ORIGINAL: skulboep

Alright so I'm beginning building my 3rd plane (Sig Four Star 60 ARF) and after searching the forums for a couple days I have discovered a trend that I thought was supposedly a BAD idea: overpowering an aircraft. Now I'm not talking about going up an engine size if one lives at high altitudes in order to compensate for the lower pressures and decreased performance, I'm talking about strapping 1.20-sized 4 stroke into a 40-sized aircraft and running an extremely low pitch prop. Every instruction manual that I've ever read also cautions about overpowering an aircraft, claiming that the aircraft can become unstable in flight, the firewall can become weak, and if no catastrophe actually happens in flight, the warantee will at least be voided. However, in looking for an engine to pair with my Four Star 60 ARF, I've become interested in Super Tigre's line, especially the .75 2-stroke (a .75 engine in a .60-sized plane sounds pretty good, right?). According to many forums, most pilots that fly this plane recommend the Super Tigre 90 over the 75, claiming the 75 is barely enough engine (furthermore the 90 is has the exact same weight as the 75, meaning that it's performance increase over the 75 is probably pretty dramatic). How can this be, especially if Sig claims that the plane is a 60-sized plane? A 90 sounds insane!!! Do you guys have any experience with a particular engine in this plane or about the topic of overpowering in general? Let me know what you think! Thanks!!!