Where is the center of gravity on a tiltrotor?
The c.g. limits change in forward and hover flight, so loading the aircraft takes special care. On the Bell XV-15, the range of c.g. was around 16 inches. For comparison, the internal cabin was 157 inches long. Based on the fuselage stations below and the image above, the c.g. limits were very close to the rotors in helicopter configuration.
For the control method in-flight, see: How do VTOL aircraft like the V-22 Osprey not tilt?
Commentary: how much forward ballast (see image below) an aircraft like the V-22 has -- I don't know (classified).




Maisel, Martin, D. C. Borgman, and D. D. Few. &quot;Tilt rotor research aircraft familiarization document.&quot; NASA TN X-62 407 (1975).