This paper was presented at the 6th European Seminar on Velomobile Design, Copenhagen 2009.
Abstract
The wind and the speed of a velomobile cause aerodynamic forces on the fairing, which can be dangerous under extreme conditions. In order to ride in a safe way, it is important to know the operation limits.
The wind can also be helpful. The sail effect adds to the propulsion even in side wind, where there is a considerable head wind component.
Wind tunnel measurements on different types of fairings give more insight in this phenomena.
In velomobile design it is often necessary to make trade offs of ideal aerodynamics to obtain a practical function. E.g. some fairings use a partly open bottom in order to make better conditions for the cyclist to enter and to get out of the vehicle. How much does it mean to the aerodynamical drag?
This, and other design detailles were studied by measuring the drag on a Leitra velomobile in down hill experiments.
(PDF, English, 928 KB)About the author
Carl Georg Rasmussen
M.Sc. and Ph.D., born 1935, has a background as research manager in Danish industry, developing laser and hot wire instrumentation for fluid flow studies. He built his first velomobile in 1950, participated in several aircraft design projects, has 35 years experience as glider and GA-pilot.
In 1980 he built the first Leitra velomobile, and in 1982 the company Leitra ApS was founded with 10 share holders.
Since then he has done more than 300.000 km in velomobiles.
He has had no car since 1982.
Contact:
Leitra DK ApS
Sandbakken 9
Toppevad Industrial Area
DK 3660 Stenløse
Denmark
leitra@leitra.dk
mobil: +45.26231226