Shrnutí Članek popisuje postup určeni momentu setrvačnosti vozidla ke svisle ose. Je navržen měřici stav pro měřeni momentu setrvačnosti založeny na principu fyzikalniho kyvadla a je analyzovan vliv chyby měřeni periody kmitu na celkovou chybu určeni momentu setrvačnosti. V programu Labview je sestaven vypočtovy postup pro přesne určeni periody kmitaveho pohybu z naměřenych dat. Funkčnost celeho měřiciho postupu je ověřena stanovenim přesnosti a opakovatelnosti měřeni.

No abstract

In general, tire deformations caused by wheel rotation are not taken into account when developing vehicle aerodynamics. On the road the tires radially expand as speed increases, which affects the actual ride height of a vehicle. In turn this often increases the real aerodynamic drag compared to values obtained using CFD or a wind tunnel as the mass flow across the relatively rough underbody increases with ground clearance. In this study, on-road ride heights were measured while running a vehicle in a straight line with fixed velocity whilst the aerodynamic lift of the vehicle was determined in a wind tunnel. Subsequently, the relationships between ride height and axle load were obtained by loading the vehicle at standstill with ballast. By comparing the ride heights at high and very low velocities with expected vertical displacement caused purely by aerodynamic lift force as computed according to the ride height -axle load equations, the ride height change due to tire radial expansion was determined.