GDel there is a thread dedicated to the stryker in the park flyers forum, I'm sure there are quite a few people there that would be more than happy to help you.
I would say it sounds as if you either don't have enough up trimmed in for launch, are you launching it at full throttle or tossing it then throttling up. If it's the B I think it has the brushed 480 motor and should have plenty of power to fly well. I know the stryker is a nice flyer and is fairly stable at slow speeds but as a first plane it will be a handfull
Go here and ask for help
http://www.rcuniverse.com/forum/m_60...tm.htm#6297767
Good Luck and have fun