met ry ▁in ▁its ▁behaviour , ▁and ▁became ▁un stable ▁during ▁sharp ▁left ▁hand ▁turns . ▁It ▁attract ed ▁interest ▁but ▁no ▁serious ▁fund ing . ▁ ▁Post - World ▁War ▁I ▁develop ments ▁ ▁In ▁ 1 9 2 2 , ▁the ▁Soviet ▁government ▁began ▁construction ▁of ▁a ▁Sh il ov sky ▁mon or ail ▁between ▁L ening rad ▁and ▁Ts ar sk oe ▁S elo , ▁but ▁funds ▁ran ▁out ▁shortly ▁after ▁the ▁project ▁was ▁begun . ▁ ▁In ▁ 1 9 2 9 , ▁at ▁the ▁age ▁of ▁ 7 4 , ▁B ren nan ▁also ▁developed ▁a ▁gy ro car . ▁This ▁was ▁turned ▁down ▁by ▁a ▁cons ort ium ▁of ▁Austin / Mor ris / R over , ▁on ▁the ▁basis ▁that ▁they ▁could ▁sell ▁all ▁the ▁conventional ▁cars ▁they ▁built . ▁ ▁Princi ples ▁of ▁operation ▁ ▁Basic ▁idea ▁▁ ▁The ▁vehicle ▁runs ▁on ▁a ▁single ▁conventional ▁rail , ▁so ▁that ▁without ▁the ▁bal ancing ▁system ▁it ▁would ▁to pp le ▁over . ▁ ▁A ▁spin ning ▁wheel ▁is ▁mounted ▁in ▁a ▁g im bal ▁frame ▁whose ▁axis ▁of ▁rotation ▁( the ▁pre cess ion ▁axis ) ▁is ▁per pend icular ▁to ▁the ▁spin ▁axis . ▁The ▁assembly ▁is ▁mounted ▁on ▁the ▁vehicle ▁ch ass is ▁such ▁that , ▁at ▁equilibrium , ▁the ▁spin ▁axis , ▁pre cess ion ▁axis ▁and ▁vehicle ▁roll ▁axis ▁are ▁mut ually ▁per pend icular . ▁ ▁For cing ▁the ▁g im bal ▁to ▁rotate ▁causes ▁the ▁wheel ▁to ▁pre cess ▁resulting