Jorge,I am a frequent International traveller bowhunter and collector.I am been able to carry up to 20 bows at times.With the TDs you don't have any trouble and you can carry in any big uffel you can buy world wide,just store your bows between layers of clothing.The problem is not the capacity of a big bag but the wait you can carry.If you excede the 50#/ 23,5 KG is better to use a second piece of luggage that will cost you 50Euro up to 23,5 KG.Instead if you stick on one piece you'll have to pay something like 15 Euro for every exceding KG.
So 3 KG can cost you like a n extra bag.Check your Airline anyway because this can change from company to company.