Author Topic: humming fly wheel (Read 18181 times)

DaveH · « **on:** April 22, 2011, 09:58:22 AM »

I would like to make a fly wheel that hums as it goes round. (Or even whistle dixie).

Remember those humming spinning tops? from the 50's - well something that hums like that.

Any sugestions?

Fly wheel diameter approx. 3"

DaveH

Blade · « **Reply #1 on:** April 22, 2011, 03:58:40 PM »

Maybe you could look at old siren designs for ideas.

Bogstandard · « **Reply #2 on:** April 22, 2011, 04:04:48 PM »

Dave,

Have it ringing a bell each revolution, it will be easier.

John

j45on · « **Reply #3 on:** April 22, 2011, 04:16:57 PM »

I cant find any info on the net as to how they work but you can buy them quite cheaply
http://gyroscope.com/d.asp?product=HUMMING
then you could figure out how it works and copy it

John Hill · « **Reply #4 on:** April 22, 2011, 04:27:51 PM »

I think you need interrupted air flow to make it hum.

Perhaps hollow spokes open near the hub end and hollow right through to holes in the outer rim, put something near the flywheel for the air to impinge against. If you can get your engine up to 10,000 rmp or so you will have a siren!

Thinking further, you might not even need the holes at the hub end, just hollow spokes with holes in the flywheel rim.

DaveH · « **Reply #5 on:** April 22, 2011, 04:29:36 PM »

I have also looked, didn't find much - did find some whistling yo yos.

So probabily needs to be hollow - with some holes in it.

Seemed a good idea at first, - now I'm not so sure.

Surely someone must have some thoughts.

DaveH

John Hill · « **Reply #6 on:** April 22, 2011, 04:34:54 PM »

Still thinking....... if it is a solid flywheel just drilling radial holes might be enough but I fear it might be impractical in a small model as to get pleasing audio frequencies it may be necessary for the flywheel to be a foot or so in diameter.

DaveH · « **Reply #7 on:** April 22, 2011, 04:37:19 PM »

John,

10000rpm I was thinking in the range 50 - 100rmp.

What about holes drilled radially on the periphery of the flywheel towards the hub, with a small holes near the hub.

Well I know what I mean

DaveH

DaveH · « **Reply #8 on:** April 22, 2011, 04:39:56 PM »

Quote from: Bogstandard on April 22, 2011, 04:04:48 PM

Dave,
Have it ringing a bell each revolution, it will be easier.
John

Ring my bell

DaveH

DaveH · « **Reply #9 on:** April 22, 2011, 04:47:48 PM »

I can make a hollow fly wheel that's not too difficult - where to drill and what size and number of holes seems tricky

DaveH

DaveH · « **Reply #10 on:** April 22, 2011, 04:50:00 PM »

Kenneth,

Slowish 50 - 100rpm Hub about 1/2 inch or so.

DaveH

DaveH · « **Reply #11 on:** April 22, 2011, 04:56:57 PM »

Has anyone seen a whistling yo yo.

Wondering how they work - number of holes ect.

DaveH

BiggerHammer · « **Reply #12 on:** April 23, 2011, 09:21:18 PM »

The old Duncan company sold many different whistling
tin yo-yos. These varied in size and had many different
designs on them. Many patterns were very colorful like
the one pictured here, with very detailed logos. Others
were simple one color models with an ink stamped logo.
All of them had one thing in common ... a tin outer shell
with two to four quarter inch holes on the outside edge
of each half. As the yo-yo spins, air is drawn through
these holes, creating a whistling or humming sound.
Each half usually had a different number of holes. This
was clever because each half would make different
sounds at different speeds. I want more tin whistlers.

Found that.

Now a question. Does the flywheel itself have to whistle or could you mount a plate with holes in it or a tube with one closed end in close proximity to the flywheel and let the air being dragged by the flywheel make a whistle? Not sure if the physics would create the desired effect though.

And my idea would be to Drill holes in the flywheel and insert closed end tubes into it. You could then change the geometry of the tube end until that puppy whistles.

