On a recent Robinson safety course Tim Tucker spoke about the R66.Your quite right Johe02 the name R66 was chosen partly to dismiss the myth R22 two seats R44 four seats etc.Allegedly when Frank was getting the R22 certified he didn't have a name and R22 was put down in a split second desicion allegdley ! .The R66 he said will have 5 seats with interestingly the rear centre pax seated slightly ahead of the ones on either side to allow more shoulder room and possibly I presume for more headroom as the turbine is mounted ala H369 /500 style so it may encroach on the inner centre cabin roofspace ? .It will have a baggage dept as well as the under seat stowage.He did say it is similar to an R44 blown up larger.I can't think of any other things , he didn't quote performance figures.