Tag Archives: iterative design

Still thinking part infinity gauntlet

Basically I’m a non-stop thinking machine, grinding on the problem that is the Sprint-T. The problem I’m grinding on this time is quicker steering and more angle at minimum cost. I keep wanting to change the input on the steering box, but last night as I was staring at the ceiling it came to me that it would be much cheaper to change the steering arm on the spindle than to put a steering quickener on the input shaft.

Basically I buy this flat plate steering arm and drill 1 hole to change the ratio at the spindle instead of this steering quickener box which is more than twice as much and weighs more than twice as much and has no adjustability. The change in steering ratio is fixed by the gears inside the quickener, but I can change how much I speed up the steering by drilling another hole in the arm closer to the kingpin than the original 1:1 arm. I can make the steering as quick as I want, not just twice as quick, and unlike the steering quickener box, I get more angle to go with the faster steering. And the small hunk of steel is seriously lighter than the steering quickener box, a few ounces compared to just under two pounds. I can’t emphasize that part enough. The downside is that is unsprung weight at the spindle compared to sprung weight at the box.

Something else I can’t stop thinking about is the limit to angle is the tierod hitting something on the axle, which means I get the most angle by putting the tierod in front because of nothing to hit except the axle itself which is almost 180° of angle. I can’t actually get that because the drag link then becomes the limit as it hits the brackets holding the axle to the frame, but placing the tierod in front means one less thing to get in the way. And thinking about that makes me think that if I route the drag link under the brackets that hold the axle so that it can’t hit anything I have no limit except how far the pitman arm moves before hitting something or the limit stops in the steering box. If I drill the hole to make the steering arm effective length 3/4 the length of the pitman arm I get 120° total steering angle which TBH is way more than enough, but only 1.5 times as quick. Drilling that hole half the length of the pitman arm quickens the ratio by 2 times and requires less throw on the pitman arm.

So to summarize, by changing one part there’s no limits to how quick I can make the steering, and no limits to how far I can turn the front wheels to the side. That’s a win on multiple fronts.

Iterative design

I use a design process called “Iterative Design”. That is I make a design, then go back and look for mistakes before I freeze the design, or I make major changes and do a comparison to see which is better, then combine the best parts of both for the next iteration. This process grew out of “Trial and Error” which is an offshoot of “Cut And Try”. Anyway, that is the major reason why I take a completed design and make major changes or even start completely from scratch.

Of course some of the times I do that it’s because the design parameters were changed by factors beyond my control, as when the minivan donor vehicle became unavailable. That was an entire design that had to be scrapped, and started from scratch on the Pentastar lightweight replacement design. But the thing is I’m doing this because this is how I do things. Every so often I just click on “Start a new drawing” and start drawing a new design. Part of that is because I know I’ll never have access to the money or materials I need to build it, part is because if I stop creating I get antsy, and other psychological “issues” crop up. Fortunately I have two outlets for creating, this blog and planning the Sprint-T.

I have also been thinking about transcribing some of my poetry to the blog. Most of it is about 20 years old at this point, and the Y2K point-and-laugh in particular are a little dated (like Conan’s “Year Two Thousand” bits). But some are still pretty good if morbid, like “Musings On a Bird, Skeletonized By Ants”. Tell me what you think in the comments.

And it’s getting early in the AM and I have things to do tomorrow.