Is it possible to change the nav bar height when push'ing to a new view/route ?

[ajonno]

I'd like to change the nav bar height on a child/push'ed route. however the child nav bar view seems to inherit the height of the parent, and i can't override it. it just may be that ive not set the correct properties on the route object ? can u please let me know if this is do-able and if so a simple example ? many thanks.