Russian writer’s means to get rid of old model (7)
I believe the answer is:
tolstoy
'russian writer's' is the definition.
(I've seen this before)
'means to get rid of old model' is the wordplay.
'means' becomes 'tools'.
'to get rid of' is a deletion indicator.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'model' becomes 'toy'.
'tools' with 'o' taken away is 'tols'.
'tols'+'toy'='TOLSTOY'
(Other definitions for tolstoy that I've seen before include "Great Russian author of 'War and Peace'" , "Count Leo . . . . . . . wrote 'War and Peace'" , "Writer of War and Peace, d.1910" , "Russian writer, 1828-1910" , "Russian novelist" .)