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Franksie

Matching Artfact and Worker Flywheels

Had a session with the digital vernier calliper and the micro gram scales tonight.  

Firstly, 6 worker wheels:



Two very closely matched pairs from this lot and two runs.  If you have a wheel that you'd like to swap from those two drop me a note and we can trade.

Next, 8 Artifact wheels.  No photo for these as I didn't have a white pen:

Weight(g) Diameter (mm)

5.24/34.94
5.41/34.95
5.41/34.91
5.30/34.95
5.29/34.95
5.46/34.90
5.19/34.93
5.28/34.96

2 decently matched pairs, 1 looser match and a runt pair again.

Overall,  this is a small sample size but the difference in tolerances between worker and Artifact are already evident.  Artifact have a spread of 0.06mm and 0.27g
Justajolt

I hope you took those measurements in a vacuum in a hypothetical universe where time stands still and that you accounted for all the neutrinos adding minute quantities of mass to those flywheels using some statistical jiggery pokery.
Franksie

Is there any other way?
Dustybin

But, neutrinos are almost massless. Also dust would add more to the mass than neutrinos, surely the neutrinos would not add mass due to weak force interactions and other quantum stuff.
Dan_jackson1985

Has anyone considered balancing flywheels? Maybe like you would a radio controlled plane propella. I imagine it would be tricky with stock wheels but possible with aftermarket.
blindgeekuk

OldNoob balances them as standard...
Franksie

That's what I was doing?
daniel k

So, which is better? But I only want the result if you have tested it with a Snikkas cage, a Artifact cage, every stock Nerf cage, and a BSP cage, in a vacuum.
blindgeekuk

If you want better grouping of shots, and lower noise, then balancing is great.

You need a decent amount to be able to find a good pair, and highly precise calipers and scales to take the measurements

As for cages. Anything machined will be better than plastic, and I know OldNoob has plans to do a proper test of stryfes with all the current options - I recommend donating via his patreon to help him out
https://www.patreon.com/foamdataservices
OldNoob

Dan_Jackson- Gravity balancing is possible BUT I have only done one set as a test, I was unable to find a gravity balancer that would take 2mm spindles, my friend lent me his micro aircraft prop one, it had no name or brand on it, he got it from another modeller.
The other issue I had was getting the weights (aluminium tape) to stay attached. The set that I did have now shed their weights.
What is needed is for the manufacturer to dynamically balance each set, the machine for this is about 5k so not a home item, but component balancing services are available and used a lot in industry. The problem is most of what we buy is made cheaply and with low quality tolerances.
Blasterparts flywheels are closest to my perfect wheel but they are TOO SMALL, which is infuriating as the shape and tolerances are superb.
What Franksie has beautifully demonstrated here is MATCHING not balancing. Matching transformed the performance of my gear, with greater precision and around +5fps vs toy tolerances.

Daniel_K- This thread has nothing to do with which is better, it's illustrating the process required to get a properly matched pair and looking at the TOLERANCES for both types. It's not a straight up money spending exercise. Franksie is showing you how to get the best out of your flywheels, not which ones shoot best. What shoots best is a well balanced, precisely built flywheel group. This has already been proven.

Being a smartarse about a proven and valuable way of gaining free power and precision just makes you look stupid.
Dan_jackson1985

oldnoob- I was referring to gravity balancing. I have used industrial balancers as u workerd at a place where we made diamond tipped wood working tools. These used a strobe light which flashed at the heavy point, I would then remove material from this area until the cutter was balanced. But these ranged from 12mm to 200mm dia. I do have an rc prop balancer but I'm yet to try it.

When you did it, did you find a definite inballance to rectify, or was it a little hit or miss?

I am currently toying with the idea of making my own cages and wheels, but I'm unsure If the performance gains would be worth the effort.

My thoughts:

Assuming the motors are running at exactly the same speed then the flywheels need to be the exact same size so that the surface speed during contact between the dart are the same. So I see matching sizes to aid spread/accuracy.

Then the weight needs to be the same so that they spin up to max speed at the same time. same again assuming the motors are exactly the same.

