My F450 setup weighs 2035g, and it runs cool as a cucumber on two 4s2600 packs, even after 8-9 minute flights.. I'm using the Graupner 10x5s, but it also ran cool on the 9x5x3 GWS 3-bladed props. Anyway, I think your problem is not the blades, it is that you are using 3s. On 4s, the motors seem...