# Is it possible to determine a rotation speed (Vr) using other known V-Speeds?

Is it possible to come up with a good estimate of rotation speed using other known V-Speeds?

For example: if I know a plane has a Vs @ 55kt. and a Vy @ 75kt, is there a reasonable method to use to come up with a safe rotation speed?

This is a general question. I'm not looking for an exact rotation speed calculation (unless one actually exists, of course).

From FAR 23.51 that covers normal, utility, acrobatic, and commuter category airplanes:

For multiengine landplanes, VR, must not be less than the greater of 1.05 VMC; or 1.10 VS1

So 110% of the Vs of a particular configuration works. (Do not use for flight.)