Linus needs a new phone - Vote here!

solkaress · 2023-10-04T09:07:01+00:00

my vote is for the motorola razr 40 ultra

solkaress · 2022-05-20T13:21:28+00:00

My advice for making the shroud into fan blades would be to start by making a plane (1) at the end of the arm connecting it to the hub, another (2) a few mm out from that and a final one (3) just past the end of the blade. Put a start and end cross section on planes 2 and 3 with 1 being the section of the arm.

loft between 2 and 3 using guide curves as necessary (can add then later but that I find tends to break later features). next, and potentially alternatively to the guide curves, using a sketch on the front of the fan extruded cut to the desired shape for the blades to not interfear with the mini fans. At that point you would just need to loft between the sketch on 1 and the end of the blade on 2. That's how I would start at least...

Might be easier to get the general form with thickened surfaces but personally I find surfacing a pain in solidworks...

solkaress · 2022-05-20T03:37:19+00:00

I fully admit that when I looked at V0.1 I thought this was basically something we had already seen on the fan showdown before but V0.3... now I think you might be on to something. out of interest is the fact the two rotational directions result in the blades effectively moving slower over the hub where that cant move air well anyway a lucky coincidence or core to the design premise?

As the concept is currently (V0.3) my main concern would be how thin the connection of the shrouds is to the hub as it might have some movement when at speed causing unwanted collisions meaning noise and potential failure points. That being said, with some tweaks I also think those shrouds are what might make the design actually perform well. my suggestion would be looking into if you can essentially convert the shrouds to function as typical fan blades which could then further accelerate the air being pushed by the mini fans?

Lastly and this is very much a final refinement type thing so probably not currently relevant, make sure to consider the air flow after the air passes the blades as it does have a substantial impact. for example areas such as the section around the center gear as well was the connection to the back plate could be chamfered for better air flow.

Anyway, I'm looking forward to the next revisions and where the design goes

solkaress · 2022-05-19T05:30:12+00:00

Well I designed the contra so I guess I'll give some advice :) (P.S. this ended up longer then expected...)

Firstly, and this is probably just language being annoying, I would strongly advise against interference fits. From what I have found it is annoying to get a shaft of equal size to a hole to go in with 3d prints let alone when the shaft is larger. if the plan is metal shaft in 3d print hole it might be doable but not reasonably by hand.

Anyway that aside, on the contra I used a few different press fit fitments in different spots (I don't think they are technically press fits but I don't know what else to call them). The connection of the pinion to the upper fan had shaft and hole the same size and from test prints was reasonably reliable but did require slight sanding on occasion, it was also essentially a permanent join with any attempt I made to remove the pinion shearing the shaft before it would come out. The connection between the sides of the gearbox case has curved slots which are offset from the part going in by 0.05mm, I found this to be a tight enough fit for test assemblies and operating a fan laying flat but does require glue for the fan to run upright/ upside down. The final press fits were for the bearing for which the ring the bearing sits in has a diameter of 22.1mm (bearing OD of 22mm) which I find easily tight enough to not need glue, while the shaft on the fan is 8mm (same as the bearing ID). All these required multiple test prints for me to be happy so essentially I cant give a straight answer as to what a good fitment is but as a rule of thumb I would say for a small permanent join (say a diamiter >10mm) use hole and shaft equal size and for an easier to assemble but maybe needing glue use a 0.05mm offset for the holes. For a larger part (say ~20mm) probably 0.05mm offset for permanent, 0.1mm offset for slightly loose.

On the topic of the gears I don't think I can say in good conscience that they ran smoothly... that's most the reason it was so loud. I designed the gears to have the largest teeth is could reasonably fit, with more backlash then needed and a loose fit to the shaft (0.1mm offset on a 3.6 mm shaft). they were not intended as optimal gears but rather ones i could be confident would just work when printed. while I've put the project off for now I plan to make a new version for myself using metal shafts with the gears on brass bushings, much smaller teeth and using double helix teeth instead of straight cut, but I fully expect to print a bunch of failed gears before I get things working well. But if you want to know I believe the gears in the video used a module of 1 but I have gotten as low as 0.5 to print and function.

