4 flywheels?

[bschwartz]

Light flicker from a 6/1 St-5 setup as I understand it is from the change in engine speed between cylinder firing pulses.  Would more flywheel weight reduce this?  Could 2 more flywheels be added to the crank shaft to add mass?  Sillier thoughts have kept me awake at night....

[dubbleUJay]

I can see it work if one use non-counterweight flywheels.
We had a clever bloke here that did it on an English CS with 2 extra counterweight flywheels, apparently he lost his flicker, but also his crank, rod & piston! 

dubbleUJay

[bschwartz]

Hmmmm.... two counterweighted, and two stover.  Funny looking rig. I'll have to keep my eyes open for an extra pair floating around New Mexico.

[dubbleUJay]

Hmmmm.... two counterweighted, and two stover.  Funny looking rig. I'll have to keep my eyes open for an extra pair floating around New Mexico.

Just keep in mind what Jens has said: "..... but you will start another heated debate on bearing load and crank stresses"

It should be safe if you keep the total weight more or less the same as the heaviest wheels ever installed on the SOM's, give or take a couple of kg's.
I'm sure the Dursley blokes had a build in safety margin on those, so you might push it a bit more. I don't know about the India ones with "proper" bearing though.

BUT, please don't quote me on any of this! 
dubbleUJay

[XYZER]

The SOM had a flywheel on the generator to tame flicker........

[AdeV]

If I were going to add additional flywheels, I'd support them on separate bearings, and connect them to the engine via a lovejoy connection, or through a friction plate clutch (the latter would make it easier to start the engine too).

[prof.blink]

adev, do that, and you will end up w/a lovejoy back smackin the cushion element to death before the shaft fractures. blink

[SHIPCHIEF]

Less flywheel would do more good on the generator, it turns faster. Also the generator shaft is supported on roller bearings, so  should be able to take it.
Truley Less is More here 
And easier to do.

[SHIPCHIEF]

Ahemm....
Me too. Chirps above 9Kw. 
I defer.

[Crofter]

I have a feeling that the heavier flywheel on the SOMs was more to aid starting than to reduce cyclic flicker.

Something must be accellerated or elevated to receive mechanical energy otherwise the force exerted against it is only turned to heat. If you take rotary momentum to the extreme minimum, start up or idling is almost impossible  and power pulsing is fierce, but taken to the other extreme thermal efficiency will go way down; though it will have lower velocity power pulses the pistons inability to accellerate as readily would force more energy into the combustion surfaces as heat.

If you move the mass to the generator pulley you will lessen its speed fluctuations but the energy of the engines fluctuations must be either cushioned or wasted by whatever form of drive connects the engine power to the generator. If it is belt it has no choice but to either change effective length or intermittently slip. I think I have heard reference to the v belt drive of the SOMs allowed the belt to squat or rise in the groove and thus soak up fluctuations. The flat ribbed belt has much less ability to do so. (it also is more efficient)

I dont think rotary fluctuation flicker can be simply cured without wasting a lot of the energy.

[Geno]

There's gotta be a compromise and it seems like Lister got pretty close.

I have SOM flywheels on my Indian 6/1. It goes through the compression stroke and the entire cycle much smoother than with the lighter flywheels. Flicker is almost non-existent and I like it a lot more this way. I made this change about 1000 hrs ago. My serp belt does shed some dust but I don't know if its alignment or slip. I cannot hear any chirping.

Thanks, Geno

[BruceM]

Glad Geno piped up; SOM flywheels are nearly double the mass of the spoked Listeoid ones, and with some measurements that Geno took for me, it would appear at least as effective as my AVR on ST3 head.  The SOM also had a much higher mass generator head also, as it had the DC starter motor on the same shaft. 

I agree also on the belt choice- Vee would be better for flicker, especially when adding mass on the generator pulley.

I wish someone would make SOM flywheels for the Listeroids so I could follow Geno's lead.  Add an AVR to setup with SOM flywheels and a weighted generator pulley and you'd have a pretty sweet setup.

I'd be nervous about adding too much weight anywhere but right next to the crankcase.

Bruce M

[Crofter]

I wonder what doubling engine flywheel mass would do to specific fuel consumption per kw of generator output and also to peak rod bearing loads. Our old heavyweights are not as fuel sipping as some lighter engines though surely there are other factors at play than horsepower per unit of rotary mass.

To a lot of us, for emergency standby power this is not particularly important compared to smooth waveform and frequency. Like in most situations though, I think choices usually are a tradeoff in cost benefit.

[bschwartz]

As I am running on WVO, a slight difference in fuel usage isn't too important.  These things run for hours on a gallon as it is.  Hmmm hadn't thought about the extra weight hanging too far away from the bearings.  Might not be too good.

[lowspeedlife]

I wish someone would make SOM flywheels for the Listeroids so I could follow Geno's lead.  Add an AVR to setup with SOM flywheels and a weighted generator pulley and you'd have a pretty sweet setup.

Bruce M

Bruce,
If you are in the UK, Stationary engine  parts sells a "custom made" solid heavy flywheel with taper lock bushings installed as a replacement for electric starting. They cost 194.00 GBP  each. here's a link http://www.stationaryengineparts.com/20-plain-flywheel-and-taper-lock-bush-2447-0.html

  Scott R.