I hope this hasn,t been covered before . What are the deciding factors in an engines ability to swing a prop ? Is it HP , torque , or a combination of the two ? I,m thinking of going gas in a BUSA N 28 . A G 26 will fly it , but with a 16 to 18 inch prop . I really would like to use a 20 -22 inch . One of the advertisers here lists G26 with different HP ratings . My knowledge of engine mods leads me to belive that when a engine is modified to produce more HP , it useually ends up making more RPM , and I think thats not what I want . So , what do I need to turn a 20 - 22 inch prop in a N28 ?