RE: Eflite Yak 54F or Copperhead Yak Stiffy?
The copperhead yak takes a bigger motor/battery pack then the E-Flite Yak. The stiffy recommends a 2212/26 or Hacker 20-20L. I fly mine with the 2212/26 on a 3c2100TP battery pack. It flies very well with that setup. Its the smoothest foamy I ever flown, it does knife edge with no tuck, and is better to practice precision flying with it. It hovers, torq rolls, harriers, etc good to. It pulls out ok of a hover, but not real quick. Its also strong, but it will still break.
I flew an E-Flite yak already. It flies more like any other foamy, the e-flite might be a little better for 3d, but it wont fly near as smooth as the stiffy or be as strong. But they both fly great.
Ryan