ARMY RESTUDYING BIG CARGO COPIER
US Army is restudying need to develop helicopter, capable of lifting 22.5 tons, after spending $146-million on development cost over past 4 yrs and amid growing Cong criticism; project, which had its inception in '70 after USSR developed 'flying crane,' may ultimately cost $1-billion; Army is committed to spend $250-million on development; USN has been developing similar craft, capable of carrying 12.3 tons (L)