Lots of variables here to answer your question. Weight? Areodynamics? Fitness? I can manage to hold 28-30 kph on my Catrike "Road" but only on the flat. (Climbing is not so good.) The Catrike 700 is very fast and the Windcheetah is right up there as well. Or, you could go with the Avatar Velo from Trisled. Fully enclosed trike that cruises at a mean 50 kph! Mike

http://www.trisled.com.au/avatarvelo.html