Lower rotating mass will inevitably lead to higher efficiency, but only if it can maintain sufficient energy transfer with that lower mass. There's always a balance. Of course with fewer blades, literal balancing of the rotor is also a crucial problem that needs solving.
Because we're talking about fans i have a question: if my fans are rated 1500rpm but i make them run at 1600rpm what could it happens to it?
Likely not much. As
@Ominence mentioned, fans are typically rated at +/- 10% rotational speed, so if rated at 1500rpm it might top out at anywhere from 1350 to 1650rpm. Of course if it tops out at 1500rpm actual rotation speed at the rated voltage and 100% PWM and you have to overvolt them to run them faster, that might cause the motor to wear out faster. Likely not much from such a small change though. A fan rated at 12V operation can often handle much higher (15-16V at least) for short periods, so a low overvoltage over time is likely entirely within its tolerances.
I doubt that. I meant the whole mITX market exists and they are are always thinking of ways to makes computers smaller and people buy that stuff.
Hm? I don't see how that's relevant. mITX is a standard. Heck, if anything, the SFF PC market is an excellent demonstration of how breaking standards leads to problems - try to google how many people have issues fitting the DTX Asus Crosshair 8 Impact into various SFF ITX cases, for example. SFF cases also tendt to be
very meticulous in documenting their clearances and limitations for non- or not-quite standardized things like radiator/fan fitment (not the size or mounting patterns, but if any can fit, how large, etc.), CPU cooler clearances, GPU size, etc. As for trying to make PCs smaller, the whole point is doing so
while maintaining compatibility. Look at the Dan A4 for example - the entire purpose of that case is allowing you to build a powerful PC with all standard components - ITX motherboard, dual-slot full-size GPU, SFX PSU. All accepted standards. There are plenty of proprietary SFF solutions from the likes of Zotac, but you can't build those yourself. DIY requires adherence to standards to work.
I clearly mentioned that thicker fans would be for those that do their own research and I don't expect them to fit everywhere.
But you're not accepting the inherent consequences of that, in (likely much) lower sales and limited compatibility. Of PC gamers (to pick a sizeable group with high performance PCs), only a small minority DIY build their PCs. Of those, only a small minority buy additional fans beyond those that come with their case. Of those, a large portion likely just buy whatever is cheapest as they discover free fan slots and are given advice online to just stuff it full of fans. So the people doing targeted purchases of brand-name fans? That's already a very small group. Adding "use cases where a thicker fan will fit and provide tangible benefit" is likely to make the target market so small as to be near meaningless. Meaning that with any significant R&D cost, these fans would become
ridiculously expensive. High end 25mm fans like the NF-A12x25 are already ridiculously expensive. Starting from scratch with literally every single part of the fan for a >35mm fan? I wouldn't be surprised if that doubled the costs from there.
How hard could it possibly be. Just give review units to LTT, JayZ, Bitwit and write in big bold letters, that these fan's won't fit everywhere. Done. And write that on your website and fan box. Now, truly done. You know, it's not like we didn't have 200mm fans or even bigger 240mm fans in computers.
You clearly have a highly optimistic view of how informed and rational people's purchase decisions are. Heck, even lots of people on these forums make poorly informed purchase decisions (excluding those who come here after the fact to seek help, which is not an insignificant group). But most people don't frequent tech/PC forums. Trying to inform your way out of breaking compatibility is a fool's errand, will inevitably mostly reach the people who already understand the issue (as those are far more likely to seek out these channels of information anyhow), and ignores entirely the game of telephone that is public discourse on any topic. Things get lost or transformed in transmission, and there's no amount of marketing or clear communication that can realistically overcome this. It can make a positive impact vs. doing nothing at all, but the problem will by no means go away.
That's because it's a pressure design, give that extra thickness to airflow design and it may do wonders.
That doesn't really make sense. The main benefit of a thicker fan is allowing for more pressure, as the thickness minimizes the effects of back-pressure resisting flow or flowing back between the blades. Also, if you look at the specs, it isn't really a pressure design - the 2200rpm 25mm Vardar is rated for 3.16mmH2O, while the 1800rpm 38mm Meltemi is rated for 2.75mmH2O. At speeds this low with fans this large, there ultimately isn't much you can do without
drastically increasing thickness - in which case stacking two 25mm fans is cheaper, easier, and likely as good. The 3000rpm version of the Meltemi is far better at 7.13mmH2O, but ... yeah, I wouldn't want that in the same room as me. The Meltemi is designed for a specific use case: pull orientation on thick, restrictive radiators, where it supposedly outperforms thinner fans due to specifics of its flow pattern and geometries. But you can't read that kind of stuff off of a spec sheet.
For that amount of trouble, might as well hire an HVAC specialist to install a separate AC unit for the case and just have a 1-2 fans blowing out the warmer air...
Ots a common case design but not the sort of environment used for testing fans
, my other is a 92mm x 38 and still going strong 12+ years later.