stop, you want the most rugged design, and that is the straight axle with drift built in. The approach I use is to drill a 4 on the floor canted car. Back two wheels canted away from the rail, front two wheels canted toward the rails, and it runs straight- no drift. I can get this most of the time, but a Cub gets it off a tad from time to time. I have one Pack that has very strict 4 on the floor rules where they roll the car on a mirror, and all 4 must roll. I also have other Packs with different kids that have loose rules and of course we will run a 3 -wheeler rail runner. So we start with a try at a 4 on the floor, and then cut the car in half just behind the front wheels. We then use either a few thin rubber bands or one big band to hold the car back together { small wood blocks added to adjust tension so wood does not move without some effort} on a simple wood jig. The jig allows a slight twist of the front wheels to get 4 on the floor very simply. It also has a hex-nut height adjustment to lower or raise the slope of the bottom of the car, and last of all you can add a few strips of newspaper to get the drift you want by testing on your tuning table.

Too make a 3- wheeler, just add the wedge under the NDFW and that rotates the front of the car to increase the set angle of the DFW, and decreases the angle of the NDFW as it lifts that wheel. It was noticed that with a 4 on the floor, only two strips of paper were needed to make the correct drift because with both front wheels touching and steering, not much extra offset to straight was needed. When the car was twisted into a 3- wheeler with the wedge, it then took 6 strips of paper to get correct drift.

Now the last adjustment you can make is to push the entire front of the car to the side so that the DFW just hits the rail, and then carefully lift off and re-test drift on your tuning table and go back and forth if you need to until you get it all the way you want. The typical Cub gets all this and quickly understands how we are adjusting the car, but he will not normally see that putting drift and rail running is faster than 4 on the floor straight. You can quickly go back and forth and show on a track if you have one. If not, you just have to say- trust me, and show a few NPWDRL videos where the car with big wiggles is out of the running..

So you can now shave off how much wood is needed to get a perfect spacing on the NDFW [ on the right] to the rail, and cut it off of just the front of the car. Leave the DFW side alone. If you mess up, it will not be a big thing to adjust the NDFW spacing over and over.
Now the best way to glue the rough body back together is something like marine epoxy with a 30 minute working time, or PC-7 which gives you a full hour to re-position and test drift and test on the track where you can change all kinds of things in an hour, and let it sit of 24 hours and you have a pre-tuned block to shape back into the 7 in. limit if needed, and smooth the bottom and sides to remove any sharp edges without messing up the area near the axle holes.