[en] We present a brief survey of some results on electroweak properties of com- posite systems that are obtained in the frameworks of our version of the instant form of relativistic quantum mechanics (RQM). Our approach describes well the π- and the ρ- mesons in wide range of momentum transfers Q"2. At large Q"2 the obtained pion form factor asymptotics coincides with that of QCD predictions. The method permits to per- form analytic continuation of pion form factor to complex plane of momentum transfers that is in accordance with predictions of quantum field theory