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Originally Posted by Blackeagle
Updates? ?
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Back in Australia again.
The Cascade SS and the G4 have been tested by Phaestus and should be heading back my way. Interesting results with the SS actually, and somewhat puts the regular Cascade to shame.
The G4 test was an interesting scenario. The G4 results, while excellent, weren't quite what I expected (I expected a little better).
Now I test with pure water. Phaestus tests with a 25% glycol mix. I am acutely aware that one of the principles in the operation of the G4 is more heavily affected by the kinematic viscosity of the liquid than some other designs. I had pretty much designed around kinematic viscosities typical of water/alcohol, but a 25% glycol mix is around 5x more viscous than water, and I strongly suspect that this is causing an issue. Certainly in the models, the kinematic viscosity is very important.
For example, in one of the accidental prototypes of the G4, in which the machinists had misprogrammed the block and left off the very things that makes the block do its job, and resulted in performance for me that was somewhat behind what Phaestus saw, basically falling to around regular copper Cascade performance.
As viscosity goes up, the effect of those elements is diminished as they are not "significant" enough to push the goop about in the way that they do with plain water. Get the goop thick enough, and they may as well not even be there.
So the plan is to very slightly modify the design to be slightly more goop tolerant, and also be a little less restrictive. These things were already planned before with a question mark, but with these results, will most likely go ahead.
I just need my blocks back again to emperically confirm the mathematical explanation to the results that Phaestus saw, and this will prompt the final design. As a result, I'll also have to include an explanation about not using >10% concentrations of glycol in one's mix to achieve best performance.
Once that is finalised, I can then get the G5 (silver) plans finished and get a prototype of that made up.
So yeah - slight spanner in the works until I can establish what the full story is. Nothing major, it just needs to be investigated, explained, and accounted for.