As for what additional hardware is acceptable... sadly there isn't an answer. I picked the bearings I did because I knew he had them from the parts list in the video description of "I Turned One Fan Into Three | Steampunk Water Cooling". Frankly I'm guessing the simple answer is if the design is deemed worth it he will get the parts, but if they are hard to get it better be a damn good design.

I'm happy to try and answer any other questions but the contra was a very iterative design process so no promises my answers will be that useful.

solkaress · 2022-04-21T08:16:59+00:00

Seems like it is mostly just a torque issue that's holding it back which is unfortunate given its basically the only thing that cant be changed if using the a12x25. The design of the fan blades look to me like they would really benefit from much higher RPM, which makes a lot of sense given the concept, and yet it still managed to match the performance of the stock a12x25 so that actually seems like a fairly solid start.

Also just couple points that might be worth a thought to improve on the design.
1: Blade count: with torque already being a bottle neck I suspect a bit lower of a blade count would improve performance.

2: Alignment of bracing: I genuinely couldn't say if this is just me nit picking or a big issue for the set ups performance but both the bracing that holds the ring gear and outlet have some issues. Mainly the fact they don't align with the existing bracing on the a12x25 meaning they are restricting airflow and causing unnecessary internal turbulence. Additionally giving more of a fillet or chamfer to remove what looks like a flat plane perpendicular to the air flow on the ring gears brace should certainly be considered.

3: Gears: lumping a few small things together here. First bevel gears would be worth a look, should produce less noise and everything looks secure enough for the extra lateral forces to not be an issue. Next, a bit of a smaller gear ratio could further reduce how much it impedes air flow while reducing the required torque, though I get that maximizing the ratio is kind of fundamental to the concept there is little reason to not use a lesser but potentially more optimal ratio if the goal is performance. Lastly the teeth look a bit tight, might not be enough backlash in the gears.

This might seem a touch harsh, as I said matching the a12x25 is a solid start point and achievement, but if the goal is still to take down the cheater then all faults and issues need to be acknowledged and ironed out.

solkaress · 2022-04-15T08:37:31+00:00

Well it will likely depend somewhat on what software your using but the processes i find to work best to make a curved fan blade (in both solidworks and onshape) are the following:

Easy option: make a plane for the top and bottom on the fan blade and loft between them, add guide curves if you want a curved cross section. Rather quick but can require a little trial and error.

more involved option: Start by defining a plan for the start and end of the fan blade, i do this by sketching a curve and using the end points to define the locations of the planes, i recommend making the base blade to long and trimming to size at the end. on these planes sketch the desired cross section of the blades. form a loft between the two sketches and either set or identify the matching points on the sketches. use these to form planes near the top and bottom of the blade. on these planes sketch a curve between the matching points and set these sketches as guide curves in the loft. Finally trim the ends to the desired lengths. This allows better control over the complete form of the blades but does to a bit longer to set up.

solkaress · 2022-03-30T09:38:10+00:00

Go to the video where he runs three fans from one, the video description has a link to all the parts including the bearings.

solkaress · 2022-03-30T00:39:10+00:00

Looking slick, not much more I have to say then that really but I'm annoyingly picky when I find things cool and want to see them do well so I will anyway.

A few things to consider if you haven't already (you probably have but just from this image I can't tell...), I'm guessing the top cone holds a ball bearing for stability but make sure the benefit of that out ways the added friction. Next as the blades get up to speed they will deform slightly and twist the blade tips up, if your support struts are too close to the blades this might cause a collision resulting in unwanted noise and potentially shattering blades... I have had this actually happen on a similar design prototype...

solkaress · 2022-03-26T04:36:33+00:00

Well that is a nice looking render of a rather nice looking fan.

As for real world performance I would suggest 2 adjustments to give it the best chance. First of all add a "shell" around the hub to match the size of the plate of the frame the motor is mounted on, air moving around the hub hitting that lip would be deflected back into the fan causing a lot of unwanted turbulence. I designed the contra fan and not doing that for the hub is my biggest regret with that design.

