From Vetter's website:
Where do I get info on the Terraplane sidecar?
The new owner produced a Terraplane Sidecar but it incorporated little more than the name Terraplane from my design. I made about four prototypes between 1973-5 and abandoned the project. The new owner of Vetter ressurected the name Terraplane and made about a thousand or so of his design, as near as I can tell.
Therefore, I know nothing about it. There is a Terraplane owners website:
Terraplane windshields are available from:
work 1 (888) 824-3443
1704 Lakeside Ave, Unit #1
St. Augustine FL 32084