Strengtening Flywheels

[bitsnpieces1]

  I've been thinking about how to help strengthen the flywwheels for Listeroids when I remembered how train wheels are built.  They have an iron rim with a steel tire.  Anybody have any ideas about the possibility of machining the outer circumference of the flywheel to accept a high tensile strength steel band that could be heat expanded and shrunk to fit tightly.  Similar to how you put a steel tire on wooden wheels.  This should resist any explosive forces and help my peace of mind. 

[GuyFawkes]

1/ FACT, your flywheels are of unknown strength, and this worries you.

2/ FACT, you propose a modification that will have unknown effects on various parameters, and this is for safety?

3/ FACT, we don't know of any lister or listeroid flywheel explosions associated with normal RPM


Being afraid of something is not unhealthy, your flywheels have a speed at which they will burst, this speed is different for every flywheel, you can only determine this speed by spinning one up until it gives, spinning one up to 1000 rpm and it not blowing won't tell you it is safe at 650, because you may have just induced flaws in it with the 1000 rpm test...

You're not trying to buy an engineering quality here, you are trying to buy piece of mind by doing some engineering of unknown (possibly negative) net value. Basically you are trying to sales / marketing / bullshit yourself that the product is something other than what it is.

Flywheels don't burst because you lacked faith in them, or insulted them, but because yield strengths were exceeded.

Live with the fear and nurture it so it turns into respect, and respect will make you balance the motor and dramatically reduce stresses, bolt the sucker to 2 ton of concrete and dramatically reduce stresses, and never over speed it and dramatically reduce stresses.

http://www.surfbaud.co.uk/Lister/Files/Flywheel_Explosions.pdf

[cujet]

I have also been thinking about doing this, but for different reasons. I want to reduce belt slip on the flywheel by installing a machined poly V section on the outside of the pulley.

By the way, you could use Kevlar to encapsulate the flywheel. This is done on aluminum high pressure bottles to reduce the risk of bursting.

Chris

[GIII]

Strenght of flywheels has been widely researched over the years and a built up rim like you sugest is possible but is not likely needed nor a casual task to design properly.  Normal practice is to limit cast iron solid rim flywheels to about 6000 surface feet per minute and this is with a standard practice of 10-15 to 1 saftey factor because one can not count on anything but class 20 iron in the casting.  Without copying all the formula and notes needed for your proposed change I would say it is not needed, but 1000 rpm should be considered 'scary fast enough'.  I would imagine that the origninal Listers were designed with plenty of safety factor and for the possibility of poor quality iron.  The Listeroids have copied a good engine and executed some of the castings with unknown, dudious quality iron that the originals no doubt anticipated, so live without fear at 650 rpm and consider 1000 not to exceed speed.

[Tom]

Or you can satisfy your self the old fashioned way before starting give each wheel a wrap with your knuckle and if it does not ring don't use it. 

[mobile_bob]

here is another thought for those that have the ability to do so

why not have a ring of steel machined, and mounted over a rubber band , to as to make the flywheel into a large vibration damper?

might be an interesting project, and if the steel band is thick enough a serpentive belt profile could also be incorportated.

here we go again, "silk purse out of a sow's ear"



bob g

[Doug]

"silk purse out of a sow's ear"

You can't sqeeze cheese from a cow before it hatches.

I'm off to the post office tommorow Bob and I'll have a shipping cost on those contactors for you.

Doug

[kyradawg]

Peace&Love, , Darren

[mobile_bob]

turning the outer ring is not a problem, as a vertical lathe would be up to the job.
just gotta find a machine shop that has one,
they have a large round t slotted face plate the turns like a lazy susan, and a bit holder that comes down.
that is how they used to make tires for rail road wheels, i have a vhs tape on the old steam trains and they have the procedure of making and
installing the tires.

as for mounting on rubber, i dunno,
perhaps pressed over the rubber band?
perhaps vulcanized on?

i dont know, don't have a vhs tape on the manufacture of vibration dampers

bob g

[bitsnpieces1]

1/ FACT, your flywheels are of unknown strength, and this worries you.

2/ FACT, you propose a modification that will have unknown effects on various parameters, and this is for safety?

3/ FACT, we don't know of any lister or listeroid flywheel explosions associated with normal RPM

OK,
!/ does worry me.

2/ you're right.  That's why I'm asking.  If anyone here has any experience with this or something similar please let me know. 

3/ makes me a little less leery. 

  Mine is a 12/1 at 1000rpm. and I plan to do a WHOLE BUNCH of thinking before I do anything like this.  I'd really rather have a basket case Lister to rebuild, but, I'l  have to make do with this one.  I love to rebuild stuff that's headed to the  furnace and make it run like new.  It's a matter of pride to make something like new again. 
  I plan to static balance the flywheels, crankshaft, con rod and piston.  Dynamic balance if needed.  I'll strip down totally and examine everything carefully just because I'm curious.  Probably run it derated for most purposes, quite possibly as a prime mover for a line shaft.  Just looking for the most flexibility AND safety.  When you handle liquid Chlorine as part of your living you learn all about suspicion of a part/situation and keep safety foremost in your mind.  Guess that's why the only car accident I've had was when I was 16 yrs old (60 now), that's called defensive driving.  The whole idea was to see what everyone thought of the idea and whether it might help OR be needed.  Looks like it really won't be needed.  Otherwise it makes for an interesting thinking project.  Remember we'd still be using stone tools if nobody bothered to think ahead.