Rick McWilliams asked about posting a photo of the Opal so, with a lot of help from a friend here is a scan of a couple of photos from the deep archives . It was illegal to build both aircraft in Australia -- without fully complying with FAR 23 and additional fatigue tests full flutter survey etc BEFORE any test flight being allowed --there was no experimental category until 1999 --only imported kits and designs (plans) were totally exempt from certification --the story would require a book but not here. The Opal was intended to be amphibious and rough dirt field capable hence the "platypus tail" shielding the prop (and fold down rear fuselage panels ) --the hull was not yet built in in this photo nor the mid wing floats --similar to Molt Taylor's Coot in floatwing with outriggers folding into the float blisters . Stiletto was flown in 1983 and resulted in me being prosecuted (again) --wings destroyed but I still have the fuselage and canard in the trailer --built a sidecar from the molds also and I will see if I can send some more photos . these are relatively conventional aerodynamics but this thread might be easiest to direct them to . Hope this sends OK.