roll rates & stiffness

[Cris]

I was wondering whether roll rates and roll stiffness refer to the same thing? If not what is the difference?

Thank you

[flavorPacket]

Stiffness is a measure of force vs. displacement. A rate is a measure of one variable versus another. So, roll stiffness will define a linear force vs. linear roll displacement or a torque vs. angular roll displacement. A roll rate may be a force vs. displacement measure, or it may measure roll vs. another variable (lateral acceleration etc). Typically the ratio of roll angle to lateral acceleration is known as the roll gradient.

Hope this helps