Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_20866024_3 ( model_designation VARCHAR, gvw__kg_ton_ VARCHAR, axle_ratio VARCHAR )

### Question ###
What's the model designation of the model with GVW of 2828/2.78 kg/ton and axle ratio of 9/47?

### Accurate SQL ###

SELECT model_designation FROM table_20866024_3 WHERE gvw__kg_ton_ = "2828/2.78" AND axle_ratio = "9/47"