I went solo in 5.30 hours in a Hiller 12E. As Whirly points out, when a 200 lb instructor gets out, the change in c of g & AUW is huge & took me by surprise as the point had not fully registered with me. With hind sight I probably wasn't ready for it. My instructor's confidence was higher than mine! Incidently he was tragically killed in the Paris air show in a Hiller 1100 many years later.