They could be dimensionally the same, and weigh the same but not be dynamically balanced due manufacturing or material defects. I imagine this would have the most effect on vibration and motor life span.

It would interesting to see how "matched" motors are. I'v had 6mtb  rhino's at one time and when testing them on the same battery pack they each had a slightly diffent tone to them.

Being a machinest I'm sceptical of injection moulded flywheels. The only way to make anything quality would be on a lathe, this is the only way too get true concentricity between the outer diameter and the centre hole.
Boff

Blasterparts flywheels look like they're CNC machined, not injection moulded. If they supplied a cage with a 2mm narrower flywheel/motor gap then it'd restore the original crush. Of course, you could create an even narrower gap to emulate the high crush seen in the artefact cages. As noted, they're pretty damn well balanced and superb quality, just too small! Very Happy

Cages are on the list of stuff to do.
OldNoob

Matching is the best most people are able to do, I recognise that dynamic balancing would be better but is outside the realms of home machining and taking material off existing flywheels is a non starter dye to thin wall sections on current wheels.
I felt gravity balancing was a bit hit and miss, i would rather start with a big sample and then pick the best pair as things stand.
People would buy a high crush, high precision dynamically balanced flywheel, which WILL need grub screw retention, this has always been my contention and until such wheels are available everything else is a stopgap.
Boff- I have a cage coming which increases the crush on Blasterparts wheels.
Dan_jackson1985

I recon that if they gave you a pair that had come off the cnc machine one after the other then they would be a better match, but chances are they are collected in a box then paired up at random. I'v worked production lathes. You check the last part off the machine and if it's within spec all parts collected in the box will also be within tolerance. The tooling would not wear that quickly machining non ferrous material so size drift would occur over a long period. The blaster parts ones made in Germany will be pukka compared to any made in china. I had a couple of German students at work they are very anal about everything!

Putting a grub screw in, good idea but could prove to be quite challenging for a number of reasons. I'm sure shaft size determains grub screw size. I would guess an m2 would be maximum the tapping drill would be smaller in diameter, it all gets a bit tricky. I'll have a look at my tools at work and see if it is something I could do.
OldNoob

There have already been metal wheels with grub screws in. I would like a hybrid with metal centre and plastic rim, that way you keep all the mass central and have the flex where you want it.
UKNerfWar

Static balancing like this is fine. It gives us good results and is good practice if you happen to have some drug dealer scales.

Dynamic balancing of such a small object is actually pretty difficult (or at least faffy). Low mass and a small radius make detecting and correcting the inbalance a bit tricky.

The answer is to make flywheels with CNC rather than moulding since the very nature of manufacture ensures that they are dynamically balanced. The Blasterparts ones are CNC turned which is why they are so wonderfully quiet. Unfortunately the development of the BP flywheels isn't very well documented so we can't deduce why the crush is so loose.

BritNerf flywheels are definitely on the cards. My lathe is up and running again after installing some fancy new roller bearings so I'll be messing about with some designs over the winter. Hopefully I can produce a few varients in the coming months and get some data on them.
Boff

I'll get a crate of darts and warm up the chronograph. Very Happy I don't know what the BP team were thinking when they knocked out their flywheels. Such a rookie error for such an experienced business. Unless they had stupid levels of foresight and foresaw the rise of 180 Hellcats and the European ballistics directive limiting things to 1J... Razz
OldNoob

They deliberately made the crush lower for better "accuracy" because someone should have given them better coffee that day.
DerpFails

OldNoob wrote:

-SNIP-
Boff- I have a cage coming which increases the crush on Blasterparts wheels.


Exactly what might this cage be? Where could I find it?

EDIT

Quotes should be shorter than your reply. ON

OldNoob

Custom build from a friend for testing purposes. It's not a production item. zip it's any good they might make one for release.
DerpFails

Will you make a video about it?
Justajolt

I think you can already see it on some foam data services videos... Correct me if I'm wrong...
OldNoob

Yes I made a flywheel matching video. I will do one on precise flywheel fitting as well.

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