It causes no vibration but it does generate a centrifugal force
on the rotor bearing. It is also balanced by the second rotor
180 degrees out of phase on a two rotor engine. What is left
is known as a "couple". The couple is caused by the two rotors
not being in the same plane. That is the function of the front
and rear counter weights. They remove the couple completely.
A similar situation arises when balancing a tire. The balance
weights must be centered on the rim width (in and out) or a couple
will be generated. This is sometimes referred to as
dynamic balance.

In the case of the one rotor the front and rear counter weights
balance the weight of the rotor. In all cases the Wankel rotary
engine is in complete balance unlike a piston engine that always
has parts rocking back and fourth such as connecting rods and valves.

Here is a mathematical balance chart for rotary engines.

The two rotor engine does not dip below zero but the one rotor
engine does indeed dip below zero as does a four cylinder four
cycle engine.

Paul Lamar

Good dissertation Paul.
I cover Static, Force, Couple, and Dynamic in my seminars
at OSH.
Archie


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