getting a new kadet LT-40. any ideas on radio and engine will help

That is a big bulky trainer. Calls for a 30-40 size engine.

They are slow for their size with a .40 size engine on them. Put at least an O.S. 46 on it and a nice futaba 4YF with standard servos inside and that should be all you need.

You'd have more fun learning on a goldberg eagle 2 with a nice .40 - .46 on it if you want my opinion. The eagle 2 looks a "lot" better in person than it shows on the advertisement! One guy in our club has one and it is capable of doing many tricks once you catch on to flying. Takeoff and landings are a breeze with the eagle 2.

An OS 40LA will fly it ok OS 46AX or Thunder Tiger Pro 46 are better choices.
As for radio?
I would hope you plan on getting an instructor at a local club, if so you should match brands with him so you will be able to buddy box with him.
4 channel radio is enough, 6 or higher computer radio is better.
How much you spend should reflect on how sincere you are about sticking with this hobby.
If you are not sure then just get the basics, you can upgrade later.
Again, for best results get with an instructor.
Best luck.

[link=http://www.rcuniverse.com/forum/m_3439708/tm.htm]Pay It Forward build thread!! LT-40 build.[/link]

Check out the build thread I did on the LT-40. If you want my opinion it's one of the better trainers out there. It flies great as you're learning, but it's also very capable of a lot of aerobatic manuevers after you solo!!! It comes in a kit or as an ARF, but either version would do well for you to learn on. I would go with a good 46 engine on it though.

Good choice

Ken

To add a bit more to RCKen's post, any trainer that starts with "Sig Kadet" is going to be a great trainer.

Hogflyer