knex engine?

hi everybody im still new and don't know anything about knex but i loved the idea of making engines is there any special kits to innovate new engines and make something new , is there any calculations?? can anybody help me by giving me information websies abou knex for beginners especially for engines.
can a knex engine work with compressed air or just with attaching the drive train with an electric motor
is it easy to make and is it good idea for prototyping you ideas??

thanks i know that i asked too much questions (im still beginner) and i know that the instuctables knex PROS will be helpful with me

PS ,can anybody tell me where can i get a good price buy for a knex kit that contain everything for my infinity innovation

As for a K'nex engine, this looks like a good one:
It's pretty big though.
As for attaching a drive shaft of a real engine to k'nex, I woulnd't recommend that. I think the plastic from the k'nex wouldn't sustain the force, and you'd destroy it. Not sure though.
For cheap k'nex, you could try looking on Ebay (here is where most knexers got theirs I think).
Hope this helped a bit
Oh brother. XD
Was that a positive, negative or neutral reaction? Kinda hard to tell on the internet