About a week ago I posted pictures of a very sweet little, 'Streets ten-wheeler tractor-trailer I made using a Lionel Piggyback REA trailer and 'Streets wheels but otherwise scratch built. Encouraged by that success (a new drive mechanism design and a few other refinements worked perfectly) - I decided to go back to eighteen wheelers and build the biggest big rig I'm likely to ever run. The red 18-wheel tractor trailer shown below is a 1:48 Peterbilt diecast cab with a New Ray box trailer all on scratch built chassis. Some details for those interested after the pictures and video.
- The rig is 13 3/8 inches long and weighs 21 ounces - the trailer is weighted with 7 ounces of shot just ahead of the rear axles to provide sufficient traction.
- The power is provided to two traction tires on the front of the two axles at the rear of the trailer, using a very large flywheel can motor (from an MTH Veranda Turbine) with 3:1 reduction gearing.
- It picks up power from all wheels and has six center pickups, one under each axle and an extra one under the cab. All that contact, and the large flywheel motor, makes it very smooth and steady running. With the 3:1 gearing it will run as slow as a scale 5 mph and as fast as 75 mph.
- The rear two axles of the tractor are a pivoting truck, and the rear of the two on the trailer is a trailing axle that can turn to follow around a curve, so this can actually run on D21 'Streets curves, and with a bit of protest, D16 curves even. It will not, however, make it through my downtown area - the trailer overhangs serious on corners and knocked one down a streetlight and a post office box before I stopped it.
- The sleeper compartment to the cab is made from a Glide dental floss container - I've wanted to do that with a model truck for a couple of years.
- The model I built the tractor from did not come with mirrors, etc., but I plan to add those and license plates.
I'm satisfied this is as perfect as I can make an 18-wheeler - or at least as I need to make: it runs smoothly and realistic speeds, it looks good while doing it, and seems to be durable. The many experiments and various things I tried over the past couple of years that did not work perfectly make a very long list, but then I learned quite a lot when I look back, even if when written down they make for only a few lines: drive the trailer, not the tractor; use a monster motor with a big flywheel; mount it horizontally - definitely don't mount it vertically; use reduction gearing; power only the leading, not both, rear axles; pivot the tractor's rear axles; connect and pivot the trailer from the same pivot point; when in doubt, add weigh over an axle. There is a reason behind each of them and a few other points I learned, and I promise someday I will write up a longer report and post it here. But i the meantime, I'm going to give the train room a rest for the rest of today and tomorrow, and spend time with family on a holiday weekend dinner.
Happy Easter everyone!
