They'll never straighten out, Cyril. Gotta rough turn em, let em dry well, then finish them off if you want to keep a shape.
I personally really like oak for nice, clean shapes. The heavy grain, flecking from the lignin strips, and clean growth lines make for nice bowls, vases, etc. It is a hard wood, will smell when turning, and will turn your tools and hands black from the tannin reacting with iron from your tools. Just make sure and clean off shavings from any metal you don't want blackened and wash your hands in lemon juice or dandruff shampoo (sulfur based) and you'll be fine.
Dietrich