On April 4, we added the necessary 20-ton shop press to our tool inventory. That evening, Byron built a special tool and jig for bending track turns quickly and easily, relieving us of a major source of frustration. We also moved a few shop tools around to accomodate the upcoming production tasks involved in laying the final ride track - a task that will begin in about two weeks. Also added to the shop is a sink for washing hands. The stainless steel legs for the massive welding table we use finally arrived - after a very prolonged wait. Now we don't have to worry about the darn thing falling over on us!
Here's a tip for you folks just beginning to consider fabricating prop mechanisms - check out McMaster-Carr (www.mcmaster.com.) This amazing and highly professional company stocks every kind of bushing, wheel, spring, shaft, tube, gear, pulley... whatever you need, and they ship to arrive within two days - usually overnight. The prices will be a bit higher than if you found a specialized supplier for a given type of part, but time is money in the prototyping process. You won't find this kind of always-in-stock availability with Grainger or other local suppliers. You owe it to yourself to visit their website.
Our drive wheel - for instance - was obtained from McMaster-Carr. It's a massive (20+ pounds) disc of cast iron wrapped with a specially formulated hard rubber tire that grips track with very little tensioning, and Byron informs me that it it is unlikely to wear out even after several seasons' use. It also serves as a flywheel, resulting in easier passage over tight turns and smoother startups ans speed transitions. This part is seriously overbuilt, and looks like it might well meet Mil-Spec.
Earlier in the week, we disassembled Lizzy and looked at all the parts and welds for wear. (She has broken in well, and is now more peppy than ever.) We're happy to say that there was virtually no wear after many passes around the teat track with wierd and heavy loads. [There's a little platform overhang on the rear of the car (see previous page) that two people can ride on as if it were the rear gate of a fire truck - if you're crazy enough to try it, and strong enough to hang on through the turns, it's a wild experience!] The 1/2 HP motor complains not at all about hauling this weight at 4.5 F.P.S. So long as all the clearences are clean, the car will even start up on a sharp turn. That bodes very well for the new motor, which should arrive on about the 15th of the month. It has less horsepower at low speed, but will be driving the car through a Cyclo-Drive with a much more friendly gear ratio.
We're looking into the feasibility of going straight to fiberglass bodies this year, but the final decision will come late this month. The powers that be like the idea of nice streamlined cars, but the making of a mold positive is a fair deal of work. You'll know more about this within a week after we decide what to do.
Through Sunday, April 7, we continued to clean up and re-arrange the shop area to make production faster and easier. Tool tables for the lathe and milling machine are in place, and more organized parts storage is a reality. Byron once again re-drew the plans for the Charon I, prior to leaving us on Monday for another two-week stint in Canada.
He spent time on Sunday afternoon checking dimensions of actual parts to see if they would all fit together properly. We'll be placing the order for laser cutting of the drive platform and the new rear guiding truck within the month, so we want to be sure that it won't need extensive shop modifications after the parts are finished.
After you've come this far, you take the time to sit down and mull everything over. We seem to be well within our time track, and once daunting tasks now seem quite within our capabilities. We have convinced the last of the sceptics that our basic design is viable. The only part we have any concern over is the hot rail pickup assembly, and that's because - due to the lack of test materials - we haven't yet been able to install the complete hot rail system on the prototype. However, these tests should be underway by the 15th of April, and we'll know what we have to do to make it work. I have several alternate designs in mind, and one of them should be a keeper.
The main concern in regard to the pickup shoe is that it must not drop power. If it does, the car drops back to slow speed from high, due to the safety-driven nature of the control board's relay logic. Our task is to find a method that assures the continuity of power supply within a ride zone. If it isn't already apparent, when a car switches zones, there will be a 'break before make' situation in the hot rail. In other words, no two zones' low voltage hot supplies must ever contact each other through the pickup shoe. In a zone change, the pickup will cross a plastic spacer, and this will cause the car to lose power momentarily. When this happens, the logic will drop it back into low speed automatically. Consequentially, speed changes within a zone must be considered such that the car will not need to be in high speed across a zone change - or if it is, such a speed change must be convenient to the layout design.
We've made a modification in the on-board logic: it will use 24V to switch the relays. This is primarily because there will be partially exposed sense switches on the lap bars, which are of steel. This adds about $25 to the cost of each car, but that's a mere sneeze for the benefit of passenger safety.
Although there's much more work to be done, all of it should present some fun in the doing - or so says the optimist in me. Stay tuned. :-)