Chilli
My understanding on the Piper singles is:
PA28 = fixed gear
PA28R = Arrer
PA28RT = Arrer 4
PA32 = fixed gear Six/Lance/Saratoga
PA32R = retract Lance or Saratoga
PA32RT = retract Lance II
However, I'm not an anorak and I will be pleased to be corrected by someone with more knowledge
