Author Topic: Oscillator with wood flywheel  (Read 3463 times)

Offline Robert Hornby

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Oscillator with wood flywheel
« on: April 15, 2020, 12:02:39 AM »
Having finished the double acting oscillator and still house bound I thought I would tackle the single acting one as I had the plans. The only thing was that I didn’t have another flywheel casting. I do have a chunk of aluminum but it would be a bit of a waste as it is much too large for what I want (about 80mm dia.). So thinking outside the square I thought why not a wood flywheel? I can add some weight around the rim with brass plugs but that may look a little strange. A second idea was to make the wheel in two halves and make annular grooves to be filled with lead which I happened to have in sheet form and able to cut into shapes.
To avoid have any engrain in the rim which after varnishing always goes darker than the side grain I will make the wheel in segments (like I did for the steering wheel on Columbine)
The first pic shows the chunk of aluminum which i wont use.
The second pic is the raw materials.
No. 3 is the segments cut.
No, 4 is the gluing and clamping (the extra bits are to assist with the clamping)
Age and treachery will always overcome youth and skill

Online crueby

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Re: Oscillator with wood flywheel
« Reply #1 on: April 15, 2020, 01:07:29 AM »
Clever solution!

Offline Brian Rupnow

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Re: Oscillator with wood flywheel
« Reply #2 on: April 15, 2020, 02:39:13 PM »
Robert--As you know, I make a lot of machinery to be driven by the small engines I build. I don't always have access to the size of aluminum I need to make a large pulley, so it is not uncommon for me to make a pulley out of wood. I will generally machine a steel hub with a flange and bolt a saw cut wooden circle  to the hub, then turn the o.d. of the wood on my lathe to end up with a decent pulley. They look a bit funky, but they get the job done.---Brian

Offline Robert Hornby

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Re: Oscillator with wood flywheel
« Reply #3 on: April 15, 2020, 11:42:04 PM »
Thanks Brian, that is pretty much what I will be doing. I will make the hub/boss out of brass.
Age and treachery will always overcome youth and skill

Offline yogi

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Re: Oscillator with wood flywheel
« Reply #4 on: April 17, 2020, 02:48:03 AM »
Great idea! That will make for a unique engine.  :popcorn: :popcorn: :popcorn:

Offline Robert Hornby

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Re: Oscillator with wood flywheel
« Reply #5 on: April 19, 2020, 08:34:59 AM »
More workshop time and the flywheel is finished, it has a nice weight to it so I am hoping it will do the job.
Age and treachery will always overcome youth and skill

Offline MJM460

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Re: Oscillator with wood flywheel
« Reply #6 on: April 19, 2020, 09:20:13 AM »
Nice job, Robert.

With the lead placed in the rim it contributes greatly to the rotational moment of inertia, or m x r^2, which is the important criteria for a flywheel.  It should go well.

Do you have an engine for it or is intended for the Munchaster?

MJM460
The more I learn, the more I find that I still have to learn!

Offline Robert Hornby

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Re: Oscillator with wood flywheel
« Reply #7 on: April 22, 2020, 05:36:42 AM »
I am puzzled why there is a relief machined into the column mating surface other than reducing the face area to minimise friction. Am I missing something here? 
Age and treachery will always overcome youth and skill

Online Jasonb

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Re: Oscillator with wood flywheel
« Reply #8 on: April 22, 2020, 07:26:47 AM »
I reduces friction, less area to lap if you want to lap the two together and also reduces any risk of the metal getting raised up around the tapped hole in the cylinder causing it to sit above the surface

My small version runs OK without a slot but does have some circular clearance around the pivot.

J

PS you can drill the inlet hole vertically down and into the base if you want to do it like your other engine, could even do the same with the exhaust

Offline gary.a.ayres

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Re: Oscillator with wood flywheel
« Reply #9 on: April 27, 2020, 10:56:25 PM »
That is one very handsome flywheel!

Offline Alan Haisley

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Re: Oscillator with wood flywheel
« Reply #10 on: April 28, 2020, 03:48:27 AM »

Nice, Robert. I wonder how you cut the segment angles. Whenever I try something like that, my angles are off just a little bit, but that adds up across that many segments.
« Last Edit: April 28, 2020, 03:55:38 AM by Alan Haisley »

Offline Robert Hornby

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Re: Oscillator with wood flywheel
« Reply #11 on: April 28, 2020, 09:58:24 AM »
Hi Alan,
Regarding the "triangles" I first just made an aluminum 'jig' with a 45 deg. angle. I used this to mark out the wood for cutting with a cross cut tenon saw.  I then milled a piece of scrap wood at 22.5 deg and set it up in the mill vise. So when I put a wood triangle in the top surface will be horizontal and I run the slot mill cutter over it. Flip it over and do the other side. I made 2 of these then put them together to check I have exactly 90 deg. I had to adjust the wood angle a bit until I achieved the 90 deg. It was straight forward after that. The notch in the wood is where the cutter runs past the triangle. I didn't take a photo of the set up unfortunately. After I had glued 4 of the triangles I could make a final cut over them to ensure the two halves would fit together without and gap.
Age and treachery will always overcome youth and skill

Offline Robert Hornby

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Re: Oscillator with wood flywheel
« Reply #12 on: May 01, 2020, 12:43:49 PM »
With plenty of time in the workshop the oscillator is almost finished. In my wishes to make the model 'clean' (minimise the external connections) I trunked the air passage away from the column and through the base, however as it is wood and I haven't a suitable 'O' ring for the seal between the brass column and the wood there is a massive air leak. The engine does run at 50psi but most of the air is wasted. So until I can escape the house and purchase a seal I cannot finally complete the project. I will post a video then.
Robert
Age and treachery will always overcome youth and skill

Online crueby

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Re: Oscillator with wood flywheel
« Reply #13 on: May 01, 2020, 02:34:28 PM »
Looks beautiful!

Offline Roger B

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Re: Oscillator with wood flywheel
« Reply #14 on: May 01, 2020, 07:08:23 PM »
Very nicely done  :praise2: :praise2: I am surprised no one on here came up with the old joke  'I thought it woodn't work'
Best regards

Roger

 

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