My first intention was to build only a simple, lightweight static model made with laminated plywood, skinned with sheet styrene, and having only exterior details and static wheels.
Harry Harris sent me a large and very detailed blueprint of the APC that was used by the Aliens props department to build the full-scale version. It came in handy, to say the least. The Halcyon kit was also a great help. I spent many hours taking measurements off the model and scaling them up. Despite double and triple checking calculations and measurements, I still ran into some minor fit problems along the way. A bit of trial fitting took care of any discrepancies.
Having never built anything like this before, I was at a loss as to how to even begin and those huge wheels seemed high on the list of what I term the "limiting factors"; no sense proceeding unless the limiting factors can be addressed. The rest of the APC seemed pretty easy to do as the hull was made up of flat plates. There were a lot of angles and shapes to deal with but it appeared to be pretty simple once the wheels were done.
Having a proper-looking APC without proper-looking wheels would just not be . . . well, proper. Besides, I'd never live it down with the boys on the Aliens Legacy Board (http://forum.alienslegacy.com/index.php?sid=8e277c50753a2e3f6efca755dcf56892).
As the most critical "limiting factor" (and the most difficult to scratch build), the wheels were the first things I wanted to tackle and get out of the way. The wheels on the APC are one of the most recognizable features on the vehicle and I really wanted to be faithful in representing the wheel detail as best I could. In that regard, the Halcyon kit wheels were handy as the wheel cover detail was good but they lacked proper tire tread detail.
I used stills from the film and other APC pictures as references to make the tire tread detail and side armor plates. I made several side armor plates and tire tread plates out of styrene and then cast enough of them to make one half of a wheel. After assembling all the side armor plates and tire treads on a wheel form, I made a mold and cast all the pieces for the wheel assemblies. The flat wheel covers, which were reproduced as resin casts, were made from 1/4" styrene and the rims and center details were made from rectangular styrene stock bent and glued in place. I later added the four small access covers on each wheel with bits of flat styrene.
The resin cast wheel components consist of a flat hub plate and two half wheel resin casts that interlock together. Thinking ahead, but with nothing specific in mind about exactly how I would attach the wheels, I centered a hard point; a sturdy block of wood, into the hollow of each wheel and filled the wheel with polyurethane foam. The hard points would eventually come in handy for the R/C conversion which would require an axle and steering mechanism for each front wheel. While built to be light, I estimated that the APC would weigh in at about 65 to 80 pounds. I looked around for off-the-shelf steering parts for large R/C vehicles but found nothing that I thought would be up to the job. It would take something substantial to handle the load and steer the vehicle.
Front wheel with Traction Band
Front wheel mounted steering parts
Note: Lower flange is attached to wood block hard point embedded in the foam.
Note, also, the bronze bushings.
"Keep it simple, Numb Nuts!"
-- FNG, USCM
Front wheel steering is made completely from off-the-shelf hardware. Initially, I used a pair of pipe flanges to anchor each wheel to the hull for static display. The flanges would later serve as a foundation on which to build the steering mechanism; a very simple, effective, and most importantly, a sturdy assembly made from bolts, eyebolts, metal washers, and nylon spacers. For the axles, I used bolts and bronze bushings set into the pipe flanges. A simple tie-rod connects the two wheels and, all things considered, the kludged steering assembly worked well the first time out for the APC's trial run. It was both a great relief and a moment of joy to finally know that the cast resin wheels and the steering assembly worked. Unlike the real deal, however, this APC has only front wheel steering. I have a movie of the first trial APC run posted(http://video.tinypic.com/player.php?v=ve88w1).
Hull mounted front steering parts, and connecting rod.
Attached to the hard point of each rear wheel is an off-the-shelf rubber and plastic wheel with axle, and on top of that there are wooden anchor plates screwed to the wheel and keyed to index onto the gear motor drive lugs. Each wheel has a 2" rubber traction band around it and those are what make contact with the ground. So far, so good! Having done all that and seen the results, I thought perhaps the wheels would be able to handle some road work.
A Composite Rear Drive Wheel
Note the traction band, cast resin outer shell, urethane foam layer, an off-the-shelf rubber and plastic wheel, wood spacer, and smaller indexed wood spacer plate for mating with the gear motor drive socket.
Copyright © 2006 by Christopher Chulamanis. All rights reserved.