its just my progression as i build these, so far Mach 1 and 2 are destroyed. Them being my first builds i didn't really have any idea what i was doing so they eventually fell apart. Still using the same 2-stroke motor though lol. I think i got lucky on it being a "good" one despite it coming with a broken fin it runs good and cool at around 100*c (200-250*f) been using a 32:1 mix (4oz to 1 gallon of gas) this whole time with cheap walmart 2-stroke oil. but i never go full throttle for more than a few seconds and i usually cruise going 20-25mph at 3/4 throttle so its probably why it's lasted this long.