flyrotary@lancaironline.net Mailing List Archive

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Rusty,

The manual flywheels do in fact replace the flexplate and balance.

It would be difficult to know exactly how the balance was done in the first place, what rotating weight were used and how were they modified.

You could take off the flexplate and weight and try a flywheel, it won't be right but it may give you some indication of the effectiveness of smoothing out the torque pulses.

George ( down under)

10lbs. That is about the weight of a rotor. But you'll be spinning it
3 times as fast, so it'll have 8 times the momentum (momentum is
velocity squared, right?). The object is to keep the shaft from
speeding up and slowing down, and I think increasing the momentum 8
times would accomplish that well.

Hi Ernest,

All WAG's appreciated. I'm not sure the biggest problem is the missing mass of the 2nd rotor, but rather the missing firing pulse. If we were to continue your momentum thought though, the flywheel advantage would be even greater than you suggested. Remember that the center of the rotor mass is traveling in a much smaller radius circle than the mass of the flywheel ring that I proposed. Heck, maybe that 1.5 lbs of weight that I had before would have made up for the missing rotor :-)

other ideas: Have the disc water/laser cut. And you don't need 4130,
so have the cutter use whatever steel they have on hand. Have a brake
shop turn the disc and balance it, or you might just be able to get a
brake rotor that would bolt right into place with little or no
modification. The heavy duty Matco rotors I just bought seem to be
around those dimensions if memory serves.

Interesting thoughts. I'm still leaning toward trying to install 4 separate weights, which makes it possible to do this without pulling the drive off. It also makes balancing a simple matter of precisely weighing the added weights. I can buy 1/2" steel discs in various diameters from McMaster Carr, so I would just have to drill a hole in the middle, and bolt them on. I wonder what the limit of a 7/16" bolt is for holding a couple pound weight spinning at 8000 rpm. Probably don't want to have anything in the arc of the flex plate the first time it was run up :-0

Dale,

I thought about flywheels, but aren't they always manual trans flywheels, made to install on the shaft itself? I need something that coexists with the current auto balance weight, flex plate, and Tracy's dampener plate.

Thanks,

Rusty (trying hopelessly to resist)

PS- Congrats to Joe! If this keeps up, people are going to think that rotaries can only fly backwards :-)