As everybody has commented this thread has gone WAY off topic. the original question was about a brake system, and not characteristics of Cubs. Let's try and keep the discussion focused on the question that was asked.

My question here would be why you want a brake system. Brake systems for RC planes are available, but they can be complicated and expensive. If you are asking about brakes simply to keep your plane from rolling so easy, or for stopping quicker, you can accomplish quite a bit of braking by simply putting a piece of fuel tubing between the wheels and the wheel collars.

Ken