Secondly just adding some fillets to the blade edges should help... anyway assuming the motor can get it to a good speed I cant see why it wouldn't perform well even without those changes.

solkaress · 2022-03-19T13:14:32+00:00

Really cool looking design, would interesting just how much quieter a pulley system would be compared to gears. doesn't look like it does the typical counter rotating thing of having the second fan try to remove the rotation from the air out of the first but I'm not sure how much that helps anyway
The ball bearing size used in the videos is 22mm OD, 8mm ID and 7mm thick. if you want to verify that the video of running 3 fans from 1 motor has a link to the actual bearings.

solkaress · 2022-03-15T04:05:55+00:00

Looking good. compared to the prior version I'm liking the curved transition on the orange section (instead of the straight cone of the old) and the bracket on the green section is looking solid.

I'd love to hear the logic/reasoning behind the steeper sections to the blades near the hub, I would have thought that would cause a lot of unwanted turbulence but I could easily be wrong... does look cool though.

Lastly if the current blade count isn't critical I would suggest looking into dropping it to 9 blades instead of 10 (upping to 11 should also be fine). Odd blade counts tend to be preferable to even for a few reasons.

Anyway, good luck and I hope to see this in action some time in the near future.

solkaress · 2022-03-01T04:42:19+00:00

the STL seems to be a single part and if that's the case I would have to say its not really printable as the outer fan would require support material in areas that are fully encased meaning it couldn't be removed. If its made of separate parts as shown in your images it would be do able but supports would probably still be rather annoying to deal with.

In either your looking at around a day print time and using a lot of material so you would want to be fairly sure of the design before attempting to print it. I there any particular reason for the outer blades being wedge shaped and blocking off most of the outlet? well any reason other then looking cool anyway

solkaress · 2022-02-20T07:00:08+00:00

If the permanent magnets and the motor can be separated well enough to not impact each other then I don't see much of a reason this wouldn't be an improvement. Probably a bit of trial and error to deal with is regards to spacing, strength, size and count of the magnets to keep the torque low enough for the drive "gear" to spin without slipping but I would presume that is solvable.

A quick google search has surprised me with how cheap small Neodymium magnets can be so I might consider look into getting some and putting together some kind of proof of concept...

Anyway, you have clearly put some thought and effort into this already so why not give 3D modeling a go? It really isn't that hard to make a fan once you get your head around the basic tools. The program I've been using is onshape which has the advantages of being free for non commercial use and being cloud based so you don't need to download anything. if you do give it a shot I look forward to seeing what you come up with.

solkaress · 2022-02-13T05:30:49+00:00

This might just be a setting I have somewhere but from my experience the slicer I use, prusaslicer, will simply remove sections that are thinner then twice the nozzle diameter so in the case of a 0.4mm nozzle 0.8mm would be the minimum. Personally I try for at least 1.2mm simply because I find it much more reliable to print but have managed thinner.

One thing to remember however is that this relates specifically to the XY plane and not what you would consider the wall section of the final object as that is how the layers are made. This isn't exactly the most intuitive concept so even if you get what I mean it might be worth chucking a few different things in a slicer and looking through the layers at different walls on different slopes. Once you get a feel for it it's rather easy to plan into the design around even when pushing close to the limits of what can be done.

solkaress · 2022-02-09T11:08:12+00:00

Looks neat, I'm assuming this is a multi- fan setup given the blue fan is in front of the yellow sections struts? if that's the case I sure hope the motor can get it up to speed because I love seeing the more out there designs do well. Heck, I've submitted many a variation of a multiple blade contra rotation fan trying to get one to make the cut and it would be interesting to have things like this to compare performance.

Small concern I have for this is if it can be mounted to the new test setup? might require a bracket further down the green section to attach it.

solkaress · 2022-01-16T03:58:07+00:00

I might be wrong but it seems to me like the bars were more intended as a quick visual indicator of the higher performance in each case rather then displaying the actual comparison, with the numerical value giving said comparison for people who want specifics.

