Would this fly wheel work on Elmer's Fancy?

[substandard]

Would a fly wheel made like the drawing below have enough mass to work on Elmer's Fancy engine?

The fly wheel would be 1.25" diameter and .312" thick made of 416 stainless steel. I have a bit of a demented project in mind and wanted to check before I got to far into it. Thanks

 

[Tin Falcon]

I would recommend against such a design. 1 there are weak spots possible breakage points and second of all if someone tries to touch it while the engine is running you may see blood fly . A saw blade would also make a fly wheel but I would not use that either unless actually sawing something and then properly guarded.
Tin

 

[Maryak]

SS,

Sorry mate but I agree with Tin, looks more like a shuriken than a flywheel and would be very dangerous.

Hope this helps.

Best Regards
Bob

 

[tel]

Would a fly wheel made like the drawing below have enough mass to work on Elmer's Fancy engine?

Only if you're happy to be called 'Stumpy'

 

[kvom]

A saw blade would also make a fly wheel but I would not use that either unless actually sawing something and then properly guarded.

Safety advice from a guy who goes for a swim in freezing water? ??? ;D

This time he's correct.

 

[substandard]

I was concentrating so hard on the design I didn't think about the blood and flesh spraying across the room part..

Good point on safety, as I know exactly who the first person would be to get their fingers in it... :

 

[Blogwitch]

SS,

This sort of discussion about safety aspects of engines has being going on for years, here is part of an old post of mine that explains why I made two different types of flywheels for basically two of the same type of finger engines.

http://www.homemodelenginemachinist.com/index.php?topic=862.msg7156#msg7156


Bogs

 

[bearcar1]

To throw fly s**t into the pepper shaker, and although I whole heartedly agree that this design would be a disaster unto itself, if you could design up a shroud of sorts to closely surround the rim (something like a dog dish etc) that would effectively keep ones fingers and loose articles of clothing from being grabbed it would be a very attractive feature on an engine. As an example, a tombstone shaped piece of brass or aluminum (stainless steel?) with a circular counterbore in its arch portion that the flywheel would revolve in could be a way to go. It would need to be as wide as the rim width. I'm not advocating this singular part design but I think that if it could be incorporated into the engine design as a whole, it could be made to be functional as well as safe at the same time. Opinions may vary but I can visualize in my minds eye the concept. The most obvious feature, other than the already stated safety concerns, that I see as a potential problem are the stark angles created where the spokes meet the central hub. A radius in this this area would reduce the overall stresses in that area as well as be a bit more eye appealing than what is drawn.

BC1
Jim

 

[Noitoen]

Could also fill the gaps in the rim with some transparent material so that the effect would be there but not the danger :hDe:

 

[Dan Rowe]

It seams to me the whole purpose of a fly wheel is to smooth out the rev's. The section that makes the most difference in a flywheel is the rim which is why it is always a thicker section. To cut away 1/3 of the rim decreases the mass at a distance makes the flywheel less effective.

Cheers Dan

 

[arnoldb]

Substandard, while I agree with what everyone here said about the safety risk, I do like your idea very much.

Most likely you can do it in a safe manner by making your flywheel as designed, then make a little mold from something like a spray can bottle top just larger than the flywheel, put the flywheel in it and fill it up with clear epoxy resin. You'll have to give it a final turning down and a LOT of polishing after the resin has set, but you will end up with a flywheel that more-or-less looks like you want, is safe because it is encased in the resin, and will have sufficient circular mass to keep a Fancy ticking right along even at slow speed.

Just an off the cuff thought, but it might be worth considering...

Kind regards, Arnold

 

[substandard]

There is a certian problem with my design that won't allow me to use a rim, can't really say more than that. Looks like I will need to go to Plan B, if this project works it will be something...if not I will sweep it under the rug... :big:

 

[PaulG]

There is a certian problem with my design that won't allow me to use a rim, can't really say more than that. Looks like I will need to go to Plan B, if this project works it will be something...if not I will sweep it under the rug... :big:

Sub, if your design requires the wheel gaps, just do it. I would then recommend a radius on the leading & trailing edges of the rim & spoke to hub if possible. I have no idea of maximum RPM of the Tiny engine, I cant imagine that it would explode. Spin test at 3x over operating speed first, a piece iron pipe would make a good scatter shield.

I am probably in big trouble with the safety wise now.

Paul

 

[Cedge]

I'd probably get past the problem with a very thin rim, leaving the spokes as the main point of interest but eliminating the danger of the swinging hammers.

Steve

 

[substandard]

Well after thinking about it, I am at a loss.....

My problem is how do you get a 1.25" diameter fly wheel to pass thru a .75" diameter hole ??? I had hoped to build Elmer's Fancy inside a bottle, had every detail worked out, even ordered the metal. THENnnnnnnn I noticed the fly wheel is 1.25" diameter and the bottle neck is .75"

My first idea was the flywheel above. The three "prongs" would be attached with a screw thru their center and the radius on the end would keep the "prongs" from rotating. I could lower the hub into the bottle then attach each prong one at a time. The finger chooping bit wouldn't be a problem inside the bottle, the prongs flying loose at high RPM would however be a serious problem....

I had planned on making the 1.375" base in two pieces cut down the center line. The base would have a threaded nipple that the column would thread over to hold the two base pieces together. I now wonder if a two piece fly wheel would work? Held with a small nut over a threaded nipple......

 

[Cedge]

Subs....
Oddly enough, I was once offered a steam engine in a bottle. I wasn't willing to pay the high price, so I don't know whatever became of it. It was represented as a running engine at the time.

Steve

 

[Noitoen]

In that case you could make a 4 spoke flywheel in 2 pieces. Each with half a hub (in the thickness), and then assemble it in a cross like manner.

 

[rickharris]

From a finger chopping point of view it can't be much worse than a model aero prop spinning at several thousand revs on a glow plug engine (on a stand of course).

 

[tel]

Well that is true Rick, but you expect the prop to be dangerous - not so a flywheel, it seems a natural reaction for some people to rest a finger on the rim of a running flywheel (I dunno why either)

 

[Tin Falcon]

Could also fill the gaps in the rim with some transparent material so that the effect would be there but not the danger

Forgive me if this was already suggested.
What about using the original Idea as a hub and making a Plexiglas or poly carbonate rim . It would give the look you were after but make for a safer design.
Tin