DaveH · « **Reply #13 on:** April 24, 2011, 05:00:47 AM »

Thanks BiggerHammer,

Worth a try I'll see what happens

DaveH

BiggerHammer · « **Reply #14 on:** April 24, 2011, 09:21:33 AM »

Quote from: John Hill on April 22, 2011, 04:27:51 PM

I think you need interrupted air flow to make it hum.

Perhaps hollow spokes open near the hub end and hollow right through to holes in the outer rim, put something near the flywheel for the air to impinge against. If you can get your engine up to 10,000 rmp or so you will have a siren!

Thinking further, you might not even need the holes at the hub end, just hollow spokes with holes in the flywheel rim.

Oooooo..... looks like I had the same ideas as you with only minor differences. You were here with the ideas first and a more accurate description. I guess I should have read the responses a bit more thoroughly. My apologies. It was late and a long day at work with a 3 hour commute home.

DaveH · « **Reply #15 on:** April 24, 2011, 11:50:30 AM »

Well drilled two holes in some 3" dia. Ali. Then spun it in the lathe.

I think I get more wind noise from the jaws than from the holes

Although I am bit wary of placing my ear too close!

I have the feeling more holes, or it might need to be hollow.

What we need here is a musical physicist

DaveH

BiggerHammer · « **Reply #16 on:** April 24, 2011, 04:42:08 PM »

Well, if all else fails you can duct tape some deer whistles to it.

What size are the holes you drilled in the aluminum? could you stick some drinking straws in them with the ends cut at an angle? Let the straw protrude from the flywheel so it can catch air? Trying various angles to see if any work? There may be a boundary layer of slower moving air near the flywheel. The flywheel may be "dragging" the air with it. Not much on fluid dynamics here, (yes, air is apparently a fluid

) but I know it can happen when an object like an airplane moves through air.

Though I have looked at some whistling arrowheads and deer whistle designs. You may be able to incorporate the arrowhead design into the flywheel.

It might also be cheaper and easier to make the prototypes out of wood instead of metal. Just from looking at the arrowheads you might try drilling the holes at about 45 degrees off center of the flywheel center.

BiggerHammer · « **Reply #17 on:** April 24, 2011, 04:55:09 PM »

Just found this. I think it may solve your problem. The Chinese YO-YO or Diablo.

http://hua.umf.maine.edu/China/ModernBeijing/pages/286_ChineseYoyo.html

DaveH · « **Reply #18 on:** April 24, 2011, 05:14:32 PM »

BiggerHammer,

Thanks very much

Looks very promising - seems my round holes is not the way to go.

Some thin slots and a square hole may well work.

I'll give it a go

DaveH

John Hill · « **Reply #19 on:** April 24, 2011, 05:21:41 PM »

Quote from: DaveH on April 24, 2011, 11:50:30 AM

Well drilled two holes in some 3" dia. Ali. Then spun it in the lathe.

I think I get more wind noise from the jaws than from the holes

If it was my lathe the box full of straight cut gears would overcome any whistle noise!

I think it might work if there is air flow and something to interrupt it. The radial holes in the flywheel would give the air flow (I think

) but they would have to be open at the hub end so air can flow right through then if there was a plate close to the rim at some part of the circle that would interrupt the air as each hole went past.

My feelings are that it will be quite hard with the low RPM and the small diameter of the typical models we play with.

Does your intended engine have an air exhaust? If so it might be practical to route that near the flywheel and use the exhaust as the source of air flow.

DaveH · « **Reply #20 on:** April 24, 2011, 05:48:09 PM »

Hello John,

I think I am battling a bit here

I've used up all the empty containers I could find. Drilling lots of holes different sizes ect.

The link from BiggerHammer could work, just have to find some more tins/container to mutilate.

I am going to try the slots - might work.

I am making some (4) finger engines for the grand-kids, I just thought I might be nice if they hummed as they went round.

I really must stop this thinking - it's detremental to my health

Seemed a good idea at the time.

DaveH

Bogstandard · « **Reply #21 on:** April 24, 2011, 07:56:57 PM »

As I said before Dave, stick a one per rev bell on them, much easier.

John

foozer · « **Reply #22 on:** April 25, 2011, 12:37:38 AM »

Just an old baseball card tracked against the spokes ought ta do it

Robert

DaveH · « **Reply #23 on:** April 25, 2011, 07:13:52 AM »

Aaaagh I thought this was going to be easy.

