Re: Flywheel turning question(s)

[Rich Rudman <rmanzan@tscnet.com>]

Victor Tikhonov wrote:
> 
> Jon,
> 
> The specification for your 5135WS14 says allowable weight on the shaft
> end to get rated front bearing life time is 8 kg (~17.64 lb), I'm quite
> surprised to see it less than for less powerful 5133 (10 kg), but that's
> the fact. So I definitely would encourage to thin down flywheel as
> much as possible for safe operation up to 10k rpm. Siemens engineer
> said, if the weight is more, no big problem and everything would
> certainly work (just get it *well* balanced), just life time can't be
> officially guaranteed.
> 
> I've called a few places where they deal with parformance and racing
> clutches trying to get an idea how thin is still safe. No one gave me
> the numbers of course, but one man said they do make flywheels out
> of aluminum (I guess with retaining steel "insert" portion providing
> friction). If you can't get the weight down close enough to 8kg,
> consider this option. He did mentioned the type of aluminum they use
> to duplicate cast iron flywheels - I believe I wrote it down
> correctly: aluminum alloy 60-61-T6.
> 
> Anyone in the list with metallurgy knowledge background could comment
> on it and/or suggest alternative material type?
> 
> As few experts mentioned here, performance difference with different
> clutch weight is practically negligible, I have simulated that in
> software.
> 
> Victor.
> 
> Jon \"Sheer\" Pullen wrote:
> >
> > Er, on my accord pre-machining the clutch assembly is 39 lbs. That's ring
> > gear and all.. I'm betting that I'll be able to machine down to 22 lbs, and
> > I have a bigger clutch and heavier flywheel than I think the CRX shipped
> > with.
> >
> > ----- Original Message -----
> > From: "Victor Tikhonov" <vtikhono@lsil.com>
> > To: <ev@listproc.sjsu.edu>
> > Sent: Friday, April 27, 2001 3:10 PM
> > Subject: Re: Flywheel turning question(s)
> >
> > > Just to clarify:
> > >
> > > I need to lighten up the clutch unit to <10 kg (22 lb) not for
> > > performance sake, it just the motor manufacturer specifies maximum
> > > allowable weight on the shaft to maintain specified life time of the
> > > motor's front bearing.
> > >
> > > So I need to do it even though it fits without any modifications
> > > and virtually no impact on performance is expected. For expensive
> > > motor it's life time is higher priority, it will likely outlast the
> > > car and migrate later into new one...
> > >
> > > Victor
> > >
Victor and folks. 6061-T6 is what I use in my heat sinks. It's not real
strong and it does machine nice.
I would assume you should use a higher strength alloy. like 7075-T6

Also there is no real problem with a heavy flywheel. Unless you are
racing. I have a pretty heavy one on my Kostov and DCP-1200. Though I
would not trust it at 10,000 rpm. This speed needs REALLY good dynamic
balencing. Like you are doing in a speed shop.

I really boils down to how much torque can the motor make at zero RPM.
If if can lug from 0, then a clutch and flywheel are really not needed.
If you want to shift, then a clutch is very much needed. but not
required. I got very good on a clutchless Starter gen set up years ago.
	With a 10,000 dynamic range, picking 1st gear or 2nd gear and NOT
shifting is a possibility. 

Rich Rudman