The OS 46 LA and OS 46 AX are apples and oranges. The LA is a modest hp bushing engine that should be ideal for your application. A better choice might be the 40 LA which is slightly less HP, is a few dollars cheaper, but has the same external dimensions.

The AX is a powerful double ball bearing engine that better belongs on a high performance sport plane. Besides more HP, it's more money and weight. I have both engines, and I would recommend the LA as the best choice considering you want to practive TOs and Landings on a simple trainer. Beginners often make the mistake of putting too much power on their models which really defeats the purpose of training or learning basic things.

Ciao,

Eagle Al