Stanchion Trailer Project

Page 1: Building the trailer

This is a really long box because this is a really long trailer. Once opened, you can see that the entire length of the box is used by the huge frame rails. There are a handful of plastic parts trees, but most of the model is aluminum parts and steel hardware. It is quite heavy.

For some reason, instructions that are printed in landscape orientation always seem odd to me. Other than that though, these Hercules Hobby instructions are of quality similar to Tamiya. This is a dual purpose manual also covering the flatbed trailer which is identical apart from the stanchions.

The aluminum bodied shocks are the same type you see on the tractor trucks. These are internally sprung with no damping, so they are really just for appearance. Two shocks are attached to each of the three rear frame cross members as shown.

Now we'll add some extra details to the frame rails. Up front is a nice solid metal plate joining the two rails which will also serve as a mount for the leg release mechanism. In the rear I've attached all the hangers and shackles for the leaf springs and radius arms of the suspension.

The six leaf spring stacks each contain 3 leaves and must be bolted together before attaching to the axle housings. The are no differentials here, just independent axle shafts, left and right, allowing the tires to turn at different rates. The bushings you see are just being used as spacers until I install the wheels later. The trailer kit came with full ball bearings.

Time to install the axles and suspension to the frame. The center axle shares a leaf spring rocker with each of the other axles, meaning that if one one them goes up, the other one goes down. A set of radius arms on each axle keeps them centered and prevents wandering front to back.

The support legs work exactly like those on a Tamiya trailer. The legs are spring loaded to be retracted, but can lock down manually. A touch to the trigger driven by the tractor's 5th wheel will automatically retract the legs and allow the trailer to be driven away. Extension is manual. You can see the spring system inside one of the legs.

On the left you can see some of the parts of the mechanism including the kingpin, the link, and the levers. On the right we can see the completed mechanism with the cover removed to show the inner workings. A touch to the cam on the left pushes the rod. The rod slides another cam which pushes the two "claws" outward. Those push the triggers on the leg supports which release the ratchet, allowing the spring loaded legs to retract. Voila!

Now I've enclosed the whole leg mechanism and installed the front guard which will keep logs (or other cargo) from sliding forward into the tractor under heavy braking. The guard and stanchions are all nice machined aluminum parts. The bottom toothed parts and the side rails are separate and are bolted together. If I have any complaints about the design of this model, it would be that there is only a single bolt holding each vertical rail to the bottom rail. This means there is nothing to react prying loads except the head of the bolt, therefore you don't want to put anything really heavy on the trailer. I've also installed the plastic fenders over each wheel.

Here I've started on the plastic rear bumper and the rubber mud flaps. On the right you see them installed on the trailer frame. I haven't decided whether or not I like the white, but that's what was called for in the instructions.

This front box would be a control panel on a real trailer, and maybe an attachment for the air brakes and lights. It can serve much the same function on the model. If the optional trailer lights are installed then the diamond plate cover must be removed to allow the wires to pass through.

Here's the rear tail light housing. It is provisioned for turn signals, brake lights, and reverse lights but the optional lighting system does not include reverse lights. There are no stickers included so nothing to use on the license plate. You can also see the tire chocks installed here. There is a mount for a spare tire in the same area, but no extra tires or wheels come with the model.

The last detail to add are the nicely plated (but plastic) side guards which do a lot to fill out the otherwise narrow trailer frame.

The completed trailer is a lot heavier than it looks, very sturdy, and fills my whole table.

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