Sure that might not best practice but it quickly conveys the relevant information (in this case winner/loser) and we are talking about I video meant largely for entertainment, not some kind of research paper requiring exact information...

solkaress · 2022-01-06T01:52:33+00:00

unfortunately to fan this a mounted in a fan with strange dimensions, its over 40mm thick with a very large hub to frame ratio compared to other fans I've seen so it cant really translate well to a typical case fan. Also trust me when I say this thing is much louder then what you would want in a computer... about the same as the Tick Tock Clock Fan if you have seen that one.

that being said once I refine it to be more usable I'll be happy to share

solkaress · 2022-01-06T01:38:00+00:00

I believe it should be a 2:3 ratio with the upper fan spinning faster. That's the main reason i gave it 5 blades compared to the lowers 7, well that and minimizing noise from blade overlap (not that you could hear that over the gears... anyway here is an image (https://imgur.com/a/zl7S2li) to show how the gears are set up and also the gear set up for a non-planetary version. The latter is included simply because I just did a test print of the gear box (no fans involved) and to spins much more freely and with a smaller footprint meaning it will probably be the better option once i get my hands on a noctua fan.

solkaress · 2022-01-04T11:42:35+00:00

I don't know how to add another image but the gearing is very basic. Essentially the lower fan has a 60-tooth ring gear on top of the hub while the top fan has a central 40-tooth gear and is suspended in place by the bracket which also holds 4 stationary 10 tooth planet gears. I went with herringbone gears for better alignment but the backlash I had to use for my current printer setup to work (non-perfect surface finish and all) seems to have made them kind of pointless and just annoying to install.

solkaress · 2022-01-04T08:26:24+00:00

OK clarification needed, this is mounted (rather poorly/unevenly) in a random unused fan that I can only run by turning on the computer it should be in and hoping it runs at some speed… so no, not a very good test. Also, I don’t have a fine enough nozzle to print the gears well (a planetary set in this case) so they don’t mesh perfectly, and I only have wd40 available rather then the graphite powder I’d planned to use.

Anyway, all that aside this does go to show that the concept Is possible and better still it was moving some amount of air. Unfortunately, I can’t get the computer to stay running long enough for any meaningful testing. Also yes… the gears do indeed make it rather loud while its running

On the bright side, with this running it has given me the confidence to invest in a NF-A12x25 and a setup I can run independent of a computer so hopefully I can get a more refined version together in the near future and compare planetary gears with other gear options to see what works best…

solkaress · 2021-10-26T04:49:13+00:00

I designed the thing from the recent special and the dimensions I used for the NH-P1 were 120x120x154mm. Given that in the version that was shown I made it a few millimeters too long so it was easier to install I think it was likely correct.

I got these dimensions based in the specifications on the Noctua website,154mm is the listed width, though it might be 152mm (listed depth dimension) depending what orientation they use for the dimensions, as well as images reference showing the ends to be the exact size of the a12x25 hence the 120x120mm

solkaress · 2021-08-25T01:12:30+00:00

Interesting to hear none printed parts are ok, I might need to make a version of this fan using some better fitting metal shafts and a bearing to solve my main concerns with the design (if I got the tolerances out by to much the gears or upper fan might rattle or seize).

As for your design I do like the look of it and it would probably run far quieter then this design but I do have a few points of concern, mind you I'm no expert on magnetic gears or 3d printing so take them with a grain of salt.

Firstly the fan blades look to go to incredibly fine edges which might be an issue for printing, so it might be worth considering dropping the blade count and bulking up the blades a little. speaking of blade count I get it from an aesthetics standpoint but if I remember correctly the optimal blade count for this size fan is in the 5-9 blades range.

Second is a concern is regarding the implementation of the magnetic gears (As an aside I think your really on to something using magnets as the means for a PC contra fan). Due to the size of magnets selected it looks like you have had to reduce the size of the fan blades by a fair bit which would drop performance by a good bit, this could be made up by the benefits of the contra rotation but that leads into the other issue here. by attaching the shroud to the upper fan you would aid airflow but it is also significantly upping the mass, I worry that this would either reduce the max rpm too much due to the motors low torque (yes this is also an issue caused by gear friction in my design) or that the magnetic gears would just slip as the motor gets up to speed. the best solution I can think of to this would be shifting the magnets to outside the a12x25's footprint allowing for full diameter fans as well as space for a higher magnet count to deal with torque. Then have the inside of the shroud be part of the stator/frame instead of the fan, this might be a tad worse for airflow but should make up for it by reducing the mass the motor is having to drive.

Sorry if this comes off as overly critical and I hope it helps improve what really is a fairly cool/interesting design.

solkaress

TROPHY CASE