Impellers
In the Modern Maid above, the cant of the dishes in the bottom rack naturally applied a circular water pattern when the water deflected off of them, thus sending water up to and spinning the rack.
I can weigh-in on the impeller/water-usage debate. The 1960 Frigidaire (sourced from D&M) impeller top-loader I have (thanks Robert > Ben ;-) ) uses very little water, if you don't count the purges to heat the water/tank and flush particulates. (It also does what it does with one long wash and two slam-bam-no-kiss-even-afterwards rinses, for a cycle time of like 22 minutes.) So I can understand the idea.
And I will say that, in my experience, the stainless-steel GE impeller machines wash circles around the Bakelite impeller machines and have way better racking. If you get one with the PowerShower on top, things just get better.
That said...
Several factors would affect why this would not be a good idea today:
1.) The shrapnel effect. Impeller machines wash with a lot of force but not concentrated directionality. They break glasses and flip things over depending on how items in the bottom rack direct the water, and anything that gets down into the impeller gets sling-shotted around in the dishwasher with incredible speed and force, possibly damaging the impeller and other dishwasher contents. No fun. Many a screen and guard was put in place to prevent this, and the stainless-steel impeller mostly protects itself, but it's not fun to encounter it. One of the nuts off a screw on the rack of my Hotpoint came loose in the tank and made it into the water stream when we were testing it, and you'd have thought it was World War III. Compare this knowledge with the interest that the average home user has with interacting with their appliances, and tell me that it'd go over well
2.) No filtration. Even if you added a passive/secondary filtration system, it doesn't lend itself well to this.
3.) Perfect loading means possibly acceptable results. Because plates in the bottom rack (and preferably flattish, not deep-cupped plates, because that affects water angle) basically create the wash environment for the items above, things like partial loads and/or placing bowls down there dramatically change the wash pattern (I'll take vids of the 1960 and show you what I mean); in fact, bowls tend to accept too much force, misdirect the water, and eventually get thrown to the corners of the tank over the course of the cycle (see broken-glass issues mentioned above). If you don't have a full load of plates to direct the water upward, then the water cannot go straight up to the top rack, and basically, all the water surges up the sides of the machine and never even hits the top. I find this aggravating and I'm an appliance fiend--again, compare this with your average, disinterested home user (or even my ex, who is continually confounded by the comparatively forgiving KDS-15), and tell me this will fly. In fact, the only reason I get passable results with the Frigidaire impeller machine is that the Plexiglas top Robert fashioned lets me monitor what's getting water and what isn't, and allows me to adjust the load accordingly. If I had the steel top back on it, I'd be forever pissed
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4.) Large, funky, or deep items--there's nowhere they can really go, and even the forcefulness of the impeller does not create a water stream that can go big distances. Deep tumblers in the top rack seldom get clean, unless they're right over a plate that sends the water all the way up to them. And people are used these days to dishwashers that allow you to stick a stock pot in the top rack. They're also used to machines that remove burned-on food, and I've never had a load get clean in that 1960 that didn't get pre-washed by hand first (which is probably a function of the short cycle time, but still--it reminds me of my 1975 GE dishwasher, which could seemingly even get clean dishes dirty after all was said and done).
I think that wash-arm systems--although, increasingly, ones that do the job without running them all at once--are just the way to go when you have little water volume and the need for extreme loading flexibility.
Oh yeah, and one more thing:
5.) Noise. Anyone want to raise their hand and tell us about the impeller machine they couldn't hear running? :-D Roger's Mobile Maid is so vicious that it scoots around the kitchen while it's washing, and we couldn't hold a conversation in the living room when it was running in the kitchen. The Frigidaire D&M I have is quieter, especially when fully loaded, but makes about as much noise as the KDS-15, which likewise necessitates turning up the volume on the TV in the living room. If water striking the tank makes noise, then having a machine design that basically operates on a basis of doing that constantly is tough to engineer around.
Maybe it'll be GE's next BOL design, though--it could hardly be worse than the turbine pump with no filtration, and with a long enough cycle and the Calrod on all the time, it might just work! :-D
Who knew back then they'd be collectible someday I sure didn't. I was more into my platform shoes and I kept them,, here they are and they still fit LOL
