I Did have to add some in the very tail above the wheel. 8oz ish,. But not too bad. I located the battery for the onboard glow as far back as I could. The saito 325 is by no means a power house but it gives about perfect power for this plane. Maybe I am just not used to draggy biplanes but even with this bigger engine I still want to get up a head of steam before any maneuvers. The sound makes it worth while! I wish there was some way to put video on here without having to youtube it!