GET AN INSTRUCTOR FOR THE NITRO!! An instructor will save you time, money, and frustration. visit www.modelaircraft.org , that is the AMA's website, they have a club locator so you will find one close by to you. If you think you can be self taught then go far far away from people, buildings, whatever. But please, look into getting an instructor before you fly the nitro. good luck!
BTW: RCU has an instructor locator feature. at the top of this page, mouse over where it says "RC community" then go down and click on "find instructor". If you find one in your area, most likely that person is affiliated with a club that will let you come down and give you a free lesson or two on the buddy box, but you might want to think about joining AMA and the club. well worth it.
sean