The RCV 120 will probably handle the 80" Hellcat. It would be too big for the Holman 64" one and the Wing 61". Those two will fly fine with a .60. I am putting an RCV 120 in a TF T-34 that will weigh close to 16#. I have Bob Sweitzer's plans for a 64" Hellcat and it was designed with just a .60.