An inertial instrument such as an accelerometer or gyroscope having scale factor functionality, and that lies generally in a plane. The gyro detects rotation rate about a gyro input axis. The gyroscope has a substrate, a generally planar scale factor gimbal flexibly coupled to the substrate such that it is capable of oscillatory motion about the input axis, a generally planar support member coplanar with and flexibly coupled to the scale factor gimbal such that the support member is capable of oscillatory motion about a drive axis that is orthogonal to the input axis, and a generally planar gyro member coplanar with and flexibly coupled to the support member such that it is capable of rotary oscillatory motion relative to the support member about an output axis that is orthogonal to the plane of the members. There are one or more first drives for oscillating the support member about the drive axis, and one or more second drives for oscillating the scale factor gimbal about the input axis. One or more gyro output sensors that detect oscillation of the gyro member about an output axis that is orthogonal to both the input axis and the drive axis.