That bell sure looks good John

I'll have one last go with slots, if I can't get it to work, I'll call it a day.

I would like to thank everyone for the help and suggestions.

DaveH

doubletop · « **Reply #24 on:** May 18, 2011, 06:39:59 AM »

I'm on the same wavelength as Johns simple solution. How about a piece of stiff cardboard held in place with a clothes peg? Used to work great on my bike when I was a kid

Pete

DaveH · « **Reply #25 on:** May 18, 2011, 01:48:44 PM »

Hi Pete,

Wasn't going to have any spokes on the flywheel.

I've sorted it out thanks, works quite well

DaveH

doubletop · « **Reply #26 on:** May 18, 2011, 03:37:58 PM »

David

If you've got it working you realise it needs a video then..............

Pete

DaveH · « **Reply #27 on:** May 18, 2011, 04:42:42 PM »

doubletop,

What I do is when the flywheel is going round I stand next to it and hum, no particular tune just a single tone hum.

It would be a terrible video to watch, I really could not subject any of you to such visual torment.

DaveH

doubletop · « **Reply #28 on:** May 18, 2011, 06:42:56 PM »

Quote from: DaveH on May 18, 2011, 04:42:42 PM

doubletop,

What I do is when the flywheel is going round I stand next to it and hum, no particular tune just a single tone hum.

Oh go on; we've all seen much worse on YouTube

Pete

picclock · « **Reply #29 on:** May 19, 2011, 11:12:08 AM »

Hi

I have no experience of this but .. .

to create a note by airflow a thin membrane with a resonant chamber is normally required. If you look at a clarinet or wind instrument they use reeds, brass instruments use the upper lip of the player. Spinning tops hum because air drawn in at the centre resonates inside the cavity, before being expelled at the edge, kinda like a mouth organ.

So IMHO you need airflow and a thin membrane or reed to create the sound and a cavity. Sound can be created by cavity resonance, without a reed, blowing over the top of a glass milk bottle, but the conditions for this are not easily set up and are fairly critical, also your flywheel will have to have a very large cavity to get into the audible range, which for maximum sensitivity needs to be around the 100 to 3000 Hz range.

At 100 rpm I don't think there will be sufficient pressure, even at the circumference. Even a spinning top has to be running at speeds well in excess of that.

However I think it may be possible to cheat

By attaching small magnets to the outer part of the flywheel it should be possible to cause a sheet of card or fibreglass to act as a sounding board with a magnet or metal piece attached to it. Alternately, if you make the outside of the flywheel castellated (or just aluminium with steel inserts) you can just use a single magnet attached to the sounding board. Obviously the tone will change frequency with the speed of rotation giving the illusion that the wheel is humming. If the sounding board is tuned to resonate at say 200 Hz this would make the sound fade as the speed reduced.

Just my 2 cents worth.

Best Regards

picclock

websterz · « **Reply #30 on:** May 19, 2011, 03:38:34 PM »

Pull the drum and pin assembly out of an old wind up music box and mount it on the flywheel axle.

doubletop · « **Reply #31 on:** May 19, 2011, 03:39:24 PM »

I see support for the cardboard and peg solution is gathering pace. Picclock's version is just a bit more elegant and he has done a good job in justifying it.

Edit

And Webertz proposal is a more elegant version of Bogs suggestion of a bell.

Pete

Imagineering · « **Reply #32 on:** May 19, 2011, 05:41:36 PM »

This is a Steam/Air Engine right?
So, we have a stream of compressed Steam/Air at the Exhaust right?
So, why not Drill a series of Axial Holes in the Rim of the Flywheel and direct the Exhaust at the Holes?
It may very well whistle, rather than hum, but I guess that any noise will do, right?
It may also be possible to drill a series of Radial Holes around the periphery of the Flywheel to achieve the same effect?

Murray.

DaveH · « **Reply #33 on:** May 20, 2011, 06:20:16 AM »

Murray,

A bit of clever thinking there

Might work.

It's finger operated engine

for the grandkids.

Nevertheless I like the idea, I may not be able to use it the finger engines but for an air engine it would be cool.

DaveH

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Author Topic: humming fly wheel (Read 18181 times)