To shoot down AI Hurricane with BF109 is not so hard (flying on full real with CEM). Just watch your proppitch and ATA (keep ATA arround 1.3 and RPMs arround 2000 most of the time), keep both radiators full open, the 109 is anyway much faster than the Hurricane. Just dont try to "dance" (twist and turn) with it. The Hurricane can do that much better than the 109.
If you have 3 or 4 against you, you better run!