Hi DKA
You are spot on about the rules and the need for a roll cage that complies, if i was to build another one i would use the prone position without question.
I come from a road racing background and the position is familiar to me and i went with what i knew, on reflection we would have been much better of with a prone possition because it reduces frontal area and therefore drag.
I also started with a road race chair as a start point for the design, even after nearly 100 prototypes we did not consider changing the seating position, i had no photos or information on any other design of sidecar built for record breaking and we used what was familiar to us at the time.
The other factor that influenced me was the rules that i had to follow, The FIM rules for a World record and Motorcycling NZ for a national record, neither have anything like as much detail in them as the SCTA rules especially for sidecars. I had no thoughts of running at Utah when i started, i only wanted to do it here in NZ.
We would however be in a much stronger position if we had used the SCTA rules because i now understand that they are the product of many years refinement and are designed to protect the rider as well as the rest of the crew, the motorcycling NZ rules are for racing sidecars and the detail on record attempts is purely environmental.
To answer your question about 2 wheel liners, our research did not cover 2 wheelers, but the guy who ran the aero team worked on the Britten powered White Lightning in the early 90's and still has all the data, he is the Wind Tunnel Engineer and a very knowledgable guy. if you send me a bit of info on what you are doing i will pass it on
www.goflyingkiwi.co.nz